Shuttle May Not Fly Until November

Two days after the return of the space shuttle Discovery, NASA officials said Thursday that the next manned mission would probably be delayed until November because engineers had been unable to figure out why insulating foam fell off the craft’s external fuel tank.

Officials had been hoping to clear up the foam problem in time for a September launch of the shuttle Atlantis.

“We didn’t find any root cause” of the foam incident, said William Gerstenmeier, program manager of the International Space Station. “It was probably a combination of events. We just need to keep looking.”

A 0.9-pound piece of insulating foam fell off Discovery’s external fuel tank during launch last month. Although the foam didn’t hit the orbiter, the incident caused the space agency to ground the shuttle fleet.

The loss of the shuttle Columbia and its seven astronauts on Feb. 1, 2003, was blamed on a similar piece of foam hitting and tearing a hole in the craft’s left wing.

Gerstenmeier said in a teleconference with reporters that five separate engineering teams were studying five cases of foam loss on the Discovery flight. The largest came off the Protuberance Air Load ramp, or PAL, a longitudinal ridge on the tank that serves to stabilize it during launch.

A second area of interest is the bipod area, which attaches the shuttle to the fuel tank. The bipod area, which was the source of the foam chunk that hit Columbia, had been extensively redesigned.

NASA spent several hundred million dollars over the last 30 months to address the foam problem.

Foam has been coming off fuel tanks, which contain the supercooled liquid hydrogen and liquid oxygen, since the first shuttle flight in 1981. Until Columbia, top managers at NASA didn’t believe the lightweight material could pose a danger to the spacecraft.

Gerstenmeier said researchers were looking at finding new ways to apply the foam. The largest piece came off an area where the foam was sprayed on by hand, causing some in NASA to suggest finding a way to machine-spray the PAL ramp, thereby guaranteeing a more uniform coating.

But Gerstenmeier said images of the tank on ascent showed foam also came off areas that were machine-sprayed.

“This is a very difficult engineering problem,” Gerstenmeier said.

One other possible solution to the PAL ramp problem may be to remove it, he said, if the engineering teams felt comfortable that doing so wouldn’t destabilize the shuttle.

Gerstenmeier said he hoped to have an explanation for the major foam losses in the next few weeks, and a possible solution in a month or two.

“We need to get to a resolution fairly quickly,” he said.