Atlantis Undocks From Space Station

HOUSTON, June 19, 2007 — -- The Space Shuttle Atlantis undocked from the International Space Station this morning after a mission plagued with computer failures at the station.

The undocking started as scheduled at 10:42 a.m. EDT.

The computers that control the space stations attitude in orbit, among other things, passed a critical test Monday which gave the Mission Management Team at the Johnson Space Center confidence the computers were really working. The computers failed last week and had engineers in Russian stumped for three days, prompting Space Station Program Manager Mike Suffredini to consider unmanning the space station if the computers couldn't be fixed.

The orbital outpost is kept aloft in the right position by a combination of Russian thrusters and U.S. gyros. The gyros alone aren't enough to keep the space station positioned, so the thrusters on the space shuttle Atlantis were used to give the space station the lift it needed until the problem could be fixed.

NASA manager Phil Engelauf is pleasantly surprised Atlantis is not staying another day. "It is amazing we are getting ready to undock given the challenges we had on this mission," he said.

It was a frustrating three days for engineers on the ground in Russia's Mission Control as they repeatedly tried to detect signs of life in their computers and reboot them.

Engelauf says they know where the computers failed, but they still don't know why the computers failed. "We do not have a definitive answer about the cause, we have traced where we think the computer board failed, we have isolated where that fault occurred, we still have not established the underlying cause yet."

STS 117 Cmdr. Rick Sturckow said goodbye to his colleagues on the International Space Station. "It's been a great mission but all good things come to an end. We are taking Suni Williams home. I know you will miss her but it is time for her to go back to planet Earth.

He also referenced the challenges the crew faced on the mission, saying, "we faced adversity together, but with the help of our crews and the mission controls on the ground we overcame it."