MOSCOW, May 12. /TASS/. Successive depressurization of the oxidizer and propellant tanks of the Soyuz-2.1a rocket’s third stage caused the loss of the cargo vehicle Progress M-27M, the head of the Russian space agency Igor Komarov said.
"In the 526.716th second of the flight the separation of the spacecraft from the rocket went wrong. As a result, the cargo vehicle was put in an orbit 40 km higher than expected (apogee), and the third stage, 20 km below the designated trajectory (apogee)," Komarov said.
Komarov said the government probe had managed to gather telemetry data and other data from objective sources, which confirmed the preliminary version of a separation mishap, "including two successive events, involving depressurization, in other words rupture (after the third stage’s engine was turned on) of the oxidizer tank, and then of the propellant tank."
The Roscosmos chief said that precisely was the cause of the unexpected mode of separation.
Komarov said further detailed computations and modeling would be needed to identify the root cause of the failure.
"The working group established on is expected to clear up the situation by May 22," he said.