Richard P. Feynman, a Nobel laureate physicist and member of the presidential commission probing the Challenger space-shuttle explosion, flew here tonight to investigate what he called "absurdly low" temperatures recorded on the suspect right solid rocket booster shortly before liftoff.
Recorded temperatures as low as 7 degrees Fahrenheit on the booster's lower surface may be crucial evidence in the investigation, National Aeronautics and Space Administration sources said.
One source said the reading appears to support a theory that extremely cold liquid hydrogen or oxygen from the shuttle's external fuel tank leaked through a hole onto the right booster, possibly freezing the rubberlike O-rings that seal segments of the rocket. If frozen, the O-rings are unlikely to function properly, officials have said.
The temperature readings also appear to raise serious questions about the flow of information from ground crews at the launch pad to top NASA officials in the "firing room" on the morning of the launch, sources said.
"Those temperature readings are an incredibly important piece of information, if true," said one source knowledgeable about shuttle operations. "The whole shuttle system was not designed to operate at those tempeartures . . . . What we don't know is who knew about those temperature readings."
Meanwhile, Philip E. Culbertson, dismissed Saturday from day-to-day operational control at NASA headquarters in Washington, said he will continue working on long-range agency planning. A NASA spokesman said Culbertson will continue to hold the position of general manager and described as inaccurate reports that he had been fired.
Feynman, in a telephone interview, said today that the temperature readings are so unusual that the commission has asked him to determine if there were "flaws in the measurements."
Readings of 7 and 9 degrees on parts of the right booster were recorded by hand-held infrared measuring devices used by a special "ice and debris" team that inspected the pad a few hours before liftoff. At the time, air temperatures were in the 20s, and surface readings on the left rocket booster were about 25 degrees. Air temperature at liftoff was 38 degrees.
The 7-degree reading was recorded on the aluminum skirt, the part of the rocket bolted to the mobile platform, officials said.
NASA spokesman Jim Mizell said today that the ground team's primary duty was inspecting for unwanted ice or frost on the sides of the external tank rather than recording temperatures on the adjacent rockets. He said the team's chief concern was that ice might loosen at liftoff and damage the orbiter's fragile heat-resistant tiles.
Mizell said the ground crew may not have reported the rocket readings to the firing room because "that would have been extraneous to what they normally do."
Mizell also said the agency could not respond to questions about the temperature readings. "All that information has been impounded by the review teams," he said.
Feynman said, "Those temperatures are absurdly low . . . . We have to check out everything. Was this really something . . . or is this a red herring?"
One former NASA official said ground crews "may have decided it was bad data and ignored it. All this could simply mean that the damn gauge wasn't calibrated right."
Last week, commission chairman William P. Rogers said the panel was focusing on the relationship between prelaunch cold weather and O-ring failures. Rogers is to testify Tuesday before a Senate subcommittee about the probe.
NASA also reported today that a submarine has retrieved small pieces of debris believed to be parts of the suspect booster. A Navy submarine is due to arrive Wednesday for retrieval operations.
Debris recovered today was found 1,200 feet under water about 40 miles northeast of Cape Canaveral, near the spot at which the right booster probably landed. NASA said it could not positively identify the wreckage.
Recovered material has been flown to the Kennedy Space Center for analysis, and underwater photographs have been flown to Marshall Space Flight Center in Huntsville, Ala., to determine if they belong to the crucial booster.