for National Geographic News
Astronauts on the International Space Station are scrambling to fix a computer that has taken down critical systems necessary to generate oxygen and maintain the station's orientation with respect to the sun.
Though NASA officials and outside observers are confident that the problem can be fixed, it raises the question of how exactly the aging station could be evacuated in the case of an emergency (pictures: space survival.)
How could the crew get home?
Option 1: Evacuation by Space Shuttle
The space station currently has ten people aboard, seven from Atlantis plus the station's three temporary residents.
But "everyone on the station now could get on it and come down, if they needed to," said Roger Launius, chair of the Division of Space History at the National Air and Space Museum in Washington, D.C.
Currently Atlantis's thrusters are keeping the station in a stable orbit, but the shuttle has only enough fuel for a few more days.
Option 2: Escape Pod
Space station astronauts arrive and depart via three-person Russian Soyuz spacecraft. One of these remains at the station at all times, specifically as an escape pod.
Since there are only three astronauts on the space station at any given time, all three could evacuate via a Soyuz craft, even without a visiting space shuttle.
Not an Option: Unmanned Cargo Ship
Unmanned Russian space freighters carry everything from food to fuel to newspapers to the station. But they do not provide a way home.
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