On August 6, a carrier rocket "Proton-M" with cargo from two satellites "Express-MD2" and "Telkom-3" was launched from the Baikonur cosmodrome. During the second start-up, the engines of the upper stage unexpectedly stopped. So the unsuccessful launch of the Proton did not allow the task to be completed - to launch two satellites into an orbit with an altitude of 36 thousand km.
Interfax, citing an anonymous source in the commission investigating the emergency launch of two satellites on August 6, calls the abnormal operation a failure in the pneumohydraulic system of the Briz-M upper stage, whose task is to provide excess pressure in the fuel tank.
So far, these are only preliminary results, but the agency's specialist believes that it was possible to “localize the place in the pneumatic hydraulic system, where there was a failure in its work. Because of this, proper pressurization was not ensured in one of the fuel tanks with fuel, and the fuel stopped flowing into the combustion chamber. " He summed up that, most likely, a breakdown will be found in the "helium supply line", which is needed to create pressure in the fuel tank of the "Briz-M" upper stage.
The source of RIA Novosti has the same opinion: the Briz-M engines worked for 7 seconds (and should have been 18 minutes) due to a defect in the fuel tank pressurization path. The news agency quotes a source: "The wording sounds much more complicated, but the problem lies in the fuel tank pressurization path."
The telemetry analysis carried out by the commission practically ruled out the likelihood of a failure in the control system, writes Kommersant. In this connection, the assumptions were made that malfunctions occurred in the operation of the propulsion system itself. The publication, referring to its source in the commission, calls the damage to the "fuel supply cable" the cause of the accident.
As of today, a connection has been established with the Telecom-3 satellite, which the Briz-M upper stage was supposed to launch into orbit, reports Lenta.ru with reference to the manufacturers. The device is operating normally, but it cannot be used for its intended purpose in a non-nominal orbit.
Until the causes of the accident are fully clarified, a ban has been introduced on the launch of Proton carrier rockets with the help of Briz-M upper stages.
