PARIS — Europe's Automated Transfer Vehicle (ATV) cargo vessel March 14
successfully completed a key test of its emergency-abort sequence, performing a
collision-avoidance maneuver that ground teams hope will never be needed when
the time comes to dock with the international space station, European Space
Agency (ESA) officials said.
In the
maneuver, the 41,887-pound (19,000-kilogram)
ATV, named Jules Verne after the 19th century French science fiction
writer, was stopped in its tracks and thrown into reverse, firing four of its
thrusters to move backwards at a speed of around 16.4 feet per second (5 meters per second) to
simulate a slow retreat from the space station.
It is this
maneuver that will be required if, as it approaches the station for a planned
April 3 docking, its speed, approach angle or some other parameter poses a
safety concern for the station and its astronauts.
The March
14 test also demonstrated the ability of ATV to switch to its independent
backup computer, which would be required only if there are multiple failures of
the main computer system, which has its own backup.
ATV
managers say it is a highly unlikely scenario, but one that must be planned for
given the delicate nature of having a machine the size of ATV approach the
station.
With its
main computers shut off, the ATV automatically placed itself into survival
mode, pointing toward the sun to continue to feed its four power-generating
solar arrays to await further instructions from ground teams.
About 95
minutes after the reverse-thrust command, the vessel's main computers were
switched back on. It will now remain in its current orbit of some 190 miles (305
kilometers) in altitude until March 18, when it will begin its transition into
higher orbit as it prepares
its approach to the space station. The station's current orbit is about 211 miles (340
kilometers) in altitude.
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