Launch: April 5, 2010
Time: 6:21 a.m. EDT
Site: Pad 39A, Kennedy Space Center
Landing: April 19 @ approx. 8:50 a.m.
Site: KSC's Shuttle Landing Facility
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Welcome to Spaceflight Now's live coverage of space shuttle Discovery's STS-131 mission to the International Space Station. Text updates will appear automatically; there is no need to reload the page.
TUESDAY, APRIL 13, 2010Engineers are troubleshooting a stuck valve in a nitrogen tank assembly that's needed to pressurize a new ammonia coolant tank installed on the space station by the Discovery astronauts.
If ground commanding does not resolve the problem, a spacewalk by the station astronauts could be required to install a spare nitrogen tank assembly to avoid a major powerdown due to higher temperatures caused by the changing orientation of the station's orbit with respect to the sun.
Engineers are hopeful it won't come to that.
1257 GMT (8:57 a.m. EDT)Efforts by flight controllers to activate the newly installed ammonia tank ran into a problem with a nitrogen valve this morning. The valve appear to be stuck, NASA says. Troubleshooting is ongoing.
1243 GMT (8:43 a.m. EDT)Discovery astronauts Rick Mastracchio and Clay Anderson have completed their three arduous spacewalks for the mission to replace a spent ammonia coolant reservoir on the International Space Station and stow the old tank aboard the shuttle for return to Earth. They encountered some frustrating struggles with troublesome bolts along the way but got the job done. Over 20 hours of EVA time was accumulated to complete the tank exchange, plus other maintenance chores outside the orbiting outpost and "get-ahead" tasks for future missions.
1240 GMT (8:40 a.m. EDT)This was the sixth EVA in the careers of both astronauts. Rick Mastracchio has accumulated 38 hours, 30 minutes and Clay Anderson 38 hours, 28 minutes of spacewalking time on their previous three excursions in 2007 and the three on this mission.
1238 GMT (8:38 a.m. EDT)EVA ENDS. Repressurization of the Quest airlock module began at 8:38 a.m. EDT, marking the official end of today's spacewalk by Rick Mastracchio and Clay Anderson. The EVA lasted 6 hours and 24 minutes.
This was the third of three spacewalks planned for Discovery's mission to the space station. The time elapsed for the excursions totaled 20 hours and 17 minutes.
1235 GMT (8:35 a.m. EDT)The airlock hatch has been closed and locked. Standing by for repressurization.
1226 GMT (8:26 a.m. EDT)The spacewalkers are climbing into the airlock to finish this final EVA of the mission.
1214 GMT (8:14 a.m. EDT)Passing the six-hour mark of the spacewalk. The astronauts are beginning to wrap things up.
1205 GMT (8:05 a.m. EDT)Clay Anderson is working at the tool boxes mounted on the outside of the Quest airlock to relocate some equipment while Rick Mastracchio moves cabling at the Z1 truss to help out the spacewalkers on Atlantis' mission next month.
1142 GMT (7:42 a.m. EDT)At the Kennedy Space Center, the roll of shuttle Atlantis continues slowly. The spacecraft's tail has emerged from its garage as the technicians back the orbiter outside for today's move to the VAB.
1140 GMT (7:40 a.m. EDT)As a "get-ahead" task to prepare for the next shuttle construction flight to the International Space Station, the spacewalkers are checking the Z1 truss area where a spare space-to-ground communications antenna will be installed.
1125 GMT (7:25 a.m. EDT)Given the delays the spacewalkers experienced with the ammonia tank today, Mission Control deleted the planned retrieval of an experiment carrier platform from the European Space Agency's Columbus lab module. That won't occur on Discovery's mission after all.
1121 GMT (7:21 a.m. EDT)Down at the Kennedy Space Center, space shuttle Atlantis has begun its departure from the orbiter processing facility this morning. Mounted atop a trailer-like transporter, Atlantis is being moved over the Vehicle Assembly Building for mating to its external fuel tank and solid rocket boosters in preparation to launch next month.
1100 GMT (7:00 a.m. EDT)The spacewalkers are moving on to other activities now. Anderson is positioning two portable foot restraints on the station's exterior and Mastracchio is stowing the grapple fixture used in moving the old ammonia tank.
1035 GMT (6:35 a.m. EDT)At last, all four bolts are torqued sufficiently. The depleted ammonia tank is locked down in the payload bay of space shuttle Discovery for the ride back to Earth.
1018 GMT (6:18 a.m. EDT)Efforts by flight controllers to activate the newly installed ammonia tank has run into a problem with a nitrogen valve that's apparently stuck.
0957 GMT (5:57 a.m. EDT)Still no luck getting the final bolt tightened.
0945 GMT (5:45 a.m. EDT)Mastracchio is having trouble getting one of the bolts engaged on the tank.
0910 GMT (5:10 a.m. EDT)With Clay Anderson now standing in a foot platform and Rick Mastracchio floating nearby, the two spacewalkers have taken the spent ammonia tank from the station's robotic arm. They will seat the tank on the cross-bay bridge structure and bolt it down.
0855 GMT (4:55 a.m. EDT)Mastracchio and Anderson are in the shuttle bay to take a manual handoff of the tank and secure it on the carrier pallet.
0830 GMT (4:30 a.m. EDT)The depleted ammonia tank is heading down into Discovery's payload bay under the control of robot arm operators Stephanie Wilson and Jim Dutton.
0805 GMT (4:05 a.m. EDT)The spacewalkers have met up with the old ammonia tank, which is perched on the end of the space station's robotic arm. They are removing the attachment fixture that had been used to connect the tank to the mobile transporter since Sunday's spacewalk. This handling tool must be demated so the tank can fit in the shuttle's bay.
0733 GMT (3:33 a.m. EDT)Discovery astronaut Clay Anderson has picked up the debris shields that have been in storage on the space station's external stowage platform No. 2 for the past few months. These panels were removed from the outer hull of the Quest airlock module during a spacewalk on the previous STS-129 mission of shuttle Atlantis last November. The shields were removed to make room for installation of a new high pressure gas tank on the airlock.
Anderson and Mastracchio will bring the panels back inside the space station for packing into the Leonardo module and return to Earth. The cargo module is well suited for hauling such equipment to the ground.
0705 GMT (3:05 a.m. EDT)The International Space Station received its new Ammonia Tank Assembly on Sunday, and now the fluid lines are connected between the replenishing reservoir and the Starboard 1 truss to complete a major goal of space shuttle Discovery's mission.
The tank contains a few hundred pounds of ammonia for the station's thermal control loops that cool onboard hardware. Discovery's previous STS-128 flight last year replaced the ammonia tank on the Port 1 truss.
"The coolant that we use is ammonia, so it gets circulated by a pump, it picks up heat from all our avionics and through a heat exchanger, picks up the heat from our internal (equipment) inside all the laboratories," said station flight director Ed Van Cise. "That ammonia gets circulated out to our radiators and the radiators allow us to reject that heat from the ammonia out to the much colder space environment. That's how we keep everything cool."
When the truss segments housing the two ammonia tanks were launched, "the vast majority of the system was launched dry," Van Cise said. "It had nitrogen in it, we vented the nitrogen and then we had to fill the system with ammonia. So the original tanks that flew up full were depleted. If we had to, for some reason, refill the lines again due to a leak or something of that nature, we don't have enough ammonia to be able to do that.
"So to preposition ourselves for the long-term utilization of the space station, we're now replacing both sets of tanks so we have a full supply of ammonia so we can compensate if we need to. On a previous mission, we replaced the first ammonia tank and on this mission we're replacing the second."
0701 GMT (3:01 a.m. EDT)The second pair of ammonia and nitrogen press lines have been connected.
0651 GMT (2:51 a.m. EDT)Mastracchio has hooked up the first of two nitrogen pressurization umbilicals and the first of two ammonia transfer lines.
0648 GMT (2:48 a.m. EDT)Now in position Starboard 1 truss, Rick Mastracchio is working to complete the leftover work on the new Ammonia Tank Assembly that the spacewalkers attached on Sunday morning. They ran into delays getting the tank bolted in place and had to defer connecting the ammonia and nitrogen umbilicals, chores that he will complete right now.
0645 GMT (2:45 a.m. EDT)Meanwhile, the space station's robotic arm has grappled and plucked the old ammonia tank off the mobile transporter where it had hung out for the last two days. The tank will be berthed into Discovery's payload bay today.
0632 GMT (2:32 a.m. EDT)The opening tasks for the EVA will take the spacewalkers to separate locations. Mastracchio is en route to the new ammonia tank on the Starboard 1 truss for connecting the fluid lines while Anderson will be retrieving the debris panels from the external stowage platform No. 2 for return to the airlock.
0614 GMT (2:14 a.m. EDT)EVA BEGINS. The spacewalkers switched their suits to internal battery power at 2:14 a.m. EDT, marking the official start time for today's EVA by Rick Mastracchio and Clay Anderson. This is the third of three spacewalks planned during Discovery's mission at the International Space Station.
The EVA is getting underway 57 minutes ahead of schedule.
0612 GMT (2:12 a.m. EDT)The depressurization has been completed and the Quest airlock's outer hatch leading to space is being opened.
0539 GMT (1:39 a.m. EDT)Airlock depressurization now underway.
0532 GMT (1:32 a.m. EDT)The inner hatch separating the airlock compartment from the rest of the space station has been closed.
0518 GMT (1:18 a.m. EDT)The spacewalkers are fully suited up and now inside the section of the airlock that will be depressurized shortly.
0420 GMT (12:20 a.m. EDT)Spacewalk preparations are going well and Mission Control projects the crew is running about 65 minutes ahead of schedule. If the astronauts keep up this pace, the EVA will start a little after 2 a.m. EDT.
0335 GMT (11:35 p.m. EDT Mon.)Astronauts Rick Mastracchio and Clay Anderson are set for a third and final spacewalk Tuesday to complete the installation of a new ammonia coolant tank aboard the International Space Station. The astronauts also will mount a depleted tank in the shuttle Discovery's cargo bay for return to Earth and retrieve no-longer-needed debris shields.
Read our full story.
0222 GMT (10:22 p.m. EDT Mon.)Wakeup time has arrived for the space shuttle astronauts to start Flight Day 9 that features the third and final spacewalk of the mission. The EVA is slated to start a little after 3 a.m. EDT to finish hooking up the new ammonia tank on the space station and stowing the old tank in the shuttle payload bay.
0215 GMT (10:15 p.m. EDT Mon.)The latest version of the NASA Television schedule (Rev. I) can be downloaded here.
MONDAY, APRIL 12, 2010Russian President Dmitry Medvedev called the International Space Station early Monday to mark the 49th anniversary of Yuri Gagarin's historic flight, suggesting an international space summit to discuss ongoing and future cooperative ventures on the high frontier.
1520 GMT (11:20 a.m. EDT)
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1015 GMT (6:15 a.m. EDT)After enjoying about five hours of free time, the astronauts are back at work. Rick Mastracchio and Clay Anderson are in the airlock module getting their suits and tools ready for Tuesday's spacewalk. The other crewmates are busy with the seemingly never-ending task of moving equipment in and out of Leonardo.
0615 GMT (2:15 a.m. EDT)The latest version of the NASA Television schedule (Rev. H) can be downloaded here.
0405 GMT (12:05 a.m. EDT)The Discovery astronauts looked forward to a half day off early Monday to relax, share a meal with their space station counterparts and enjoy the view from 220 miles up. Later in the day, they will resume cargo transfer work before gearing up for a third and final spacewalk early Tuesday.
Read our full story.
0230 GMT (10:30 p.m. EDT Sun.)The latest version of the NASA Television schedule (Rev. G) can be downloaded here.
0152 GMT (9:52 p.m. EDT Sun.)As space shuttle Discovery's mission reaches the half-way mark, the astronauts are beginning Flight Day 8 that will include some off-duty time to catch their breath before continuing with Leonardo logistics transfers and preps for Tuesday morning's spacewalk. They'll also participate in some live television interviews at 11:36 a.m. EDT.
Read our earlier status center coverage.
Join Miles O'Brien, David Waters and Leroy Chiao for our live launch webcast from Kennedy Space Center starting at 2 a.m. EDT on launch morning.
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