Work Begins To Seal A Space Shuttle Gas Leak
CAPE CANAVERAL, Fla. (AP) _ Technicians moved into the cargo bay of the space shuttle Discovery on Tuesday to set up shop for the work of sealing a small gas leak discovered a month ago in a steering engine compartment.
After opening the 60-foot-long cargo bay doors, they erected a tent-like structure over the rear bulkhead to prevent loose debris from getting into the rest of the bay or into a nearby enclosure where Discovery’s payload, a communications satellite, is waiting to be loaded aboard.
Because Discovery is poised vertically on the launch pad, the technicians will have to do much of the work on their hands and knees or lying on their stomachs on the cargo bay’s rear bulkhead.
On Wednesday the technicians will use a routing tool to cut two holes through the rear bulkhead and two more in the engine compartment wall to gain access to a seal leaking nitrogen tetroxide gas from a vent line.
The line services a steering engine system that is separate from the three main engines test-fired on the launch pad last week.
The plan is to install a clamshell-shaped device over the leak and fill it under pressure with a sealant.
The repair and subsequent testing are expected to take about a week, said NASA spokeswoman Lisa Malone.
Although the leak was detected a month ago, NASA decided to put off repairing it until after the main engine test firing.
The launch team continued troubleshooting the only fault resulting from the test firing - a small amount of hydrogen gas detected by a sensor in an area where lines join the shuttle with its external fuel tank, which is loaded with liquid hydrogen and oxygen to fuel the main engines.
Malone said the source of the hydrogen remains a mystery and that pressure tests on Monday failed to detect any leak. She said officials did not consider it a serious problem.
″Once the source of the hydrogen is found, engineers will determine whether it is an acceptable condition or what course of action is necessary to proceed,″ Malone said.
Elsewhere, at the Morton Thiokol plant in Utah, engineers prepared for Thursday’s fifth and final pre-launch test-firing of a redesigned solid fuel booster rocket. Insulation, seals and O-rings have been deliberately flawed in segment joints to see how well backup systems contain the blazing exhaust gas.
A faulty booster rocket joint was blamed for the explosion of Challenger and the loss of its seven-member crew on Jan. 28, 1986.
If the Utah test is successful, NASA is expected to set a late September or early October launch date for Discovery and its five-man crew on the first post-Challenger shuttle flight.