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
5:35 PM, 6/16/08, Update: Pad repair likely will involve brick removal, application of spray-on Fondu Fyre
Engineers assessing extensive damage to launch pad 39A during the shuttle Discovery's May 31 takeoff said today they are confident the "flame trench" that diverts exhaust to either side can be repaired in time for NASA's next mission, the Oct. 8 launch of shuttle Atlantis on a flight to service the Hubble Space Telescope.
Repair options will be presented to shuttle Program Manager John Shannon on June 26, leaving about two months to complete the pad rehab before the planned Aug. 29 rollout of Atlantis.
"We feel we're on the right path for a design solution and we're working to get there," Perry Becker, chief of NASA's structural systems branch at the Kennedy Space Center, told reporters today. "We're working very extensively with a few vendors in industry, we're starting to put that plan together. ... We're confident, regardless of the scope of the work here, that we can repair this pad in time and support the rollout."
During Discovery's takeoff, some 5,300 heat-resistant bricks lining the northeast wall of the flame trench under the shuttle's mobile launch platform were blown away, some blasted more than 1,800 feet, heavily damaging a security fence around the pad perimeter. The interlocking bricks, held in place by epoxy and metal clips anchored in concrete, are used to protect an underlying 3-foot-thick concrete wall that helps form the structural backbone of the pad.
The missing bricks exposed an irregular area of the concrete wall measuring roughly 20 feet by 75 feet. New bricks cannot be manufactured in time to support the Hubble mission, but Becker said engineers believe the trench can be repaired by stripping away additional bricks around the damage area, erecting a steel mesh framework and then spraying on a thick coating of a refractory material like Fondu Fyre.
A five-inch-thick coating of Fondu Fyre currently covers the inverted V-shaped flame deflector that diverts main engine exhaust to one side of the pad and booster exhaust to the other. About 20 feet of the flame trench extending from the deflector on the booster side already is covered by Fondu Fyre, giving way to bricks. The idea would be to extend that coating to cover the areas damaged during Discovery's launching.
"We're certainly looking strongly at Fondu Fyre, we've got a history with it out here, we know its properties," Becker said. "There are a couple of other materials on the market that we're looking at, so we haven't down selected that definitively. But it is a leading candidate."
Despite the intense heat and pressure produced by the shuttle's solid-fuel boosters, Becker said the Fondu Fyre coating the flame deflector holds up well to the extreme heat and pressures produced by the shuttle's huge solid-fuel boosters.
"The erosion rate we would expect on the side walls (of the flame trench) would be very, very minimal based on some Fondu Fyre that we have up near the main flame deflector itself," he said. "That has performed very well."
It is not yet known how many more bricks will need to be stripped away or how large an area might ultimately be covered by Fondu Fyre, assuming program managers approve that approach.
"I like to talk about it as if you're redoing tile in your bathroom at your house," said Ed Mango, launch director for the Hubble servicing mission. "One tile gets loose, then you've got to chase it. This is a similar thing. The tile in your shower is there to protect the wall behind it. We have the brick here to protect the concrete behind it. Of course, the over pressure and the amount of water is much worse!"
Looking at trowel marks on the exposed concrete, engineers believe the epoxy used to help hold the bricks to the wall was not uniformly applied. So-called "tap tests" have revealed possible voids behind other sections of the flame trench where bricks are still in place.
"We have seen indications on the visibly damaged sections of trowel marks in some areas on the wall there that shows less than full engagement of the bricks to the back wall structure when it was originally manufactured," Becker said. "Certainly, that is one component of several possibilities of the root cause of failure."
Becker downplayed the question of whether the original construction was flawed, saying "there's no such thing as a perfectly vertical or smooth wall. So there are going to be voids and surface imperfections, that's common in the construction industry."
The Hubble crew cannot take advantage of "safe haven" aboard the international space station if Atlantis suffers any damage that might prevent a safe re-entry. As a result, NASA plans to have a second shuttle, Endeavour, ready for takeoff from nearby pad 39B if a rescue mission is required.
Both shuttle pads were built in the 1960s for the Apollo moon program and engineers are carrying out tests and inspections to assess the health of pad B.
"We're evaluating that state of pad B as we speak and if we find anything, we'll take the appropriate action," Becker said.
First used in 1967, pad 39A has withstood 12 Saturn 5 launchings, including the first Apollo moon landing mission, and 70 shuttle flights. Pad 39B, first used in 1969, supported one Saturn 5 launch, four Saturn 1B flights and 53 shuttle missions, including Challenger's final flight.
11:30 AM, 6/14/08, Update: Shuttle Discovery glides to Florida landing (UPDATED at 1:11 p.m. with crew exit from shuttle; quote from commander; UPDATED at 4:55 with crew news conference)
Commander Mark Kelly guided the space shuttle Discovery to a sun-drenched Florida landing today, setting down on runway 15 at the Kennedy Space Center to close out a virtually flawless space station assembly mission, leaving a new Japanese lab module behind and bringing flight engineer Garrett Reisman back to Earth after 95 days in space.
Strapped into a reclining seat on Discovery's lower deck, Reisman endured the uncomfortable return to the tug of Earth's gravity as Kelly deftly piloted Discovery to a tire-smoking touchdown at 11:15:19 a.m. Barreling down the 300-foot-wide runway at more than 200 mph, Kelly brought the nose down, Ham released a red-and-white braking parachute and the orbiter coasted to a halt.
"Houston, Discovery, wheels stopped," Kelly radioed in a traditional call to mission control.
"Roger wheels stopped, Discovery," replied astronaut Terry Virts in Houston. "Beautiful landing, Mark, and congratulations on a great mission."
"OK, Terry, thanks, great to be back," Kelly said. "It was great for all of us to be part of a big team that made the station a little bit bigger and a little bit more capable."
Mission duration was 13 days 18 hours 13 minutes and seven seconds, covering 217 complete orbits and 5.7 million miles since blastoff May 31 from nearby pad 39A.
"What an awesome sight to be able to watch the space shuttle land live here on board the space station," Gregory Chamitoff, Reisman's replacement, called down from orbit. "And What a beautiful landing! Congratulations to the entire team. It was a spectacular mission from end to end, practically flawless. We have a new 'hope,' the Kibo module, here on the space station and it's a great success."
With Discovery safely home, NASA will set its sights on readying the shuttle Atlantis for blastoff Oct. 8 on a long-awaited flight to service and repair the Hubble Space Telescope. It will be NASA's final visit to Hubble, launched from Discovery 18 years ago, and the only mission in the 10 remaining shuttle flights that doesn't go to the space station.
Key to making the Oct. 8 launch target is repairing the "flame trench" at pad 39A, which was heavily damaged during Discovery's liftoff.
NASA managers are optimistic the work can be done, but engineers have not yet completed their assessment of the damage. More than 5,300 Apollo-era firebricks lining the flame trench under the shuttle's boosters were blown out during Discovery's takeoff and the walls must be shored up before Atlantis can take off.
Because the Hubble crew cannot take advantage of "safe haven" aboard the space station if the shuttle suffers damage that might prevent a safe re-entry, the shuttle Endeavour will be processed for launch from nearby pad 39B to serve as a rescue vehicle if needed.
Assuming all goes well with Atlantis, however, Endeavour will be hauled to pad 39A and launched Nov. 10 on the year's final shuttle flight, a space station assembly mission to deliver critical supplies and Chamitoff's replacement, astronaut Sandy Magnus. Chamitoff will return to Earth aboard Endeavour after a six-month stay in space.
But for now, NASA managers, engineers and technicians were focused on welcoming Discovery's crew back to Earth after a virtually trouble-free mission.
Kelly, Ham, Reisman and their crewmates - flight engineer Ronald Garan, Karen Nyberg, Michael Fossum and Japanese astronaut Akihiko Hoshide - doffed their pressure suits and met managers and technicians on the runway about an hour and 45 minutes after touchdown. All looked fit and in good spirits, although Nyberg appeared a bit shaky as she readjusted to gravity.
"It's great to be here on the runway in sunny Florida and it's great to bring Discovery back in good shape," Kelly said. "We had a really exciting mission that from our point of view was very successful. We're really glad to have been involved in making the space station a bigger and more capable place."
Returning space station astronauts typically do not attempt to walk around on the runway after landing, but Reisman showed up in a blue flight suit, smiling and chatting with well wishers, moving carefully but looking relatively fit after three months in space.
In orbit, he joked about the advantages of being short, saying "my sensory organs are a little closer to my center of gravity and my heart has a little less distance to pump to my brain. I've been waiting my whole life and finally I think being short is going to come in handy!"
At a post-landing news conference late today, he said "I think maybe we're on to something here! We need to get more short people in the astronaut office."
"There's probably a variety of reasons I'm feeling a little better than I expected and I'm very happy about that," he said. "We have a very good countermeasures program now and I kept up with that rigorously when I was on orbit. There's a lot of variation from person to person, too. We don't know the science yet because we don't have enough data points, but we're working on that.
"But I think it's mostly because I'm short. I'm happy that's finally come in handy for something other than limbo contests! It's great to be here."
It typically takes returning station astronauts a month or so to get their land legs back and up to a full year to completely recover from the effects of weightlessness on bones and muscles. But judging by Reisman's appearance, it might not take that long this time around.
In orbit, he said his top priority after getting back to Earth was seeing his wife, Simone. She was waiting in crew quarters when the astronauts arrived after landing.
"The reunion was fantastic," Reisman said. "It was everything I was hoping for. She got a hair cut, actually, while I was gone. And so I hesitated for a moment as soon as the doors to the elevator opened up and I saw her. But it was fantastic, it was a very tender moment when I got a chance to go over and hold her again. It was really nice."
Reisman was launched to the station in March. He was replaced by Chamitoff, who joined Expedition 17 commander Sergei Volkov and Oleg Kononenko the day Discovery docked with the lab complex.
Along with swapping out the two U.S. flight engineers, Discovery's crew also delivered and installed Japan's 15-ton Kibo laboratory module and carried out three spacewalks by Fossum and Garan to outfit the lab; retrieve a shuttle heat shield inspection boom; install a nitrogen tank needed by the station's cooling system; and test techniques for cleaning contamination from a critical solar array drive gear.
10:15 AM, 6/14/08, Update: Shuttle braking rockets fired
Flying upside down and backward over the Indian Ocean, commander Mark Kelly and pilot Kenneth Ham fired the shuttle Discovery's twin braking rockets for two minutes and 34 seconds starting at 10:10:12 a.m. to being an hourlong descent to touchdown on runway 15 at the Kennedy Space Center in Florida. There are no technical problems with the shuttle and the weather forecast is "go" for a landing at 11:15 a.m.
8:30 AM, 6/14/08, Update: Payload bay doors closed; runway selection; updated deorbit time
The Discovery astronauts closed the shuttle's cargo bay doors at 7:33 a.m. and after evaluating possible sun glare in the cockpit, flight controllers have agreed to proceed with an approach to runway 15 at the Kennedy Space Center. Time of ignition for Discovery's deorbit rocket firing has changed by a few seconds to 10:10:12 a.m. and the duration of the burn is now two minutes and 34 seconds. There are no technical problems aboard the shuttle and with good weather expected, touchdown remains on track for 11:15 a.m.
6:15 AM, 6/14/08, Update: Astronauts gear up for landing
With good weather expected, the Discovery astronauts prepared the shuttle for re-entry and landing today to close out a two-week space station assembly mission. Commander Mark Kelly and pilot Kenneth Ham plan to fire Discovery's twin orbital maneuvering system rockets at 10:10 a.m., setting up touchdown at the Kennedy Space Center at 11:15 a.m. A second opportunity is available one orbit later, at 12:50:44 p.m. If the weather or technical problems prevent a Florida landing today, the astronauts will stay in orbit and try again Sunday.
But Discovery is in good shape and the Spaceflight Meteorology Group at the Johnson Space Center in Houston is predicting near ideal conditions for the first opportunity, with just a few clouds at 3,000 feet and winds out of the northeast at four knots, gusting to six.
"Yeah, Mark, it's still looking good for the first attempt. The winds are pretty light out of the northeast, you'll have a crosswind, zero six zero at six (knots), and there's no rain in the forecast for the first opportunity," astronaut Terry Virts radioed from Houston a few minutes before 6 a.m. "There'll be a sea breeze picking up as the day goes on, but early in the morning at our (landing) time it should not be a factor. The second opportunity does have a slight chance of rain showers. But right now, it looks pretty good."
"OK, copy, thanks," Kelly replied.
Kelly, Ham, flight engineer Ronald Garan, Karen Nyberg, Michael Fossum, Japanese astronaut Akihiko Hoshide and returning space station flight engineer Garrett Reisman were awakened at 2:32 a.m. by a recording of "A Life on the Ocean Wave," the official march of the U.S. Merchant Marine Academy. Kelly graduated from the academy in 1986.
"Good morning, Houston," he radioed. "Want to thank the staff, midshipmen and alumni of the Merchant Marine Academy for sending that up to us. The mission's coming to an end, but it's going to be good to get home today."
Discovery took off May 31 from pad 39A, carrying Japan's 15-ton Kibo laboratory module and Reisman's replacement, Gregory Chamitoff. Fossum and Garan staged three spacewalks to outfit Kibo, install a fresh tank of high pressure nitrogen for the station's cooling system and to test techniques for cleaning contamination from a solar array drive gear.
Launched to the space station in March, Reisman is returning to Earth after 95 days in space. He will make the trip home resting on his back in a recumbent seat on the lower deck of Discovery's crew cabin.
"As far as what I'm looking forward to the most, that's easy," Reisman said earlier. "I can answer that with two words and it's Simone Francis, who's my wife. No doubt about that. And our cat, Fuzzy. Not really, but Simone, yeah, definitely."
Answering a wakeup call Friday, Reisman told his wife: "Get ready, doll face. Discovery's coming home!"
Garan and Nyberg plan to close Discovery's cargo bay doors at 7:30 a.m.
If all goes well, Kelly and Ham will fire Discovery's twin braking rockets at 10:10:17 a.m. for two minutes and 36 seconds, slowing the shuttle by 197 mph. A half hour later, the shuttle will fall back into the discernible atmosphere at an altitude of 75.7 miles above the south Pacific Ocean.
The shuttle's ground track will carry the ship over the western coast of Mexico near the border of Guatemalo and then over the Yucatan Peninsula and the Gulf of Mexico just west of Cuba. Crossing the Florida coast near Naples, Discovery's flight computers will guide the shuttle to the Kennedy Space Center where Kelly will take over manual control at an altitude of about 50,000 feet.
Flying the shuttle through a sweeping 244-degree left overhead turn, Kelly plans to give Ham about 20 seconds of hands-on "stick time" before taking over for the final moments of the descent to runway 15. Because of possible sun glare in the cockpit, Kelly could opt for a right overhead turn to line up on runway 33 instead. Either way, flight surgeons will be standing by to assist Reisman.
"I've been very diligent about keeping up with the exercise regimen we use as our primary countermeasure for keeping our bones and muscles healthy," he told CBS News in an interview Friday. "Of course, vestibular effects, balance and stuff, it's a little more difficult to predict how that's going to hit me. I'm cautiously optimistic on the basis of anecdotal evidence because I'm short. So my sensory organs are a little closer to my center of gravity and my heart has a little less distance to pump to my brain. I've been waiting my whole life and finally I think being short is going to come in handy!"
Here is the timeline for today's re-entry and landing opportunities (in EDT; statute miles):
EDT...........EVENT Rev. 217 Deorbit to Kennedy Space Center 06:10 AM......Begin deorbit timeline 06:25 AM......Radiator stow 06:35 AM......Mission specialists seat installation 06:41 AM......Computers set for deorbit prep 06:45 AM......Hydraulic system configuration 07:10 AM......Flash evaporator cooling system checkout 07:16 AM......Final payload deactivation 07:30 AM......Payload bay doors closed 07:40 AM......Mission control 'go' for OPS-3 entry software load 07:50 AM......OPS-3 transition 08:15 AM......Entry switch list verification 08:25 AM......Deorbit maneuver update 08:30 AM......Crew entry review 08:45 AM......Commander/pilot don entry suits 09:02 AM......Inertial measurement unit alignment 09:10 AM......Copmmander/pilot strap in; mission specialists don suits 09:27 AM......Shuttle steering check 09:30 AM......Hydraulic system prestart 09:37 AM......Toilet deactivation 09:45 AM......Payload bay vent doors closed for entry 09:50 AM......Mission control 'go' for deorbit burn 09:56 AM......Mission specialists strap in 10:05 AM......Single hydraulic power unit start 10:10:17 AM...Deorbit ignition (dV: 197 mph; dT: 2:36) 10:12:53 AM...Deorbit burn complete (alt: 218.8 miles; vel: about 17,200 mph) 10:43:37 AM...Atmospheric entry (alt: 75.7 miles; vel: about 16,978 mph) 10:48:36 AM...1st roll command to left (80 degrees) 10:50:00 AM...Start peak heating (approx) 11:00:00 AM...End peak heating (approx) 11:02:00 AM...C-band radar acquisition 10:58:33 AM...1st left to right roll reversal (62 degrees) 11:08:46 AM...Velocity less than mach 2.5 (alt: 85,500 feet) 11:11:00 AM...Velocity less than mach 1 (alt: 50,200 feet) 11:11:50 AM...Start 244-degree left overhead turn (alt: 38,000 feet) 11:15:18 AM...Landing on runway 15 Rev. 218 Deorbit to KSC 11:26 AM......Mission control 'go' for deorbit burn 11:32 AM......Mission specialists seat ingress 11:41 AM......Single hydraulic power unit start 11:46:32 AM...Deorbit ignition (dV: 198 mph; dT: 2:37) 11:49:09 AM...Deorbit burn complete (alt: 220.6 miles; vel: about 17,200 mph) 12:19:03 PM...Atmospheric entry (alt: 75.5 miles; vel: about 16,978 mph) 12:23:59 PM...1st roll command to right (80 degrees) 12:25:00 PM...Start peak heating 12:35:00 PM...End of peak heating 12:37:02 PM...1st right-to-left roll reversal (61 degrees) 12:44:13 PM...Velocity less than mach 2.5 (alt: 85,900 feet) 12:46:27 PM...Velocity less than mach 1 (alt: 49,700 feet) 12:46:57 PM...Start 281-degree left overhead turn (alt: 42,300 feet) 12:50:44 PM...Landing on runway 15
5:00 PM, 6/13/08, Update: Discovery cleared for Saturday landing in Florida; good weather expected; NASA will not staff backup sites before Monday
The shuttle Discovery is in good shape and ready for landing Saturday at the Kennedy Space Center to close out a successful space station assembly mission, entry Flight Director Richard Jones said today. The Spaceflight Meteorology Group at the Johnson Space Center in Houston is predicting near ideal conditions for the first of two landing opportunities Saturday.
But if the weather doesn't cooperate, or if a technical problem develops that might prevent an on-time re-entry, Jones said the shuttle has enough supplies on board to stay in orbit until Tuesday if necessary. But NASA's focus is getting Discovery back to Florida this weekend and given the forecast, Jones said NASA would not staff its backup landing site at Edwards Air Force Base, Calif., until Monday at the earliest.
"Tomorrow, we're going to be looking at end of mission at KSC only," Jones said. "The weather is looking very good tomorrow, we have a decent shot. ... All of the ceilings and the surface winds are all going to be within flight rule limits and we're looking at a pretty good opportunity tomorrow."
LeRoy Cain, chairman of NASA's Mission Management Team, said analysts had finished an assessment of the shuttle's heat shield and concluded the ship was in good shape for entry.
"As of today, Discovery's TPS system is all in very good shape, including all the thermal protection system tiles, all of the blankets, all of the reinforced carbon carbon on the wing leading edge and nose cap and all of the associated support systems," Cain said. "All of that has been determined to be good and acceptable and safe for entry and landing. ... There were no dissenting opinions on that. Just a very clean vehicle overall with regard to the TPS."
As for a small 1-inch by 2.5-inch thermal barrier clip that floated away from Discovery's rudder/speed brake earlier today, Cain said the hardware was only needed during launch and that its absence posed no threat to the shuttle during entry.
Discovery commander Scott Kelly and pilot Kenneth Ham plan to fire Discovery's twin braking rockets at 10:10:17 a.m. Saturday for two minutes and 36 seconds, slowing the ship by 197 mph to drop it out of orbit. After a half-hour free fall, the shuttle will slip into the discernible atmosphere 400,000 feet above the Pacific Ocean at 10:43 a.m.
If all goes well, the shuttle will cross Central America and the Yucatan Peninsula, skirt the west coast of Cuba and cross the Florida coast south of Fort Myers. Approaching the Florida spaceport from the southwest, Kelly will guide Discovery through a sweeping left overhead turn to line up on runway 15 at the Kennedy Space Center. Touchdown is expected at 11:15 a.m.
Here is a timeline of re-entry events for both of the crew's Saturday landing opportunities (in EDT throughout):
EDT...........EVENT Rev. 217 Deorbit to Kennedy Space Center 02:32 AM......Crew wakeup 05:12 AM......Group B computer powerup 05:27 AM......Inertial measurement unit alignment 06:10 AM......Begin deorbit timeline 06:25 AM......Radiator stow 06:35 AM......Mission specialists seat installation 06:41 AM......Computers set for deorbit prep 06:45 AM......Hydraulic system configuration 07:10 AM......Flash evaporator cooling system checkout 07:16 AM......Final payload deactivation 07:30 AM......Payload bay doors closed 07:40 AM......Mission control 'go' for OPS-3 entry software load 07:50 AM......OPS-3 transition 08:15 AM......Entry switch list verification 08:25 AM......Deorbit maneuver update 08:30 AM......Crew entry review 08:45 AM......Commander/pilot don entry suits 09:02 AM......IMU alignment 09:10 AM......CDR/PLT strap in; mission specialists suit don 09:27 AM......Shuttle steering check 09:30 AM......Hydraulic system prestart 09:37 AM......Toilet deactivation 09:45 AM......Vent doors closed for entry 09:50 AM......Mission control 'go' for deorbit burn 09:56 AM......MS seat ingress 10:05 AM......Single hydraulic power unit start 10:10:17 AM...Deorbit ignition 10:12:53 AM...Deorbit burn complete 10:43:37 AM...Entry interface 10:48:36 AM...1st roll command to left 10:50:21 AM...Start peak heating (approx) 11:00:21 AM...End peak heating (approx) 11:02:00 AM...C-band radar acquisition 10:58:33 AM...1st left to right roll reversal 11:08:46 AM...Velocity less than mach 2.5 11:11:00 AM...Velocity less than mach 1 11:11:50 AM...Shuttle on the HAC 11:15:18 AM...Landing Rev. 218 Deorbit to KSC 11:26 AM......Mission control 'go' for deorbit burn 11:32 AM......Mission specialists seat ingress 11:41 AM......Single hydraulic power unit start 11:46:32 AM...Deorbit ignition 11:49:09 AM...Deorbit burn complete 12:19:03 PM...Entry interface 12:23:59 PM...1st roll command to right 12:25:47 PM...Start peak heating 12:35:47 PM...End of peak heating 12:37:02 PM...1st right-to-left roll reversal 12:44:13 PM...Velocity less than mach 2.5 12:46:27 PM...Velocity less than mach 1 12:46:57 PM...Shuttle on the HAC 12:50:44 PM...LandingIf Discovery is unable to land Saturday, the crew will have two more opportunities to make it back to Kennedy on Sunday, at 10:03 a.m. and 11:38 a.m.
11:05 AM, 6/13/08, Update: Debris may be one of three insulation clips from shuttle rudder (UPDATED at 11:30 a.m. with confirmation of debris identity; not a concern; UPDATED at 1 p.m. with CBS News crew interview)
Engineers at the Johnson Space Center in Houston believe a flashing bit of debris spotted floating away from the shuttle Discovery this morning was a clip used to secure thermal insulation in the ship's rudder/speed brake to protect against engine heat during ascent. Flight controllers told the astronauts the lost clip poses no threat to a safe re-entry.
As for an apparent bump, or protrusion, spotted on the shuttle's vertical rudder/speed brake, engineers concluded it looked that way before launch and was not considered a problem, welcome news on an already busy Friday the 13th.
"As you know, we've been talking about this down here and we're confident this is going to be no impact to entry," said astronaut Terry Virts in mission control. "I'll talk about the two different objects we saw separately. First of all, the bump that you saw on the rudder/speed brake we think is nominal. We compared it with pre-flight imagery and it looks exactly like it did pre flight. I think the reason you could see it was because the rudder was kind of angled to the left after the FCS (flight control system) checkout a little bit. But there's no issue with that.
"The other object that floated away, turns out was a trailing edge split-line barrier. Thanks to the pictures you took the resolution was very good, we were able to confirm it was that. That trailing edge split-line barrier, it looks like a (V-shaped) clip, its function is for ascent heating only. This is something we've seen ever since STS-1, orbiters have come back with those missing. It's just not a factor for entry."
Commander Mark Kelly told CBS News a few minutes later during an already scheduled interview that he had no concerns.
"Mike (Fossum) happened to be looking out the window when we were doing FCS checkout to try to get some images of the aerosurfaces moving and saw what turned out to be a clip floating away and fortunately, got a really good picture of it," Kelly said.
Flight controllers later sent up a Powerpoint presentation that compared Fossum's pictures with engineering drawings and "we were impressed at how quickly, the quality of the work they were able to do in that short amount of time," Kelly said. "It was interesting, the picture that Mike took had those three tack welds on it. ... You could line those up with the ground images and you can pretty conclusively say that's the same clip."
Otherwise, Kelly said, Discovery's entry systems checked out well and with good weather expected in Florida, the crew is optimistic about making an on-time return to the Kennedy Space Center to close out a successful space station assembly mission. Touchdown on runway 15 is targeted for 11:15 a.m.
Astronaut Garrett Reisman, returning to Earth after three months aboard the international lab complex, said he's looking forward to seeing his wife, friends and family again, "sleeping in my own bed and using my own toilet."
Reisman will make the trip back to Earth resting on his back in a reclining seat on Discovery's lower deck to ease his return to the uncomfortable tug of Earth's gravity. He said today he's hopeful a strict exercise schedule will help him re-adapt without any major problems.
"I've been very diligent about keeping up with the exercise regimen we use as our primary countermeasure for keeping our bones and muscles healthy," he told CBS News. "Of course, vestibular effects, balance and stuff, it's a little more difficult to predict how that's going to hit me. I'm cautiously optimistic on the basis of anecdotal evidence because I'm short. So my sensory organs are a little closer to my center of gravity and my heart has a little less distance to pump to my brain. I've been waiting my whole life and finally I think being short is going to come in handy for once!"
Reisman, Kelly and their crewmates - pilot Kenneth Ham, flight engineer Ronald Garan, Karen Nyberg, Michael Fossum and Japanese astronaut Akihiko Hoshide - were awakened shortly after 3 a.m. to begin their final full day in space. Appropriately enough, mission control beamed up a recording of "Baby Won't You Please Come Home" by Louis Prima and Keely Smith.
"Good morning, Houston. And a special good morning to Simone, my favorite earthling," Reisman radioed to his wife. "Get ready, doll face. Discovery's coming home!"
Kelly, Ham and Garan tested Discovery's re-entry systems early today, firing up one of the ship's three hydraulic power units, cycling the orbiter's ailerons and rudder and test firing maneuvering jets. There were no problems of any significance.
But a few minutes after the tests concluded, Kelly reported seeing a piece of debris floating away around 7:35 a.m.
"We observed an object depart aft of the starboard wing," Kelly said. "Looked like, and obviously it's hard to tell dimensions and size looking out the aft windows, but it looked like it might have been a foot to a foot and a half in width. And we've got a pretty reasonable image of it."
A few minutes later, the crew reported seeing a small protrusion where two sections of the rudder/speed brake come together. They downlinked a short video clip of the debris, along with still pictures shot with a digital camera, and offered to power up Discovery's robot arm for a closer look at the rudder.
Flight controllers told the astronauts to sit tight and a few hours later, Virts told Kelly that engineers were able to confirm the debris was, in fact, a clip used to hold a thermal barrier in place in the rudder/speed brake.
"Well there was a little bit (of concern) when we saw it, not knowing what it was," Kelly told WCBS Radio. "But fortunately, Mike got some good pictures of it, sent them down to the ground and within a couple of minutes they took a look and were able to narrow it down to a part that protects the rudder/speed brake during ascent, from the heating during liftoff. So we've seen these things come off before and it's not a concern at all for entry."
6:45 AM, 6/13/08, Update: Astronauts test entry systems; pack for Saturday landing (UPDATED at 8:10 a.m. with crew report of object departing shuttle; protrusion on rudder/speed bake)
The Discovery astronauts tested the shuttle's re-entry systems today and packed up for landing Saturday at the Kennedy Space Center. The tests went well, but the crew reported seeing a piece of debris of some sort floating away from the shuttle a few minutes later. They also called attention to a small protrusion on the shuttle's rudder/speed brake where a bit of insulation might have been displaced. It did not appear serious, but flight controllers are discussing whether any additional observations might be required.
The astronauts have two landing opportunities Saturday, at 11:15 a.m. and 12:50 p.m., and with good weather expected, NASA is not staffing its backup landing site at Edwards Air Force Base, Calif.
The astronauts were awakened at 3:02 a.m. today by a recording of "Baby Won't You Please Come Home" by Louis Prima and Keely Smith. The song was beamed up from mission control for space station flight engineer Garrett Reisman, who is returning to Earth after 95 days in space.
"Good morning, Houston. And a special good morning to Simone, my favorite earthling," Reisman radioed to his wife. "Get ready, doll face. Discovery's coming home!"
Commander Mark Kelly, pilot Kenneth Ham and flight engineer Ronald Garan began testing the shuttle's re-entry systems around 6:30 a.m., firing up one of three hydraulic power units and exercising the ship's control surfaces. Reisman, Karen Nyberg, Michael Fossum and Japanese astronaut Akihiko Hoshide spent the morning packing up and readying the shuttle for entry.
The flight control system checkout went smoothly, but around 7:35 a.m. Kelly called down and told mission control the crew had spotted an apparent piece of debris of some sort floating away from the shuttle.
"We observed an object depart aft of the starboard wing," Kelly said. "Looked like, and obviously it's hard to tell dimensions and size looking out the aft windows, but it looked like it might have been a foot to a foot and a half in width. And we've got a pretty reasonable image of it."
The crew managed to capture a few seconds of video showing a rectangular object floating away to the left of the shuttle's tail fin, flashing with reflected sunlight as it slowly tumbled. The object was seen a few minutes after the crew finished test firing the shuttle's maneuvering jets.
The astronauts also called attention to a small protrusion toward the back of the shuttle's big rudder/speed brake. It was barely visible and not an obvious problem, but the crew offered to take a closer look with the shuttle's robot arm. Flight controllers said they would consider that option.
This afternoon, the astronauts will set up a special reclining seat on Discovery's lower deck that Reisman will use Saturday to provide extra support as he returns to the uncomfortable tug of gravity after three months in space.
CBS News, WCBS Radio and WINS Radio will interview the astronauts starting at 11:52 a.m. Entry Flight Director Richard Jones plans to brief reporters on landing plans at 2 p.m.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision P of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/13/08 03:02 AM...12...10...00...Crew wakeup 06:07 AM...12...13...05...Cabin stow begins 06:37 AM...12...13...35...Flight control system checkout 07:47 AM...12...14...45...Reaction control system hotfire 09:37 AM...12...16...35...Landing simulator practice 10:22 AM...12...17...20...Deorbit review 10:52 AM...12...17...50...Crew meal 11:52 AM...12...18...50...CBS News crew interview 12:12 PM...12...19...10...Cabin stow resumes 12:12 PM...12...19...10...Landing comm checks 01:42 PM...12...20...40...Ergometer teardown 01:57 PM...12...20...55...Recumbent seat setup 02:00 PM...12...20...58...Mission status briefing on NTV 02:27 PM...12...21...25...Launch/entry suit checkout 03:00 PM...12...21...58...Mars Phoenix lander briefing on NTV 03:02 PM...12...22...00...KU antenna stow 06:32 PM...13...01...30...Crew sleep begins 07:00 PM...13...01...58...Daily video highlights reel on NTV 06/14/08 02:32 AM...13...09...30...Crew wakeup 05:12 AM...13...12...10...Group B computer powerup 05:27 AM...13...12...25...Inertial measurement unit alignment 06:10 AM...13...13...08...Deorbit timeline begins 07:30 AM...13...14...28...Payload bay door closing 10:10 AM...13...17...08...Deorbit ignition (rev. 217) 11:02 AM...13...18...00...C-band radar acquisition 11:15 AM...13...18...13...Landing
5:30 PM, 6/12/08, Update: Cain optimistic about launch pad repair; says Hubble flight not threatened
Serious damage to the "flame trench" at launch pad 39A during the shuttle Discovery's May 31 takeoff will require extensive repairs, officials said today, but engineers believe the work can be completed in time to support the planned Oct. 8 launch of shuttle Atlantis on a long-awaited flight to service the Hubble Space Telescope.
"We have a plan to fix pad A and we have a high degree of confidence in our ability to do that," LeRoy Cain, chairman of NASA's Mission Management Team, told reporters today. "We don't have any issues relative to being able to do this work and be ready to launch the HST mission."
During Discovery's climb out, the exhaust plume from the shuttle's two solid-fuel boosters blew out about 5,300 heat-resistant bricks lining one side of the flame trench below the orbiter's launch stand. Blasted out like shrapnel, bricks and fragments littered the pad perimeter and severely damaged a heavy duty security fence some 1,800 feet away.
The shuttle was not struck by any debris and Cain said a re-assessment of the environment in the flame trench during launch that was carried out after DIscovery's take off confirmed there is virtually no chance for debris from inside the trench to ricochet or otherwise overcome the exhaust plume to strike the orbiter.
Recommendations on what sort of repair work might be needed will be presented to shuttle Program Manager John Shannon on June 26. Cain said he did not want to provide details of proposed fixes until the engineering team has had time to fully assess the options. But he said engineers believe enough time is available to implement any of the repair scenarios under discussion.
"By the end of this week I think we're going to be done inspecting in the pad A area and we're going to get to work in earnest on doing the cleanup work and on putting a repair in place after we hear it at the program board," he said. "We're going to better understand this problem, obviously, as a result of all this.
"We will be able to repair the pad A flame trench damage that we've sustained here and it's going to be in time to support the STS-125 Hubble mission. There's no reason for us to look at going to pad B for that mission, we have high confidence in being able to go do this."
NASA has set up two teams to assess the pad damage and its implications. John Casper, a veteran shuttle commander and program official who is participating in the damage assessment, told CBS News today he agrees with Cain's optimism about getting repairs done in time for the Hubble flight. But he described the work as "a big job."
"It's amazing when you think about what those pads have been through," he said. "They've really held up remarkably well."
NASA's two shuttle launch pads, LC-39A and LC-39B, were built by the U.S. Army Corps of Engineers in the 1960s to support the Apollo moon program and later, launches for the Skylab space station and Apllo-Soyuz Test Program. The pads were modified in the mid 1970s to support the space shuttle.
First used in 1967, pad 39A has withstood 12 Saturn 5 launchings, including the first Apollo moon landing mission, and 70 shuttle flights. Pad 39B, first used in 1969, supported one Saturn 5 launch, four Saturn 1B flights and 53 shuttle missions, including Challenger's final flight.
The pads are built around long rectangular flame trenches that measure 490 feet long, 58 feet wide and 42 feet deep. The space shuttle, mounted atop a mobile launch platform, is positioned directly above the flame trench. Exhaust from three hydrogen-fueled main engines and two solid-fuel boosters passes through cutouts in the mobile launch platform and into the trench. A flame deflector, shaped like an inverted V, is positioned directly below the MLP openings to divert engine exhaust to one side of the pad and booster exhaust to the other.
The pressures and temperatures in the main engine section of the flame trench are much less than what the structure must endure from the shuttle's boosters. At ignition, each booster generates some 3.3 million pounds of thrust and a 5,000-degree exhaust plume.
The flame deflector is covered with a 5-inch-thick coating of Fondu Fyre, a heat-resistant Apollo-era material that is mixed with water, sprayed on and allowed to cure. The walls of the flame trench were built using interlocking heat-resistant bricks that use epoxy and metal clips to hold them to a 3-foot-thick concrete wall. The clips are attached to every other brick horizontally and every sixth row vertically.
Each brick measures 6-by-3-by-13.5 inches and features a half-moon-shaped groove on one surface and an opposite protrusion on the other. The protrusion on one brick fits into the groove on the one above or below to lock them together. The epoxy was used to help hold the bricks to the underlying concrete wall.
For added protection from the heat of booster ignition, Fondu Fyre covers bricks in the floor and side walls of the trench from the flame deflector out to about 20 feet. After that, the trench walls are bare brick.
During Discovery's launching, some 5,300 bricks on the northeast side of the flame trench were blown out, leaving bare concrete in an area roughly measuring 20 feet by 75 feet. While engineers later found signs of ricochets in the flame trench, video and still images show nothing came close to hitting the shuttle or even the underside of the mobile launch platform.
Engineers soon discovered the metal clips that help hold the bricks to the walls of the flame trench were severely rusted and corroded, probably due to decades of exposure to the acidic byproducts of booster exhaust. Inspectors also found areas where the absence of trowel marks indicates the epoxy intended to help hold the bricks to the underlying concrete wall was not uniformly applied. Subsequent "tap tests" have indicated voids behind 30 percent of the bricks that are still in place.
Engineers suspect similar problems may be lurking at pad 39B. Inspections and tap tests are ongoing.
A variety of repair options are being assessed for pad 39A. The original brick vendor, A.P. Green, has inspected the pad, along with representatives of Atlantic Firebrick and Supply Co. Molds of the original bricks are still available, officials say, but there is no existing stockpile. New bricks can be made, but not in time for the October launching.
"We have talked to the original vendor," Cain said. "The brick contracting company and the original vendor were on site to evaluate this issue for us. There apparently are no applications similar, or necessary, today and so they don't make this kind of brick. Whether or not it could be done, I don't know if we know the answer to that yet."
Among the options under consideration are removing all the bricks and spraying the underlying concrete with a thick coating of Fondu Fyre or a similar material; removing the bricks and leaving bare concrete; and leaving the bricks in place and using Fondu Fyre to fill in the damaged areas.
"As an old structural engineer, I can't see how we'd launch with any of the existing bricks in place," said one senior manager. "Maybe on the (main engine side), but not on the SRB side. The little clips that hold the bricks to the steel beams imbedded in the concrete wall are rusted badly. Many (are) gone. So even the ones behind the bricks that are still standing must be in the same shape."
Removing bricks and spraying on a coating of Fondu Fyre "is a big job," he said, "but smaller than replacing all the bricks."
Cain declined to provide any details about possible repair options, saying "I don't want to talk about that today because I don't want to get out in front of the team that's working on all those options."
"But fundamentally, it's fair to say one of the options is looking at spraying the areas where we've lost brick," he said. "Possibly removing more brick and spraying would be a different option, or doing something other than spraying Fondu Fyre in the areas where we've lost brick to preserve those areas.
"What we're really saying is any of those options doesn't look like, in terms of time and schedule and resources, that they would be an issue for us to complete them. We just have to go figure out which ones make the most sense given the problem we're facing today."
Casper said the near-term goal is to come up with a fix in time for the Hubble mission that would carry over through the 2010 end of the shuttle program. A longer-term fix, possibly using a fresh batch of firebricks, may be implemented for the Constellation program's Ares rockets that will replace the shuttle.
NASA plans to haul Atlantis to the launch pad on Aug. 29 to prepare the ship for blastoff Oct. 8. If possible, Casper said, NASA would like to complete any spraying of Fondu Fyre or similar material before the shuttle is moved to the pad. But engineers are looking into the possibility of spraying after rollout if required.
The Hubble flight is the only mission left on the shuttle manifest that does not go to the space station. Because Hubble is in a different orbit than the lab complex, the crew of the servicing mission cannot take advantage of "safe haven" aboard the station if any major problems develop that might prevent a safe re-entry. As a result, NASA Administrator Mike Griffin decided early on to have a second shuttle prepped and ready for takeoff from nearby pad 39B if an emergency rescue mission is needed.
If so, the rescue flight would be launched from pad 39B as soon as possible. Otherwise, Endeavour will be moved to pad 39A for launch on a space station resupply mission currently targeted for launch Nov. 10.
The goals of that flight are to deliver supplies to the station and begin a spacewalk repair of a critical solar array rotary joint. Equally important, Endeavour will ferry a fresh space station flight engineer - Sandy Magnus - to the lab complex and bring Gregory Chamitoff home after six months in orbit.
Complicating the end-of-year schedule, NASA cannot launch shuttles to the station between around Nov. 27 and Dec. 17 and between Jan. 27 and Feb. 11 because of thermal issues related to the angle between the sun and the plane of the station's orbit. Because NASA wants to avoid missions extending from one year to the next, the so-called "beta angle cutout" effectively means no launches between the end of November and the first of the year.
It takes about a month to prepare the launch pad for another flight. If the Hubble mission is delayed more than three weeks or so, the November shuttle flight could be delayed into next year, extending Chamitoff's stay in space well beyond the currently planned six months.
"We've looked very hard at that, that is right in the middle of our radar screen, with the large beta cutout that we have at the end of this calendar year," Cain said. "I asked the team to look at that before this mission launched, actually."
THe result, he said, is that if Atlantis takes off by Oct. 27 or thereabouts, NASA could still launch the STS-126 station mission from pad 39A before the beta cutout begins. Just barely.
"We have almost three weeks, essentially, to get HST launched before it's going to begin to impinge on our ability to get 126 launched before the beta cutout," Cain agreed.
8:30 AM, 6/12/08, Update: Astronauts enjoy time off
The Discovery astronauts took the day off today, enjoying the view from 210 miles up and chatting with family members in private teleconferences. The only mission related activity on the schedule is a rocket firing around 4:20 p.m. to adjust the shuttle's orbit slightly to improve landing opportunities at the Kennedy Space Center. LeRoy Cain, chairman of NASA's Mission Management Team, will brief reporters today at 3:30 p.m. on the health of Discovery's heat shield and its overall readiness for landing Saturday to wrap up a successful space station assembly mission.
Commander Mark Kelly, pilot Kenneth Ham and flight engineer Ronald Garan plan to test the shuttle's re-entry systems Friday while their crewmates - Karen Nyberg, Michael Fossum, Japanese astronaut Akihiko Hoshide and returning space station flight engineer Garrett Reisman - pack up and ready the ship for landing.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision P of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/12/08 03:32 AM...11...10...30...Crew wakeup 06:02 AM...11...13...00...Crew off duty 10:32 AM...11...17...30...Crew meal 11:32 AM...11...18...30...Crew off duty 01:32 PM...11...20...30...Crew interviews (ESPN/ABC News) 02:02 PM...11...21...00...Heat shield boom (OBSS) berthing 03:02 PM...11...22...00...Shuttle robot arm (SRMS) powerdown 03:30 PM...11...22...28...Mission Management Team briefing on NTV 04:20 PM...11...23...18...Orbit adjustment rocket firing 07:02 PM...12...02...00...Crew sleep begins 08:00 PM...12...02...58...Daily highlights reel on NTVFor readers interested in a look ahead, here is an updated list of deorbit burn and landing times for Saturday, Sunday and Monday (in EDT):
ORBIT...DEORBIT.......LANDING.......SITE 06/14/08 217.....10:10:17 AM...11:15:18 AM...Kennedy Space Center, FL (KSC) 218.....11:46:32 AM...12:50:44 PM...KSC 06/15/08 232.....09:01:00 AM...10:03:00 AM...KSC 233.....10:36:00 AM...11:38:00 AM...KSC 234.....12:06:00 PM...01:09:00 PM...Edwards Air Force Base, CA (EDW) 235.....01:42:00 PM...02:44:00 PM...EDW 06/16/08 248.....09:24:00 AM...10:27:00 AM...KSC 249.....10:56:00 AM...11:59:00 AM...Northrup Strip, NM (NOR) ........11:00:00 AM...12:02:00 PM...KSC 250.....12:30:00 PM...01:32:00 PM...EDW ........12:32:00 PM...01:34:00 PM...NOR 251.....02:06:00 PM...03:07:00 PM...EDW
3:45 PM, 6/11/08, Update: NASA managers consider cleaning, SARJ bearing replacement on next station assembly flight
NASA managers are considering a plan for the crew of the next space station assembly mission, scheduled for launch around Nov. 10, to clean up and lubricate a damaged, debris covered solar array drive gear and to replace 12 bearing assemblies in a bid to use the mechanism as long as possible before switching to a backup gear, an official said today.
Kenny Todd, space station integration and operations manager at the Johnson Space Center, said the replacement of a single bearing during the shuttle Discovery's mission, along with a spacewalk cleaning test, is giving engineers confidence about attempting a near-term repair.
"That will hopefully allow the joint to rotate a little more smoothly and cut down on the amount of vibration we're seeing," Todd said. "At this point, we're targeting the ULF-2 (mission) timeframe to go out and do something proactively with the starboard SARJ."
The space station is equipped with two motor-drive 10-foot-wide solar alpha rotary joints, one on either side of the lab's main power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. The devices are crucial for maximizing the electricity the station's solar panels can generate.
The left-side SARJ is operating normally, but last summer engineers began noticing higher-than-usual vibration levels in the right-side SARJ mechanism, along with electrical current spikes indicative of increased friction as the gear rolled through 12 trundle bearing assemblies. During a subsequent spacewalk inspection, astronauts discovered extensive metallic contamination covering the active drive gear and degradation, or erosion, of at least one of the gear's bearing surfaces.
Despite extensive troubleshooting, engineers still don't know what might be causing the damage. One possibility is a small crack or breakdown in the hardened bearing surface that produced debris that was then crushed as it passed through the trundle bearings, causing more damage and creating more debris. Whatever the cause, it is a serious problem and flight controllers no longer operate the right-side SARJ in "auto-track" mode.
"Our thinking right now on the starboard SARJ is that in the ULF-2 timeframe, we will go out and most likely replace the trundle bearings," Todd said. "We did do that on one of the EVAs on this flight, we went in and installed a TBA so obviously, that helps us get more comfortable with that particular operation. Our thought right now is to go out and install the new TBAs during that flight. Prior to installing those TBAs, our thought is to do what we call lubing of the ring."
A cleaned and lubricated drive gear, along with new trundle bearing assemblies, may reduce vibration levels to the point where near-normal operation is possible. NASA managers still believe they ultimately will be forced to switch over to the SARJ's undamaged backup drive gear, but they don't want to take that step until there is no other choice.
"Every piece of hardware we can get down on the ground related to this anomaly gives us additional insight," Todd said. "Getting these TBAs on the ground will allow us to inspect the bearings within them and try to understand the makeup of any residue on the bearings, how are the bearings themselves fairing, are they coming apart, are there any cracks in them, is there anything there that gives us cause for concern?
"So our thought is, let's go replace all the bearings, get those down, do the investigation on them, see what that rolls into in terms of our fault tree. As far as lubing the ring itself, the existing ring, we did a detailed test objective on this flight that had us go out and take a small portion of the ring and do a wipe of it with some lubricant to see how successful we would be in trying to get some of the residue off the ring and get us in a position maybe to try to continue to use that ring with some additional lubrication. The crew gave us some very good anecdotal-type feedback."
As far as ultimately switching to the backup drive gear, "that's something we're looking at downstream," Todd said.
The Discovery astronauts undocked from the space station earlier today and spent the afternoon carrying out a detailed inspection of the shuttle's reinforced carbon carbon nose cap and wing leading edge panels. Lead Flight Director Matt Abbott said no obvious damage could be seen during the initial stages of the inspection, but it will take engineers a full day or so to evaluate the data.
"The survey started right on time," he said. "We'll be taking all the data down from those surveys and inspections and the teams are already starting to look at them, of course. They'll look at those through the night and into the morning. We expect to have some early word mid morning tomorrow before the Mission Management Team meets tomorrow afternoon. We're looking forward to some good results there from the surveys."
7:50 AM, 6/11/08, Update: Discovery undocks from space station (UPDATED at 9;25 with final separation; quotes)
With pilot Ken Ham at the controls, the shuttle Discovery undocked from the international space station today as the two spacecraft sailed 210 miles above the south Pacific Ocean just north of New Zealand.
"Houston and station from Discovery, physical separation," shuttle commander Mark Kelly radioed at 7:42 a.m. as Discovery slowly pulled away.
Joining Ham and Kelly aboard Discovery were flight engineer Ronald Garan, Karen Nyberg, Michael Fossum, Japanese astronaut Akihiko Hoshide and outgoing space station flight engineer Garrett Reisman, returning to Earth after 95 days in space.
Reisman was replaced by Gregory Chamitoff, who remained behind on the station with Expedition 17 commander Sergei Volkov and Oleg Kononenko. The two Russians plan to return to Earth aboard a Soyuz spacecraft in October while Chamitoff will remain aloft until the next shuttle visit in November.
"I just want to say to Sergei, Oleg and Greg that we wish them the best with their expedition and we hope we left them a better, more capable space station than when we arrived," Kelly radioed shortly before undocking. "Sayonara."
"Copy that, Mark," Chamitoff replied. "It was a great adventure with all of you guys, the adventure of a lifetime. It's amazing how much got done here. I'm so glad everything worked out so well. We wish you guys a terrific flight back, an awesome landing and I look forward to seeing you on the ground."
"We'll see you in about, hopefully, a little less than six months," Kelly said.
After completing a 360-degree fly around, Ham fired Discovery's maneuvering jets to leave the area for good. Following naval tradition, Chamitoff rang the ship's bell in the Destiny lab module, saying "Discovery departing after a successful mission to the international space station, leaving behind great memories and new hope - Kibo - for the future."
He was referring to the Japanese laboratory module installed Discovery's crew. The module is known as Kibo, or "hope" in Japanese.
"Thank you, Alpha," Kelly replied. "It was great to spend some time with you guys there and we'll see you back on Earth."
"Thanks, Mark, it was terrific," Chamitoff said. "The whole mission was really enjoyable with everybody. We're sad to see you guys go, but we look forward to seeing you guys on the ground."
Reisman chimed in a few minutes later, saying "just wanted to let you know that you can have all my uneaten Snickers bars."
"And Garrett, we found those last night and broke into them," Chamitoff laughed. "Thanks!"
Discovery is scheduled to land Saturday morning at the Kennedy Space Center.
06:00 AM, 6/11/08, Update: Shuttle crew prepares for station undocking
The Discovery astronauts geared up for undocking from the international space station today at 7:42 a.m., leaving astronaut Gregory Chamitoff behind with Expedition 17 commander Sergei Volkov and flight engineer Oleg Kononenko and bringing Garrett Reisman home after three months in space.
Reisman and his shuttle crewmates were awakened shortly after 4 a.m. by a recording of John Fogerty's "Centerfield" beamed up from mission control for pilot Kenneth Ham.
"Good morning, Discovery. And a special good morning to you today, Ken," astronaut Shannon Lucid radioed from Houston.
"Appreciate the song," Ham replied. "And that is from my absolutely wonderful wife, Michelle. Girl, you are my home. And all of us are going to start our journey home today. And by my rough calculation, that's a little over a million miles, but we're going really fast! So we're on our way. Just remember, babe. I love you more."
Ham will be at the controls when the shuttle undocks from the station, guiding the ship to a point roughly 400 feet directly in front of the lab complex. At that point, he will begin a one-lap photo-documentation flyaround, guiding Discovery over the top, directly behind and then below the station before looping back in front and leaving the area.
"I'm looking forward to that, of course," Ham told CBS News before launch. "It's kind of nice because over the years it has not gained as much attention, the details, as rendezvous. When Mark (Kelly) flies the rendezvous with station, he's under a lot of scrutiny. When I fly the fly around, there really aren't a whole lot of people watching. So I get to fly with looser constraints, if you will, maybe even be a little more creative with how to fly and experiment with the orbiter. And I think that's why we as an office have developed it, it's a chance for a pilot to get comfortable flying this big old quarter-million-pound spaceship so that maybe down the road, if he gets to be a commander, he has a lot more confidence in what he can do."
Once clear of the station, the astronauts will reconfigure the shuttle's computer network and take a break for lunch. Ham, Karen Nyberg and Michael Fossum then will position the shuttle's robot arm for a detailed inspection of the ship's reinforced carbon carbon nose cap and wing leading edge panels, which experience the most heat during re-entry. Ronald Garan will take Nyberg's place for the nose cap and left wing surveys.
Discovery was launched without an orbiter boom sensor system, the 50-foot-long extension normally used the day after launch to look for signs of damage to the shuttle's most critical areas. Discovery's payload, the Kibo laboratory module, was so large there was no room for the OBSS in the shuttle's cargo bay.
As a result, the crew of a shuttle mission in March left their inspection boom behind on the space station. Fossum and Garan retrieved it during the first of their three spacewalks and it will be used today to carry out an inspection identical to what normally would have been done on flight day two.
"The only thing really that we haven't done is a detailed scan of the undersides, the lower surfaces of both leading edges," said lead Flight Director Matt Abbott. "Of course, from the (rendezvous) photography and the other imagery that we've taken, we haven't seen anything that gives us any indication of concern at this point. What we don't have is the detailed resolution that we get with the LDRI, the laser systems and the OBSS sensors. So that's what we'll be looking for, taking that very detailed look. But there certainly has been nothing to this point that warrants any concern."
If any problems are found, Discovery's crew would have the option of returning to the space station to attempt repairs. A repair kit to fix damage to leading edge panels normally stays on the space station, but Discovery is bringing it home.
"The next mission to launch is the Hubble (servicing) mission," Ham said in a NASA interview. "They need to fly that patch kit for their mission, obviously, because they canÕt get to space station."
Today's inspection is scheduled to begin around 11:12 a.m. with an examination of Discovery's right wing. The nose cap survey will begin just before 1 p.m. with the left wing inspection on tap about 50 minutes later. A mission status briefing is scheduled for 2 p.m.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision O of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/11/08 04:02 AM...10...11...00...Crew wakeup 06:02 AM...10...13...00...ISS daily planning conference 06:27 AM...10...13...25...Centerline camera setup 06:37 AM...10...13...35...Group B computer powerup 06:57 AM...10...13...55...Undocking timeline begins 06:58 AM...10...13...56...Noon 07:17 AM...10...14...15...Docking port prepped for separation 07:26 AM...10...14...24...Sunset 07:42 AM...10...14...40...UNDOCKING 07:43 AM...10...14...41...ISS holds attitude 07:47 AM...10...14...45...Range: 50 feet 07:49 AM...10...14...47...Range 75 feet 07:52 AM...10...14...50...Docking port depressurization 08:02 AM...10...15...00...Sunrise 08:11 AM...10...15...09...Range: 400 feet; start fly around 08:20 AM...10...15...18...Range: 600 feet 08:22 AM...10...15...20...Shuttle directly above ISS 08:29 AM...10...15...27...Noon 08:34 AM...10...15...32...Shuttle directly behind ISS 08:45 AM...10...15...43...Shuttle directly below ISS 08:57 AM...10...15...55...Separation burn No. 1 08:57 AM...10...15...55...Sunset 09:25 AM...10...16...23...Separation burn No. 2 09:27 AM...10...16...25...Post undocking computer reconfig 09:27 AM...10...16...25...Group B computer powerdown begins (media channel) 09:52 AM...10...16...50...Undocking video replay 10:12 AM...10...17...10...Crew meal 11:12 AM...10...18...10...Starboard wing survey 11:45 AM...10...18...43...GLAST launch (media channel) 12:57 PM...10...19...55...Port wing survey 02:00 PM...10...20...58...Mission status briefing on NTV 03:00 PM...10...21...58...Mars Phoenix lander briefing 03:47 PM...10...22...45...Laser data downlink 05:32 PM...11...00...30...ISS crew sleep begins 07:32 PM...11...02...30...STS crew sleep begins 08:00 PM...11...02...58...Daily video highlights reel on NTV
5:05 PM, 6/10/08, Update: Shuttle crew closes hatches, prepares for station undocking Wednesday
The shuttle Discovery's crew bid farewell to space station commander Sergei Volkov, Oleg Kononenko and incoming flight engineer Gregory Chamitoff today, sharing a few final thoughts, hugs and handshakes before closing hatches and preparing the shuttle for undocking early Wednesday.
Discovery's crew ferried Chamitoff to the station to replace outgoing flight engineer Garrett Reisman after a three-month stay in space. Now a member of Discovery's crew, Reisman had some final advice for his replacement:
"It's a huge responsibility, taking care of this tremendous national asset and the national assets of our international partners," he said, floating with the combined crew in the station's Harmony module. "And if that ever feels like a tremendous burden, just remember this advice I have for you: with great responsibility also comes great power!" Laughing, Reisman continued "you're going to do a fantastic job, from a running start you've been doing absolutely fantastic and you have some great crewmates to help you out, too. You're going to do great."
"For me, this is a very satisfying moment, one I was looking forward to for a long time," Reisman said. "It was not a perfect performance by myself, but I managed not to break anything really expensive. And I'm leaving now with the station in good hands and with a tremendous feeling of satisfaction."
For his part, Chamitoff said he could hardly believe the long-awaited moment had finally arrived.
"It's been an amazing adventure," he said. "Garrett's been a great host for us, he's really helped us with everything, especially me, teaching me the ins and outs of everything on the station," Chamitoff said. "I've really appreciated that very much. Garrett's done an amazing job taking care of this side of the space station, along with Sergei and Oleg. Everything's in really great shape and he's done a great job for NASA and all the international partners.
"It's really sad to see you guys go," Chamitoff said. "But I'm looking forward to the adventure ahead with Sergei and Oleg, getting the (Japanese lab module) up and running, getting the science program started, doing science in the U.S. module and (the European Space Agency's) Columbus."
Reisman, Discovery commander Mark Kelly, pilot Kenneth Ham, flight engineer Ronald Garan, Karen Nyberg, Michael Fossum and Japanese astronaut Akihiko Hoshide then floating through a short tunnel into the shuttle and hatches were closed to set the stage for undocking at 7:42 a.m. Wednesday.
Over the course of the docked phase of the mission, the astronauts attached Japan's huge Kibo laboratory module, moved a logistics module to its permanent home atop Kibo and staged three spacewalks by Fossum and Garan to outfit the laboratory, install a fresh nitrogen tank for the station's cooling system and test techniques for cleaning a contaminated solar array rotary joint.
"It's really been a wonderful mission from the start up until this point," said lead Flight Director Matt Abbott. "We've got a few days to go, and I couldn't be more proud of this team and this crew for what they've been able to accomplish. ... The one thing that will make me happier is when we get Discovery and the crew safely on the ground and are able to see them on the runway looking up at the vehicle. That's how I feel every mission."
Discovery's crew plans to carry out a detailed inspection of the ship's nose cap and wing leading edge panels after undocking Wednesday. They will enjoy a day off Thursday before packing Friday for a landing Saturday back at the Kennedy Space Center. Touchdown is expected around 11:15 a.m., weather permitting.
Reisman will make the trip back to Earth resting on his back in a reclining seat on Discovery's lower deck to ease his re-adaptation to gravity after 95 days aloft.
During a crew news conference Monday, Reisman, laughing, said seeing his wife was No. 1 on his list of post-landing priorities. Today, he told a reporter "I talked to her last night on our IP telephone from up here and she was furious with me for embarrassing her like that. But the truth is, when I look out the window at the planet and I look down at all the people down there, I'm usually just thinking about just one of all those billions of people. And that's definitely who I'm looking forward to seeing the most."
He said he would miss the station, though, and the sheer fun of zooming about in weightlessness like a super hero.
"The station is enormous, it's really ready now for a six-person crew, we have enough room to spare," he said. "There's actually enough space that you can lose people. You can go from stem to stern and try and find somebody and not find them, that's how big this place is. It's incredibly complex and there's so much equipment up here and so much tonnage of material, it is ready to be utilized, especially now with the addition of this huge Japanese laboratory.
"Daily life, you know, it's extremely busy, especially for me. My whole time up here has been action packed, there hasn't been a dull moment at all. And so it's just a matter of operating this enormous space station. It's really something straight out of science fiction. And when you take a look around, it's just really impressive that we've pulled this off. The best part about it is being able to fly around like a super hero."
Chamitoff is scheduled to return to Earth in November with the crew of the next station assembly mission. He said years of training helped prepare him for his six-month stay in space but "there are definitely aspects of this that the training really, you know, can only do so much to prepare you for."
"The last bit of training is actually from Garrett himself, he's been showing me the ropes on board, showing me day-to-day life on station, how to actually get things done, where to find things," Chamitoff said. "He gave me his phone number. He's probably going to change his number after he gets down there! Anyway, it's been a really good time having him show me how to live up here."
7:40 AM, 6/10/08, Update: Shuttle crew enjoys final docked day; Reisman prepares for home
The Discovery astronauts are working through a final day of equipment transfers to and from the international space station before closing hatches late today and undocking early Wednesday. Outgoing flight engineer Garrett Reisman, returning to Earth after three months in space, planned to squeeze in a final few hours of handover time, briefing his replacement, Gregory Chamitoff, on the intricacies of life aboard the station.
"We schedule a minimum of 16 hours of handover between the two flight engineers when one is leaving and one's coming up," station Flight Director Emily Nelson said early today. "If you can imagine, you're going to leave your house and someone else is going to live in it for six months. You need to show them where everything is, you need to show them what you do on a regular basis to keep everything up and maintain it.
"A lot of what is in their handover package ... shows where we've thought out in advance, here are all the things that you need to show Greg, in this case, so that he knows immediately where everything is, he's had everything shown to him, everything from the basic housekeeping tasks of cleaning filters and changing out batteries and those kinds of things to how to operate the internet protocol phone, how to get logged into email on the machines that are up there, even how to use the cycle ergometer, the bikes they've got up there.
"So it's mostly just your kind of day to day, all the things that they're going to be doing in the background all day long," Nelson said. "A lot of payload details get passed from one to the other at that time, any lessons learned ... tips and tricks for how to get by up there."
Reisman was launched to the station last March. Assuming an on-time landing Saturday aboard Discovery, he will have logged 95 days in space. Early today, engineers in space station control centers in Houston, Cologne, Germany and Moscow congratulated Reisman on a productive station stay.
"Garrett, best wishes to you as you spend your last day of this mission on the space station," said Mark Vande Hei at the Johnson Space Center. "Thanks for all your hard work in space over the last several months. We all look forward to your return."
"Thanks, Mark, it's really nice for you to say that," Reisman replied. "I couldn't imagine what these past three months would have been like without all the great help you've given me. And that goes out to all the centers, I just want to say thank you to everybody. ... You guys have been just better than I ever expected."
"Yeah, we appreciate those words and those sentiments are definitely felt down here as well," Vande Hei said.
The Discovery astronauts plan to take a break this afternoon, enjoying a few hours of off-duty time before gathering in the Harmony module for a farewell ceremony with Chamitoff, station commander Sergei Volkov and flight engineer Oleg Kononenko. Hatch closure is expected around 4 p.m., setting the stage for the shuttle's undocking at 7:42 a.m. Wednesday.
"I think when they leave, it's going to be very sad for me to see them go," Chamitoff said Monday. "I think that one moment, when we close the hatch, that's going to be the hard moment. After that, I'm with really good friends that I've spent years training with and they've already been here for two months, so they know how to do it and they'll show me the ropes."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision M of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/10/08 04:32 AM...09...11...30...Crew wakeup 06:32 AM...09...13...30...ISS daily planning conference 07:32 AM...09...14...30...Middeck transfers 09:42 AM...09...16...40...Oxygen system teardown 10:42 AM...09...17...40...EVA gear stowed 12:12 PM...09...19...10...Crew meal 01:12 PM...09...20...10...Crew off duty period 02:10 PM...09...21...08...Media interviews 02:45 PM...09...21...43...Mission status briefing on NTV 03:57 PM...09...22...55...Farewell ceremony 04:07 PM...09...23...05...Hatches closed 04:32 PM...09...23...30...Rendezvous tools checkout 04:32 PM...09...23...30...Orbiter docking system leak checks 07:32 PM...10...02...30...ISS crew sleep begins 08:02 PM...10...03...00...STS crew sleep begins 09:00 PM...10...03...58...Daily video highlights reel on NTVFor readers interested in a look ahead, here's an updated undocking timeline for Wednesday (in EDT and mission elapsed time):
EDT........DD...HH...MM...EVENT 06/11/08 06:58 AM...10...13...56...Noon 07:26 AM...10...14...24...Sunset 07:42 AM...10...14...40...UNDOCKING 07:43 AM...10...14...41...ISS holds attitude 07:47 AM...10...14...45...Range: 50 feet; reselect -X jets 07:49 AM...10...14...47...Range 75 feet; low Z 08:02 AM...10...15...00...Sunrise 08:11 AM...10...15...09...Range: 400 feet; start fly around 08:20 AM...10...15...18...Range: 600 feet 08:22 AM...10...15...20...Shuttle directly above ISS 08:29 AM...10...15...27...Noon 08:34 AM...10...15...32...Shuttle directly behind ISS 08:45 AM...10...15...43...Shuttle directly below ISS 08:57 AM...10...15...55...Separation burn No. 1 08:57 AM...10...15...55...Sunset 09:25 AM...10...16...23...Separation burn No. 2
6:30 PM, 6/9/08, Update: Fossum says port SARJ looks good compared to damaged starboard rotary joint; cleaning feasible, but a 'big job'
The powder-like debris dusting the outer edge of the space station's left-side solar array rotary mechanism does not appear to represent a serious problem, spacewalker Mike Fossum said today. He said the grease and debris seen on the port solar alpha rotary joint does not look anything like the much more severe contamination that has hobbled the station's right-side SARJ.
"There's really no similarity because on the starboard side, the damage is extensive and apparent," Fossum said during a crew news conference aboard the station. "The bearing surface itself is severely eroded, maybe not very thick but there's definitely a lot of damage there. On the port side, you really didn't see that at all. You see a little bit of the grease that some expected, and some didn't. It's really unclear.
"The particles over there (on the port drive gear), it's just a few fine, almost powder-like particles. On the starboard side, it's metallic particles that are clinging to things, you can see magnetic pattern kind of features in there, the way they cling to corners and things like that. On the port side, there's nothing like that. It's more like just a little bit of dust, maybe kind of like the dust you have on your brakes."
The international space station is equipped with two motor-drive 10-foot-wide SARJ gears, one on either side of the lab's main power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. The devices are crucial for maximizing the electricity the station's solar panels can generate.
Last summer, engineers began noticing higher-than-usual vibration levels in the right-side joint mechanism, along with electrical current spikes indicative of increased friction as the gear rolled through 12 trundle bearing assemblies. During a subsequent spacewalk inspection, astronauts discovered extensive metallic contamination covering the active drive gear and degradation, or erosion, of at least one of the gear's bearing surfaces.
Despite extensive troubleshooting, engineers still don't know what might be causing the damage. One possibility is a small crack or breakdown in the hardened bearing surface that produced debris that was then crushed as it passed through the trundle bearings, causing more damage and creating more debris. Whatever the cause, it is a serious problem and flight controllers no longer operate the right-side SARJ in "auto-track" mode.
The left-side SARJ is operating normally, but Fossum spotted buildups of grease during an inspection Thursday. Photographs also indicted small amounts of an unknown material dusting the outer edge of the drive gear.
Engineers believe the grease may be coming from one or more of the trundle bearings the gear rolls through and it may be beneficial in slowing or preventing the sort of surface breakdown that has damaged the right-side gear. In any case, the grease is not thought to be an issue. The source of the powder-like material is not yet known, but Fossum collected samples during a spacewalk Sunday.
Each SARJ is made up of two identical drive gears, only one of which is used at any given time. NASA managers are holding open the option of moving all 12 trundle bearings and two drive motors to the backup gear in the right-side SARJ, but they don't want to take that step without first knowing what happened to the current drive gear to make sure the problem doesn't crop up again.
In the near term, astronauts may attempt to clean up the contamination in the starboard SARJ using grease and cloth wipes to get as much mileage out of the damaged gear as possible before switching to the backup gear. Fossum tested cleaning procedures during a spacewalk last Tuesday and while they seemed to work, "that's going to be a big job."
"What you'd really like to do is go out there with a shop vac, but that's not going to work for obvious reasons," Fossum said today. "And they don't want to use a brush that would cause all those particles to end up just in other places or perhaps clinging to solar arrays and causing other problems.
"So the grease looks like it's a pretty good answer. It's going to be a lot of work, but you can lay down a bead of grease, kind of wipe it across the surface you're trying to clean, and then scrape that up to get most of (the debris) and then go over it with essentially a terry cloth wipe, It's kind of a mitt with terry cloth on one side to clean up most of the grease. Maybe we see from the port side that a little bit of grease isn't a bad thing."
Fossum and his crewmates - commander Mark Kelly, pilot Kenneth Ham, flight engineer Ronald Garan, Karen Nyberg, Japanese astronaut Akihiko Hoshide and returning space station flight engineer Garrett Reisman - spent the day replacing spacesuit battery chargers in the Quest airlock module, testing the Japanese Kibo module's robot arm and re-opening a storage module that was bolted to the top of Kibo on Friday.
Reisman's replacement - Gregory Chamitoff - will remain behind aboard the station with Expedition 17 commander Sergei Volkov and Oleg Kononenko when Discovery undocks Wednesday. Hatches between the two spacecraft will be closed Tuesday evening.
"This is so much fun," Chamitoff said today. "The station is huge and there's plenty or room here for 10 people to work hard and do what we've done. I think when they leave, it's going to be very sad for me to see them go. I think that one moment, when we close the hatch, that's going to be the hard moment. After that, I'm with really good friends that I've spent years training with and they've already been here for two months, so they know how to do it and they'll show me the ropes."
Reisman, launched to the station in March, said he's looking forward to getting back to Earth.
"As far as what I'm looking forward to the most, that's easy. I can answer that with two words and it's Simone Francis, who's my wife," he said, laughing. "No doubt about that. And our cat, Fuzzy. ... Let's see, as far as what I'll miss most, it's definitely just floating. We call it floating, but really it's more like flying because as soon as you push off, you're moving through the air like some kind of super hero and being able to do that every day as you're commuting to work, it's unreal. That's what I'll miss the most.
"As far as what I'm looking forward to eating the most, of course, I would love to have a good slice of pizza. We don't really have much bread on board," he said. "We eat mostly tortillas because bread makes too many crumbs. So a nice, big, fat hamburger bun or something like that would be great. And that's what I think about.
"But the truth is, adjusting back to gravity is not so easy. Just like adjusting to weightlessness takes some time, adjusting to gravity takes some time, too. So even though I have visions of stepping off the shuttle and chowing down on a giant T-bone steak or something, that's not going to happen. But eventually it will, and I'm looking forward to that day where I can enjoy my favorite foods and do some of the things I love to do that I haven't been able to do from up here."
6:38 AM, 6/9/08, Update: Astronauts plan robot arm tests; logistics module ingress
The Discovery astronauts plan to exercise the Japanese Kibo module's robot arm today and then stow it for the remainder of the shuttle crew's mission. The astronauts also plan to re-open the Japanese logistics module mounted atop Kibo Friday and replace two of four spacesuit battery chargers in the Quest airlock module.
The astronauts were awakened around 5 a.m. by a recording of the Texas A & M flight song beamed up from mission control for spacewalker Michael Fossum.
"Good morning, Discovery. And a special good morning to you this morning, Mike," astronaut Shannon Lucid called from Houston.
"That's the spirit of Aggie land!" Fossum replied. "Texas A & M University is indeed a very special place. Thanks to my Aggie wife this morning for that wakeup music, to all my Aggie friends and the hundreds of thousands of Aggies on campus and around the world. It's going to be a great day."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision K of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/09/08 Mon 05:02 AM...08...12...00...Crew wakeup Mon 07:02 AM...08...14...00...ISS daily planning conference Mon 08:02 AM...08...15...00...Spacesuit component swap Mon 08:07 AM...08...15...05...Japanese robot arm (JRMS) final deploy Mon 08:32 AM...08...15...30...EVA gear prepped for transfer to shuttle Mon 08:42 AM...08...15...40...JRMS maneuver to stow position Mon 09:27 AM...08...16...25...JRMS brake checkout Mon 09:32 AM...08...16...30...EVA gear transferred to shuttle Mon 09:52 AM...08...16...50...Middeck transfers Mon 10:42 AM...08...17...40...JRMS hold-release mechanism hold Mon 11:17 AM...08...18...15...Crew meals begin Mon 12:17 PM...08...19...15...Quest battery charge module changeout Mon 12:42 PM...08...19...40...Logistics module vestibule outfitting (part 2) Mon 01:00 PM...08...19...58...GLAST pre-launch briefing on NTV Mon 02:22 PM...08...21...20...Logistics module ingress Mon 04:27 PM...08...23...25...Logistis module emergency power enable Mon 05:02 PM...09...00...00...Joint crew news conference Mon 05:42 PM...09...00...40...Joint crew photo Mon 06:30 PM...09...01...28...Mission status briefing on NTV Mon 08:02 PM...09...03...00...ISS crew sleep begins Mon 08:32 PM...09...03...30...STS crew sleep begins Mon 09:00 PM...09...03...58...Daily video highlights reel on NTV
4:40 PM, 6/8/08, Update: Spacewalk No. 3 ends
Astronauts Michael Fossum and Ronald Garan returned to the space station's Quest airlock module and began repressurizing the cramped chamber at 4:28 p.m. to officially end a 6-hour 33-minute spacewalk, the third and final excursion planned for the Discovery astronauts.
"Well, fellas, you did an awful lot of good work today," commander Mark Kelly radioed from just outside the airlock. "You ought to be very proud of yourselves."
"The people who deserve the credit are the people who got us here," Fossum replied. "Our EVA team ... those guys have worked tirelessly for the last year and a half to pull this off. They put up with a lot of stuff, figured out a lot of things. We're just the lucky guys on the pointy end out here."
The spacewalkers accomplished all of their primary objectives, installing a fresh tank of high-pressure nitrogen to help pressurize the station's cooling system; re-installing a repaired television camera; completing work to rig the new Kibo lab module for normal operations; installing micrometeoroid shields; and collecting samples of debris on the drive gear of the station's left-side solar array rotary joint.
They also completed several low-priority "get-ahead" tasks.
This was the 112th spacewalk devoted to station assembly and maintenance since construction began in 1998, the 13th so far this year and the third for Fossum and Garan. Total station spacewalk time now stands at 706 hours and 36 minutes, with Discovery's total at 20 hours and 32 minutes. Fossum now ranks 12th on the list of most experienced spacewalkers with a total of 42 hours and one minute in six spacewalks over two missions. Garan is making his first shuttle flight.
"It's dark and lonely out here in space," Garan joked at one point. "Everyone can hear you scream.'"
With just 10 shuttle missions left before the program ends in 2010, no astronaut can be assured of another flight and as one of the spacewalkers said today, "you never know when it's your last EVA." Both men marveled at the view from time to time, savoring the experience.
"Guys, we're coming over Houston right now," pilot Ken Ham radioed at one point.
"Oh my God."
"Goodness sakes," one of the spacewalkers exclaimed, looking down on Texas from 210 miles up.
"Wow."
12:50 PM, 6/8/08, Update: Nitrogen tanks swapped out; port SARJ debris collected
Perched on the end of the space station's fully extended robot arm, astronaut Ronald Garan manually carried a 528-pound nitrogen tank from one side of the lab's main power truss to the other today, enjoying a spectacular there-and-back windshield-wiper ride that carried him eight stories above the research station.
"Isn't that great view?" crewmate Michael Fossum asked.
"Unbelievable."
"And Ronny, you're coming up on the coast of Peru," astronaut Kenneth Ham radioed from inside the shuttle Discovery.
"All right. Beautiful!"
Working in orbital darkness 210 miles up, Garan first carried an empty nitrogen tank from its attachment slot on the right side of the space station's main power truss to a stowage platform on the left side of the station where Fossum was waiting. After mounting the empty tank on the stowage platform, Garan took the fully-charged replacement tank back to the right-side of the truss, enjoying a daylight ride over the Pacific Ocean and northern South America.
The spacewalkers were ahead of schedule at that point and Fossum was cleared to make his way to the nearby left-side solar alpha rotary joint, or SARJ, to collect samples of presumed debris he spotted on the mechanism's drive gear during a spacewalk Thursday.
After removing a thermal cover, Fossum used Kapton tape to capture samples of a powdery material on the 10-foot-wide drive gear. The joint had been repositioned since his last inspection, but Fossum reported seeing the same grease buildups on the gear that he noticed Thursday.
"The cover's removed and I see ... the same kind of streaking we had on the other side and one of the little, uh, grease balls," he reported, peering inside the joint. "I do see another feature on datum A (surface) that is gold in color. It's near a gear tooth, I definitely recommend getting a picture of that. It's hard to get an angle on it. It is a surface deposit also, I can see it sitting on the surface."
A few moments later, he collected debris samples from the outer canted surface of the drive gear.
"OK, Mike, next you're going to remove the tape and fold it in half, sticky side to sticky side, put it in your trash bag," Ham instructed.
"Roger that."
The station is equipped with two SARJ gears to rotate outboard solar arrays like paddle wheels to track the sun. The right-side SARJ has suffered a mysterious breakdown in one of its bearing surfaces, generating extensive metallic shavings and debris. During a spacewalk Tuesday, Fossum tested techniques for eventually removing the contamination to permit normal, or near normal, operation of the mechanism.
The left-side SARJ is working normally, but astronauts have been periodically inspecting it to make sure no problems are developing. Grease buildups, presumably from one or more of the 12 bearing assemblies the gear rolls through, were seen during an inspection last October and again when Fossum looked under thermal covers Thursday. But he also saw a powder-like debris on the outer edge of the drive gear and mission managers decided to add debris collection to the list of chores planned for today's spacewalk.
WIth the nitrogen tanks exchanged and the port SARJ inspection complete, Garan and Fossum will make their way to the Japanese Kibo module to remove window cover launch locks and thermal insulation on the lab's robot arm. They also plan to re-install a repaired television camera on the station's power truss.
9:55 AM, 6/8/08, Update: Spacewalk No. 3 begins
Running 37 minutes ahead of schedule, astronauts Ronald Garan and Michael Fossum, floating in the space station's Quest airlock module, switched their spacesuits to battery power at 9:55 a.m. to officially begin the Discovery crew's third and final planned spacewalk.
This is the 112th spacewalk devoted to station assembly and maintenance since construction began in 1998 and the 13th so far this year. Going into today's outing, total station assembly EVA time stood at 700 hours and three minutes while Fossum and Garan have logged 13 hours and 59 minutes outside during spacewalks Tuesday and Thursday.
7:45 AM, 6/8/08, Update: Astronauts prepare for final spacewalk
Astronauts Michael Fossum and Ronald Garan are preparing for a third and final spacewalk today, a six-and-a-half-hour excursion highlighted by a dramatic robot arm ride over the top of the international space station to replace a nitrogen tank. Dubbed the "windshield wiper maneuver," the ride from one side of the station to the other will put Garan "clearly on top of the world," said arm operator Karen Nyberg, as he carries the 550-pound tanks.
"If you think about it, I'm going to be on the end of the arm and as we're doing this windshield-wiper maneuver right here at the top, I'll be 80 feet above the station looking down at the station, looking down at the Earth," Garan said before launch. "It's going to be really exciting, it's going to be really challenging, but I'm really looking forward to it."
Fossum will stow the old tank and hand Garan the fully charged replacement. Fossum also plans to re-visit the left-side solar alpha rotary joint, or SARJ, remove a thermal cover and use Kapton tape to collect samples of dust-like debris he spotted on the joint's big drive gear during an inspection Thursday.
The space station is equipped with two SARJ gears, one on either side of the lab's main power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. The right side SARJ has suffered considerable damage to the surfaces of the 10-foot-wide drive gear that are gripped by 12 three-roller trundle bearings.
The left-side SARJ is operating normally, but Fossum spotted buildups of grease during an inspection Thursday. Photographs also indicted small amounts of an unknown material dusting the outer edge of the 10-foot-wide drive gear.
Engineers believe the grease may be coming from one or more of the trundle bearings the gear rolls through and it may be beneficial in slowing or preventing the sort of surface breakdown that has damaged the right-side gear. In any case, the grease is not thought to be an issue.
The dust-like material was somewhat of a surprise, Fossum said, but it is nothing like the damage and debris seen in the right-side SARJ.
"I don't believe it looks at all like the starboard side," Fossum told a reporter Saturday. "The starboard side definitely has metal shavings that show up and you can see some damage to the metal surface. There's just some things look different on the side we looked at the other day, the port side. It really looks to me like a little bit of grease, which is not a terribly big surprise when you're dealing with a bearing surface.
"Through the photographs, there might be a little bit of dusting of some other deposits around there. We plan to go out with a little bit of special tape and collect some of that dust from around the edge of the bearing. But really, that bearing looks to be in pretty darn good shape."
The crew was awakened at 5:32 a.m. by a recording of "The Mickey Mouse Club March" beamed up from mission control. The spacewalk, the 112th devoted to station assembly and maintenance since construction began in 1998, was scheduled to begin at 10:32 a.m. (as of 7:30 a.m., the astronauts were running about a half-hour ahead of schedule).
Along with the nitrogen tank swap out and SARJ work, the spacewalkers also plan to re-install a repaired TV camera on the power truss and remove launch locks and insulation from the Japanese robot arm on the outboard end of the Kibo lab module.
But the major objective of today's work is to replace a nitrogen tank assembly, or NTA, used to pressurize the station's ammonia coolant loops. The depleted tank is located in the right side S1 segment of the station's power truss while the replacement, launched earlier, is mounted on an external stowage platform - ESP-3 - on the left side of the truss.
After exiting the Quest airlock module, Fossum will make his way to ESP-3 to prepare the new tank for handoff while Garan proceeds to the right side of the truss to pull out the depleted tank.
"This is going to be an absolutely spectacular EVA," Garan said in a NASA interview. "What's going to happen is I'm going up to the (right side of the) truss, to S1, where the old NTA is and I'll do the final preparations to pull it out of the truss. Meanwhile, Mike is going to translate all the way out to (the left side of the power truss) where the spare is and he's going to make the final preparations to receive the old NTA and to get the new NTA ready to move.
"So when everything is all set, I'm going to get onto the end of the space station's robotic arm and I'm going to pull the NTA out of the truss as the arm is backing away from the truss. And so when we get out a safe distance away from the truss, I'll have this 550-pound box in my hand and the space station's robotic arm is basically going to do what we call the Ôwindshield wiper maneuver' and it's going to go over the top over to ESP-3. So this maneuver takes about 20 minutes and on the top here I'll be almost (six stories) above the station looking straight down on the aft side of the station and the Earth (210) miles below. So it'll be a pretty spectacular view and, and pretty spectacular ride over to ESP-3."
Nyberg, assisted by Japanese astronaut Akihiko Hoshide, will be operating the station arm.
"It's going to be a fun ride for him because the arm is going to go completely stretched out up in a big arc over to the other side of the truss and so he'll be clearly on top of the world at that point."
Once on Fossum's side of the power truss, "we will stow the old nitrogen tank assembly on ESP-3," Garan said. "I'll grab the new one and we'll just do the maneuver right back to the other side where I'll install it back on S1. Meanwhile, Mike's out and tying up ESP-3, making sure that that NTA is ready to come back to Earth when we're ready to do that on a later mission. So that's the big thing that we're going to do.
"After that, we've got a number of other tasks, a whole bunch of maintenance of tasks on the station. Mike's going to go back out to the Japanese laboratory and finish some of the work on the robotic arm that we couldn't do because on EVA-2 it was in the launch configuration and we couldn't get at some of the covers and some of the fasteners that we needed to undo."
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision K of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/08/08 05:32 AM...07...12...30...Crew wakeup 06:02 AM...07...13...00...ISS daily planning conference 06:12 AM...07...13...10...EVA-3: 14.7 psi repress/hygiene break 06:57 AM...07...13...55...EVA-3: Airlock depress to 10.2 psi 07:22 AM...07...14...20...EVA-3: Campout EVA preps 08:57 AM...07...15...55...EVA-3: Spacesuit purge 09:12 AM...07...16...10...EVA-3: Spacesuit prebreathe 10:02 AM...07...17...00...EVA-3: Crew lock depressurization 10:32 AM...07...17...30...EVA-3: Spacesuits to battery power 10:37 AM...07...17...35...EVA-3: Airlock egress 11:07 AM...07...18...05...EVA-3: Fossum: Retrieve ESP-3 NTA 11:07 AM...07...18...05...EVA-3: Garan: Remove S1 NTA 12:17 PM...07...19...15...EVA-3: Fossum: Stow S1 NTA on fram 12:27 PM...07...19...25...EVA-3: Garan: S1 NTA install 12:47 PM...07...19...45...EVA-3: Fossum: Cleanup ESP-3 worksite 01:22 PM...07...20...20...EVA-3: Garan: SSRMS cleanup 01:27 PM...07...20...25...EVA-3: Fossum: JRMS insulation and launch lock removal 02:07 PM...07...21...05...EVA-3: Garan: S1 NTA connections 02:42 PM...07...21...40...EVA-3: Fossum: Kibo launch locks 02:42 PM...07...21...40...EVA-3: Garan: TV camera installation 02:57 PM...07...21...55...EVA-3: Fossum: Deploy micrometeoroid shields 03:02 PM...07...22...00...Logistics module vestibule outfitting 04:27 PM...07...23...25...EVA-3: Cleanup and airlock ingress 04:52 PM...07...23...50...EVA-3: Airlock repressurization 05:02 PM...08...00...00...Spacesuit servicing 07:00 PM...08...01...58...Mission status briefing on NTV 08:32 PM...08...03...30...ISS crew sleep begins 09:02 PM...08...04...00...STS crew sleep begins 10:00 PM...08...04...58...Daily video highlights reel on NTV; repeated hourly
8:44 AM, 6/7/08, Update: Japanese robot arm tests on tap (UPDATED at 3:30 PM with Fossum description of SARJ work; engineers want debris, not grease, samples)
The Discovery astronauts unlimbered the Kibo laboratory module's Japanese robot arm today and prepared spacesuits and equipment for a third and final spacewalk Sunday to collect samples of debris from a solar array rotary joint mechanism and install a tank of pressurized nitrogen for the space station's ammonia coolant loops.
"Preparations for the third walk are going great," said spacewalker Michael Fossum. "We've got the suits checked out and just about ready to go, all our tools packed up and after a few final procedures reviews, we'll be ready to go out the door tomorrow."
Mission managers early today approved a plan for Fossum collect samples of apparent debris he saw inside the station's left-side solar alpha rotary joint during the crew's second spacewalk Thursday.
The space station is equipped with two SARJ gears, one on either side of the lab's main power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. The right side SARJ has suffered considerable damage to the surfaces of the 10-foot-wide drive gear that are gripped by 12 three-roller trundle bearings.
The left-side SARJ is operating normally, but Fossum spotted buildups of grease during an inspection Thursday. Photographs also indicted small amounts of an unknown material dusting the outer edge of the drive gear.
Engineers believe the grease may be coming from one or more of the trundle bearings the gear rolls through and it may be beneficial in slowing or preventing the sort of surface breakdown that has damaged the right-side gear. In any case, the grease is not thought to be an issue.
A senior space station manager said in an email grease had been seen during an earlier inspection during shuttle mission STS-120 in October 2007 as well as during ground testing.
"Pictures after the EVA during (assembly mission) 10A did show us a similar appearance," he said. "The pictures from this EVA are of higher resolution and allow us to more definitively conclude it to be grease from the rollers. This is not unexpected as it was seen during our ground life tests."
The dust-like material was somewhat of a surprise, Fossum said, but it is nothing like the damage and debris seen in the right-side SARJ.
"I don't believe it looks at all like the starboard side," Fossum told a reporter today. "The starboard side definitely has metal shavings that show up and you can see some damage to the metal surface. There's just some things look different on the side we looked at the other day, the port side. It really looks to me like a little bit of grease, which is not a terrible big surprise when you're dealing with a bearing surface.
"But it was not expected. Through the photographs, there might be a little bit of dusting of some other deposits around there so right now, and this plan is changing by the hour, tomorrow we plan to go out with a little bit of special tape and collect some of that dust from around the edge of the bearing. But really, that bearing looks to be in pretty darn good shape."
During today's work aboard the space station, the astronauts continued outfitting and activating the Japanese Kibo lab module and re-establishing connections between Kibo and a smaller logistics module that was mounted atop the new laboratory on Friday.
Japanese astronaut Akihiko Hoshide also moved Kibo's robot arm, which will be used in the future to manipulate externally mounted payloads and experiments, for the first time to give Fossum and Ronald Garan access to launch locks that will be removed during Sunday's spacewalk.
The arm "was too close in the launch configuration to the module itself so that Ron and Mike cannot access those launch locks," Hoshide said in a NASA interview. "So what we're trying to do is to deploy it just a little bit, and that's called the 'initial deploy,' so they can access. We'll have them take off the launch locks and then we'll do a final deploy so that's away from the module and then later in the mission we'll do a checkout of the arm, making sure that the brakes are working correctly and then move it into a storage configuration."
Hoshide and shuttle commander Mark Kelly will take a call from Japanese Prime Minister Yasuo Fukuda at 7:02 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):
EDT........DD...HH...MM...EVENT 06/07/08 06:02 AM...06...13...00...Crew wakeup 08:02 AM...06...15...00...ISS daily planning conference 08:52 AM...06...15...50...Shuttle robot arm maneuver 09:02 AM...06...16...00...Airlock preps for EVA-3 09:27 AM...06...16...25...Middeck transfers 09:47 AM...06...16...45...EVA-3: Tools configured 10:27 AM...06...17...25...Kibo robot (JRMS) arm setup 11:17 AM...06...18...15...JRMS hold/release mechanism test 12:17 PM...06...19...15...JRMS initial deploy 01:32 PM...06...20...30...ISS crew meal 02:02 PM...06...21...00...Crew media interviews 02:22 PM...06...21...20...Shuttle crew meal 03:22 PM...06...22...20...Logistics module vestibule outfitting 05:02 PM...07...00...00...Station robot arm maneuver 05:27 PM...07...00...25...EVA-3: Procedures review 07:02 PM...07...02...00...Japanese VIP event 07:30 PM...07...02...28...Mission status briefing on NTV 07:57 PM...07...02...55...EVA-3: Mask pre-breathe/tool config 08:30 PM...07...03...28...VIP event replay with English translation; on NTV 08:42 PM...07...03...40...EVA-3: Airlock depress to 10.2 psi 09:02 PM...07...04...00...ISS crew sleep begins 09:32 PM...07...04...30...STS crew sleep begins 10:00 PM...07...04...58...Daily video highlights reel on NTV
8:30 PM, 6/6/08, Update: Astronauts may collect grease sample from port SARJ; photos of wing panel requested
The Discovery astronauts may be asked to collect a sample of the presumed grease seen inside the space station's left-side solar alpha rotary joint. NASA managers have not made a final decision, but engineers would like to get a sample to pin down where the grease might be coming from and astronaut Michael Fossum will be in the area during a third and final spacewalk Sunday.
"There is some discussion about potentially going back and looking at the port SARJ on EVA-3," Flight Director Annette Hasbrook said late today. "Some folks are interested in getting a sample of the grease that was seen. That is still very preliminary and that request will be taken to mission managers tomorrow morning for discussion. We need to be prepared to give the crew a briefing message on that so we are preparing a package for the crew telling them what we'd have to do if that decision is made to go out and re-inspect the port SARJ."
The station has two SARJ mechanisms, one on each side of the main solar power truss, that are designed to rotate outboard solar arrays like giant paddle wheels to track the sun. Each joint features a motor-driven 10-foot-wide gear that is gripped by 12 trundle bearing assemblies. The port SARJ is working normally, but the right-side SARJ has suffered major erosion of its bearing surface that has generated extensive metallic contamination.
During a spacewalk Tuesday, Fossum tested techniques for cleaning up the contamination and carried out a quick inspection of the left SARJ during a spacewalk Thursday. During a previous inspection of the port SARJ, grease was noted on the bearing surface. Engineers believe it may be coming from one or more trundle bearings and that it may be beneficial in slowing or preventing the sort of surface breakdown that has damaged the right-side gear.
In any case, engineers are not sure where the grease is coming from and a sample would help resolve the issue.
The astronauts were also asked to use a digital camera with a telephoto lens to take photographs of two of Discovery's wing leading edge panels. The shuttle's nose cap and wing leading edge panels endure the most extreme heating during re-entry and they are normally scrutinized with a laser scanner and high resolution cameras the day after launch.
But Discovery was launched without its heat shield inspection boom. The Kibo lab module it carried to the station was too big to include the boom and the crew of a shuttle mission in March left theirs behind for Discovery. It was retrieved during Tuesday's spacewalk and it will be used after undocking for a detailed inspection.
In the meantime, engineers are evaluating other photographs and data from sensors mounted behind the leading edge panels. Readings from one sensor showed a "spike" of 1.4 Gs during a flip maneuver during the shuttle's final approach to the space station. "There's been a request that you take some 800-millimeter photos of the starboard wing RCC panels 15 and 16," mission control radioed. "During your RPM (rendezvous pitch maneuver) on flight day three, we saw some pulses from the wing leading edge sensors, something on the order of about 1.4 Gs. Now that's normally in family, nothing that would cause any alarm all by itself, however we did not have all the wing leading edge sensors turned on. So 1.4 Gs, if that was the panel where the pulse originated, wouldn't be a big deal. But there's a chance that pulse originated from a panel that didn't have a wing leading edge sensor. Given the inverse square law and the damping, we don't have a whole lot of insight into how big that pulse would have been. That's why we want to take the pictures.
"There is not a high level of concern about this, but we do need to run this to ground and this data will help us close this out."
8:30 AM, 6/6/08, Update: Astronauts gear up for module move (UPDATED at 4:40 p.m. with module relocation)
The Discovery astronauts are working through a busy day inside the international space station, continuing the outfitting of the Japanese Kibo laboratory module and moving a smaller storage module to its permanent home on Kibo's upward-facing port.
At 8 a.m. today, video from cameras mounted on the shuttle's solid-fuel boosters was played on the NASA satellite television system, showing dramatic views of the orbiter as it climbed toward space last Saturday. The booster cam footage is part of NASA's post-Columbia focus on monitoring the health of the shuttle's heat shield from launch through end of mission.
The video released today was some of the best footage yet of a shuttle launch from the perspective of the boosters. While small bits of debris could be seen swirling between the shuttle and its external tank just before booster separation, nothing major could be seen and nothing of any significance hit the orbiter.
The major item on the agenda today for the Discovery astronauts was to move the Japanese pressurized logistics module, or JLP, from its temporary mounting point atop the Harmony module, where it was positioned after delivery in March, to its permanent location on the outboard upward facing port of the Kibo module.
Eight of Kibo's equipment and experiment racks were launched inside the logistics module and all eight had to be moved into the laboratory before the storage module could be moved today. In preparation for the move, the crew late Thursday locked one end of the station's robot arm to a grapple fixture on the front face of the station's main solar power truss. The other end of the arm was locked onto the logistics module.
After depressurizing the vestibule between the logistics module and Harmony, Karen Nyberg, space station flight engineer Gregory Chamitoff and Japanese astronaut Akihiko Hoshide disconnected and carefully maneuvered the module about 30 feet or so to its final location. Motorized bolts were then driven home to firmly lock the two modules together and by 4:04 p.m., the relocation was complete.
Hoshide planned to test the video workstation in Kibo that will be used later to operate the module's robot arm. He also planned to disengage brakes on the arm's joints and then reapply them in a procedure designed to release any stresses that might have built up in the arm during launch.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision H of the NASA television schedule):
EDT........DD...HH...MM...EVENT 06/06/08 06:32 AM...05...13...30...Crew wakeup 08:00 AM...05...14...58...Solid rocket booster video replay on NTV 08:17 AM...05...15...15...ISS daily planning conference 09:42 AM...05...16...40...Logistics module (JLP) vestibule configure for demating 09:47 AM...05...16...45...Middeck transfers 12:12 PM...05...19...10...JLP vestibule depressurization 12:27 PM...05...19...25...Media interviews with shuttle, station commanders 01:02 PM...05...20...00...Crew meals begin 02:02 PM...05...21...00...JLP grappled 02:12 PM...05...21...10...Harmony/JLP demate 02:57 PM...05...21...55...JLP unberthed 03:07 PM...05...22...05...JLP moved to Kibo (JPM) outboard 03:37 PM...05...22...35...JLP install on JEM 03:57 PM...05...22...55...1st stage bolts 04:17 PM...05...23...15...2nd stage bolts 05:57 PM...06...00...55...JLP vestibule pressure check 06:57 PM...06...01...55...Japanese robot arm activation 07:27 PM...06...02...25...Japanese robot arm stress release 07:30 PM...05...02...28...Mission status briefing on NTV 09:32 PM...06...04...30...ISS crew sleep begins 10:02 PM...06...05...00...STS crew sleep begins 11:00 PM...06...05...58...Daily video highlights reel on NTV
6:25 PM, 6/5/08, Update: Spacewalk No. 2 ends
Ending a seven-hour 11-minute spacewalk, astronauts Michael Fossum and Ronald Garan, assisted by shuttle commander Mark Kelly, began repressurizing the space station's Quest airlock module at 6:15 p.m. to close out the second of three planned excursions.
Today's spacewalk, the 111th devoted to station assembly and maintenance, pushed total station EVA time to 700 hours and three minutes since construction began in 1998. Garan and Fossum now have 13 hours and 59 minutes of spacewalking time through two EVAs and Fossum moves up to 23rd on the list of most experienced spacewalkers, with 35 hours and 28 minutes through five EVAs during two flights.
5:50 PM, 6/5/08, Update: Fossum inspects port SARJ; observes apparent grease streaks; unclear if damage present (UPDATED at 8:45 p.m. with mission briefing; port SARJ thought to be in good shape)
Toward the end of today's Kibo outfitting spacewalk, astronaut Michael Fossum removed a thermal cover over a section of the space station's left side solar alpha rotary joint for a quick inspection of its drive gear and bearing surfaces. He reported what looked like streaks of built-up grease but no signs of the sort of metallic filings and surface damage that have forced NASA to stop normal use of the station's right-side SARJ.
The port SARJ has been operating normally and Flight Director Annette Hasbrook said engineers believe the drive gear is in good condition. The grease, she said, may have originated with one or more of the 12 trundle bearing assemblies that hold the gear and allow it to smoothly rotate. A similar grease build up was spotted the last time the joint was inspected last year.
"What they saw, the trundle bearing as it's riding may not ride completely flat, there may be a little bias so you could see some, it's not grooving, but in a sense streaking, or wearing of material. And then the rest of it, it looked like a grease that was potentially on the bearing surface.
"They're pretty sure these trundle bearings have leaked a little bit of grease and that could be one of the reasons that we're not seeing any of the wearing on this assembly. It could be a lubrication factor. It could be something that's helping the rolling mechanism so you don't get any friction build up and you're not seeing any degradation."
But all in all, she said, the port SARJ appears to be in good shape.
The two SARJ mechanisms are critical to space station operations. They feature 10-foot-wide motor-driven gears gripped by powerful roller bearings to turn outboard solar arrays like giant paddle wheels to track the sun and maximize power generation.
Last summer, engineers noticed the right-side SARJ drive motor was working harder than expected. That, coupled with high vibration levels, led engineers to suspect some sort of interference or friction in the mechanism. An inspection during a subsequent spacewalk revealed extensive metallic shavings on the drive gear and bearing surface degradation.
Extensive troubleshooting has not yet been able to pin down what might be causing the damage. But engineers suspect a small crack or defect in one bearing surface might have resulted in cracks or debris that, as it ground through the bearings, caused further damage. Engineers want to make sure no similar process gets started on the left-side SARJ or the right-side SARJ's backup drive gear.
During a spacewalk Tuesday, Fossum experimented with scrapers, grease and towels to help engineers determine the best way for future crews to clean up the metal shavings and permit normal, or near-normal operation for as long as possible. Each SARJ is equipped with a backup drive gear and while many engineers think they will be forced to switch to the other, undamaged right-side gear sooner or later, they would like to get as much mileage as possible out of the damaged gear before taking any last-resort steps.
During today's spacewalk, Fossum was asked to take a quick look at the port SARJ gear just to make sure nothing unusual was going on there. His initial report caught everyone's attention but it later became apparent what he was seeing was similar to what was observed the last time the SARJ was inspected in 2007.
"OK. I'm looking at the outer ring, datum-A, and I see two features, which unfortunately look a whole lot like what we had on the other side," Fossum radioed, peering into the SARJ mechanism. "The overall condition, I do not see filings. There is one line in the datum A (bearing surface) that appears to be a drag line. It's about a quarter inch, three eighths of an inch in from the inside edge. There's a definite wear line at that location. It looks to me just like other damage I've seen to bearings the brakes and such. It's not totally uniform, there are some striations in it. There's some marks, and this around the, you can see the wear... can you see my WVS (helmet camera video) at all?"
"I can see something that looks like a groove," pilot Kenneth Ham replied from inside the shuttle Discovery.
"Yeah, there' a groove on the inside edge."
"Yes, on the inside edge, I can see that," Ham agreed.
"OK. There's also some features right under my finger," Fossum said. "Do you see my finger?"
"Yes sir."
"Right under that. And I can't tell if it's (raised) up or (depressed) down. It looks to me like it's a deposit. And as I get along the edge... yes, it's a deposit. It's not a divot. It's on the surface."
"OK, now is that in the path of where the bearing goes?" Ham asked. "Or is the bearing inside of that?"
"It's right on the edge," Fossum replied. "You can see the wear line where the bearing goes and it's right on the outside edge of that wear line."
"OK, so the bearing does not go over that."
"That's affirmative. That's affirmative," Fossum said. "And the other one is on the inside edge. They almost look alike, I mean it almost even looks like some grease where more of it got squished to the inside and just a few bits kind of gummed up and rolled out on the outside."
"OK, a little bit earlier you said it looked like a drag line," Ham said. "Now you're thinking it's possible it might be a, like grease piled up there?"
"There are features that run along the ring that you can see," Fossum said. "It's a dragging mechanism of some kind, it appears to me. You can see lines in it, it's not a uniform gray line."
A few minutes later, he reassured flight controllers, saying "again, I do not see any signs of metal shavings or any of the other kind of stuff that we had all over under the covers on the other side. This is a lot cleaner."
"It appears there's none of the kind of surface damage we had on the starboard SARJ?" Ham asked.
"No, there's not," Fossum replied. "There's not. There are a few lines that almost, again, almost look like grease or someting that's kind of squished out to the outside edge."
Hasbrook said engineers will study photographs of the area inspected by Fossum, but "it looked very similar to what was seen (last year)."
2:20 PM, 6/5/08, Update: Cameras installed; robot arm thermal shields removed; docking port prepped for logistics module
Astronauts Ronald Garan and Michael Fossum installed two television cameras on the Japanese Kibo module today, removed insulation from the joints of the lab's robot arm and prepared a docking port for the attachment Friday of a Japanese logistics module that was launched in March and temporarily mounted on the nearby Harmony module. The spacewalk is proceeding smoothly and the astronauts now are installing thermal covers over the fittings that helped secure Kibo in the shuttle Discovery's cargo bay for launch. There have been no problems of any significance and the spacewalkers are running a few minutes ahead of their timeline.
11:05 AM, 6/5/08, Update: Spacewalk No. 2 begins
Running a half hour ahead of schedule, astronauts Michael Fossum and Ronald Garan switched their spacesuits to battery power at 11:04 a.m. to officially begin a planned six-and-a-half-hour spacewalk to rig the new Kibo lab module for normal operation.
This is the 111th spacewalk devoted to station assembly and maintenance since construction began in 1998, the 12th so far this year and the second of three planned by Fossum and Garan. Total spacewalk construction time going into today's excursion was 692 hours and 52 minutes.
"Beautiful day on the Mediterranean coast," Fossum observed from the open airlock, looking down on Spain and southern France 210 miles below.
The first item on the agenda today is to install two television cameras on the Kibo lab module to help with future robot arm operations.
7:39 AM, 6/5/08, Update: Astronauts gear up for second spacewalk
Astronauts Michael Fossum and Ronald Garan are gearing up for a planned six-and-a-half-hour spacewalk today to mount cameras on Japan's Kibo lab module, remove launch locks and prepare a docking port for the attachment Friday of a Japanese logistics module.
The spacewalk, the second of three planned for the shuttle Discovery's mission, is scheduled to begin at 11:32 a.m. when Fossum and Garan, floating in the station's Quest airlock module, switch their spacesuits to battery power.
The spacewalkers spent the night in the airlock at a reduced air pressure of 10.2 pounds per square inch to help purge nitrogen from their bloodstreams as part of a standard protocol intended to prevent the bends after working in NASA's 5-psi spacesuits.
The astronauts were awakened at 6:32 a.m. by a recording of "Fly Away" by Lenny Kravitz beamed up from mission control.
"Good morning, Discovery," astronaut Shannon Lucid called from Houston. "A special good morning to you today, Ron."
"Good morning, Shannon," Garan replied. "Just want to thank my beautiful wife, Carmel, for that song and say hi to her and to my boys, Ronny, Joseph and Jake. Mike and I are getting ready to go out the door for our second spacewalk today, It's going to be a wonderful day! And i