Launch Remains On Schedule For August 7... For Now

NASA engineers managed to make some headway Wednesday in tracking down a stubborn air leak inside the shuttle Endeavour's crew compartment. The leak has been traced to one of two positive pressure-relief valves, which ensure that the crew cabin does not become over-pressurized.

As ANN reported this week, workers plan to remove and replace the suspect valve -- located behind a wall, near the orbiter's lavatory compartment -- using a valve from Atlantis. Work was scheduled to begin Wednesday night, and be completed Thursday.

Assuming all goes to plan, that should give NASA enough time to test the replacement valve, and verify the orbiter is airtight in time for the shuttle's planned liftoff next Tuesday, reports The Associated Press.

Also causing engineers some grief Wednesday was one of two thermostats inside an auxiliary power unit onboard the shuttle. After briefly pondering whether to swap out both thermostats -- another costly move, time-wise -- NASA determined the faulty sensor is good enough fly as-is, due in part to redundancy built into the system.

Alas, mechanical troubles aren't the only ones plaguing NASA this week -- the weather is also giving the agency fits. Thunderstorms around Kennedy Space Center have already delayed work on Endeavour, and forced a 24-hour postponement with the launch of the space agency's Mars Phoenix Lander.

For the moment, Phoenix is set to liftoff Saturday morning... giving NASA the necessary 48-hour turnaround time needed to launch Endeavour on schedule.

Should Phoenix get bumped once again, it would have priority over Endeavour on the launch schedule -- as the launch window to Mars closes in three weeks, and a new one doesn't open for two years.

FMI: www.nasa.gov