Astronauts take 1st spacewalk of shuttle mission

In this image made from video and released by NASA, astronauts Rick Mastracchio, center, is seen preparing the external stowage platform on the International Space Station for the new ammonia tank during the first spacewalk on the International Space Station, Friday April 9, 2010. It will take three spacewalks to complete the job. (AP Photo/NASA)

Two astronauts from the shuttle Discovery began a six-and-a-half-hour spacewalk Friday, working on an ammonia tank on the outside of the International Space Station, NASA said.

Mission specialists Clayton Anderson and Rick Mastracchio left the shuttle's airlock at 0531 GMT for the first of three space walks during the 13-day mission to resupply the space station.

Mastracchio, the lead spacewalker, was seen in images beamed to Earth working on an ammonia tank on the outside of the space station, which will be replaced with a new tank. The ammonia is used in the space station's cooling system.

They will also retrieve a science experiment from a Japanese laboratory facility on the station's porch.

The Discovery, which blasted off from Kennedy Space Center at Cape Canaveral, Florida on Monday, docked on Thursday with the International Space Station.

Eight tons of supplies, gear and racks of science experiments were transferred from the shuttle to the space station in an Italian-made module known as Leonardo.

Besides the replacement ammonia tank, the gear included a freezer to preserve samples of blood, urine, saliva, plants or microbes used in micro-gravity experiments for later analysis back on Earth.

earlier related report
Discovery unloads supplies for space station
Washington (AFP) April 7, 2010 - The Discovery crew began to deliver supplies to the International Space Station on Thursday and prepared for the mission's first spacewalk a day after the US space shuttle docked with the orbiting station.

Discovery astronauts opened the hatch to unload the Italian-made Leonardo Multi Purpose Logistics Module to start the transfer some eight tonnes of science racks and other supplies into the space station, a job that will take several days, NASA said.

Discovery's Clayton Anderson and Soichi Noguchi opened the hatch to the "moving van" at around 1200 GMT.

American Stephanie Wilson and Japanese Naoko Yamazaki operated the ISS robot arm to extract the Leonardo and attach it to the Harmony node around 0430 GMT.

Discovery had carried the scientific equipment along with extra sleeping quarters to the ISS.

Other gear hauled into space included a freezer to preserve samples of blood, urine, saliva, plants or microbes used in micro-gravity experiments for later analysis back on Earth.

Discovery is also carrying an exercise machine designed to study the effects of weightlessness on the body's musculoskeletal system. Muscles can atrophy during long sojourns in space so astronauts have to exercise regularly.

The astronauts bunked down later and prepared for the mission's first spacewalk at 0541 GMT Friday.

The Discovery crew was welcomed with hugs and handshakes Wednesday aboard the International Space Station after a successful docking high over the Caribbean.

It marked the first time ever that four women were in orbit together, as well as the first time two Japanese astronauts were in space at the same time.

Discovery blasted off Monday from Kennedy Space Center at Cape Canaveral, Florida in a launch marred only by the failure of an antenna used to transmit television pictures back to Earth that also is part of its radar docking system.

The 13-day mission is one of the last before the US shuttle fleet is retired at the end of this year after 30 years of service.

The International Space Station, a 100-billion-dollar project begun in 1998 with the participation of 16 countries, is financed mainly by the United States.

Once the shuttle program ends, the United States will depend on Russian Soyuz spacecraft to ferry their astronauts to the station until a new US launch vehicle is ready to take over around 2015.