"The work has gone extremely well today," NASA said after astronauts Doug Wheelock and Tracy Caldwell Dyson wrapped up work on the exterior of the ISS, some 350 kilometers (217 miles) above the Earth.

"It was a textbook space walk for Wheelock and Dyson," the US space agency said.

On Saturday, the pair tried without success to wrest the faulty pump module from the outside of the station during an eight-hour walk that was the longest in ISS history, and the sixth longest ever.

The astronauts successfully disconnected three of four fluid lines connected to the pump but a fourth line leaked, forcing them to stop work, NASA said.

The pump, which failed unexpectedly July 31, will be replaced with a spare pump module during a third spacewalk scheduled for "no earlier than Sunday," NASA said.

Conditions on the ISS remained stable and the station's six-person crew -- three Americans and three Russians -- was not in danger, NASA officials said.

Astronauts switched to a back-up cooling system and the ship's crew transferred batches of experiment samples to a different freezer to preserve them, NASA said.

If the second of the two ISS cooling units fails -- a highly unlikely scenario, according to NASA -- then the ISS astronauts would no longer be able to cool most of space station components.

But the crew would not be in danger because they could move to the Russian segment of the ISS, which has its own cooling system.

According to NASA figures, without thermal controls the ISS's sun-facing side would roast at 250 degrees Fahrenheit (121 Celsius), while the outpost's dark side would plunge to some minus 250 degrees Fahrenheit (minus 157 Celsius).

The ISS, a 100-billion-dollar project involving 15 countries, is a sophisticated platform for scientific experiments. It has been manned continuously since October 1990.

earlier related report
Astronauts embark on second spacewalk to fix cooling system
Washington (AFP) Aug 11, 2010 - NASA astronauts aboard the International Space Station Wednesday began a second spacewalk to work on repairing a failed cooling system, the space agency said.

Astronauts Doug Wheelock and Tracy Caldwell Dyson suited up and switched to independent power in the space station airlock at 1227 GMT, initiating the walk in space.

Once outside the station, they will work to unhook and remove a busted pump module that caused the cooling problem in preparation for attaching a replacement.

"If all goes as planned, the spare pump will be installed during the third spacewalk," said the US space agency, adding that that operation would be possible "no earlier than Sunday."

Wheelock and Dyson's first spacewalk on Saturday lasted eight hours and three minutes, the sixth longest ever, but they were unable to remove the defective pump.

They disconnected three of four fluid lines connected to the pump but a fourth line leaked, causing them to stop work, NASA said.

Conditions on the ISS remained stable and the station's six-person crew -- three Americans and three Russians -- was not in danger, NASA officials said.

If the spacewalk efforts this week fail -- a highly unlikely scenario, NASA has said -- the astronauts would no longer be able to cool most of the space station components.

But the crew would not be in danger because they could move to the Russian segment of the ISS, which has its own cooling system.

According to NASA figures, without thermal controls the ISS's sun-facing side would roast at 250 degrees Fahrenheit (121 Celsius), while the outpost's dark side would plunge to some minus 250 degrees Fahrenheit (minus 157 Celsius).

The ISS, which orbits 350 kilometers (220 miles) above Earth, is a sophisticated platform for scientific experiments.

It is a 100-billion-dollar cooperation between 15 countries, and has been manned uninterrupted since October 1990.

Astronauts plan second spacewalk to fix ISS cooling system
Astronauts aboard the International Space Station were preparing Wednesday to conduct a second spacewalk to repair a failed cooling system on the orbiter, NASA said.

Once outside the station, spacewalkers Doug Wheelock and Tracy Caldwell Dyson will work towards unhooking and removing the busted module that has caused the cooling problem before they can attach a replacement.

"If all goes as planned, the spare pump will be installed during the third spacewalk," said the US space agency, adding that that operation would be possible "no earlier than Sunday."

Wheelock and Dyson on Saturday undertook the longest spacewalk outside the ISS and, at eight hours and three minutes, the sixth longest ever, but still could not wrest the faulty pump module from the outside of the station's first starboard truss.

Conditions on the ISS remained stable and the station's six-person crew -- three Americans and three Russians -- was not in danger, NASA officials said.

If the spacewalk efforts this week fail -- a highly unlikely scenario, NASA has said -- the astronauts would no longer be able to cool most of the space station components.

But the crew would not be in danger because they could move to the Russian segment of the ISS, which has its own cooling system.

According to NASA figures, without thermal controls the ISS's sun-facing side would roast at 250 degrees Fahrenheit (121 Celsius), while the outpost's dark side would plunge to some minus 250 degrees Fahrenheit (minus 157 Celsius).

The ISS, which orbits 350 kilometers (220 miles) above Earth, is a sophisticated platform for scientific experiments.

It is a 100-billion-dollar cooperation between 15 countries, and has been manned uninterrupted since October 1990.

del.icio.us	Digg	Reddit
YahooMyWeb	Google	Facebook

Memory Foam Mattress Review

SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News