Space crew weathers a scare during re-entry

James Oberg NBC News space analyst

Russia’s Mission Control endured a brief but private scare during this week's return of a Soyuz spacecraft from the international space station with three riders aboard, those familiar with the flight now say.

As the Soyuz descent module headed back to Earth, instruments indicated that air was leaking out — the same kind of failure that killed three cosmonauts in June 1971 on their way home from the world’s first space station, Russia's Salyut 1.

Since that tragedy, all passengers aboard Soyuz spacecraft have worn pressure suits during such mission-critical phases. Had Monday’s air leak been severe enough, the suits would have saved the men’s lives.

Cosmonaut Sergey Krikalev, the just-returned veteran Russian space traveler who had been the space station's commander for the past six months, discussed the problem openly during a Moscow news conference on Thursday.

“We had certain problems with pressurization before undocking,” Krikalev said. He added that there had also been problems with the craft’s airtightness during the descent: “In principle this was an anomalous situation of medium complexity. ... In fact, it was a fairly serious situation.”

Krikalev was commander of the Soyuz spacecraft for the descent and landing. He was accompanied by NASA astronaut John Phillips, who had been his crewmate on the six-month-long Expedition 11 aboard the station, and by millionaire space passenger Gregory Olsen, who had purchased his 10-day sojourn to the station and back commercially.

NASA refers to anomaly
NASA’s “On-Orbit Status Report” on Thursday contained a brief reference to the anomaly. The space agency said Russian officials “are investigating a slight pressure drop of the Soyuz TMA-6 spacecraft's atmosphere at the time of undocking, reported by the crew via radio.  Since no telemetry could be received during the usual time of plasma blackout, data stored in the Soyuz descent module's recorder are being awaited.”

Other NASA sources said it remained to be seen whether the air leak was real, or whether there was only a failure in the pressure sensor. The sources discussed the problem on condition of anonymity because they weren't cleared to make official comment.

In Houston, NASA spokeswoman Kylie Clem told MSNBC.com that the Russians had informed NASA of the leak at the weekly meeting of the Mission Management Team on Thursday. "They have the flight data recorder returned to Moscow," she said, and a special commission will report preliminary results next week.

A real pressure leak, apparently the first in more than 30 years, would raise questions about the airtightness of the Soyuz TMA-7 spacecraft that was launched Oct. 1 and is currently docked to the station as a landing vehicle for the space station's current crew members, William McArthur and Valery Tokarev.

NASA The Soyuz TMA-6 spacecraft leaves the international space station, as seen through a station porthole. The craft consists of three modules: from left, the service module with solar arrays, the descent capsule and the spherical orbital module.

The full Soyuz spacecraft consists of a descent capsule, an orbital habitation module and a service module. During the return to Earth, the descent module, with up to three crew members inside, separates from the other two components.

Chris Kridler of the newspaper Florida Today reported Monday that “mission controllers in Russia had a scare when they lost communications with the Soyuz as its three modules separated,” and that “controllers repeatedly called out to the crew, then had Tokarev [aboard the station] describe his camera view of the glowing ship with inconclusive results.”

Although loss of communications is normal during the most fiery phase of the spacecraft’s atmospheric entry, the anxiety in the voices from Moscow may have been based on their awareness of the potential cabin depressurization.

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