STS-122 shuttle mission – what are the engine cutoff sensors (ECO)?
STS-122, which was scheduled to launch today at 4:31 EST, was rescheduled to liftoff Friday December 7th after mission management discovered that two of the four engine cutoff sensors (ECO) failed to respond to pre-launch specifications for a go-for-launch.
But, just what are engine cuttoff sensors?
In a March 2006 status report NASA stated that, “These sensors indicate whether the tank still has fuel during its climb to orbit. ”
In a press briefing in April 2005, NASA Associate Administrator William Readdy said this about the ECO, “The launch commit criteria for those things–and basically what they do is they signal that the tank has either got fuel in it or it’s empty.”
Source: NASA Press Briefing, April 29, 2005
In a NASA press release today (Dec 6) NASA said:
The tank’s liquid oxygen and liquid hydrogen will be drained from the tank, and preparations will begin for a possible launch attempt tomorrow. NASA’s launch rules have a preplanned procedure that states in the case of ECO sensor system failure, engineers need to drain the tank and verify all the sensors are working as they go dry.
More information on the ECO sensors:
- See a picture of the engine cutoff sensors (ECO).