NASA Still Working On Several Launch Issues

NASA managers at Cape Canaveral and Houston are reportedly considering whether to forego the launch window that stretches between May 15th and June 3rd. The next earliest window for the shuttle's Return To Flight would be in July.

The shuttle Discovery, grounded with the remaining space planes after the Columbia disaster more than two years ago, sits on a Kennedy Space Center launch pad, being made ready for the mission designated STS-114, slated to blast off into that May-June window. But CBS Radio News space consultant Bill Harwood now reports the mission might be delayed until July because of remaining issues stemming from the Columbia disaster.

Shuttle managers were meeting in a teleconference late Thursday to decide whether to delay until the next launch window opens up, July 13th.

What's The Problem?

There are several, according to CBS Radio's Harwood. First, tests on the new external fuel tank design -- a retool mandated by the Columbia Accident Investigation Board -- show ice build-ups on two different parts of the tank are still problematic.

First, ice appears to be building up on the flexible line in the so-called intertank region between the hydrogen tank above and the oxygen tank below. The line is covered with a bellows to allow flexing during launch.

Ice build-ups have also been reported around a bracket that holds the line in place.

The other icing problem is reported near the tip of the huge external tank. Specifically, ice appears to be accumulating on yet another bracket that holds a repressurization line in place. In neither case can shuttle managers conducting what's called a debris verification review could not rule out the possibility that the ice accumulations might pose threats to the orbiter itself, according to CBS Radio News.

NASA managers are contemplating the installation of at least one other heater to deal with the icing. But if that happens, Discovery will have to be rolled back to the Vehicle Assembly Building, definitely ruling out a launch during the window that opens May 15th.

Harwood also reports there are other outstanding issues that must be resolved before Discovery returns to flight.

During a tanking test earlier this month, NASA said one of the four hydrogen depletion sensors installed in the external tank failed. All four must be operational for the shuttle to launch, according to the rules. Fixing or replacing the sensor would require engineers to remove the external tank's insulation around an access hatch, climb inside and make the repair.

Another issue that cropped up during the April 14th tanking test, according to CBS Radio's Harwood, was the excess cycling of a pressurization relief valve. This could be a sensor problem -- it might not even be a real problem. But NASA workers will have to figure it out before the launch.

Harwood reports engineers also want to replace approximately 20 insulation blankets near one of the shuttle's main engine nozzles. They were recently contaminated by hydraulic fluid and could become a fire hazard during a normal launch and ascent.

FMI: www.nasa.gov