SAN FRANCISCO — An independent NASA panel reviewing data related to the Aug. 24 failure of the Russian Soyuz rocket transporting cargo to the international space station has confirmed that the Russian space agency correctly identified the cause of the problem and is taking appropriate steps to resolve it before the rocket’s next launch, scheduled for Oct. 30, said William H. Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate.
The Russian space agency, Roscosmos, determined that the most likely cause of the failure was contamination in the rocket’s fuel lines or stabilizer valve, which caused low fuel supply to the gas generator, Gerstenmaier told lawmakers Oct. 12 during a hearing of the House Science, Space and Technology Committee’s space and aeronautics panel.
“Roscosmos and its contractors have a plan in place to validate engines for the near-term launches including improving quality control, such as adding additional inspectors and videotaping critical actions related to component assembly,” Gerstenmaier said.
After meeting with the Russian accident investigation commission and reviewing pertinent data, the independent NASA team affirmed the “conclusions regarding the likely cause of the engine shutdown and plans for corrective actions,” Gerstenmaier said. The NASA team will begin sharing its findings with NASA engineers and the aerospace community immediately, he added.
If Roscosmos is able to successfully launch a Soyuz rocket and Progress cargo vehicle Oct. 30, the long-term impact on the international space station will be minimal, said retired U.S. Air Force Lt. Gen. Thomas P. Stafford, a former astronaut and chairman of the International Space Station Advisory Committee. The last few space shuttle flights delivered enough consumable supplies and spare parts to last space station crews through 2012, Stafford told lawmakers.
The biggest concern at this time, Stafford said, is the ability to return to a six-person crew onboard the space station. On Sept. 16, three of the six space station crew members returned to Earth in one of the Soyuz capsules docked at the station. If the upcoming Soyuz launches are successful, the next three-man crew will travel to the space station on or around Nov. 13 and the space station will once again have a six-person crew in late December, he added.
In the wake of the space shuttle’s retirement and U.S. demand for access to the space station, Roscosmos has accelerated its Soyuz launch schedule. That accelerated schedule has put some pressure on Roscosmos, but NASA officials do not believe it contributed to the recent Soyuz failure, Gerstenmaier said.
“We have been watching that activity to make sure it does not cause problems for us,” he told lawmakers. “We specifically looked at this [in the recent accident review] to make sure there were not systemic problems or problems that occurred from the fact that they were increasing their flight rate.”
Overall, Soyuz is a highly reliable booster that is based on a design that has been flying for decades. That long history of flight made it far easier to pinpoint the cause of the Soyuz accident and to ensure that it will not reoccur than it will be if similar problems occur with the new cargo ships U.S. commercial firms are building to transport cargo to the international space station, Gerstenmaier said.
“The Progress vehicle has a tremendous history but yet it still failed,” Gerstenmaier said. “As the commercial cargo providers are coming on line there is a fairly high likelihood they could have a problem and potentially lose a cargo vehicle at the beginning of their programs. We need to be prepared to accept that, understand that, fix the problem and move on.”
If instead a commercial launch failure leads government officials to conduct an extremely lengthy investigation, the overall commercial cargo transportation program could suffer, Gerstenmaier said. NASA officials should begin discussing the steps they would take in the aftermath of a commercial cargo vehicle accident, he added.