Atlantis will launch today, barring further anomalies

CAPE CANAVERAL, Fla. – NASA will try again today to launch Atlantis, even though engineers are unable to repair or even explain a recurring problem with the shuttle’s fuel sensors.

Liftoff of Atlantis and its seven astronauts will come at 3:21 p.m. – if the sensors don’t act up again as the shuttle is fueled this morning and if nothing else goes wrong.

“If everything works perfectly, we’ll go fly,” Wayne Hale, the National Aeronautics and Space Administration’s shuttle program manager, said Saturday evening. “If we have any other anomalies, then we will stand down and troubleshoot it.”

Forecasters predicted an 80 percent chance of favorable weather.

Long considered a crucial part of the safety system, the four hydrogen “engine cutoff” sensors ensure that the shuttle’s three main engines don’t shut down too soon or too late due to a fuel problem.

Three of the four sensors aboard Atlantis failed Thursday, scrubbing a launch attempt and baffling engineers who thought they had solved the intermittent problem that has plagued several flights in recent years.

Atlantis’ launch window closes Thursday, leaving engineers with too little time to examine the sensors, but mission managers believe they have found a way to work around the problem.

Basically, they are tightening flight rules and adding a layer of redundancy to the system.

The crew is assigned to spend 11 days in space, delivering a European laboratory to the International Space Station.