The Russian space agency’s panel of inquiry probing into the loss of the Progress M-27M cargo vehicle late last month lacks data to say exactly what caused the emergency, a senior source in the space rocket industry familiar with investigation has told TASS.

"The telemetry data are not enough to name the cause of the incident with certainty. The commission’s members have been dispatched to various manufacturers involved in order to scrutinize space rocket technologies from the same batch and to simulate the emergency. This is essential, as there still is no clarity regarding the real cause of the mishap," the source said.
According to the official the probe, originally scheduled to be over May 14, has been prolonged till May 22 and may continue after that.

"True, some findings may be presented by May 22. In the meantime specialists will keep working at individual enterprises after that date," the source said.

A member of the Tsiolkovsky Russian Cosmonautics Academy, editor-in-chief of the Novosti Kosmonavtiki (Cosmonautics News), Igor Marinin, has told TASS that the real cause of the incident may never be established.

"When such accidents occur, the real cause can be accurately established very rarely. As a rule, all conclusions are probabilistic to a large extent. For instance, there is a 90% certainty that this or that factor was to blame, but there still remains a 10%-chance the cause was different. The probability only one cause will be identified is very low. Such cases are very rare," the expert said.

Another specialist, associate member of the Tsiolkovsky Cosmonautics Academy, Andrei Ionin disagrees. "I believe that the telemetry data available are quite enough. Inquiries at sub-contractor enterprises are the normal second phase of any technical probe, when specialists have clearer suspicions of what happened. Now they will be inspecting the manufacturers," he told TASS.

The Soyuz-2.1a rocket carrying a Progress cargo vehicle blasted off from the Baikonur space site in Kazakhstan on April 28. It soon turned out that the cargo craft had entered a wrong orbit and communication with it was lost. On May 8 the abortive delivery vehicle burned up in the atmosphere. Roscosmos said the accident was due to decompression of the rocket’s propellant and oxidizer tanks, which upset the normal separation of the third stage and the vehicle. Inquiries are now focused on factors that might have been behind decompression.