ECO Sensor Glitch Postpones Atlantis Once Again
ANN REALTIME UPDATE 12.06.07 2120
EST: NASA now says the launch of the space shuttle
Atlantis will take place no earlier than Saturday, due to a
stubborn glitch with a fuel cutoff sensor system inside the
shuttle's external fuel tank.
The fuel cutoff sensor system is one of several that protect the
shuttle's main engines by triggering their shut down if fuel runs
unexpectedly low. Launch Commit Criteria require that three of the
four sensor systems function properly before liftoff.
Space Shuttle Program managers will hold a Mission Management
Team meeting Friday at 2 pm to discuss the issue and determine the
steps necessary to start a new launch countdown.
For the moment, there is no scheduled launch time for
Atlantis... but if NASA can fix the sensor problem, launch will
likely occur at 1543 EST Saturday.
"At least the issue wasn't weather." That's how one CNN
commentator summed up NASA's postponement of the launch of the
space shuttle Atlantis Thursday, due to two malfunctioning sensors
on the shuttle's external fuel tank.
There are four such engine cutoff (ECO) sensors, which measure
liquid hydrogen levels in the external tank to determine when the
shuttle's main engines should cutoff. NASA protocols require at
least three of those sensors to be operational to launch the
NASA engineers discovered the problem when they commanded the
sensors to indicate the tank was empty. The two problem sensors
continued to show the tank was full, NASA spokesman Paul Foerman
told The Associated Press.
A similar problem postponed the September 2006 launch of
Atlantis, as ANN reported. The delay
put an end to NASA's streak of three on-time shuttle launches this
Another attempt is scheduled for Friday, providing engineers are
able to determine the nature of the sensor problem.
STS-122 will deliver the European Space Agency's Columbus
scientific laboratory to the International Space Station.
ESA has worked on Columbus for over 22 years... making the
launch delay a nerve-wracking stutter for those involved in what
ESA station program manager Alan Thirkettle called "our
cornerstone, our baby, our module, our laboratory."
On Wednesday, NASA Administrator Michael Griffin admitted the
agency fell behind on design and development of the International
Space Station, though he said the agency has executed the plan well
"We the United States, as the senior partner in the space
station coalition, did not plan it well," Griffin said on the eve
of Columbus' launch. "It has taken far too long and I'll just leave
it at that."