By Jefferson Morris

Aerospace Daily 01/06/2003

NASA is investigating a crack found on a component in the shuttle Discovery's liquid oxygen lines and this week will assess whether the shuttle Columbia can safely launch for the STS-107 science mission later this month.

Inspectors discovered the potential problem during a standard inspection of Discovery in December. The crack is located on a 2.25-inch metal ball that is part of the Ball Strut Tie Rod Assembly (BSTRA) inside the orbiter's 17-inch liquid oxygen line. Several BSTRA assemblies are located in both the liquid oxygen and hydrogen lines of the shuttles, where they act as flexible supports.

Further inspections of Discovery's liquid oxygen lines found no further cracks, according to NASA. Testing on spare BSTRA balls is ongoing to determine the extent of the problem, according to STS-107 Lead Flight Director Kelly Beck.

"We're ... trying to generate cracks in those balls, and then also seeing what kind of performance they have once they are cracked, to make sure they can still perform their function," Beck said during a press conference Jan. 3. Shuttle officials are meeting Jan. 6 to discuss the results of the tests, she said, and a flight readiness review is scheduled for Jan. 9.

Flight controllers are working under the assumption that similar cracks are present in Columbia's BSTRA, Beck said, and do not plan to inspect the orbiter. Instead, NASA is concentrating on verifying that the shuttle still can fly safely with the cracks.

Meanwhile, preparations continue at Kennedy Space Center, Fla., for the launch of STS-107, a 16-day mission devoted to scientific experiments that will not visit the International Space Station (ISS). Columbia is scheduled to lift off from Launch Pad 39A no earlier than Jan. 16.

The seven-person crew, which will include the first Israeli astronaut, will be split into two alternating teams working around the clock. The teams are to conduct more than 80 experiments that will study Earth and space science, advanced technology development, and astronaut health and safety.

Originally scheduled for launch last July, NASA delayed STS-107 after cracks were found in metal liners inside the propellant lines of shuttles Atlantis and Discovery that led to the grounding of the fleet (DAILY, June 25, 2002).

STS-107 Commander Rick Husband said he is optimistic the mission will not be delayed again.

"Leading up to just about every mission, there's usually some issue that comes up because the folks who process the orbiters ... do such a great job with the maintenance in inspection of the hardware," Husband said. "It looks like [NASA] will come up with sufficient rationale for it to be perfectly fine for us to fly."

Congressional direction

The decision to include a science mission in the midst of a rigorous period of ISS assembly came from Congress, according to STS-107 Mission Scientist John Charles.

"Missions like STS-107 were inserted into the manifest ... with the goal of keeping the scientists who are involved in this kind of activity engaged and productive and moving forward until the space station can assume the leading role in research," he said.

However, to his knowledge, STS-107 will be the only such mission "for the foreseeable future," he said. "There are continuing discussions about whether we want to put these kinds of missions into the shuttle manifest, but I don't know of any decision that's been made to go ahead and do that."

Columbia currently isn't capable of docking with the ISS, although it will be modified to allow docking after STS-107 is completed, according to Beck.