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NASA wrestles over timeline for shuttle flights

/ Source: NBC News

More than four months after the Columbia catastrophe and the grounding of the three remaining space shuttles, NASA officials are wrestling with the question of when flights can resume. Estimates and guesses range from “the end of the year” through mid-2004.

The factors that will drive the answer are still unknown, and the biggest uncertainty remains in what recommendations the Columbia Accident Investigation Board will make as requirements for approving a new shuttle launch.

But NASA has anticipated the sorts of things that will be necessary. They include reduced foam shedding at launch, enhanced inspection and repair of the fragile thermal protection system in flight, and a more responsive management and safety system.

Current plans call for the next flight, on Atlantis, to carry supplies and possibly a replacement crew to the international space station. Veteran pilots Eileen Collins and Jim Kelly will fly the shuttle, with two veteran mission specialists also aboard.

October? No way has obtained a number of internal NASA planning documents that address this schedule question. The most optimistic “planning date” for next launch is Oct. 1, which nobody believes. A more serious schedule, published by the Flight Design and Requirements Office of the space shuttle program, is “no earlier than Dec. 18.” Other high-level briefings have mentioned dates between April and June of 2004.

During a May 23 internal briefing, astronaut James Halsell, the NASA official in charge of coordinating the “return to flight” effort, reported that his team was “moving aggressively and proactively toward near-term return to flight” with a goal of resuming shuttle missions as soon as safely as possible to “mitigate ISS risks” — that is, to rescue the space station.

According to Halsell, a return to flight by Dec. 3 was “not impossible,” but he added several caveats:

“Environments validation,” a study of the true conditions under which the shuttle will have to operate, “will not be completed until Jan-Mar 2004.”

Redesign of the external fuel tank’s liquid hydrogen “Intertank Flange” hardware, if required, “could push RTF [return to flight] to Apr 2004.”

If NASA has to unfasten Atlantis’s reinforced carbon-carbon leading-edge wing panels for detailed inspection and refurbishment, this “could push RTF to Jan-Feb 2004.”

NASA’s current preferred plan is to remove and inspect the panels of the oldest remaining shuttle, Discovery. For Halsell the critical issue is whether this data will be enough to clear Atlantis for launch, or whether data is also required from Atlantis and the third surviving shuttle, Endeavour. Another question is whether the requirement for examining the leading-edge wing panels can be accomplished with them in place on the wings, or whether it requires them to be physically dismounted.

Complicating the schedule is a set of what NASA calls “beta cutouts” (“beta” is the angle between an orbit and the Earth-sun line) in the winter of 2003-2004. During this time, the station’s alignment with the sun precludes shuttle visits due to heating issues. Most of December 2003, and the first half of February 2004, is excluded from shuttle flights on these grounds.

Fix-it plans proceeding
The good news is that several fix-it projects will be completed in time for a flight before the end of the year. This includes a redesign of the “bipod ramp,” the area of the external fuel tank where foam insulation debris broke off during Columbia’s ascent in January. Investigators believe that debris could well have caused mortal damage to Columbia’s wing.

NASA planners also believe they can develop better inspection and repair capabilities for the shuttle’s fragile tiles in time for a flight in 2003. However, a similar capability for the leading-edge panels cannot be completed until much later in 2004.

“Total elimination of all debris is not a realistic goal,” Halsell said, echoing the view of experts on the investigation board. “Significant reduction in risk of critical debris is realistic.”

Halsell also described the need for improvements in the management process, in response to a widespread perception that the shuttle operations managers simply did not worry enough about the catastrophic potential of the debris impact on Columbia’s left wing.

For the mission management team, Halsell prescribed several steps: “Elevate reporting detail; Improve process rigor and discipline; Strengthen communication; Improve processes for elevating engineering issues; Ensure against information overfiltration; Enhance in-flight anomaly assessment process.”

The critical issue here, he continued, was in “developing criteria for interpreting inspection results.” The fixed process “must avoid [a] ‘what now?’ dilemma” and provide hard guidelines for adequate responses, he said.

On the issue of inspection and repair, he said that “an inspection capability exists for ISS flights, but without depth measurement.” He said it would take more time to come up with the tools and materials needed for in-flight shuttle repairs, and to work out a procedure for inspecting the shuttle that didn’t involve the station.

“If we stay on time, with no development surprises, we may have a well-defined recommendation for each facet of this problem in mid-June,” he predicted. This would provide tile repair capability in November, and similar capability for the leading-edge panels “later.”

“There is much work to do between now and then,” the astronaut concluded, “and no guarantees.”

James Oberg, space analyst for NBC News, spent 22 years at the Johnson Space Center as a Mission Control operator and an orbital designer.