Do not praise the day before the sunset - this phrase will be surely remembered by Dmitry Rogozin, Deputy Prime Minister of Russia, who said on November 29, 2016: "The Russian space industry has made a significant breakthrough in the creation of advanced technologies after overcoming a series of defeats, hurtful accidents and catastrophes and stabilizing issues of quality...". Nobody puts a question mark on quality of Russian rockets, but reality shows, that accidents were not eliminated as Prime Minister would like to see.
Mission od MS-04 was planned for yesterday and after successful launch, flight seemed to proceed normally. First, booster separated and core was continuing its flight until separation of upper stage Blok-I. As live broadcast showed no problems during flight, already at T+6'22" Blok-I and Progress were not communicating correctly with Mission Control Center and telemetry data were not received. Further informations given during broadcast mentioned only about problems with unfolding solar arrays of Progress, but truth was different. Upper stage powered with RD-0110 engine burning LOX/RP-1 and providing thrust of 297.9 kN failed to deliver Progress into correct orbit; it reached only altitude of 190 km and it stopped to work. Later under force of gravitation both Progress and Blok-I (probably separately) performed destructive reentry. This what remained from upper stage and spacecraft after reentry fall on forests of Choisky District in Tuva Republic. Today RIA Novosti announced that crash site is placed around 70 km west of Kyzyl town (51°43′N, 94°27′E). Not confirmed officially reports from Tuva Republic mentioned about explosion visible in the sky which appeared just around 14:58 UTC, when MCC lost contact with vehicle. Roscosmos officially confirmed accident yesterday at 17:39 UTC.
Just as special State Commission started investigation, first suppositions leaked to press. Today in the morning hours TASS news agency announced, that Commission considers RD-0110 engine of the Blok-I as possible source of problems during flight. It was not mentioned precisely, which part of propulsion system caused malfunction, but according to TASS and its sources most probable version is "burn-through of the combustor chamber". Same source gave explanation of such version: it could be possible due the presence of foreign object inside engine or even quality problems during assembling engine in the Voronezh Mechanical Plant, manufacturer of this engine model. More interesting theories appeared on sites of Novosti Kosmonautiki forum. One of the members (or guests) presented theory about emergency engine cut off command, which was send from onboard computer of the rocket. This command is used for terminating flight in case of leaving correct trajectory and creating risk for falling on Earth, or if engine is losing power rapidly. Due the fact, that rocket lost communication just before malfunction and telemetry data were received until end of flight it is possible to consider this theory rather impossible. Telemetry from Blok-I was not showing any problems with trajectory or RD-0110 engine. Also another interesting thing is fact that Anti-Aircraft Defense Forces of Central Military District spotted on their radars two objects at 14:56 UTC and at 14:57 UTC what points that reason for losing communication could be explosion or even premature separation of Progress (TASS). One thing is sure - it is first accident with launch vehicle this year for Roscosmos. Main competitors also suffered problems this year - American SpaceX Falcon-9 FT exploded on launch site with Amos-6 satellite two days before launch; Chinese also had bad luck in 2016 - Long March 4C failed to deliver Gaofen-10 satellite on September 1, 2016 (same day when Falcon-9 exploded with Amos-6).