Mysterious space shuttle oxygen leak being probed
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: December 8, 2005
NASA and contractor engineers are studying data indicating a possible oxygen leak in the shuttle Discovery's aft engine compartment during its return-to-flight mission last July.
One catch bottle did not operate properly and the other three, which opened before the two in question, showed normal oxygen concentrations. Engineers initially thought the high readings were a measurement glitch, but they are taking the indications seriously and trying to pin down what, if anything, was amiss.
"There are a couple of ways to look at it," LeRoy Cain, manager of
shuttle launch integration at the Kennedy Space Center, said Wednesday in an
interview with CBS News. "For sitting on the ground, it was (a) large
(leak). For in-flight performance, telemetry from the engines and what not,
I don't believe we'd see it. From the standpoint of (over pressurizing) the
aft, like during entry, it's not large. It's an order or two magnitude
smaller than what would overpress the aft. ... But we've got to go look at
The catch bottles are the sole means of detecting in-flight leaks in the engine compartment other than changes in the performance of the shuttle's three main engines. During Discovery's launching, all three engines operated normally and there is nothing in the telemetry to suggest a significant oxygen leak.
Possible sources for oxygen leakage include the engines, the plumbing associated with the main propulsion system, the shuttle's life support system and its electricity producing fuel cell system. But those all passed pre-launch leak checks and other than high oxygen concentrations in two of the catch bottles, there is no other evidence of a problem.
"The guys are looking at it very hard," said Cain, who served as the ascent/entry flight director in mission control for Discovery's mission. "It's too soon to know" what, if any, impact the issue might have on Discovery's processing for launch next spring.