Russian investigators say a technical malfunction, not crew error, was to blame for the recent off-course landing of a Russian Soyuz spacecraft returning to Earth from the International Space Station.
Three weeks after the Soyuz capsule touched down on the steppes of Kazakhstan, nearly 500 kilometers from its intended landing site, the three-man crew was cleared of any wrongdoing.
The head of the investigative commission looking into the May 4 incident, Nikolai Zelenshchikov, told reporters in Moscow that there was a failure in the descent guidance system, which automatically steers the capsule to its designated landing spot.
Mr. Zelenshchikov said the malfunction came as a surprise to everyone, because the instrument used to control the spacecraft's descent had been used without fail for more than 20 years.
The official said the commission will continue to look into the circumstances that had mission control ground crews searching for more than two hours to locate the capsule and its crew.
The return flight was the first manned landing since the American space shuttle Columbia disintegrated during re-entry in February, killing its seven-person crew.
The subsequent grounding of American shuttles has left the Soyuz as the primary vehicle to carry humans and cargo to and from the International Space Station.
That means that any serious problem with the Soyuz would stall the space program and maroon the crew aboard the space station. That crew is scheduled to return to Earth in October.
Russian investigators said they have already devised a method to repair the descent device should such a situation occur again. But the commission investigating the incident also took time to make some recommendations.
The investigators said it is necessary to place search and rescue helicopters and planes in the designated area of future landings. In addition, the commission recommends equipping the re-entry capsule with a mobile satellite telecommunications system.
According to Mr. Zelenshchikov, the first satellite phone may be delivered to the space station by a Progress cargo craft due to be launched June eighth.