HOUSTON — Appearing before a House oversight panel this week, NASA’s chief human spaceflight official and two of the agency’s independent safety experts endorsed Russian efforts to investigate and recover from the Aug. 24 loss of a Soyuz rocket without forcing an evacuation of the six-person International Space Station.

The loss of the Soyuz-U booster carrying a Progress cargo capsule revealed the pitfall of a decision by U.S. policy makers to retire the space shuttle in July — at least four to five years before NASA-nurtured commercial crew capabilities are expected to be ready to take on the role of transporting astronauts to and from the orbiting science laboratory.

Russia responded quickly, identifying a contaminant blockage in a third-stage fuel line or stabilizer valve as the root cause and implementing a recovery strategy, according to Bill Gerstenmaier, NASA’s associate administrator for human exploration and operations.

“NASA is confident that our Russian partners identified the most likely failure cause and a sound return-to-flight plan,” Gerstenmaier told the House Space and Aeronautics Subcommittee on Oct. 12 in Washington.

The Russian response received a similar vote of confidence from Thomas Stafford, the retired U.S. Air Force lieutenant general and Apollo-era astronaut who chairs NASA’s International Space Station Advisory Committee, and Joseph Dyer, the retired U.S. Navy vice admiral who chairs the agency’s Aerospace Safety Advisory Panel (ASAP).

U.S. Rep. Steven Palazzo (R-Miss.), the committee chairman, and other lawmakers raised a series of issues, including Russia’s diligence in identifying the root cause of the loss to the prospects of returning the retired shuttle fleet to flight.

“This would have been a great research question three or perhaps four years ago,” Dyer said of a shuttle encore. “But it’s not a good question, or a practical question, at this time.”

The Russian commission that investigated the loss concluded the contamination was most likely introduced during an inspection that followed a hot-fire acceptance test of the engine, Gerstenmaier told the panel. Once in flight, the blockage reduced the fuel flow to the RD-0110 engine just more than 300 sec. into the flight from the Baikonur Cosmodrome. The reduction triggered a computer shutdown of the engine that sent the Progress plummeting into a mountainous region of Altai.

Similarities

The Soyuz-U shares a similar third stage to the Soyuz-FG used to transport three-person crews to and from the space station.

The investigation included a factory recall of 18 upper-stage Soyuz engines for reinspection. Further contamination was not found, supporting the conclusion that the failure was not caused by a design flaw.

Additional quality control inspectors have been added to the RD-0110 production line along with video documentation of the assembly processes, according to Gerstenmaier, who was briefed on the findings by Russian officials. The human exploration chief charged a NASA team with assessing the Russian conclusion. It agreed with the assessment.

As part of the recovery, Russia agreed to a pair of unmanned Soyuz missions ahead of the next crew launch. The first of the “test flights” occurred successfully on Oct. 2 with the launching of a Soyuz-2 rocket with a Glonass-M navigation satellite from Plesetsk.

The second flight will be an Oct. 30 launch of a Soyuz-U from Baikonur to the space station with the Progress 45 freighter. If the Soyuz-U launch is a success, Russia will prepare the Soyuz 28 mission for launch with an American and two Russians to the space station on Nov. 14.

Author : Mark Carreau