Spacewalk Includes Hurling Huge Components Into Space Today

NASA carefully studied the potential risks that might be created today when International Space Station (ISS) Astronaut Clay Anderson lobs hugely heavy, unneeded components into the void of space, deciding that there is no risk that later they might come sailing out of the darkness to strike the ISS, Space Shuttle Endeavour or other spacecraft or satellites.

Endeavour is set to launch from Kennedy Space Center on the STS-118 Mission to the space station at 7:02 p.m. ET Aug 7. (Please see Space & Missile Defense Report, Monday, July 16, page 6.)

Flight Engineer Anderson, part of the Expedition 15 crew on the space station, will venture outside the ISS through the Quest airlock to perform various tasks on his first-ever spacewalk, in a joint extravehicular activity (EVA) with Russian Cosmonaut Fyodor Yurchikhin, commander of the ISS Expedition 15, who will be marking his third EVA.

One task will have Anderson stand on the end of the Candarm2 robotic arm controlled by Cosmonaut Oleg Kotov, as Anderson tries out his fastball pitching skills on two unneeded components, hurling them away from the space station.

The spacewalkers will have jetpacks on their suits, so that if their tethers were to break they won’t go drifting off into space.

Bob Dempsey, Expedition 15 lead flight director, and Daryl Schuck, Expedition 15 lead spacewalk officer, briefed news media on the jettisoning plan.

Before the trash disposal move, the space station will be turned around so that discarded items will be thrown to the rear, with the artificial moon moving away from those items.

One item going into the dustbin of history will be the Early Ammonia Servicer (EAS), a unit no longer needed on the space station.

Even in the low-gravity environment of orbital space, Anderson may have to use some muscle on the EAS. On Earth, it tips off the scales at a hefty 1,400 pounds.

It turned out to be little needed on the space station, and a decision was made to jettison the system, rather than to spend money and effort to transport it back to Earth on a space shuttle. Also, there was little room on remaining shuttle flights, which will cease in 2010.

The EAS certification for use on the space station soon will expire, and recertification made less sense than pitching it, according to briefers.

Because items shoved off the space station may later come back into the same orbit, where they might hit the orbiting space home, the ISS will be moved into a higher orbit by firing thrusters on a Progress 25 spaceship docked with the ISS. The space station will be boosted to an orbit about 183 to 184 nautical miles above Earth. “We were going to have to do a re-boost anyway,” Dempsey said.

The jettisoned components are large enough that NASA will have no trouble tracking it, to ensure that it won’t endanger other spacecraft. “We should be able to track them extremely well,” because of their size, Dempsey said.

Eventually, the orbits will decay on the hefty components chucked off the space station, and they will reenter the atmosphere.

It’s possible that some shredded pieces of the EAS might survive the fiery trip through the upper atmosphere, but they likely would hit the ocean rather than land.

Space Station Video Tour

NASA launched a Web site that gives viewers a video tour of the International Space Station.

The Web address is http://www.nasa.gov/station on the Web.

That site also provides an up-to-date interactive overview of the station’s complex configuration, design and component systems.