The Russian commission investigating the December 1, 2016 failure of the Progress MS-04 cargo spacecraft launch has concluded that foreign particles in the third stage engine’s oxidizer pump may have been the cause. Defective workmanship is suspected. The next Progress launch is currently scheduled for February 21, 2017.

Progress MS-04 was the fourth of the newest generation of Russian cargo spacecraft used to resupply space stations. The first Progress was launched in 1978 to support the Soviet Union’s Salyut 6 space station. Dozens have been launched since then to support Salyut 6, Salyut 7, Mir and the International Space Station (ISS). The vehicle’s design has evolved over the decades and given updated designations: Progress, Progress-M, Progress M_M, and now Progress MS. The first of the MS series was launched on December 21, 2015.

Filled with 2.6 tons of food, water, supplies, and fuel, Progress MS-04 was launched on December 1, 2016, but something went awry 382 seconds after liftoff during the firing of the third stage. A usually reliable Soyuz-U rocket launched the spacecraft and initial indications were that the third stage and the spacecraft separately prematurely. Debris from both fell in Russia’s Tuva Republic, although most reportedly burned up in the atmosphere.

Today’s statement from Russia’s space state corporation Roscosmos and an associated story in TASS said the third stage’s oxidizer pump caught fire resulting in its destruction and release of fragments that ripped the engine open. The oxidizer pump “may have caught fire for various reasons, such as the likely presence of foreign particles or violation of the engine 11D55’s assembly procedures…..Defective workmanship manifested itself in flight…”

A plan will be presented soon on “priority measures” to be taken in the space industry to ensure that the next launch, Progress MS-05, is successful, TASS said.

On January 1, TASS reported that three Progress spacecraft would be launched to the ISS in 2017 on the following dates: February 2, June 14 and October 12. Today it reported that the February 2 date has slipped to February 21.

Russia launches several variants of the Soyuz rocket. This launch involved the Soyuz-U, while other Progress spacecraft have been launched on the newer Soyuz 2-1a, including the failed Progress M-27M launch in April 2015. It is not clear which of those two will be used for Progress MS-05.

Soyuz is also the name of the spacecraft that takes crews to and from the International Space Station. Those Soyuz spacecraft are launched on the Soyuz-FG version of the rocket. It is expected that Russia will wait for a successful Progress MS-05 launch before attempting to launch another crew. In its January 1 story, TASS said that Soyuz spacecraft would be launched on March 27, May 29, September 12 and October 26. Whether those dates hold remains to be seen.

Russia is the only country capable of launching crews to the ISS today. The United States has not been able to launch people into space since it terminated the space shuttle program in 2011.

By contrast, Russia is only one of the ISS partners capable of sending cargo to the ISS. The United States and Japan both launch cargo spacecraft. NASA relies on two companies, Orbital ATK and SpaceX, to deliver cargo on their Cygnus and Dragon spacecraft, respectively. The Japan Aerospace Exploration Agency (JAXA) launches its HTV (Kounotori) cargo spacecraft to ISS. HTV6 is currently berthed there.