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. Last Updated: 07/27/2016

Soyuz Recorders Suggest a Glitch

An initial analysis of data from flight recorders on the Soyuz-TMA-1 shows that a technical glitch rather than human error caused the capsule to land about 500 kilometers off-course on the wind-swept Kazakh steppe May 4, a senior Russian space official said.

The Soyuz-TMA-1 was shipped on May 6 to the offices of its designer and producer, Energia, in Korolyov, where engineers retrieved the flight data recorders. The glitch should be pinpointed by Tuesday, said the official, a senior designer at Energia.

The designer, who asked not to be named, said in a telephone interview Thursday that a glitch in Soyuz-TMA's control system or onboard computer might have forced the capsule into a steep descent.

Energia engineers have already analyzed the capsule's voice recorder, which contains every word uttered by cosmonaut Nikolai Budarin and U.S. astronauts Kenneth Bowersox and Donald Petit during the descent, the designer said.

Soyuz crew members are required to describe out loud every command they enter during a flight back to Earth, the designer said. The voice recorder indicates that the crew played by the book, he said, adding, however, that only a thorough analysis of all the flight recorders would show whether human error or a technical glitch led to the steep descent.

The three crew members told a news conference in Star City outside Moscow on May 6 that they did not enter any wrong commands.

One minute before the controlled descent was to have started, the Soyuz-TMA's control system went into so-called ballistic trajectory mode, sending the capsule into a steeper and far less comfortable dive to Earth, Budarin told reporters May 6.

Meanwhile, the head of a commission investigating the Soyuz's descent, first deputy Energia chief Nikolai Zelenshchikov, said Thursday that U.S. experts would not be involved in the investigation. The statement contradicted earlier information from NASA chief Sean O'Keefe, who said last Monday that U.S. experts would take part in the probe.

Zelenshchikov told Itar-Tass that including NASA officials in the investigation "would create difficulties in its [the commission's] work."

He added that no Russian experts had been included in the U.S. investigation of the Columbia shuttle disaster, in which all seven crew members were killed. No Russians were on board the Columbia.

"We will definitely inform our American colleagues about the results of the work and will give them full information, but for now we have nothing to give," Zelenshchikov said.

He said his commission would finish its investigation by May 23.