NASA Crew Was Aware Of Problem

SPACE CENTER, Houston--Space shuttle Challenger Pilot Michael J. Smith exclaimed "Uh-oh!" at the moment the spacecraft exploded, and some of the crew apparently lived long enough to turn on emergency air packs, the National Aeronautics and Space Administration (NASA) said yesterday.

Smith's remark, heard on a tape of the shuttle's intercom system, was the first indication that any of the seven astronauts killed may have been aware of the January 28 disaster, the worst in the history of space exploration.

The astronauts probably survived the explosionand breakup of the shuttle orbiter and could havehad 6 to 15 seconds of "useful consciousness"inside the crew compartment after the blast, saidDr. Joseph Kerwin, an astronaut-physician whoinvestigated the cause of death for the crew.

The force of the crew compartment hitting theocean was so destructive, however, that theprecise cause of death for the crew could not bedetermined, he said.

The intercom tapes were recovered from thewreckage of the Challenger and analyzed by NASAand IBM engineers.

The tape, a transcript of which was released byNASA on yesterday, offered no verbal evidence thatany crew members other than Smith knew anythingwas abnormal prior to his single exclamation 73seconds after launch--the very second that groundcontrollers lost all communication with the craft.

Previously, the last known words from theChallenger were those heard from Commander DickScobee to ground controllers, when he responded"Roger, go at throttle up," confirming that theshuttle's main engines had been raised to fullpower.

School teacher Christa McAuliffe and missionspecialists Ronald McNair and Gregory B. Jarvisare not heard on the recording.

NASA said the three "could monitor all voiceactivity but did not make any...comments."

As recently as July 17, NASA said its reviewsof the voice tape indicated that the crew wasunaware of the events preceding the breakup of theorbiter.

NASA said yesterday, however, that furtheranalysis showed that Smith's final comment offeredthe first potential indication of crew awarenessof the accident.

Smith's exclamation could indicate "there was amoment of awareness," said Admiral Richard H.Truly, associate administrator for space flight.

Four of the air packs were recovered and threehad been turned on, with an analysis of gauges ontwo of the air packs showing threefourths toseveneighths of the air had been breathed, Kerwinsaid.

One of the air packs that had been turned onbelonged to Smith, Truly said. It was not knownwho the other two activated air packs belonged to,and the recovered air pack that was not turned onbelonged to Scobee, NASA said.

Smith and Scobee could not easily have turnedon their air packs without getting out of theirlaunch couches, Truly said.

Astronauts Judy Resnick and Ellison Onizukawere riding just behind Smith and Scobee, and theymay have assisted Smith, he said.

"The most plausible explanation is that one ofthe two reached over and turned on Mike's airpack," Truly said.

Kerwin said that it was possible the crewmembers lost consciousness due to a loss ofpressure inside the crew compartment. The loss ofpressure could be deadly, even if the crew memberswere breathing from the air packs, he said.

The packs, designed to be used for a shuttleemergency on the ground, normally hold about fiveminutes worth of air, NASA said.

Investigators say the accident occurred when ajoint in a solid rocket booster failed and causedsuperheated gases to burn through the externalfuel tank containing liquid hydrogen and liquidoxygen, triggering the explosion.

The crew cabin tore loose at 45,000 feet, arcedupward to about 65,000 feet, and then began a2-minute, 45-second plunge to the Atlantic Ocean,Kerwin said.

Acceleration forces at the time of the breakupwere estimated at 12 to 20 times the force ofgravity for about 2 seconds, the report said.

"Medical analysis indicates that theseaccelerations are survivable, and that theprobability of major injury to crew members islow," it said.

An analysis showed that if the crew memberslost consciousness due to a loss of pressure, theywould not have had time to revive as the crewcompartment fell into denser air at loweraltitudes, Kerwin said