By William Harwood
CBS News/Kennedy Space Center
The following copy originally was posted on the Current Mission space page at http://cbsnews.com/network/news/space/current.html.
Comments, suggestions and corrections welcome!
TABLE OF CONTENTS
8:55 PM, 3/26/08, Update: Shuttle Endeavour glides to smooth night landing (UPDATED at 12:05 a.m. with post-landing news conference)
Running one orbit late because of troublesome low clouds, the shuttle Endeavour plunged back to Earth today, dropping out of the night for a picture-perfect landing at the Kennedy Space Center to close out a marathon 16-day space station assembly mission. Joining the shuttle astronauts for the trip back to Earth was European Space Agency astronaut Leopold Eyharts, launched to the station in February and returning after 48 days in space.
"I can't imagine the mission could have gone any better," said NASA Administrator Mike Griffin. "They made it look easy."
Reflecting on the addition of the first of two Japanese modules and the assembly of a Canadian maintenance robot during Endeavour's five-spacewalk mission, Griffin said "if you look around, there really isn't, any more, a U.S. human spaceflight program or a Russian human spaceflight program. There is a world human spaceflight program, centered around the building and then later utilization of the international space station. And we hope when we get that under our belt, this partnership will return to the moon and later go on to Mars."
Flying upside down and backward over the Indian Ocean, commander Dominic Gorie and pilot Gregory Johnson fired Endeavour's twin braking rockets for two minutes and 48 seconds starting at 7:33:14 p.m., slowing the ship by about 206 mph and dropping the far side of the shuttle's orbit deep into the atmosphere.
After a half-hour free fall, Endeavour plunged back into the discernible atmosphere at 8:07 p.m. at an altitude of 76 miles above the south Pacific Ocean. Minutes later, the shuttle's heat shield was subjected to 3,000-degree temperatures as the spaceplane decelerated from its orbital velocity of 5 miles per second.
Crossing high above Central America's Yucatan Peninsula, Endeavour's flight computers guided the shuttle across the Gulf of Mexico and then over the west coast of Florida just south of Tampa, dropping through 84,000 feet at 1,700 mph seven minutes before touchdown.
Three minutes later, at an altitude of about 50,700 feet, Endeavour's speed dropped below Mach 1 and a double sonic boom rumbled across the space center. Gorie took over manual control a few seconds later and after letting Gregory get a few moments of "stick time, guided the shuttle through a sweeping 255-degree left overhead turn to line up on runway 15.
As Gorie pulled the shuttle's nose up just before touchdown, Johnson lowered Endeavour's landing gear and the orbiter settled to a tire-smoking touchdown at 8:39:08 p.m. as jets of flame from the exhaust ports of the ship's three hydraulic power units flared in the night.
"Houston, Endeavour. Wheels stopped," Gorie radioed as the shuttle rolled to a stop.
"Welcome home, Endeavour," astronaut James Dutton called from mission control. "Congrats to the entire crew, to JAXA and CSA (the Japanese and Canadian space agencies), on a very successful mission."
"Thanks, Jim," Gorie replied. "It was a super rewarding mission, exciting from the start to the ending and we just thank you for all your help. Looking forward to seeing you guys soon."
It was the 16th night landing at KSC and the 22nd in shuttle history. Mission duration was 15 days 18 hours 10 minutes and 54 seconds, covering 6.6 million miles and 249 complete orbits since blastoff March 11 from nearby launch complex 39A.
Observers were startled by the hydraulic power units' exhaust jetting from vents on either side of Endeavour's vertical tail fin. The exhaust is produced by the orbiter's three auxiliary power units, which provide the muscle needed to move the ship's wing flaps, speed brake, landing gear brakes and nose wheel steering. The exhaust appeared normal in infrared views, but was more pronounced than usual in NASA's visible-light camera. NASA spokesman Kyle Herring in mission control said the APUs were operating normally.
Gorie, Johnson and their shuttle crewmates - flight engineer Michael Foreman, Richard Linnehan, Robert Behnken and Japanese astronaut Takao Doi - doffed their pressure suits and joined technicians and NASA managers on the runway about an hour after landing for a traditional walk-around inspection.
Eyharts made the flight back to Earth resting on his back in a special recumbent seat on Endeavour's lower deck. As with all returning long-duration space station astronauts, a team of flight surgeons was standing by to monitor Eyharts as he began the long process of readjusting to Earth's gravity. The French air force general was replaced aboard the station by NASA astronaut Garrett Reisman, who hitched a ride the lab complex aboard Endeavour.
Eyharts and his shuttle crewmates are expected to fly back to the Johnson Space Center in Houston on Thursday.
Endeavour's 16-day mission was the longest yet for a space station assembly flight and the five spacewalks carried out by Linnehan, Behnken, Foreman and Reisman set another one-flight station assembly record of 33 hours and 28 minutes.
Endeavour took off March 11 and docked with the space station two days later. The day after that, Doi, operating the shuttle's robot arm, moved a Japanese storage module into position for attachment to the station while Linnehan and Reisman staged the mission's initial spacewalk.
During the next spacewalk, Linnehan and Behnken then began assembly of the Canadian Space Agency's special purpose dexterous manipulator, a maintenance robot known as Dextre. Attached to the end of the station's robot arm, Dextre can be used to replace components on the station that might otherwise require a spacewalk.
Along with mounting the Japanese module and building Dextre, the astronauts also transferred critical spare parts to the station and mounted Endeavour's heat shield inspection boom on the lab for use by the next shuttle crew. That shuttle, Discovery, is carrying Japan's huge Kibo lab module and does not have enough room for the inspection boom as well.
Liftoff had been scheduled for May 25 - minutes before NASA's Phoenix lander is scheduled to touch down on Mars - but Griffin confirmed Wednesday that launch will slip a few days because of late delivery of the shuttle's external fuel tank.
"You can go watch the Phoenix landing (at the Jet Propulsion Laboratory in Pasadena, Calif.)," Griffin told a reporter. "We're working on the exact date for STS-124." He said launch would take place within a few days of May 25, "but we know you'll be deconflicted enough that you can manage with a round-trip ticket. Because I'll tell you this, the landing day on Mars is fixed! It ain't moving."
NASA is still assessing its schedule for subsequent shuttle flights. Eleven more flights are planned before the shuttle fleet is retired in 2010, with four flights on tap this year, four in 2009 and three in 2010.
Along with Discovery's upcoming station flight, the shuttle Atlantis is scheduled for launch Aug. 28 on a final mission to service the Hubble Space Telescope. Endeavour returns to orbit in October for a space station resupply mission and Discovery closes out the year in December with a flight to deliver a final set of solar arrays to the international lab.
But external tank production problems at Lockheed Martin's Michoud Assembly Facility in New Orleans threaten delays for downstream flights. The tank needed by Discovery for the next mission reached the Kennedy Space Center behind schedule Wednesday and while that flight remains roughly on track, the Hubble mission could slip into October when all is said and done, triggering domino-like slips for subsequent flights.
NASA managers have not yet made any official changes. But Bill Gerstenmaier, chief of space operations for NASA, said Wednesday production of new tanks based on post-Columbia design modifications involves numerous changes and based on actual experience, it appears delays are likely.
"The tanks we're getting now, you can think of them as clean-build tanks, whereas before, the tanks we had were built before the Katrina hurricane and we were repairing and making modifications to those tanks," Gerstenmaier said. "So we're gaining some experience and seeing how long it takes to put those tanks together, how to fabricate them.
"And then HST is a little unique because we need to have two tanks down here ready to go support that mission, the tank for the flight itself and the tank for the contingency (rescue) flight. So we're off evaluating now what that production schedule looks like. We really don't have a good handle on that schedule yet. Once we understand a little bit better where that fits, we'll then announce where those flights are going, if they're going to move.
"But right now, it's a little early to look at that," Gerstenmaier said. "But we understand the work is a little bit different than we had before and we're going to have to have a different production schedule. So things will slip, probably, a little bit for those tanks."
07:36 PM, 3/26/08, Update: Shuttle braking rockets fired
Encouraged by improving weather, commander Dominic Gorie and pilot Gregory Johnson fired the shuttle Endeavour's twin braking rockets for two minutes and 45 seconds today starting at 7:33:14 p.m., slowing the ship by about 206 mph to drop out of orbit. Landing at the Kennedy Space Center in Florida is targeted for around 8:39:06 p.m. This status report will be updated after Endeavour lands or as conditions warrant.
05:30 PM, 3/26/08, Update: Shuttle landing delayed one orbit
Florida's hard-to-predict weather surprised NASA forecasters today, forcing flight director Richard Jones to delay the shuttle Endeavour's re-entry by one orbit because of low clouds over the Kennedy Space Center. Shuttle commander Dominic Gorie and pilot Gregory Johnson are now setting up for a deorbit rocket firing at 7:33 p.m., which would result in a landing at 8:39 p.m.
"Dom, unfortunately the weather trend did not improve as we had hoped," astronaut James Dutton radioed from Houston. "So we are going to be waving off one orbit."
"Jim, we copy the waveoff for one rev," Gorie replied.
"The forecast for the second opportunity is scattered (clouds) at 5,000," Dutton said. "So we're looking for some improvement."
There are no technical problems of any significance and the weather remains the only concern. If Gorie and his crewmates cannot get down on their second opportunity, the mission will be extended 24 hours and they will try again Thursday.
02:30 PM, 3/26/08, Update: Endeavour astronauts ready shuttle for landing
The Endeavour astronauts are working through their deorbit timeline today, rigging the shuttle for re-entry and touchdown on runway 15 at the Kennedy Space Center at 7:05 p.m. There are no technical problems of any significance and forecasters continue to predict good weather for landing.
"All right, Dom, we just took the weather brief and it's looking really nice at KSC for the first opportunity," astronaut James Dutton radioed commander Dominic Gorie from mission control. "The forecast remains 'go,' scattered (clouds) at 5,000 (feet), seven miles vis, winds zero-nine-zero, 8 (knots) peak 12. That's a cross(wind) of 11, headwind of 5. So the clouds have lifted a bit. We'll be keeping track of those, but we think it's looking really nice to get you home on the first opportunity."
"Thanks, Jim, that sounds great. It sounds like the weather forecasters were really accurate on this one," Gorie replied. "They're doing a great job. Thanks!"
The astronauts were awakened at 10:58 a.m. by a recording of Train's "Drops of Jupiter" radioed up from mission control.
"Good morning Endeavour. And good morning to you, Box," astronaut Al Drew called from Houston, using pilot Gregory Johnson's fighter pilot call sign.
"Good morning, Al. Wow, that's a great song to listen to on landing day," Johnson replied. "I'd like to thank my wife, Cari, and my kids Matthew, Susan and Rachel. That's one of the songs that we play in Max Q, our all-astronaut band. We do keep our day jobs, though. But this has been a two-week adventure, it's been a pleasure and an honor to be on it and although we had wonderful events and some great successes, we're ready to get home. ... We'll see you guys on the ground."
"I'm sure your families will be happy to see you back on the ground there in Florida and we'll look forward to seeing you back here in Houston when you get here," Drew said.
"Thanks, Al. I've also got my 1984 (Air Force) academy shirt on."
"'84, hard core..." said Drew, a fellow academy graduate.
"Wings that soar," Johnson finished.
Gorie, Johnson, flight engineer Michael Foreman, Richard Linnehan, Robert Behnken, Japanese astronaut Takao Doi and returning space station flight engineer Leopold Eyharts, a European Space Agency astronaut returning to Earth after 48 days in space, have two landing opportunities today, one at 7:05:08 p.m. and the other at 8:39:06 p.m.
The first opportunity occurs in daylight and the second in darkness. The crosswind limit for daylight landings is 15 knots, decreasing to 12 knots at night. But the winds are expected to decrease as the evening wears on and crosswinds are expected to peak around 9 knots for the second opportunity.
With a good forecast, NASA is not staffing its backup landing site at Edwards Air Force Base, Calif., and if the weather or some other problem prevents a touchdown today, the astronauts will remain in orbit an additional 24 hours and try again Thursday.
Working through a carefully scripted timeilne, the astronauts planned to close the shuttle's cargo bay doors around 3:18 p.m. and to fire the shuttle's twin braking rockets for two minutes and 51 seconds starting at 5:58:14 p.m. That will slow the shuttle by 209 mph, just enough to cause the ship to drop out of orbit.
About a half-hour later, at 6:33 p.m., Endeavour will fall into the discernible atmosphere at an altitude of about 76 miles. Within a few minutes, atmospheric friction will produce temperatures of more than 3,000 degrees Fahrenheit on the reinforced carbon carbon nose cap and wing leading edge panels as the shuttle rapidly slows down from its orbital velocity of 5 miles per second.
Endeavour's ground track will carry the shuttle across Central America west of the Panama Canal, high above central Cuba and then up the east coast of Florida. Dropping through 83,000 feet, Endeavour will have slowed to a velocity of 1,700 mph by around 6:58 p.m. and to Mach 1 three minutes later, producing twin sonic booms as Endeavour drops below the speed of sound at an altitude of 51,100 feet.
At that point, Gorie will take over manual control, guiding the spaceplane through a sweeping 195-degree left overhead turn to line up on runway 15.
Here is a timeline of re-entry events (in EDT throughout):
EDT...........EVENT ..............Rev. 248 descent to KSC runway 15 01:58:00 PM...Begin deorbit timeline 02:13:00 PM...Radiator stow 02:23:00 PM...Mission specialists seat installation 02:29:00 PM...Computers set for deorbit prep 02:33:00 PM...Hydraulic system configuration 02:58:00 PM...Flash evaporator cooling system checkout 03:04:00 PM...Final payload deactivation 03:18:00 PM...Payload bay doors closed 03:28:00 PM...Mission control 'go' for OPS-3 entry software load 03:38:00 PM...OPS-3 software loaded 04:03:00 PM...Entry switch list verification 04:13:00 PM...Deorbit maneuver update 04:18:00 PM...Crew entry review 04:33:00 PM...Commander/pilot don entry suits 04:50:00 PM...Inertial Measurement Unit alignment 04:58:00 PM...CDR/PLT strap in; mission specialists don suits 05:15:00 PM...Shuttle steering check 05:18:00 PM...Hydraulic power system prestart 05:25:00 PM...Toilet deactivation 05:33:00 PM...Vent doors closed for entry 05:38:00 PM...Mission control 'go' for deorbit burn 05:44:00 PM...MS seat ingress 05:53:00 PM...Single APU start 05:58:14 PM...Deorbit ignition (Alt: 215.2 sm; Vel: 17,251 mph; dV: 209 mph; dT: 2:51) 06:01:05 PM...Deorbit burn complete 06:33:06 PM...Entry interface (alt: 75.7 sm; Vel: 16,979 mph; range: 4,959 sm) 06:38:03 PM...1st roll command to left 06:52:00 PM...C-band radar acquisition 06:54:34 PM...1st left to right roll reversal 06:58:36 PM...Velocity less than mach 2.5 (alt: 83,000 ft; vel: 1,709 mph) 07:00:47 PM...Velocity less than mach 1 (alt: 51,100 ft; vel: 613 mph) 07:02:05 PM...Shuttle on the heading alignment cylinder 07:05:08 PM...Landing ..............Rev. 249 descent to KSC runway 15 07:13:14 PM...Mission control 'go' for deorbit burn 07:19:14 PM...MS seat ingress 07:28:14 PM...Single APU start 07:33:14 PM...Deorbit ignition (alt: 216 sm; vel: 17,251 mph; dV: 206 mph; dT: 2:48) 07:36:02 PM...Deorbit burn complete 08:07:23 PM...Entry interface (alt: 75.6 sm; vel: 16,979 mph; range: 5,055 sm) 08:12:18 PM...1st roll command to right 08:21:14 PM...1st right-to-left roll reversal 08:26:00 PM...C-band radar acquisition 08:32:34 PM...Velocity less than mach 2.5 (alt: 83,900 feet; vel: 1,704 mph) 08:34:46 PM...Velocity less than mach 1 (alt: 50,700 feet; vel: 613 mph) 08:35:32 PM...Shuttle on the heading alignment cylinder 08:39:06 PM...Landing
12:00 AM, 3/26/08, Update: Good weather expected for shuttle landing
The Endeavour astronauts tested the shuttle's re-entry systems Tuesday and packed for landing Wednesday at the Kennedy Space Center to close out a 16-day space station assembly mission. Entry Flight Director Richard Jones said the shuttle is in good shape and the weather is "go" for a late afternoon descent.
"The flight control system behaved beautifully, there are no issues to really talk about," Jones said of today's entry preparations.
Flying upside down and backward, Gorie and pilot Gregory Johnson plan to fire Endeavour's twin braking rockets for two minutes and 51 seconds starting at 5:58:14 p.m., slowing the ship by about 209 mph and dropping it out of orbit.
Flying northward over Central America just west of the Panama Canal, the shuttle's flight path will carry it high above central Cuba and then up the east coast of Florida before a left overhead turn to line up on runway 15. Touchdown is expected at 7:05:08 p.m.
Jones said one of the shuttle's three hydraulic power units appears to be suffering a slight decrease in fuel pressure, but telemetry indicates the problem is a slow nitrogen leak, which poses no problem for the auxiliary power unit in question.
"We started APU 1 during FCS (flight control system) checkout," Jones said. "As you know, we have been monitoring a small, slight fuel tank pressure decrease for many days now. ... They determined that this leak behaved and looked like a gaseous nitrogen leak. We started that APU today to go through FCS checkout so that we could essentially get a warm fuzzy that it is behaving exactly like we had intended. And sure enough, APU 1 did just great and there's nothing that would tell me or the flight control team that that APU is not ready for entry. Because it is."
"We got into that mode for a specific reason, so that we could look at the GPS system," Jones said. "This vehicle, the Endeavour, is a three-string GPS vehicle. It's the only one in our fleet and we are going to use that system to come home tomorrow. GPS is one of our primary navigation aids. That system also did very well."
Endeavour's primary steering thrusters also were test fired and again, no problems were uncovered.
But engineers were notified of an orbital debris impact on one of the shuttle's cockpit windows. The ding is about the size of a BB, but Jones said an engineering analysis shows the multi-pane window has plenty of margin for entry.
"We've seen these dings before that have happened throughout the course of our shuttle history," he said. "This ding was looked at today by our engineering community. It's about one eighth to about three sixteenths of an inch in diameter, so it's very small. But our engineers did look at it, it's cleared for entry and we have plenty of margin in that window."
Gorie and Johnson took turns practicing landing procedures using a computer flight simulator. While Endeavour is healthy and checked out for entry, Gorie told a reporter he still gets butterflies thinking about his responsibilities.
"The orbiter's really been performing really marvelously this whole flight, we don't have any concerns at all about it," he said. "We were just talking a little bit ago when Box (Johnson) and I were working the little trainer for the landing. You always have a little butterflies when you approach an event like that. We're certainly not scared about it, but yeah, you're a little bit nervous about wanting to do it just right and just like you've been training for. But Endeavour's in great shape and we're looking forward to getting back into Florida right before sunset tomorrow."
Because of the favorable weather forecast, NASA is not staffing its backup landing site at Edwards Air Force Base, Calif. Endeavour's crew will have two opportunities, on successive orbits, to land in Florida at 7:05 p.m. and 8:39 p.m. respectively. If the weather or some other problem blocks both opportunities, the astronauts will remain in orbit an extra day and try again Thursday. The shuttle has enough on-board supplies to stay in orbit until Friday.
11:30 AM, 3/25/08, Update: Astronauts prepare for Wednesday landing
The Endeavour astronauts faced a busy day in space today, testing the shuttle's re-entry systems and packing up for landing Wednesday at the Kennedy Space Center to close out a 16-day space station assembly mission. There are no technical problems of any significance and forecasters are predicting good weather for Endeavour's 7:05 p.m. Wednesday touchdown.
Commander Dominic Gorie, pilot Gregory Johnson and flight engineer Mike Foreman planned to fire up one of the shuttle's hydraulic power units this afternoon for a detailed flight control system checkout before test firing maneuvering jets to make sure the orbiter's entry systems are ready for the descent from orbit.
The astronauts also will set up a reclining seat on the shuttle's lower deck for European Space Agency astronaut Leopold Eyharts, returning to the uncomfortable tug of Earth's gravity after 48 days in weightlessness. Eyharts was launched to the international space station Feb. 7 to help commission ESA's Columbus research module. His replacement, Garrett Reisman, was ferried to the outpost aboard Endeavour.
Two final astronaut interview sessions are on tap today, one with Eyharts at 6:33 p.m. and the other, at 8:13 p.m., with U.S. reporters. A mission status briefing with entry flight director Richard Jones to review the weather and landing preparations is scheduled for 10 p.m.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision M of the NASA television schedule):
02:30 AM, 3/25/08, Update: Contamination samples point to possible bearing problem in solar array joint; but troubleshooting not definitive
Analysis of metallic contamination from a critical solar array rotary joint on the international space station indicates a "high-friction event" of some sort, possibly a misaligned bearing roller or some other like defect, has chewed up and damaged one of the surfaces of a 10-foot-wide gear and bearing race, the station's program manager said Monday.
A definitive answer to what caused extensive damage to the race ring is not yet complete and as a result, NASA managers have not yet decided what sort of repairs might be needed to restore the joint to normal operation. But Program Manager Mike Suffredini said an analysis shows the station's solar arrays can generate enough power for near-normal station operations through the rest of this year and early next with the right side solar alpha rotary joint, or SARJ, locked in place or only occasionally moved to improve power generation.
"We may have to manage how we do research, but we should be able to do the research that we planned," he said.
But this is a critical issue for the long-term health of the space station and Suffredini provided the most detailed update yet on where the ongoing troubleshooting stands.
The space station is equipped with two SARJ joints, one on each side of its main power truss. Each SARJ features two 10-foot-wide drive gears, one of which is a backup. The main gear/race ring is gripped by 12 so-called trundle bearing assemblies spaced evenly around the circumference. The trundle bearings each feature three rollers that grip different faces of the drive gear/race ring. The gear is driven by a motor called a drive lock assembly, or DLA. Each joint features two DLAs, but only one is used at a time.
The SARJ system is critical to the station's long-term viability. To provide the power necessary to run all the station's planned science operations, along with life support systems, computers, communications gear, cooling systems, etc., the solar arrays must track the sun as the station circles the planet.
The station's left-side SARJ is operating normally. But last fall, engineers noticed higher-than-expected vibration levels in the right-side SARJ and drive motor power spikes indicative of mechanical resistance of some sort.
During a subsequent spacewalk inspection, extensive internal metallic contamination was discovered in the form of apparent shavings found clumped and scattered across one face of the race ring. The surface of the ring itself appeared mottled and damaged. To minimize additional damage, flight controllers decided to suspend "auto-track" drive operations, although the starboard SARJ is occasionally repositioned to improve power generation.
During previous spacewalks, astronauts removed 17 of 22 thermal covers around the circumference of the joint to look for signs of micrometeoroid impact damage or any other issues that might explain the problem. In addition, one of the 12 trundle bearing assemblies positioned around the race ring - TBA No. 5 - was removed and returned to Earth for analysis, along with samples of the metallic debris.
During the Endeavour crew's fifth and final spacewalk Saturday, astronaut Mike Foreman removed the final five thermal covers and looked inside the joint. There were no signs of any impact damage. He also examined a small spot on the undamaged "datum A" race ring that was seen in earlier photographs. Engineers were not sure whether the blemish was a pit or a bump-like defect caused by a buildup of contaminants. Foreman said it felt rough to him, indicating it might be a depression, but with thick gloves on, the astronaut could not be definitive.
NASA managers initially held out hope spacewalking astronauts could somehow clean up the contamination and restore the joint to normal, or near-normal, operation. That no longer appears possible and NASA is expected to order a switch to the redundant drive gear at some point. But that's a last-resot sort of option. Engineers want to make sure they understand the cause of the problem first, to make sure the same thing won't happen on the backup gear.
"SARJ is going to take us a while to figure out," Suffredini said. "But we did bring home quite a bit of information on the last flight and we did learn a few things that we're still working on. The data does suggest, from the way that the material has come off of the race, that it was caused by a high-friction event. We have been postulating for a while that perhaps contamination had gotten on the race and when we rolled over it, we created a weak spot in this brittle surface that we talked about, perhaps it was damaged that way, kind of like the pothole in the road theory, and chewed it up. The problem with that theory was we chewed it up awfully quick if it started off as one small spot.
"So based on the way the material has come off and where the fracture lines are - and it is incredible to watch these guys do this work to try to do detailed analysis of these very small particles we brought home - but they've been able to conclude that ... some of these larger flakes that we brought home were the result of high-friction events. And what that tells you is that perhaps we had either a roller that was cocked or one that wasn't quite rolling as freely as we thought. There are a number of scenarios that lead you down that path. So that is a piece of information we gleaned from that.
"One of the interesting things from the last EVA, we sent the crew to go look at what we had assumed was contamination, maybe I should say we wished was contamination. The crew seems to have indicated that the spot that they saw was rough. Now that may be contamination that got pressed on to the race as we rolled over it. That is a more likely candidate, but we couldn't tell. Was it rough because it's high? Was it rough because it's low? So we'll have to think about that.
"Damage to datum A would be an interesting piece of information," Suffredini said. "To date, we've seen the damage only on the upper inclined surface. And so if you postulated that we had a roller or something that was canted wrong for whatever reason, not aligned quite right, then that would explain why only that surface was damaged. If over a much longer period of time we were starting to see the same thing on datum A, of course, that makes our theory a little more difficult. But there are still 111 branches on our fault tree and 300-plus actions left to be closed. And so our job is to give the team as much time as possible to try to sort this out."
A major question mark throughout the troubleshooting is how long station assembly and operation can go without having full auto-track solar power available. Suffredini said the latest analysis shows NASA can go ahead and attach Japan's huge Kibo research module in May as planned and even bolt on the S6 solar array segment to complete the right side of the station's power truss. That flight, known as assembly mission 15A, currently is scheduled for launch in December, although external tank delivery issues could force a delay.
In any case, the station should have enough power without any SARJ repairs until the next flight in the sequence, launch of a third Japanese component next spring.
"We have, for all intents and purposes, cleared ourselves through the 15A stage, which means we can install the S6 truss on the 15A flight and make our way all the way to the end of that stage," Suffredini said. "As you may know, the flight after that is the exposed facility for JAXA, which requires not an insignificant amount of power. So that's probably the next bump we have to get through on the road.
"In order to get through that hump and keep runway in front of us before we actually have to do something like swap races, one option is we're looking at whether we can do the analysis that lets us temporarily rotate that joint during low-power periods," he said. "Today, we try to hold it locked. And so, if we can get about 60 days worth of rotations out of that joint, then perhaps we can buy ourselves a little more time to finish our failure analysis and decide what changes we might need to make. If it's just a matter of swapping over (to the outboard, redundant race ring), I can do that almost any time. But we might decide there are some hardware changes we want to implement, which would take us a little more time.
"Today I don't know the answer to what causes this problem, we have a number of legs left to work down the fault tree where every day we get a new piece of data. We pulled all the rest of the covers off (during Forman's spacewalk Saturday) and we didn't find an MMOD (micrometeoroid debris) strike that started this whole thing. So that was important information for us. And so if we can give the team enough time, I'm convinced we can figure out how to prevent this once we go to outboard ops. So our job is to work the failure analysis as hard as we can and give the team as much time to do that before we have to swap to outboard ops. That's kind of where we're at."
Asked if the station could operate normally in the near term without an operational right-side SARJ, Suffredini said: "We may have to manage how we do research, but we should be able to do the research that we planned.
"We won't be able to line everybody up and run them at the same time, but typically crew time doesn't allow us to do that anyway," he said. "So I would not see any major implications to research during that particular stage. Somewhere in there, we'll also finish our analysis on whether we can rotate the SARJ for a certain period of time and so we'll have that in our hip pocket as well."
NASA has one spare set of trundle bearings. Suffredini was asked if NASA might consider simply installing the new bearings on the damaged race ring, preserving the option of switching to the outboard ring later if necessary.
"The race is damaged to a significant level such that my personal opinion is it would be difficult to get the structural life that we would need out of the outboard truss if we kept running along that damaged race," he said. "That is something we've looked at and thought a lot about. Of course, when we go to outboard ops we'll replace all of those bearings. So if we can figure out that that's the cause, then we have a dozen of those bearings sitting on the ground and we can certainly check them for whatever we believe the root cause is."
One option, perhaps, would be to "go ahead and do the reconfiguration to outboard ops but not rotate, get the rest of those trundle bearings home and see if we can find a smoking gun."
"But that's just one of many things that we've talked about doing," Suffredini said. "But I don't think I have an option, if I have to continually rotate the SARJ, I really don't think structural life is going to allow me to rotate on that bad race. Other than structural life, though, I think the system can drive through and our speculation is it will get easier over time as we knock the high points off that rough surface. I think the system can drive through it even with the existing bearings we have, but it'll just chew up the structural life of those quickly."
Asked if NASA had ruled out moving the bearings to the outboard race this year, Suffredini said "I learned a long time ago not to make those kind of predictions. You guys trained me that way."
08:30 PM, 3/24/08, Update: Shuttle Endeavour undocks after solar panel glitch resolved
With shuttle pilot Gregory Johnson at the controls, the Endeavour gently undocked from the international space station this evening, a half hour behind schedule because of problems getting one of the lab's solar arrays locked in place. After a second command successfully got the left-side outboard arrays to latch as required, Endeavour disconnected from the station's shuttle docking port at 8:25 p.m.
"Houston, Endeavour, we have physical separation," an astronaut radioed as the shuttle slowly pulled away, 215 miles above the Indian Ocean west of Australia.
Newly arrived station flight engineer Garrett Reisman, following a naval tradition established by NASA's first station commander eight years ago, rang the ship's bell mounted in the Destiny laboratory module and formally announced, "Endeavour. Departing."
"Copy, fair winds and following seas to you guys," shuttle commander Dominic Gorie radioed.
"Well, we're the happy recipients of the (Japanese) Kibo module and Dextre, we really appreciate everything you've done for us over the last couple of weeks," station commander Peggy Whitson replied. "Thanks a bunch, and especially thanks for being such great guys."
"Thanks, Peggy," Gorie said. "My friends, we'll see you on the ground here in about a month."
Endeavour, oriented with its tail toward Earth and its open payload bay facing the space station, pulled straight away from the outpost in its direction of travel as the two spacecraft streaked through low-Earth orbit at five miles per second. Johnson planned to guide the ship through a slow 360-degree loop to photograph the lab complex from a variety of angles before leaving the immediate area. Landing back at the Kennedy Space Center is scheduled for 7:05 p.m. Wednesday.
06:00 PM, 3/24/08, Update: Shuttle astronauts bid station crew farewell
With hugs and handshakes, the Endeavour astronauts said farewell to their space station colleagues today, gathering one last time to mark the end of a marathon five-spacewalk assembly mission before floating back into the shuttle, closing hatches and preparing to undock.
European Space Agency astronaut Leopold Eyharts, launched to the station aboard the shuttle Atlantis in February to help activate ESA's new Columbus research module, departed with Endeavour's crew, leaving his replacement, Garrett Reisman, behind with Expedition 16 commander Peggy Whitson and flight engineer Yuri Malenchenko.
"Expedition 16 has had a number of flight engineers, I've already called Garrett "Clay" (Anderson) once," Whitson laughed. "I'm sure I'll be messing up some more, but we really had the privilege of having some great flight engineers. ... I want to especially thank Leo for being here at a special time when we inaugurated the Columbus module and especially thank him for all the work he did inside the Columbus module.
"I think the ground team is just as proud of him as I am, and I'm really glad he was here during this stage," Whitson said. "I'm really looking forward to all the laughs I'm going to have with Garrett, because he is just a lot of fun and I think it's going to be a great time, the next few weeks we have together before Yuri and I bail on him."
Whitson and Malenchenko are scheduled to return to Earth in April after being replaced by Expedition 17 commander Sergey Volkov and Oleg Kononenko. Reisman will remain aboard as part of Volkov's crew until he is replaced by astronaut Gregory Chamitoff, scheduled for launch May 25 aboard the shuttle Discovery.
"It's hard for me to believe that it's already finished," Eyharts said of his seven-week stay in space. "It has been a great flight, it was a great team and a great crew. I'd like to thank all who have made the flight possible. I mean, bringing the station up to what it is now, bringing the Columbus here and activating it and making it a scientific laboratory. This was a great time. ... Of course, I'd like to wish all the best to Garrett. I know he has a lot of things coming on his plate. He will do well. I would like to thank Peggy and Yuri and the 122 and 123 crews for their tremendous help and for their friendship, too."
Reisman than took the microphone, saying "I have to tell you, it's a little intimidating taking over, replacing Leo, because Leo is a general in the French air force and I never even made it through (Cub Scout) Weblos, let along getting on to Boy Scouts. So I feel a little mismatched!
"But I will do my best, and I want to thank Leo for leaving us in such great shape, especially all the hard work and long hours you put into Columbus," said Reisman. "You did a fantastic job getting Columbus activated and checked out and we're all going to benefit from that. Finally, I just want to say I already feel nostalgia coming on about the STS-123 crew. It was really fantastic being a part of this crew. It's a crew that excels not only on a professional level, but also a human level. I mean that with all sincerity. It's just been a wonderful chapter in my life to be a part of all that."
Looking at his former shuttle crewmates, Reisman joked: "I'm really going to miss all of you. Except you, Rick (Linnehan)." Then, to pilot Gregory Johnson, "Have a great landing - don't forget (to lower the) gear - and I look forward to seeing you all back home in a couple of months."
Shuttle commander Dominic Gorie thanked Whitson for the station crew's help staging a record five space station assembly spacewalks, adding "we had a great time here, looking forward to a wonderful return home."
"It's sort of a strange feeling to want to see your families but not wanting to leave a wonderful place," Gorie said. "You made it that way, so thank you very much."
As the shuttle crew floated through the hatch toward Endeavour, Reisman jokingly moved to join them, prompted Whitson to grasp him firmly about the waist.
The hatches were closed at 5:49 p.m., setting the stage for undocking at 7:56 p.m.
12:30 PM, 3/23/08, Update: Astronauts prepare for farewell, undocking
The Endeavour astronauts are gearing up to undock from the international space station this evening to close out a marathon five-spacewalk assembly mission. A brief farewell ceremony is planned for 5:13 p.m., followed by hatch closure around 5:30 p.m. With shuttle pilot Gregory Johnson at the controls, Endeavour is scheduled to disconnect from the space station's forward docking port, pressurized mating adapter No. 2, at 7:56 p.m. After looping around the lab complex for a photo survey, Johnson will fire the shuttle's maneuvering jets to leave the area around 9:40 p.m.
"There are a number of key steps both vehicles have to go through to make sure the undocking goes smoothly," said space station Flight Director Bob Dempsey. "First of all, we have to maneuver the combined space station-orbiter vehicle to the undocking attitude, as it's called. Normally, when the orbiter's docked there, the PMA-2, or the pressurized mating adapter 2 (docking port) is flying in the direction the vehicle is going. When the orbiter is docked, we actually flip the vehicle 180 degrees around ... so the delicate thermal protection system on the orbiter, the tiles, are not into the wind, as we say, and vulnerable to debris strikes. So we fly with the shuttle sort of in the back with the belly sort of facing downwind.
"But we can't undock in that position. So we will flip the station around 180 degrees to get them in the right orientation. Then another thing we will do to get ready for the undock is we will park the KU antenna on the space station. We do that so we don't radiate the orbiter. ... And then we will begin a series of minor power downs. The reason we're doing that is, the next thing we have to do is configure the solar arrays on the space station, both the giant U.S. arrays and the Russian arrays, so that as the orbiter's undocking and it's firing its thrusters, that impinges material that can dirty up and push, do some structural damage, to the solar arrays. So we park those so they're kind of edge on to the thrusters so when the orbiter's backing away, we minimize the amount of impact to the solar arrays.
"So once we do all those things, we're in the undocking configuration," Dempsey said. "The shuttle will give the commands and back off from the space station. It'll move away slowly, we don't want to impart a big moment to the space station and push it very hard, cause it to tumble or anything like that. So it'll back off slowly and once the crew gets far enough away, they'll start some minor thruster firings, do it as gently as possible ... then they'll actually do a fly around."
Johnson will guide Endeavour through a full 360-degree loop, flying directly above, behind and below the station for a detailed photo survey.
"That's going to be a great thing for a pilot," Johnson told CBS News before launch. "Undocking is about the opposite of docking, you're leaving the space station at a pretty controlled rate. And then at the end of the undocking timeline, when we get about 300 to 400 feet away, then we start what's called a fly-around and that's where you take the orbiter and go 360 degrees all the way around the station, about 45 minutes of flying. You get to see angles of space station that aren't normally observed and just a great, exciting period for the whole crew."
When the shuttle is a safe distance away, station commander Peggy Whitson, flight engineer Yuri Malenchenko and newly arrived flight engineer Garrett Reisman will begin work to put the station back into its normal operating mode, putting the solar arrays back in sun-track and powering up systems that were shut down earlier. Because of ongoing problems with one of the station's solar array rotary joints, the S4 solar panels on the right side of the complex will remain locked in place.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision L of the NASA television schedule):
"The orbiter crew will be taking all kinds of high resolution photos of the space station and we can use that to check the configuration, make sure everything looks healthy. We will get some baseline photos of the JLP, the Japanese pressurized module that we just installed during this mission and then over time, we'll be able to compare those to other photos ... and just monitor over time. So it gives us a good opportunity to check out the space station."
Departing station crews normally carry out a detailed heat shield inspection just after undocking to make sure the orbiter's nose cap and wing leading edge panels were in good shape for re-entry. Endeavour's crew did that inspection Friday and stowed the shuttle's inspection boom on the station during a spacewalk Saturday so it will be available to the next station assembly crew. Because of interference issues with the Japanese Kibo research module scheduled for launch in May, there was not enough room to carry an inspection boom on that mission.
If all goes well, Johnson, commander Dominic Gorie, flight engineer Michael Foreman, Richard Linnehan, Robert Behnken, Japanese astronaut Takao Doi and returning European Space Agency astronaut Leopold Eyharts will pack up Tuesday and prepare the ship for landing Wednesday evening at the Kennedy Space Center.
Landing is targeted for 7:05:08 p.m. Wednesday and forecasters are calling for good weather, with scattered clouds at 3,500 feet and winds out of the north at eight knots, gusting to 12. A second landing opportunity is available one orbit later, at 8:39:06 p.m.
"I know we're still three days out from landing but the weather is looking pretty reasonable," astronaut Terry Virts radioed the shuttle Sunday evening. "For now it looks good. We'll keep our fingers crossed."
12:45 PM, 3/23/08, Update: Astronauts take a break, prepare for undocking Monday
The Endeavour astronauts are enjoying a final few hours of off-duty time today before making preparations for undocking Monday evening. The joint shuttle-station crews will share an Easter meal later today before participating in a news conference to discuss the progress of the mission.
"Fortunately, the mission has been going extremely well so there's not a whole lot left for the crew to do," said space station Flight Director Bob Dempsey. "In fact, they're getting a half-day off to give them a chance to rest after the five EVAs and all the busy work they've been doing. And of course, preparing for the undocking and re-entry in a few days."
The astronauts were awakened at 12:28 p.m. by a recording of "I am Free" beamed up from mission control. The song was recorded by members of astronaut Mike Foreman's church near the Johnson Space Center.
"Good morning Endeavour," astronaut Al Drew called from mission control. "And a happy Easter to you, Mike."
"Thanks, Alvin," Foreman replied. "That's one of my favorite songs in church, so I especially want to thank all my friends at Friendswood United Methodist Church for their thoughts and prayers. ... That was awesome, how appropriate for this special day. It sounded as good up here as it does down there. Happy Easter."
"The main things that are left open is some transfer items, for example, the crew has some laptops they've been using for the last few days during the mission that need to be transferred back to the shuttle for return to Earth," he said. "There's also a number of biological specimens that need to be returned and because they're frozen, we keep them in the freezer on the space station up until the last possible moment. That'll happen later today. ... And then the spacesuits need some final configuration and transfer over to the shuttle.
"There are two suits we need to transfer back to the shuttle," Dempsey said. "This is is how we accomplish things like rotating suits on the space station. Two new suits come up on the space shuttle, are used and then are left behind and we take two of the older suits (and bring them down). In addition, we need to configure those suits so that if the shuttle crew has to do a contingency spacewalk before re-entering they would have two good suits. So that'll be the main activities today by several of the crew members.
"And then the final thing that's kind of on the open to-do list is the very important crew photo. That's where both the station and shuttle crew will get together and take sort of a goodbye photo, a team photo, of everyone together."
Undocking is targeted for 7:56 p.m. Monday, which will set the stage for landing at 7:04 p.m. Wednesday. The preliminary weather forecast calls for favorable conditions.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision K of the NASA television schedule):
10:50 PM, 3/22/08, Update: Spacewalk No. 5 ends (UPDATED at 2:30 AM with mission status briefing; SARJ update)
Astronauts Robert Behnken and Michael Foreman staged a successful six-hour two-minute spacewalk Saturday, mounting the shuttle Endeavour's heat-shield inspection boom on the station, deploying an experiment package and carrying out a critical inspection of a stalled solar array positioning mechanism. It's still not clear what is causing internal contamination, but an impact from orbital debris does not appear to be the root cause.
"You were just fabulous out there today," spacewalk coordinator Richard Linnehan radioed as the spacewalk ended. "I can't say enough. Thanks for making everyone look good."
Thank you, Rick," Foreman said.
"It was an absolutely fantastic EVA today, fellas, I'm just happy to have had a chance to play along," added space station flight engineer Garrett Reisman, who helped Linnehan direct the operation. "Thanks for letting me join in."
It was the 109th spacewalk devoted to station assembly and maintenance since construction began in 1998 and the fifth and final excursion for Endeavour's crew. Total station EVA assembly time now stands at 687 hours and 11 minutes. Total spacewalk time for Endeavour's crew stands at 33 hours and 28 minutes.
During today's outing, Behnken and Foreman bolted Endeavour's heat shield inspection boom to the station's solar power truss for use by the next shuttle assembly crew. The shuttle Discovery is scheduled for launch May 25 to deliver Japan's huge Kibo research module to the station, a payload so large there's no room in the shuttle's cargo bay for an inspection boom.
The astronauts also deployed a materials science experiment that could not be attached earlier and installed thermal covers over fittings on a newly installed Japanese logistics module.
"We now have the OBSS transferred and installed over on station," said lead station Flight Director Dana Weigel. "It has power to both of its heater strings, so it'll be nice and toasty when flight 1J goes up to retrieve it at the end of May. We also went back to install the MISSE-6 payloads we had problems with before. We were able to get them installed. Bob had the same problems with the pit pins he had before, but a hammer helped persuade them in place and now they're secure on station."
The astronauts plan to take time off Sunday before making final preparations for undocking Monday evening and landing back at the Kennedy Space Center on Wednesday. Weigel said engineers assessing data from laser scans of the shuttle's nose cap and wing leading edge panels Friday, a "late inspection" to look for signs of micrometeoroid impact damage, found no problems of any significance.
"Over on the orbiter side, the ground teams have completed the analysis for all of the late inspection imagery that we took yesterday and the TPS (thermal protection system) has been cleared for entry," she said. "Tomorrow is flight day 14, and it's a certainly well-deserved off-duty day for the crew."
Trouble with the starboard Solar Alpha Rotary Joint, or SARJ, has proven especially troubling for station engineers. The lab complex is equipped with two massive SARJs, one on each side of the station's main solar power truss, that use 10-foot-wide motor-driven gears to turn outboard solar arrays like giant paddle wheels to track the sun. Last fall, engineers discovered extensive internal metallic contamination in the right-side SARJ indicative of a major problem of some sort. To minimize additional damage, flight controllers no longer run that starboard SARJ in "auto-track" mode, although it is occasionally repositioned to improve power generation.
During previous spacewalks, astronauts removed 17 of 22 thermal covers around the circumference of the joint to look for signs of micrometeoroid impact damage or any other issues that might explain the problem. In addition, one of the 12 trundle bearing assemblies positioned around the race ring was removed and returned to Earth for analysis, along with samples of the metallic contamination.
During the Endeavour crew's fifth and final spacewalk Saturday, Forman removed the final five thermal covers and looked inside. So far, nothing obvious has emerged. But Weigel said today's inspection should let engineers close at least one branch of the fault tree.
"One of the key things that we learned during the EVA today was that we don't have any obvious MMOD (micrometeoroid debris) hit through the covers," Weigel said. "They're aluminum plates with beta cloth over them. We're looking to see if we have an MMOD hit through them and if that's a source of the debris. That's a big help for us, that kind of narrows down one of the chains of the fault tree."
Engineers are assessing a variety of potential repair options, ranging from cleaning up the debris and resuming normal operation to moving the 12 trundle bearing assemblies to a redundant, outboard gear/race ring. But the latter is a last-resort option, requiring several spacewalks, and mission managers do not want to take that step without understanding the cause of the current problem.
The right-side SARJ can still be used to periodically move its solar panels to improve power generation and an analysis of the station's electrical demand, even with the addition of Japan's Kibo research module in May, shows near-normal operation is possible without putting the SARJ in auto track.
"In terms of when decisions need to be made from a power standpoint, we're actually doing pretty well," Weigel said. "We can get by for quite a few more flights. The program, though, was interested in kind of coming up with more of a game plan by the end of March, just so we can figure out when we want to start attacking the different pieces of this puzzle. And there are a lot of different options we have.
"One is to try to clean it up and live with using the current race ring as is. And that's something they're going to go and talk about now that we've finished the rest of the inspection and we understand we do have uniform debris around the ring. We also have experience now with cleaning. I think with those pieces, we'll be able to figure out if we want to go clean and use it as is. I'm not exactly sure when we'll talk about if we want to go to the outboard ops. If we have a good solution that lets us stay on the inboard or the current race ring, then we're not as anxious to get to the outboard because we don't have as much redundancy when we run in that configuration. So I think the first decision point is going to be the end of March.
"Our current power predictions show that we're good for the next couple of flights without auto tracking, so we can continue to do what we've been doing, which is positioning the solar arrays strategically. For certain power contingencies, we could get into cases where we'd want to auto track for a while so it's desirable to get into a configuration where we could do it if we wanted to. Technically, we can auto track right now, it's just that we're putting the hardware at higher risk by doing that. So we really want to make sure we understand what's going on and clean it up as much as we can before we commit to using it in auto-track mode."
One of the items Foreman inspected was a small blemish on the race ring that appeared to be either a small divot or perhaps an accumulation of debris. Flight controllers could not tell whether the blemish represented a bump or a depression. Foreman's inspection was not totally conclusive, but Weigel said it appears to be a small divot. It's not yet clear whether there's any relationship between the blemish and the overall SARJ problem.
9:15 PM, 3/22/08, Update: Experiment package installed; solar array joint inspected
Astronaut Robert Behnken successfully mounted an experiment package on the Columbus research module after initial attempts during a spacewalk last week were called off due to problems with an attachment fitting.
Known as MISSE-6, for "materials international space station experiment," the briefcase-size folding package is designed to expose a variety of materials and coatings to the space environment.
"So Houston, that complete the MISSE-adventure," Behnken radioed after he secured it in place.
"And from Houston, Bob and the team, great job," astronaut Steve Robinson called from mission control. "I guess your new call sign will be Thor."
"All right, Thor, Bam Bam, whatever it takes," spacewalk Michael Foreman radioed, using Behnken's nickname. "We're here to serve."
"We're really glad we making humor up here because it alleviates some of the stress," said station flight engineer Garrett Reisman. "Bob's done a great job and we're really happy for the MISSE investigators in that we were able to get these payloads installed for them because we know there's a lot of good science to be had. I know they've been walking on eggshells watching all this, so everything's good."
"Houston definitely concurs," astronaut Steve Robinson radioed from Houston.
Astronaut Michael Foreman, meanwhile, was busy inspecting the space station's right-side solar alpha rotary joint, or SARJ. The SARJ uses a 10-foot-wide drive gear to turn outboard solar arrays to track the sun. But a problem of some sort has marred the right side bearing race ring and generated large amounts of metallic contamination.
During spacewalks late last year and earlier this year, astronauts removed 17 of 22 thermal covers around the joint to inspect the bearing race ring and look for signs of damage. The flight plan called for Foreman to remove the final five covers today to complete the inspection.
Looking inside the mechanism, Foreman observed "it's pretty ugly."
"You're talking about the race ring, right?" Reisman asked.
"Yeah, the race ring. It looks all corroded or something, it's real rough in most spots."
"Garrett, for Mike, we'd like a little bit more description as to what he sees," Robinson radioed. "Is it different than the similar location or the similar site that he saw under a previous cover? Or is it different radially, or circumferentially?"
"It looks exactly the same," Foreman said. "It looks like where the bearing rides on the surface, it's about a one-inch-wide track all the way across. It's like very rough in some spots, just sort of bubbled in other spots. So it looks the same."
Looking under a different cover, Foreman reported: "It looks exactly the same, the same mottled surface. There's a cover missing next to this one so I can see a good three feet of circumference here and it looks all the same. ... Nothing significant. It's not the best lighting conditions, but I don't see ... anything that looks like a divot. I don't see anything like that on this one."
The thermal covers themselves showed no signs of any impacts from orbital debris.
Running well ahead of schedule, Behnken was asked to perform a get-ahead task, installing thermal covers on the massive keel fittings used to hold a newly installed Japanese logistics module in the shuttle Endeavour's cargo bay during launch.
7:00 PM, 3/22/08, Update: Heat shield inspection boom mounted on space station
Astronaut Garrett Reisman, operating the space station's robot arm, handed the shuttle Endeavour's 50-foot-long heat shield inspection boom to spacewalkers Robert Behnken and Michael Foreman, who plugged in keep-alive power and mounted it on the front of the station's solar power truss.
Behnken's end snapped into an attachment fitting with no problem, but Foreman had to wrestle his into place due to minor alignment problems. After several adjustments, he coaxed his end into its mounting bracket.
"Wait, I've got it soft docked, Rick," Foreman called to spacewalk coordinator Richard Linnehan as his end snapped into place.
"Good work, Mike," Behnken called.
"OK, copy soft dock, Mike," said Reisman. "It looks like you're right on the edge of good alignment."
"Yeah, with a little elbow grease," Foreman replied. "I've got good alignment with the plates on the outside where they belong."
"Excellent, good job, Mike."
THe spacewalkers then attached a thermal cover to the boom's instrument package to keep its laser scanner and camera system from getting too cold over the next few weeks.
Endeavour's orbiter boom sensor system, or OBSS, was stowed on the space station because the crew of the next shuttle assembly mission, scheduled for launch May 25, is ferrying the huge Japanese Kibo lab module to the station. That module is so large, the shuttle Discovery will not have enough room to carry an OBSS of its own.
The Discovery astronauts will retrieve Endeavour's boom and use it to inspect their shuttle's heat shield after they have docked with the station and attached Kibo.
WIth the OBSS safely mounted on the station, Behnken and Foreman are moving on to separate tasks. Behnken will attempt to install a materials science space exposure experiment package to the Columbus module while Foreman begins an inspection of the station's right side solar array rotary joint.
05:00 PM, 3/22/08, Update: Spacewalk No. 5 begins
Running well ahead of schedule, astronauts Robert Behnken and Michael Foreman switched their spacesuits to battery power at 4:34 p.m. to officially kick off the Endeavour crew's fifth and final spacewalk. The primary goals of the excursion are to mount the shuttle's heat shield inspection boom on the space station; to deploy a materials science experiment package; and to inspect the station's right side solar array rotary joint.
The 50-foot-long orbiter boom sensor system, or OBSS, is in the process of being handed from the shuttle's robot arm to the station's arm, operated by pilot Gregory Johnson. Behnken will attach an extension cord to the boom to provide keep-alive heater power before the spacewalkers mount it on the front side of the station's solar power truss.
01:00 PM, 3/22/08, Update: Astronauts suit up for fifth spacewalk
Astronauts Robert Behnken and Michael Foreman are preparing for a fifth and final spacewalk, a six-and-a-half hour excursion this evening to mount the shuttle Endeavour's 50-foot-long heat shield inspection boom on the space station for use by the next station assembly crew. The astronauts also plan to install an experiment package they were unable to attach earlier and inspect the station's right-side solar array rotary joint in an ongoing effort to determine what might be causing internal interference and contamination.
This will be the 109th spacewalk devoted to station assembly and maintenance since construction began in 1998, the 10th so far this year and the third each for Behnken and Foreman. The spacewalk is scheduled to begin around 5:23 p.m. when the astronauts switch their spacesuits to battery power. For identification, Behnken, call sign EV-1, will be wearing a suit with no markings. Forman, EV-2, will be wearing a suit with broken red stripes around the legs.
The primary goal of the spacewalk is to install the shuttle's 50-foot-long orbiter boom sensor system, or OBSS, on the station for use by the next shuttle crew in late May. The goal of that flight is to deliver Japan's huge Kibo lab module to the space station.
"That mission is very full, Discovery's payload bay is carrying up the very large Japanese pressurized module and there just simply wasn't enough room to carry up the boom as well," said station Flight Director Ginger Kerrick. "So a long time ago, the program decided to go ahead and leave it on board. We're going to be keeping it powered and keeping a very close watch on it and we promise it will be ready to support that mission when they arrive in May."
The boom will be attached to brackets on the front face of the station's solar power truss.
While the spacewalkers are setting up their tools and running a 30-foot-long power cord down the truss, the shuttle's robot arm will hand the sensor boom to the station arm. As soon as possible, Behnken will plug the power cable into the boom to activate internal heaters to keep the boom's laser scanner and camera warm. The arm then will release the boom so Behnken and Foreman can bolt it in place.
With the OBSS mounted on the station, Behnken and Foreman will split up. Behnken will float to Endeavour's cargo bay, retrieve the briefcase-size MISSE-6 experiment package, and make his way to the Columbus lab module. The astronauts made an initial attempt to attach the materials exposure package to a mounting plate on the outboard side of Columbus during the crew's third spacewalk last Monday. But they were unable to insert locking pins in the mounting bracket. This time around, Behnken has smaller pins and cable ties.
While Behnken focuses on MISSE-6, Foreman will make his way to the right side of the station's main power truss to inspect the starboard solar alpha rotary joint, one of two massive motor-driven joints that turn outboard solar panels to track the sun.
Last fall, engineers became concerned about high vibration levels and power usage and ordered an inspection. To their dismay, spacewalking astronauts reported metal shavings covering the interior of the bearing race ring and damage to the ring itself. One of 12 bearing assemblies later was removed and returned to Earth for analysis, along with samples of the contamination. Engineers are still not sure what is causing the damage and the joint is no longer allowed to "auto track" the sun.
Engineers are considering a plan to remove all 12 bearing assemblies and move them to an identical race ring that is available as a backup. But the work would require multiple spacewalks and flight planners don't want to take that last-resort step until they have a better idea of what might be wrong.
Behnken and Foreman originally planned to replace the bearing assembly that was removed earlier. But that task was deferred to give Behnken time to install the higher-priority MISSE package. Instead, Foreman will focus on inspection only, removing five thermal covers to examine areas of the race ring that have not yet been assessed.
Kerrick said the absence of one bearing assembly is not expected to affect flight controllers' ability to reposition the joint as required.
"The joint has an inner ring and an outer ring and evenly spaced along those rings are 12 trundle bearing assemblies," Kerrick said. "Their primary function is to hold the two rings together and provide a rolling surface for the rings that will allow the joint to rotate. Will it be a problem that we're not installing it? The short answer is no. Right before we removed the trundle bearing back in December, we had our engineering teams go off and assess whether or not we would be good operating the SARJ with 11 of 12 of those trundle bearings installed and they declared that we would be. So while we would prefer to be in our nominal config with a total of 12, it doesn't impede our operations any."
The SARJ is protected by 22 thermal blankets. Astronauts have examined the mechanism under 17 of those blankets and Foreman will inspect under the final five during this evening's spacewalk.
"The signature we were seeing was indicative of a resistance in the rotation of the joint," Kerrick said. "So the things we want to look for, we want to inspect all the mechanical components to make sure they're not wearing unevenly or somehow breaking up and causing this resistance. We would also want to investigate the potential for having a debris impact.
"So what we have been doing in a series of EVAs leading up to this (is) opening covers, because all those mechanical components are underneath thermal covers. So you open up the cover and inspect the mechanical components and then you also inspect the cover for potential debris strikes. So we've done pieces of that and for this EVA, there are five covers left - there's 22 covers total in the SARJ - so five left to go. And then we're going to go off and re-inspect one particular area."
Pictures taken during a January spacewalk showed a small area on the race ring that might be a pit or depression.
"We couldn't tell if it was damage or if it was buildup of material," Kerrick said. "So we want the crew to take a second look there because the answer to that question will help us narrow down the scope of potential problems that could be causing this."
Assuming an on-time start, the spacewalk will end around 11:53 p.m. Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision J of the NASA television schedule):
02:40 PM, 3/21/08, Update: Heat shield inspection on tap (UPDATED at 12:30 AM with completion of heat shield inspection)
The Endeavour astronauts carried out a final heat shield inspection Friday and prepared for a final spacewalk Saturday night to mount the shuttle's inspection boom on the space station's solar power truss for use by the next station assembly crew.
Shuttle crews normally carry out so-called "late inspections" after undocking from the station. But the next assembly mission, scheduled for launch in late May, will deliver Japan's huge Kibo laboratory module to the station and there's not enough room in the shuttle Discovery's cargo bay for the module and an inspection boom. So Endeavour' boom will be mounted on the station during a fifth and final spacewalk Saturday and left behind for Discovery's crew to use and bring home.
"We had an absolutely fantastic day today," said lead shuttle Flight Director Mike Moses. "This is something we've been working on for a very long time, a lot of people on the ground spent a lot of time getting this docked late inspection ready to go. The crew executed perfectly. They actually went faster than we thought.
"The starboard wing (inspection) was a brand new procedure and we literally started by scanning up on top of it and then pulling the arm the whole way out, underneath the orbiter, sticking it under the belly and scanning the bottom half. So that was a very complicated set of maneuvers and to sequence all that together went fantastic."
The data collected during the inspection will be analyzed on the ground to make sure Endeavour's critical nose cap and wing leading edge panels have not been struck by orbital debris since a similar inspection the day after launch. Assuming no problems are found, 50-foot-long inspection boom will be mounted on the station's solar power truss.
"That sensor boom is going to be left on station because the following mission is going to deliver the next portion of the Japanese laboratory," said spacewalker Robert Behnken in a NASA interview. "That module is a very large module and thereÕs actually not room in the shuttle payload bay to launch both that module and this sensor boom on the same shuttle flight.
"So to provide the inspection capability to allow that next shuttle mission to be able to inspect their thermal protection system before they come back for re-entry, theyÕre going to need to have a sensor boom. They canÕt bring their own and so our flight is going to do an inspection late in the mission and then weÕll stow the boom during our EVA 5 on the ISS and hook up the power to it and itÕll be all ready for those guys when they actually arrive and install the Japanese module."
Behnken and his crewmates were awakened today by a recording of Metallica's "Enter Sandman" radioed up from mission control.
"Good morning Endeavour. And good morning to you, Dr. Bob," astronaut Al Drew called from Houston.
"Good morning, Alvin. I hope everything's going great down there," Behnken replied. "Thanks for that great wakeup music and I'd like to thank my fiance for choosing that for me. I just want to tell her I miss her and I can't wait to get back and see her here in a couple of days."
"Thanks for the good words, Bob. The music has got us awake down here, I'm sure that shook you out of bed as well."
"It did, Al. Thanks!"
Along with carrying out the late heat shield inspection, the astronauts also plan to move an experiment rack from the U.S. Destiny laboratory to the European Space Agency's new Columbus research lab. The work will take about four hours to complete.
"Four hours seems like a long time to move a rack from one location to another," said station Flight Director Ginger Kerrick. "This is a special rack, it has an active rack (vibration) isolation system and there are a lot of individual pieces of hardware that the crew is going to have to remove in order to (move) that rack. A standard rack relocation, you would power down the rack, you would remove all the electrical connectors, you'd remove all the thermal connectors, the vacuum system connectors. But this rack has all those additional pieces of hardware that are designed to isolate the experiments inside from the effects of any (vibration) that may be going on in the space station, for example, running on the treadmill or using the exercise bike."
Another rack will be moved later in the mission.
In one other bit of news, Kerrick said engineers are still looking into a glitch involving the Canadian Space Agency's Dextre maintenance robot. During testing after the robot's assembly, one of its joints did not operate as expected.
"We positioned arm 2 of the SPDM (special purpose dexterous manipulator) in a good location that would provide the EVA crew access to remove the thermal cover on (the hand of) arm number two," Kerrick said. "After we repositioned the arm, we sent the crew to bed and the ground team proceeded with performing some checkouts that were not performed when we originally relocated SPDM to the lab. And that check out was to test out an alternate power path through the PDGF (lab power and data grapple fixture). We have a primary path and an alternate. We had powered up on the primary and just wanted to make sure the alternate power path worked.
"Well, the alternate power path did work. But when we repowered up the SPDM, the shoulder roll joint on its arm number two did not know what position it was in. And this was the exact same joint we had just repositioned for the EVA. We power cycled again and were not able to talk to it. The software gave us the message 'unknown position.' We have some diagnostic tests we can run to help us figure out where inside that roll joint the problem is occurring. But we can't run the diagnostics test until we clear that message. So our CSA counterparts are off investigating whether or not we can uplink a software patch that will clear that message for us so we can run the appropriate diagnostics test.
"But for right now, we had no other planned use of the arm. It was in a good config for the EVA. ... So still more work to be done on that, but no impact to the mission."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision I of the NASA television schedule):
05:00 AM, 3/21/08, Update: Shuttle external tank production issues slow delivery; launch delays possible
With the shuttle Endeavour's mission entering the home stretch, shuttle Discovery remains on track for blastoff May 25 to ferry a huge Japanese laboratory module to the international space station. But subsequent near-term flights, including a high-profile mission to service the Hubble Space Telescope, face possible delays, sources say, because of ongoing external tank production issues.
The tank used by Endeavour for its current mission was the last in the inventory of tanks built before the 2003 Columbia disaster and subsequently modified to reduce potentially dangerous losses of foam insulation. The tank slated for use with Discovery in late May, ET-128, is the first so-called "in-line" external tank built from the ground up with post-Columbia upgrades, including a new ice-frost ramp design and titanium oxygen line support brackets. Both improvements address areas of possible foam shedding.
ET-128 departed Lockheed Martin's Michoud Assembly Facility in New Orleans Thursday for the 900-mile barge trip to the Kennedy Space Center in Florida.
But a backlog of work at Michoud is hampering downstream tank deliveries. The tank that would be needed for a rescue mission should some mishap strand Discovery's crew in orbit is not expected to reach the Kennedy Space Center until late summer. NASA managers say the space station has enough supplies on board to support a combined crew for more than three months if necessary and as of this writing, Discovery's launch remains on track.
But the picture is cloudier for NASA's next shuttle flight, a mission by the shuttle Atlantis to service the Hubble Space Telescope. Launch currently is targeted for Aug. 28. ET-127, the tank designated as the emergency backup for Discovery's May mission, is the prime tank for the Hubble flight.
Safe haven aboard the space station is not an option for Atlantis' crew if major heat shield damage occurs. The observatory and the station are in different orbits and the shuttle does not have the ability to move from one to the other. As a result, NASA Administrator Mike Griffin early on approved plans to have a second shuttle, Endeavour, ready for launch on a rescue mission just in case.
That means NASA needs two ready-to-fly external tanks for the Hubble mission, ET-127 and ET-129 respectively. Manpower and production issues, triggered in part by unplanned work to upgrade low-level hydrogen fuel sensors and other post-Columbia design upgrades, have slowed external tank manufacturing and sources say the Hubble mission faces a possible delay to October.
Senior program managers visited Michoud for a first-hand look earlier this week and a more realistic assessment of the tank production schedule is expected in the next week or so. For now, the Hubble mission remains officially targeted for launch Aug. 28.
Shuttle Program Manager John Shannon told CBS News Thursday that NASA has "added many new features to further ensure the safety of this tank and since these were the first in-line tanks, we took extra time to make sure we got it right."
"We have margin in the schedule to absorb small delays and we have learned a lot in the process of putting these tanks together so that the '09 and '10 tanks will flow much faster," he said.
Shannon did not address specific launch dates.
NASA plans to complete the space station and retire the shuttle by the end of fiscal 2010. The current manifest calls for four more flights this year - in May, August, October and December - four in 2009 and up to three in 2010.
12:40 AM, 3/21/08, Update: Spacewalk ends (UPDATED at 04:10 a.m. with mission status briefing)
Astronaut Bob "Bam Bam" Behnken and Michael "Dr. Goo" Foreman wrapped up a six-hour 24-minutes spacewalk early today, successfully replacing a faulty circuit breaker and testing a promising heat-shield repair technique, one of the final steps in NASA's recovery from the Columbia disaster. The tile repair demonstration went smoothly and while a complete assessment will require detailed post-landing analysis, the astronauts and NASA managers were pleased with the results.
"This was a huge success for a lot of people on the ground, a lot of people on the space station," said Zeb Scoville, lead spacewalk officer at the Johnson Space Center in Houston. "We're just thrilled with the way it turned out."
Efforts to develop viable heat shield repair options in the wake of the 2003 Columbia disaster were "a monumental effort that has been going on for years by hundreds of people, literally, to develop the tools and the techniques to be able to pull off this tile repair test," Scoville said.
"I remember in 2003, shortly after the Columbia accident, they hadn't really figured out what the root cause was of the accident. And there was an EVA officer at the time who leaned over to me and said, 'Zeb, regardless of what happens, we're going to have to figure out a way to repair tiles.' And now this person is the ISS lead flight director sitting right next to me."
He was referring to Dana Weigel, lead space station flight director for Endeavour's mission.
"For many years she worked as one of the lead operations officers trying to develop this technique and the tools and the repair capability, along with just hundreds of people in engineering and the contractor world, developing the materials and making sure the material's properties were correct," Scoville said. "So I really salute everyone involved. I feel it's a little unfair for me to sit up and talk about what a great success it was without really giving them as much credit as I possibly can. I congratulate them all on a huge success."
Behnken and Foreman tested a pressure-drive gun-like applicator and a heat-resistant two-compound material known as STA-54, squirting the pink goo into deliberately damaged or scooped-out heat shield tiles mounted on a sample board. On Earth, bubbles that form when the compounds mix and flow out of the applicator rise to the surface. Engineers worried that in the space environment, the bubbles would be more evenly distributed, causing the STA-54 to swell like a rising loaf of bread.
That could cause problems if the repair material bulged out beyond the surface of surrounding tiles because it could disrupt airflow during re-entry and cause extreme downstream heating.
But the material proved relatively easy for the spacewalkers to manage and swelling, while present, was not extreme.
"I'm thrilled with what we saw today," Weigel said. "In fact, I actually thought the material would swell quite a bit more than it did. It behaved very similar to what we've seen on the ground. That gives me a lot of comfort. We've done a lot of testing in the vacuum chamber, so we do have a lot of experience with the off gassing and what that looks like, both while we're manipulating the material and also post repair.
"My expectation is when we get this material to the ground and cross section it, we'll find that everything with the material's performance is very much in family with all the testing that we've done. We learned a lot in terms of validating what we've done on the ground. But we really didn't have any big surprises. So I'm confident that it performed very well and as we expected it to."
Behnken and Foreman also completed two get-ahead tasks, freeing launch locks on two Harmony module ports and removing a thermal cover from the Canadian Space Agency's Dextre maintenance robot. Foreman also inspected one of the robot's joints that did not operate properly after power was turned off and back on. Engineers don't yet know what the problem is, but Weigel said they are working to resolve the issue.
The spacewalkers were unable to unplug a stuck electrical connector from a patch panel in the station's Z1 truss that would have re-routed power to one of four control moment gyroscopes. CMG-2 and CMG-3 were wired into the same circuit in the wake of an earlier failure and the cable change today was needed to hook CMG-2 back up to its own power supply, restoring lost redundancy. As it now stands, a single failure could take out both CMGs, a situation NASA wanted to correct.
The astronauts made two attempts to free the connector. Working in the so-called "rat's nest" where dozens of cables are routed to various station systems, Foreman made an initial attempt early in the spacewalk and Behnken had another go at it toward the end of the excursion. But the connector refused to budge.
Weigel said the CMGs were left in the same state they've been in for several years and that there was no pressing urgency to rectify the situation.
This was the 108th spacewalk devoted to station assembly and maintenance since construction began in 1998 and the fourth of five planned for Endeavour's mission. The crew's cumulative EVA time now stands at 27 hours and 26 minutes. Total station EVA time through all 108 spacewalks is 681 hours and nine minutes.
Behnken and Foreman plan a fifth and final spacewalk - the third for each astronaut - Saturday evening.
10:00 PM, 3/20/08, Update: Heat shield repair tests go smoothly
Astronaut Michael Foreman earned some of the more unusual kudos in spacewalking history this evening during tests of a new heat shield repair technique. Filling deliberately damaged tiles with a thick pink toothpaste-like material, "Mr. Goo" was praised his skill as a "tile and grout specialist," a "brain surgeon" and a "Rembrandt" for his deft work.
After testing a pressure-driven caulk gun-like applicator, Foreman, assisted by Robert Behnken, began filling various cavities in a tile sample board mounted on the bottom of the Destiny laboratory module.
"Looking for a success here," Foreman said as the work began.
"You are Capt. T-RAD, Mr. Goo," Richard Linnehan replied from inside the shuttle Endeavour. "You're in control today."
The repair material, known as STA-54, looks like pink silly putty. It is made up of two compounds that are mixed together in a pressure-driven applicator gun just before they exit the nozzle. The gun, called a tile repair ablator dispenser, or T-RAD, was operated by Foreman, wearing an STA-54 reservoir attached to the bottom of his spacesuit's emergency jetpack.
One of the compounds making up STA-54 causes bubbles to form. On Earth, those bubbles typically rise to the top. During this evening's test in the absence of air or gravity, the bubbles tended to spread throughout the material causing it to bulge slightly in a phenomenon known as "bread loafing."
Too much bulging could cause the material to swell up over the surface layer of surrounding tiles, disrupting air flow during re-entry and causing excessive downstream heating. Based on this evening's tests, though, the STS-54 appeared to behave more benignly. While bubbles formed, the astronauts were able to use pads to tamp the material down and as the STA-54 "set up," the swelling seemed to diminish.
"You're going to be our tile and grout specialist," Linnehan said at one point as Foreman worked the material in a cavity.
"I hope we don't need one," Foreman said.
Later, he said "I can see the bubbles under the surface, those little nodule-type bubbles, they're still forming in the material but it's not building as much as it was. ... It's still bread loafing, but it seems like when I hit it with the tamping it doesn't bounce back quite as quickly or as much."
"And for Houston, we're pretty happy with how things are going," Linnehan called to flight controllers in Houston. "These guys are doing a great job and the material is reacting in a very, I guess, tame way."
"Endeavour, Houston, EVA," Steve Robinson replied from mission control. "We are absolutely captivated by what you guys are doing here. It's like brain surgeons up there."
"You hear that Mike? You're a brain surgeon," Linnehan said.
"I've never been called that before."
"Probably never will be again," Linnehan agreed.
Wrapping up the work, Behnken added: "Mike, you're a regular Rembrandt. I think he was a brain surgeon."
"I'm sure not every work was a masterpiece," Foreman said.
"This is."
Foreman and Behnken finished the tile repair demonstration well ahead of schedule.
After cleanup, the astronauts were expected to make another attempt to free a stuck electrical cable on a patch panel on the space station's Z1 truss. Foreman attempted to move the cable to a different connector after a circuit breaker was replaced earlier in the spacewalk. The goal was to reconnect one of the station's four gyroscopes, CMG-2, to its own power supply. Without the cable swap, CMGs 2 and 3 remained connected to the same circuit. A failure in that circuit could take out both CMGs, a condition NASA wants to rectify with the cable swap.
07:05 PM, 3/20/08, Update: Circuit breaker replaced; stuck electrical connector prevents cable change
Astronaut Robert Behnken replaced a faulty space station circuit breaker today but fellow spacewalker Michael Foreman was unable to disconnect an electrical cable as part of a patch panel reconfiguration. As a result, flight controllers were not immediately able to switch one of the station's four stabilizing gyroscopes back to its own power supply as planned.
Before beginning the patch panel work, Foreman reported an apparent strike from a micrometeoroid on a tool box door.
"And Rick, I don't know if you can see this from up here, but on the port door, lower hinge, there's a nice crater right there by my right index finger," Foreman radioed.
"We do see that Mike, and it's good you're doing this inspection," Richard Linnehan called from inside the shuttle. "I didn't pick that up in the dark."
"Yeah, that looks like a direct hit from something else," Foreman observed.
A few minutes later, both spacewalkers ran into problems. Behnken wasn't initially able to get the failed circuit breaker, known as a remote power control module, or RPCM, out of its slot in a rack in the S0 truss; and Foreman was unable to disconnect a cable from an electrical patch panel as required.
"The (connector-locking) bale is past the over center, all the way back," Foreman radioed.
"Houston, do you think it's worth a cycle on the bale, back and forth, would that help, maybe, loosen it?" Linnehan asked.
"I think where it clicks in there, it's just not coming out," Foreman said. "Can I tap it with a waist tether or something?"
"And Rick, I've also got eight turns in there," Behnken joined in. "The RPCM did move to the unlock position, but it still seems to be engaged."
A few minutes later, however, he managed to pull the RPCM out of its slot.
"Bob, good work, I see you got that RPCM out now," Linnehan radioed.
"Yeah, I just kept wiggling it," Behnken said. "It was a little ornerier than I thought it would be."
Foreman, meanwhile, was still having problems with the stuck cable connector.
"Send Bam Bam up here!" he said, referring to Behnken. Behnken was on his way back to the airlock to retrieve the equipment needed for a heat shield tile repair demonstration.
Foreman made several more attempts to free the cable before Flight Director Dana Weigel, a former spacewalk planner, decided to call of the effort and to leave the connector in place.
"Endeavour, Houston, for EVA. We can see MIke trying his absolute best," astronaut Steve Robinson radioed from Houston. "We think at this point, if you guys concur, that it's time to re-throw the bale, put the cap back on and move on to greener pastures."
"Sounds good, Steve. Sorry about that, guys," Foreman replied.
"Good work, Mike, thanks for sticking with it that long," Linnehan said.
Lead Flight Director Mike Moses said one of the goals of the RPCM swap-out and cable reconfiguration was to restore lost redundancy to control moment gyro No. 2, one of four used to stabilize the space station and change its orientation as required. Because of the earlier RPCM failure, CMG-2 was tied into the power circuit supplying CMG-3.
"Both are being fed by one unit so if that one failed, it would take down two CMGs," Moses said earlier today. "We prefer them to each be on their own to provide redundancy.
6:10 PM, 3/20/08, Update: Spacewalk No. 4 begins
Running 24 minutes ahead of schedule, astronauts Robert Behnken and Michael Foreman, floating in the Quest airlock module, switched their spacesuits to battery power at 6:04 p.m. to officially kick off a six-and-a-half-hour spacewalk. The goals of the excursion are to replace a faulty space station circuit breaker and to test a shuttle heat shield repair technique.
After a half-hour setting up tools and tethers, the astronauts will split up for the circuit breaker swapout. Behnken will release the faulty electronic unit in the station's S0 solar power truss segment while Foreman reconfigures an electrical patch panel to restore redundant power to one of the station's stabilizing gyroscopes.
That work should take about an hour to complete. The rest of the spacewalk will be devoted to testing a caulk gun-like tool designed to help astronauts repair damaged heat shield tiles. See the 2:20 p.m. CBS News STS-123 Status Report for complete details.
2:20 PM, 3/20/08, Update: Astronauts set for heat shield repair test
Astronauts Robert Behnken and Michael Foreman are gearing up for a six-and-a-half-hour spacewalk today to replace a faulty space station circuit breaker and to test a new heat shield repair technique that represents one of NASA's final post-Columbia safety upgrades.
"I consider it to be kind of the last thing we're going to do on the return to flight tile and (wing leading edge) repair tasks that we took on," said shuttle Program Manager John Shannon. "We have high confidence in it, but this will just be the final activity that we'll do to verify that's indeed a good repair capability."
NASA plans to launch the shuttle Atlantis in late August on a final Hubble Space Telescope servicing mission, a flight that cannot take advantage of safe haven aboard the space station if major heat shield damage occurs. While a second shuttle will be standing by if a rescue mission is required, a successful test today would give NASA added confidence about dealing with any heat shield damage that might occur on the Hubble mission or any other shuttle flight.
This will be the 108th spacewalk devoted to station assembly and maintenance since construction began in 1998, the ninth so far this year and the fourth of five planned for Endeavour's crew. For identification, Behnken, call sign EV-1, will wear a white suit with no markings. Foreman, EV-2, will wear a suit with broken red stripes around the legs.
The spacewalk is scheduled to begin at 6:28 p.m. The first item on the agenda is to replace the faulty circuit breaker, known as a remote power control module, or RPCM. As it now stands, two of the station's four control moment gyroscopes, or CMGs, are tied to a single RPCM. By replacing the faulty unit, the astronauts will restore lost redundancy.
But to do that, flight controllers first must power down numerous station systems, including one of the lab's two external ammonia cooling loops.
"Right now, CMG-2 and I think it's CMG-3 are both hooked up to a single RPCM," said lead flight director Mike Moses. "Both are being fed by one unit so if that one failed, it would take down two CMGs. We prefer them to each be on their own to provide redundancy.
"The power downs that are required, a good analogy is if you're about to go do electrical work in your house and change out an outlet, you want to turn the circuit breaker off upstream. This IS the circuit breaker, so we have to go one step further and take down the power distribution units upstream, which feed power to a whole lot more than just this bank of circuit breakers. We require two inhibits, so we have to take two things upstream down to verify that the EVA crew will be safe while they're working with this hardware."
Behnken will change out the circuit breaker in the central S0 solar array truss segment while Foreman moves to the Z1 truss atop the central Unity module to reconfigure an electrical patch panel.
With the RPCM installed, flight controllers will reactivate the powered down systems while Behnken and Foreman make their way back to the Quest airlock module to retrieve the equipment needed for the heat shield repair test. The work will be conducted on the bottom of the Destiny laboratory module.
"We'll actually take a couple of bags of equipment with us, all the things that you might have in your garage if you were going to do some spackling and some dry-wall repair," Behnken said in a NASA interview. "We'll have that stuff in the bag. We'll have scrapers and brushes and all that sort of equipment. We'll also have some engineering equipment. If you wanted to really understand how well of a repair job you're doing, we're taking some thermometers and a camera and things like that so that we can actually assess the progress of the repair material and our repair technique and see how we're doing with it."
The repair material, known as STA-54, looks like thick, pink silly putty. It is made up of two compounds that are mixed together in a pressure-driven applicator gun just before they exit the nozzle. The gun, called a tile repair ablator dispenser, or T-RAD, will be operated by Foreman, wearing an STA-54 reservoir attached to the bottom of his spacesuit's emergency jetpack.
"Mike Foreman will get in a foot restraint to give him good reach and access and restraint while he's working," said Moses. "He'll be the one actually dispensing the goo into the samples. Bob Behnken will be there to assist with cleanup and handing tools back and forth as he needs them."
Foreman will fill in a variety of cavities in a tile sample board. The astronauts will use pads and brushes to smooth the material out before it cures and hardens.
Some of the cavities were machined while others represent actual foam impact or ice damage. Engineers will dissect the repaired tiles after they are returned to determine the mechanical properties of the material, it's ability to adhere to the underlying tile and how much it swells due to bubbles that form when the materials are mixed in the gun just before application.
"There are a number of different sizes and shapes of samples and really, this correlates to the different objectives we're trying to get out of this test," said Zeb Scoville, the lead spacewalk planner. "Some of of our tests are going to be involving a study of the material itself, how it adheres to tile substrates, how it expands, if it bubbles, what sort of density it's going to have. Other objectives of this test are really to focus on how well the crew can operate and perform. It's one thing to be able to repair a very evenly machined sample. It's another thing to have a divot or pock mark that's been cut by an ice impact or foam damage. So we've modeled a couple of tile damage samples to represent things we've seen on previous missions or on ground testing.
"There's really one main reason why we're trying to perform this test," Scoville said. "On the ground, we were able to develop techniques in a vacuum chamber to see how the material would react and then we performed tests on NASA's zero gravity airplane to understand how the repair process works in a zero gravity environment, albeit for a short period of time. But being able to combine both the vacuum and the zero gravity aspects of these together is what we're trying to figure out here."
When the two compounds making up STA-54 are mixed, a chemical reaction causes bubbles to form. On Earth, those bubbles typically rise to the top. In space, they may be more evenly distributed throughout the material. This is a critical question because it could affect the material's ability to protect damaged tiles from the heat of re-entry.
"One of the big questions we have, in zero gravity are those bubbles going to rise to the surface or are they going to act more like a bread loaf as it bakes with the gas expanding in the material and being evenly distributed bubbles that then cause the surface to rise up over the top?" Scoville explained.
If the "bread loaf effect" causes the material to swell up above the surface of the surrounding tiles, it could disrupt the airflow across the belly of the shuttle during re-entry, causing more severe downstream heating.
"The surface smoothness is a big key in understanding how this will react during a re-entry scenario," Scoville said. "If you have a lot of bubbles and expanded ridges and what not, this can disrupt the airflow ... and cause a turbulent flow transition, which can cause downstream heating and damage the orbiter on re-entry. So being able to understand how this material's going to react and expand and what we can do to control that is really one of our primary objectives of this test."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision G of the NASA television schedule):
10:00 PM, 3/19/08, Update: Astronauts take a break (UPDATED at 10:00 p.m. with CBS News interview)
Midway through a grueling 16-day mission, the Endeavour astronauts and their space station counterparts enjoyed a second half-day off today, taking a call this evening from Japan's prime minister and fielding questions from reporters before gearing up for a fourth spacewalk Thursday.
In an interview with CBS News, station commander Peggy Whitson said the time off was a welcome break.
"We're having a great time, taking a break, just relaxing a little bit," she said. "I think we really needed it. For the station guys and for the shuttle guys, we had to do a pretty big sleep shift to get to this time, to (get in synch) with the launch and the landing and everything. So it was nice to be able to get eight hours of sleep."
The Endeavour crew gave flight engineer Garrett Reisman a lift to the space station. He will remain behind when the shuttle undocks next Monday night and European Space Agency astronaut Leopold Eyharts will return to Earth in his place after a month and a half in orbit.
Asked to describe the fast-growing space station, Reisman said the crew was struck by the view during final approach and similarities with the famous space station scene in the movie "2001: A Space Odyssey" by Stanley Kurbrick and Arthur C. Clarke. Clarke died Tuesday at the age of 90.
"It's interesting you should bring that up," Reisman said. "As we were rendezvousing, a bunch of us commented about that movie and how much the view out the window of the space station approaching, all we needed was 'The Blue Danube' playing in the background and it would have been just like the movie.
"Coming in from the shuttle, which is relatively small volume, it was pretty overwhelming. It's amazing how big station is, it's about the same size from stem to stern as a Boeing 767 and it's been astonishing to me how long it takes just to get from one end to the other. It's so big, you actually have to plan how you carry your stuff around because if you have to go back and get something, it takes time. And that's really marvelous."
For his part, Eyharts said he's looking forward to seeing his family again. And returning to a bit more relaxed life style.
"Of course, I'm looking forward to seeing my family after seven weeks on board the station," he said. "It has been a relatively short flight for a (station crew member), but very busy, with two shuttle flights and a lot of work with Columbus. So I'm looking forward also to having a little bit of rest and kind of a normal life back on Earth."
Linnehan, veteran of three spacewalks during Endeavour's mission and three during a 2002 Hubble Space Telescope servicing flight, provided an interesting insight into what it's like to walk in space.
"We were talking about this yesterday. I feel really lucky to have had the opportunity to have gone to Hubble and now the station," he said. "You know, we talk about 'spacewalks' but it's a bit of a misnomer. It's more like space floating. You're really not out there walking. I guess the best analogy I can tell everybody is, if you can imagine yourself scuba diving in a suit of armor, that's about what spacewalking is like."
The astronauts were awakened for their 10th "day" in space around 1:40 p.m. by a recording of Elvis Presley's "Burning Love" radioed up from Houston.
"Good morning, Endeavour, these were words from the 'King' for another sort of king, I guess, captain, U.S. Navy, MIke Foreman," radioed Canadian astronaut Julie Payette. "Good morning to you all."
"Good morning, Houston, and thank you Elvis," Foreman replied. "And I especially want to thank my wife, Lorrie, whom I've been with for a long time and I still have a burning love for her. I couldn't do it without you."
The Canadian Space Agency's Dextre maintenance robot, now fully assembled and mounted on the Destiny lab module, is in good shape and ready for use when needed. Station Flight Director Ginger Kerrick said one minor glitch during testing Tuesday, when the robot's waist joint turned the opposite direction from what controllers expected, can easily be fixed with a software patch.
"It is on its new temporary home on the lab," Kerrick said. "I say temporary, but it'll stay there until we have a planned use for it. Right now, we don't have a planned use for it until the 2 J/A mission sometime next spring. It's in great shape. You may have heard about some software funnies as we attached it to the lab yesterday. We have taken a look at that, we understand what happened and it's just going to take a quick fix, nothing to worry about and no concerns for future operations."
Work with the mission's other major payload, a Japanese equipment storage room now attached to the station's Harmony module, also is complete, as are a variety of get-ahead tasks. The storage module ultimately will be attached to Japan's huge Kibo pressurized laboratory module, scheduled for attachment to the station in late May.
"There's not a whole lot of exciting things to tell you about that right now," Kerrick said of the logistics module. "They are done. They were pretty much done with the setup yesterday, not only on the activities that were scheduled for this docked mission, but also for the activities that were scheduled after the shuttle left, before the arrival of the next shuttle. So you'll see a couple of five- to 10-minute activities on the timeline but it's really just to take pictures and to document the configuration that it's in."
Japanese astronaut Takao Doi, Whitson and shuttle commander Dom Gorie chatted with Japanese Prime Minister Yasuo Fukuda this evening, showing off the newly attached logistics module and answering questions from school kids.
"Doi-san, thank you for the hard work. Congratulations on the completion of the first stage of (the attachment of) Kibo," Fukuda said in Japanese. "Congratulations. Doi-san, for a very long time have been engaged in this project. How do you feel now, the fact that you've completed the first step, what is your impression? What are your thoughts?"
"Hello, prime minister, from space station," Doi replied. "Kibo module is filled with the dreams of the Japanese people. I'm very happy to be able to complete the first step, the attachment. People on the ground have been working hard supporting us up in space and we thank all of you very much indeed."
Said Whitson: "It's been a very special honor to me to welcome JAXA (the Japanese space agency) officially aboard the space station with the addition of this module. We are very happy to have Kibo up here with us."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision G of the NASA television schedule):
4:00 PM, 3/18/08, Update: Astronauts work through busy day of robotics (UPDATED at 11:55 p.m. with Dextre, pallet moves; mission status briefing)
The Endeavour astronauts carefully moved the Canadian Space Agency's 3,400-pound Dextre robot from its assembly pallet to a long-term mounting point on the space station's Destiny laboratory module today. The robot's construction pallet was then moved back to the shuttle's payload bay for return to Earth.
"They have successfully reconfigured and stowed the robotic arms of Dextre and Dextre is now grappled to the lab, which is where it will remain for the next several weeks," said station Flight Director Kwatsi Alibaruho. "The significant robotics activities today, the stowing of Dextre and the relocation of the Spacelab pallet, are the major activities on the crew's timeline.
The astronauts will enjoy a few hours of off-duty time early Wednesday and another break Wednesday afternoon before beginning preparations for a fourth spacewalk Thursday.
"One of the things that we've had to really manage with these crews, this shuttle crew and this station crew particularly, is that they're so efficient and so motivated. ... We've been working them at a pretty good pac e and they've gotten very far ahead on the activities that were prescribed for this mission. ... They've gotten far enough ahead that we certainly won't have to twist their arms too much to get them to rest tomorrow."
Getting the special purpose dexterous manipulator built and tested has taken up most of the crew's time through the first half of the 16-day mission. Prior to installation on the Destiny module today, the astronauts and flight controllers completed a series of tests to make sure the robot's multi-joint arms, grapple fixtures and television system were working as expected.
The only issue today cropped up when commands were sent to rotate the robot's waist joint. The joint moved in the opposite direction from what flight controllers expected. Alibaruho said engineers suspect an incorrect sign in a configuration file may be to blame and they are optimistic a simple software patch will resolve the matter. Otherwise, the robot operated as expected.
Dextre's components were carried into orbit mounted on a Spacelab pallet. The SLP was moved to an attachment point on the front of the station's solar power truss for the robot's assembly. After mounting Dextre on the Destiny module, the station arm, operated by shuttle pilot Gregory Johnson, locked onto the SLP and moved it back to the shuttle's cargo bay for return to Earth. The astronauts were assisted by camera views from the shuttle's robot arm.
After the Spacelab pallet was locked in the shuttle's payload bay, the flight plan called for the station arm to move back to the front of the solar power truss and lock onto its mobile transporter for a short trip to a different worksite.
During a spacewalk overnight Monday by Richard Linnehan and Robert Behnken, two space exposure experiment packages could not be attached to a mounting plate on the Columbus module because of interference issues with the pins needed to lock the first package in place. Mission managers today tentatively decided a second attempt will be made during the crew's fifth spacewalk Saturday.
To make time for the unscheduled work, the astronauts likely will forego mounting a bearing assembly on the station's right side solar alpha rotary joint, or SARJ. The starboard SARJ has been experiencing problems and is not being used to turn outboard arrays to track the sun. One of the bearings in the right-side SARJ was removed during an earlier mission and returned to Earth for analysis. But installation of a replacement, originally planned for the fifth spacewalk, is not a pressing issue and can be done later with no major impact to station operations.
"We took a look at that list of priorities and we determined there were a couple of tasks we could defer, one of which being the trundle bearing assembly installation," said station Flight Director Ginger Kerrick. "It's not required for the mission, it's not required for the time frame between this mission and the next and it provided an opportunity to re-arrange some activities on that day to allow a couple of hours for the installation of MISSE (the experiment packages)."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision G of the NASA television schedule):
EDT...........EVENT
..............Rev. 248 descent to KSC runway 15
01:58:00 PM...Begin deorbit timeline
02:13:00 PM...Radiator stow
02:23:00 PM...Mission specialists seat installation
02:29:00 PM...Computers set for deorbit prep
02:33:00 PM...Hydraulic system configuration
02:58:00 PM...Flash evaporator cooling system checkout
03:04:00 PM...Final payload deactivation
03:18:00 PM...Payload bay doors closed
03:28:00 PM...Mission control 'go' for OPS-3 entry software load
03:38:00 PM...OPS-3 software loaded
04:03:00 PM...Entry switchlist verification
04:13:00 PM...Deorbit maneuver update
04:18:00 PM...Crew entry review
04:33:00 PM...Commander/pilot don entry suits
04:50:00 PM...Inertial Measurement Unit alignment
04:58:00 PM...CDR/PLT strap in; mission specialists don suits
05:15:00 PM...Shuttle steering check
05:18:00 PM...Hydraulic power system prestart
05:25:00 PM...Toilet deactivation
05:33:00 PM...Vent doors closed for entry
05:38:00 PM...Mission control 'go' for deorbit burn
05:44:00 PM...MS seat ingress
05:53:00 PM...Single APU start
05:58:14 PM...Deorbit ignition (Alt: 215.2 sm; Vel: 17,251 mph; dV: 209 mph; dT: 2:51)
06:01:05 PM...Deorbit burn complete
06:33:06 PM...Entry interface (alt: 75.7 sm; Vel: 16,979 mph; range: 4,959 sm)
06:38:03 PM...1st roll command to left
06:52:00 PM...C-band radar acquisition
06:54:34 PM...1st left to right roll reversal
06:58:36 PM...Velocity less than mach 2.5 (alt: 83,000 ft; vel: 1,709 mph)
07:00:47 PM...Velocity less than mach 1 (alt: 51,100 ft; vel: 613 mph)
07:02:05 PM...Shuttle on the heading alignment cylinder
07:05:08 PM...Landing
..............Rev. 249 descent to KSC runway 15
07:13:14 PM...Mission control 'go' for deorbit burn
07:19:14 PM...MS seat ingress
07:28:14 PM...Single APU start
07:33:14 PM...Deorbit ignition (alt: 216 sm; vel: 17,251 mph; dV: 206 mph; dT: 2:48)
07:36:02 PM...Deorbit burn complete
08:07:23 PM...Entry interface (alt: 75.6 sm; vel: 16,979 mph; range: 5,055 sm)
08:12:18 PM...1st roll command to right
08:21:14 PM...1st right-to-left roll reversal
08:26:00 PM...C-band radar acquisition
08:32:34 PM...Velocity less than mach 2.5 (alt: 83,900 feet; vel: 1,704 mph)
08:34:46 PM...Velocity less than mach 1 (alt: 50,700 feet; vel: 613 mph)
08:35:32 PM...Shuttle on the heading alignment cylinder
08:39:06 PM...Landing
EDT........DD...HH...MM...EVENT
03/25/08
10:58 AM...14...08...30...Crew wakeup
01:53 PM...14...11...25...Orbit adjust rocket firing
01:58 PM...14...11...30...Cabin stow begins
02:28 PM...14...12...00...Flight control system checkout
03:53 PM...14...13...25...Reaction control system hotfire
04:08 PM...14...13...40...PILOT landing simulator practice
06:08 PM...14...15...40...Crew meals begin
06:33 PM...14...16...05...ESA PAO event
08:13 PM...14...17...45...U.S. media interviews
08:33 PM...14...18...05...Cabin stow resumes
08:33 PM...14...18...05...Entry video setup
09:28 PM...14...19...00...Launch/entry suit checkout
10:00 PM...14...19...32...Mission status briefing on NASA TV
10:28 PM...14...20...00...Recumbent seat setup
10:38 PM...14...20...10...Wing leading edge sensors deactivated
10:58 PM...14...20...30...Laptop computer teardown (part 1)
11:18 PM...14...20...50...KU-band antenna stow
11:28 PM...14...21...00...Deorbit review
03/26/08
02:58 AM...15...00...30...Crew sleep begins
03:00 AM...15...00...32...Daily video highlights
10:58 AM...15...08...30...Crew wakeup
12:58 PM...15...10...30...Group B computer powerup
01:13 PM...15...10...45...Inertial measurement unit alignment
01:58 PM...15...11...30...Deorbit timeline begins
05:58 PM...15...15...30...Deorbit ignition (rev. 248)
07:05 PM...15...16...37...Landing
EDT........DD...HH...MM...EVENT
03/24/08
11:43 AM...13...09...15...Crew wakeup
02:58 PM...13...12...30...Spacesuits transferred to shuttle
04:13 PM...13...13...45...Oxygen system teardown
05:13 PM...13...14...45...Farewell ceremony
05:28 PM...13...15...00...Hatch closure
05:33 PM...13...15...05...Group B computer powerup
05:58 PM...13...15...30...Leak checks
06:39 PM...13...16...11...ISS maneuvers to undocking attitude
06:42 PM...13...16...14...Sunrise
06:43 PM...13...16...15...Centerline camera setup
07:09 PM...13...16...41...ISS in undocking attitude
07:13 PM...13...16...45...Noon
07:13 PM...13...16...45...Undocking timeline begins
07:21 PM...13...16...53...US solar arrays in undocking configuration
07:23 PM...13...16...55...PMA-2 departure config
07:44 PM...13...17...16...Sunset
07:56 PM...13...17...28...UNDOCKING
07:58 PM...13...17...30...ISS holds attitude
08:01 PM...13...17...33...Range: 50 feet; reselect -X jets
08:03 PM...13...17...35...Range 75 feet; low Z
08:13 PM...13...17...45...Sunrise
08:25 PM...13...17...57...Range: 400 feet; start fly around
08:34 PM...13...18...06...Range: 600 feet
08:36 PM...13...18...08...Shuttle directly above ISS
08:40 PM...13...18...12...ISS in TEA attitude
08:44 PM...13...18...16...Noon
08:48 PM...13...18...20...Shuttle directly behind ISS
08:59 PM...13...18...31...Shuttle directly below ISS
09:11 PM...13...18...43...Separation burn No. 1
09:15 PM...13...18...47...Sunset
09:39 PM...13...19...11...Separation burn No. 2
09:43 PM...13...19...15...Post undocking computer reconfig
09:45 PM...13...19...17...Sunrise
10:28 PM...13...20...00...Group B computer powerdown
10:28 PM...13...20...00...PMA-2 leak checks
10:30 PM...13...20...02...Mission status briefing on NASA TV
10:58 PM...13...20...30...ISS crew sleep begins
11:03 PM...13...20...35...EVA unpack and stow
11:03 PM...13...20...35...Undocking videoi replay
11:28 PM...13...21...00...Shuttle arm (SRMS) powerdown
03/25/08
02:58 AM...14...00...30...Crew sleep begins
03:00 AM...14...00...32...Daily video highlights reel on NASA TV
The fly around, Dempsey said, is "a good chance for us to really view the space station all the way around."
EDT........DD...HH...MM...EVENT
12:28 PM...12...10...00...Crew wakeup
03:28 PM...12...13...00...Crews off duty
06:30 PM...12...16...02...Mission status briefing on NASA TV
08:18 PM...12...17...50...Joint crew meal
09:18 PM...12...18...50...EVA prep for transfer to shuttle
09:18 PM...12...18...50...Rendezvous tools checkout
11:18 PM...12...20...50...Joint crew news conference
11:58 PM...12...21...30...Joint crew photo
03/24/08
01:43 AM...12...23...15...RIGEX activation
03:13 AM...13...00...45...ISS crew sleep begins
03:43 AM...13...01...15...STS crew sleep begins
04:00 AM...13...01...32...Daily video highlights reel on NASA TV
09:30 AM...13...07...02...Flight director update on NASA TV
11:43 AM...13...09...15...Crew wakeup
For readers interested in looking ahead, the undocking timeline is posted on the CBS News STS-123 Quick-Look page, along with the latest NASA television schedule and an updated list of deorbit opportunities.
EDT........DD...HH...MM...EVENT
12:28 PM...11...10...00...Crew wakeup
01:08 PM...11...10...40...EVA-5: 14.7 psi repress/hygiene break
01:58 PM...11...11...30...EVA-5: Airlock depress to 10.2 psi
02:28 PM...11...12...00...EVA-5: Campout EVA preps
02:28 PM...11...12...00...Station arm (SSRMS) EVA-5 setup
03:48 PM...11...13...20...EVA-5: Spacesuit purge
04:03 PM...11...13...35...EVA-5: Spacesuit prebreathe
04:53 PM...11...14...25...EVA-5: Crew lock depressurization
05:23 PM...11...14...55...EVA-5: Spacesuits to battery power
05:28 PM...11...15...00...EVA-5: Airlock egress
05:33 PM...11...15...05...SSRMS grapples inspection boom (OBSS)
05:48 PM...11...15...20...EVA-5: Setup
06:03 PM...11...15...35...Shuttle arm (SRMS) releases OBSS
06:08 PM...11...15...40...EVA-5: OBSS KAU install
06:18 PM...11...15...50...OBSS handoff to spacewalkers
07:33 PM...11...17...05...Crew meals begin
07:43 PM...11...17...15...EVA-5: OBSS stow
08:58 PM...11...18...30...EVA-5 (EV1): MISSE experiment package install
08:58 PM...11...18...30...EVA-5 (EV2): Starboard SARJ inspection
11:08 PM...11...20...40...EVA-5: Cleanup
11:33 PM...11...21...05...EVA-5 Airlock ingress
11:53 PM...11...21...25...EVA-5: Airlock repressurization
03/23/08
12:08 AM...11...21...40...Post EVA spacesuit servicing
12:28 AM...11...22...00...SRMS powerdown
01:30 AM...11...23...02...Mission status briefing on NASA TV
03:58 AM...12...01...30...ISS crew sleep begins
04:28 AM...12...02...00...STS crew sleep begins
05:00 AM...12...02...32...Daily video highlights reel on NASA TV
09:30 AM...12...07...02...Flight director update on NASA TV
12:28 PM...12...10...00...Crew wakeup
EDT........DD...HH...MM...EVENT
03/21/08
01:28 PM...10...11...00...Crew wakeup
04:03 PM...10...13...35...Heat shield sensor boom (OBSS) starboard wing survey
04:43 PM...10...14...15...Logistics transfers resume
05:23 PM...10...14...55...Experiment rack 3 transfer
06:33 PM...10...16...05...OBSS laser scan downlink
07:43 PM...10...17...15...OBSS nose cap survey
07:43 PM...10...17...15...OBSS mounting bracket assembly
09:08 PM...10...18...40...Crew meals begin
09:13 PM...10...18...45...OBSS port wing survey
10:23 PM...10...19...55...EVA-5: Tool config
11:00 PM...10...20...32...Mission status briefing on NASA TV
11:18 PM...10...20...50...Airlock prep
03/22/08
12:18 AM...10...21...50...OBSS laser scan downlink
12:58 AM...10...22...30...EVA-5: Procedures review
02:43 AM...11...00...15...EVA-5: Mask pre-breathe/tool config
03:33 AM...11...01...05...EVA-5: Airlock depress to 10.2 psi
03:58 AM...11...01...30...ISS crew sleep begins
04:28 AM...11...02...00...STS crew sleep begins
05:00 AM...11...02...32...Daily video highlights reel on NASA TV
09:30 AM...11...07...02...Flight director update on NASA TV
12:28 PM...11...10...00...Crew wakeup
EDT........DD...HH...MM...EVENT
01:28 PM...09...11...00...Crew wakeup
02:13 PM...09...11...45...EVA-4: 14.7 psi repress/hygiene break
03:03 PM...09...12...35...EVA-4: Airlock depress to 10.2 psi
03:23 PM...09...12...55...EVA-4: Campout EVA preps
04:53 PM...09...14...25...EVA-4: Spacesuit purge
05:08 PM...09...14...40...EVA-4: Spacesuit prebreathe
05:58 PM...09...15...30...EVA-4: Crew lock depressurization
06:28 PM...09...16...00...EVA-4: Spacesuits to battery power
06:33 PM...09...16...05...EVA-4: Airlock egress
06:38 PM...09...16...10...EVA-4: Setup
06:58 PM...09...16...30...EVA-4 (Behnken): RPCM R&R
06:58 PM...09...16...30...EVA-4 (Foreman): Patch panel
07:28 PM...09...17...00...EVA-4: T-RAD worksite setup
08:48 PM...09...18...20...EVA-4: T-RAD demonstration
10:33 PM...09...20...05...EVA-4: Tool cleanup
11:13 PM...09...20...45...EVA-4: Payload bay ops
11:58 PM...09...21...30...EVA-4: Node 2 ACBM launch locks removal
03/21/08
12:18 AM...09...21...50...EVA-4: Cleanup
12:38 AM...09...22...10...EVA-4: Airlock ingress
12:58 AM...09...22...30...EVA-4: Airlock repressurization
01:13 AM...09...22...45...Spacesuit servicing
03:00 AM...10...00...32...Mission status briefing on NASA TV
04:58 AM...10...02...30...ISS crew sleep begins
05:28 AM...10...03...00...STS crew sleep begins
06:00 AM...10...03...32...Daily video highlights reel
10:30 AM...10...08...02...Flight director update on NASA TV
01:28 PM...10...11...00...Crew wakeup
EDT........DD...HH...MM...EVENT
03/19/08
02:58 PM...08...12...30...ISS crew off duty
04:28 PM...08...14...00...STS crew off duty
07:08 PM...08...16...40...Japanese VIP event
08:58 PM...08...18...30...CBS News, NBC News, WMUR-TV interviews
09:28 PM...08...19...00...Joint crew meal
11:00 PM...08...20...32...Mission status briefing on NASA TV
11:13 PM...08...20...45...T-RAD tile repair preps
11:58 PM...08...21...30...EVA-4: Tools configured
03/20/08
01:28 AM...08...23...00...EVA-4: Procedures review
03:43 AM...09...01...15...EVA-4: Mask pre-breathe/tool config
04:38 AM...09...02...10...EVA-1: Airlock depress to 10.2 psi
04:58 AM...09...02...30...ISS crew sleep begins
05:28 AM...09...03...00...STS crew sleep begins
06:00 AM...09...03...32...Daily video highlights reel on NASA TV
10:30 AM...09...08...32...Flight director update on NASA TV
01:28 PM...09...11...00...Crew wakeup
EDT........DD...HH...MM...EVENT
02:28 PM...07...12...00...Crew wakeup
04:28 PM...07...14...00...ISS daily planning conference
04:43 PM...07...14...15...Dextre arm 1 stow
05:13 PM...07...14...45...Cabin water line inspection
05:43 PM...07...15...15...Dextre arm 2 stow
06:13 PM...07...15...45...Module outfitting
06:43 PM...07...16...15...Dextre roll
06:43 PM...07...16...15...Retrieve jive boom
06:53 PM...07...16...25...Dextre stow on lab module
07:53 PM...07...17...25...C