Two astronauts from US completed a second spacewalk
Two astronauts from the US shuttle Discovery completed Sunday a second spacewalk as part of efforts to replace a depleted ammonia coolant tank Sony VGP-BPS9 ,Sony VGP-BPS8A outside the International Space Station.Mission specialists Rick Mastracchio and Clay Anderson finished their seven-hour, 26-minute walk in open space at 8:56 am EDT (1256 GMT), after installing a new ammonia tank on a space station truss, NASA officials said.
During the first spacewalk on Friday, Anderson and Mastracchio retrieved an experiment from the Japanese Kibo Laboratory on the station's porch and replaced a Rate Gyro Assembly, part of the station's navigation system Sony VGP-BPS8 ,Sony VGP-BPS9 .The final spacewalk of the mission is scheduled for Tuesday.
The Discovery, which blasted off from Kennedy Space Center at Cape Canaveral, Florida on Monday, docked on Thursday with the International Space Station.Besides the replacement ammonia tank, the gear included a freezer to preserve samples of blood, urine, saliva,and Sony VGP-BPS13 battery plants or microbes used in micro-gravity experiments for later analysis back on Earth.
ESA said the 700-kilogram (1,543-pound) CryoSat 2 is designed to pinpoint the effects of global warming on the Arctic and Antarctic ice, which cover about ten percent of Earth's surface and prove crucial for the Earth's climate on Dell latitude d520 battery ."Since Discovery's Ku-Band communications system is not functioning correctly, the space station's Ku system will transmit the heat shield video and laser scan to Mission Control for imagery experts to analyze," NASA said in a statement.
Using radar technology from 447 miles (720 kilometers) above Earth's surface, CryoSat 2 will measure the thickness of both land and floating ice and pinpoint changes to within 1 centimeter (0.39-inch) ¡ª impressive considering that the Antarctic ice sheet Dell latitude d600 battery can be up to 3.1 miles (5 kilometers) thick.
"The polar regions work like the refrigerators of the climate system," German glacial scientist Heinrich Miller explained. "These areas are really the important ones for our Earth climate."Scientists know there have been significant changes Dell latitude d610 battery in the polar regions and recent summers have seen record lows in the extent of summer ice cover in the Arctic sea, ESA said. But too little is known about how thick the ice is.
Meanwhile, the US National Aeronautics and Space Administration announced Saturday that Discovery's mission Sony VGP-BPS8 battery had been extended by an extra 24 hours for routine heat shield inspections.Landing was now scheduled for Monday, April 19, at 1254 GMT (8:54 am local time) to cap what will be a 14-day mission.
For coastal cities and islands, the specifics may be a question of survival.Discovery's Ku-Band system has been down since the shuttle reached orbit April 5.Normally the shield inspection Sony VGP-BPS8A battery is done before reentry but after undocking from the ISS. It is aimed at making sure heat shields have not been damaged by space debris or small meteorites.
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