Spacewalk performed despite approaching space junk
September 3, 2009 By MARCIA DUNN , AP Aerospace Writer
In this Tuesday Sept. 1, 2009 photo provided by NASA, astronaut Nicole Stott, Expedition 20 flight engineer, participates in the STS-128 mission's first session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 35-minute spacewalk, Stott and astronaut John "Danny" Olivas unseen, mission specialist, removed an empty ammonia tank from the station's truss and temporarily stowed it on the station's robotic arm. (AP Photo/NASA)
(AP) -- Two astronauts stepped out on a spacewalk to install a new tank of space station coolant Thursday as a large piece of orbiting junk headed their way.
The old rocket part was expected to pass within two miles of the shuttle-station complex late Friday morning, considered a safe distance by NASA specialists. Managers decided there was no need to move the linked spacecraft out of the way and proceeded with the spacewalk as planned.
Danny Olivas and Christer Fuglesang were nearly an hour late heading out the hatch because of minor spacesuit problems. It was the second spacewalk in three days for the Discovery and space station crews.
Their main job 220 miles up was to collect the new fully loaded ammonia tank from Discovery and hook it up to the space station. The old tank, launched seven years ago, was removed during Tuesday night's spacewalk. It will be returned to Earth next week aboard Discovery.
The tanks are big and awkward for spacewalkers to handle: nearly 5 feet long, 7 feet wide and 4 feet high. The new one weighs 1,700 pounds.
Both men are experienced spacewalkers. Fuglesang is Swedish.
At one point Wednesday, NASA considered moving Discovery and the space station into another orbit because of the space junk, and possibly even delaying this spacewalk. But by Thursday morning, the track of the debris became clearer and experts were able to say with certainty that the two spacecraft and 13 astronauts were safe where they were.
A third and final spacewalk is scheduled for Saturday.
Discovery is scheduled to undock from the space station Tuesday.
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Sep 02, 2009 |
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Surely more desireable and cost-effective than manouvering the massive station and any deliver vehicles out of the course of space debris? Within a few years those types of manouvers are going to become constant.
How much fuel will that require?
How does it effect onboard equipment and experiments?
With varying orbits, altitude, Earth/Moon Gravity/EM fields and vibration from the ISS thrusters, how can onboard experiments maintain 'stable' conditions throughout their lengthy runs? Isn't the thruster vibration alone going to cause increased maintenance to the extended arms carrying delicate equipment such as the solar arrays?
Ballistic deflection or retrieval/deflection robot units should be more cost effective in the long term, and permit greater stability to the ISS orbit.