Engineers check faulty gauges on Atlantis

Washington – Nasa will test next week the faulty fuel tank sensors that grounded the Atlantis mission to the International Space Station until January, space shuttle programme manager Wayne Hale said.

The results of the tests to be conducted December 18 will help decide the launch date for Atlantis, he told reporters via teleconference on Tuesday.

The Atlantis and its crew of seven, including a German and a French astronaut, are to install the European Columbus laboratory on the orbiting ISS.

Launch was originally set for December 6, but had to be delayed four times, with Nasa on Sunday announcing it had been rescheduled for January 2 at the earliest.

Faulty gauges have been a recurring problem on Nasa’s shuttle fleet since 2005.

“We have hopes that it will yield the definitive location of our problem and thereby allow us to solve it,” Hale said of the tests that will be conducted next week with the shuttle’s external tank fully fuelled.

Nasa said its engineers and staff will take a few days off for the Christmas holiday.

Testing will focus on 30m of electrical wiring connecting the four sensors at the bottom of the tank to the shuttle’s cryogenic engines.

The four gauges, three of which are redundant for back-up safety, signal to onboard computers when the hydrogen fuel in the external tank is about to run out, eight-and-a-half minutes after liftoff when orbit is achieved.

The signals automatically cut off the shuttle’s three cryogenic engines, which can explode if they keep running without fuel.

In an internal email sent Friday at Nasa and posted on Aviation Week’s website on Tuesday, Hale says the sensors probably were never reliable since the current shuttle fleet came on line in 1981.

“It seems to me likely that we have been flying the entire history of the programme with a false sense of security, that is a really sobering thought,” Hale said in his message to shuttle security engineers at Nasa’s Johnson Space Centre in Houston, Texas.

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