A new study shows that despite regular exercise, astronauts on long-duration spaceflights experience significant muscle wasting and a surprising loss of force, reducing their efficiency in space and their ability to respond to emergencies when returning to Earth.

The research suggests the reduction in the capacity for work after six months in space can exceed 40 percent, which would temporarily reduce the performance of a returning astronaut to that of an 80-year-old. The study suggests more effective exercise techniques are required to keep astronauts in shape during long missions.

Robert Fitts of Marquette University, lead author of a paper published … Read more

KENNEDY SPACE CENTER, Fla.--Astronauts Douglas Wheelock and Tracy Caldwell Dyson wrapped up a successful spacewalk Monday, installing a new ammonia pump to help flight controllers recover from a failure that shut down half the International Space Station's cooling systems.

"We had an extremely successful EVA today," Kirk Shireman, deputy manager of the space station program at the Johnson Space Center, said after the spacewalk. "We're very pleased with the results. We still have some more activities this afternoon and tomorrow to fully recover from the pump module failure, but things are certainly looking positive … Read more

KENNEDY SPACE CENTER, Fla.--Spacewalker Douglas Wheelock, given permission to "shake violently" a stuck ammonia connector, used a healthy dose of elbow grease to finally get a troublesome coolant system quick-disconnect fitting to release Wednesday on the International Space Station.

With the fourth and final ammonia line finally free, Wheelock and crewmate Tracy Caldwell Dyson removed a faulty coolant pump, clearing the way for installation of a replacement during a third spacewalk planned for Monday.

A fourth spacewalk likely will be required later to wrap up loose ends and move the old pump to a permanent stowage location.… Read more

KENNEDY SPACE CENTER, Fla.--Flight controllers are revising plans for a second spacewalk Wednesday to replace a coolant pump aboard the International Space Station, adding work to isolate an ammonia leak that should clear the way for installation of a new pump during a third spacewalk Sunday.

A formal decision on whether to proceed with the Wednesday spacewalk is expected after NASA's space station Mission Management Team reviews preparations during a meeting Tuesday at the Johnson Space Center in Houston.

The pump module, one of two in independent coolant loops, circulates ammonia through huge radiators to dissipate the heat … Read more

NASA is refining plans for two spacewalks by astronauts to replace a large ammonia pump module that shut down Saturday, knocking out one of the International Space Station's two cooling loops.

Astronauts Douglas Wheelock and Tracy Caldwell Dyson hope to carry out the first spacewalk Friday, starting at 6:55 a.m. EDT, and a second excursion August 9 to finish the job, one of the so-called "big 14" on a list of critical components that require spacewalk repair if problems crop up.

NASA managers initially targeted Thursday for the first spacewalk and Sunday for the second … Read more

Trouble with one of the International Space Station's external coolant loops (PDF), used to dissipate the heat generated by the lab's electronics systems, triggered an extensive powerdown late Saturday. NASA managers met Sunday and gave preliminary approval to a difficult two-spacewalk repair job, starting as early as Thursday, to restore the critical system to normal operation.

It is not yet clear what went wrong, but the ammonia pump module that is part of coolant loop A, mounted on the right side of the station's main power truss, failed around 8 p.m. EDT Saturday. A problem somewhere … Read more

NASA's aging Spirit Mars rover, stuck in loose soil and forced to endure the harsh Martian winter with reduced solar power, has not phoned home since March 22. Officials warned Friday that "a miracle" may be needed to restore the rover to limited operation.

No longer mobile, Spirit was unable to orient itself to maximize solar-power levels before the onset of its fourth winter on Mars. Engineers expected the rover to put itself into electronic hibernation, suspending communications and conserving power to warm and recharge its batteries and to run an internal clock.

The rover is programmed … Read more

A House committee on Thursday approved an amendment to a bill that would clear NASA to launch an additional shuttle flight next summer to deliver critical supplies and equipment to the International Space Station.

The move came as the House Committee on Science and Technology was reviewing its version of NASA's $19 billion 2011 funding package. The Senate version of the appropriations legislation already included the additional flight. But major differences remain in other key areas, including how much money goes to support development of a new private-sector manned launch industry, the timetable for development of a NASA heavy-lift … Read more

KENNEDY SPACE CENTER, Fla.--An unmanned Russian supply ship successfully docked with the International Space Station Sunday, two days after an interference issue with a television transmitter in a backup docking system triggered an unexpected abort.

For the second attempt, the backup TORU system was not activated, there was no interference, and the KURS automated rendezvous system worked flawlessly, lining the Progress up for a docking at the Zvezda command module's aft port.

After a brief period of station-keeping, the cargo ship resumed its approach, docking on time at 12:17 p.m. EDT as the two spacecraft sailed … Read more