MOSCOW, December 2. /TASS/. The causes of Thursday’s loss of the Progress cargo spacecraft are unlikely to be established, because neither telemetry data nor debris of the Soyuz-U rocket that was taking the cargo vehicle in orbit are available.

"Telemetry transmission from the rocket was disrupted instantly, so it is practically impossible to establish the sequence of events to identify the causes of the emergency. As for material evidence, such as debris of the rocket’s third stage that might provide some clues, it is not available, either," the source said.

The probe will now focus on the likelihood of certain scenarios and on modelling them, as well as on examination of identical equipment still on the ground, such as the latest Soyuz-U rocket at Baikonur, the source said.

For the time being, he added, the third stage engine’s combustion chamber burn-through is the priority explanation of the instant and full loss of telemetry from the rocket.

The cargo space capsule Progress MS-04, launched from the Baikonur space site with a Soyuz-U rocket was lost at an altitude of 190 kilometers over Tyva. Most of the debris burned up in the atmosphere. A source in the space rocket industry has told TASS that a mishap in the rocket’s third-stage engine was most probably to blame.

Progress MS-04 was carrying about 2.5 tonnes of various cargoes, including food, oxygen and water for the ISS crew.