Russian space agency official Sergei Krikalev told a Russian audience today that the Soyuz MS-10 launch failure was caused by a malfunctioning sensor and the next crew may launch to ISS on December 3. His remarks were reported by Russia’s official news agency, TASS, which also said Roscosmos has set November 16 as the date for the launch of the next Russian cargo resupply mission, Progress MS-10.

The launch of Soyuz MS-10, carrying Russian cosmonaut Aleksey Ovchinin and NASA astronaut Nick Hague, aborted about two minutes after the Soyuz-FG rocket lifted off from the Baikonur Cosmodrome when something went wrong as the first and second stages separated. Automated systems immediately detached the crew capsule from the rest of the rocket. Ovchinin and Hague landed safely in the steppes of Kazakhstan where rescue teams quickly arrived and returned them to Baikonur. Both are fine.

NASA Administrator Jim Bridenstine was at Baikonur for the launch and one day later, while in Moscow, gave a press conference at which he expressed confidence that the next crew would launch on schedule in December. He reiterated that optimism at the National Space Council meeting last week. The next crew, Soyuz MS-11, was expected to launch on December 20.

Today, Krikalev put the date even earlier — December 3 — though it was not definitive. He said every effort was being made to meet that date.

According to TASS and the Associated Press (AP), Krikalev said the launch failure was traced to a bad sensor. AP summarized his statement as a “malfunction of a sensor which signals the jettisoning [of] one of the rocket’s four side boosters caused the booster to collide with the second stage of the rocket.”

Krikalev, one of Russia’s most experienced cosmonauts, is now executive director for human spaceflight at Roscosmos.

The Soyuz rocket is the workhorse of the Russian space program and has several variants. The type used for crew launches is Soyuz-FG. Russia plans several Soyuz launches before the next crew flight. They were already scheduled, but now can be used to test common systems. One has already taken place successfully — a Soyuz-2.1b from Plesetsk on October 23. Next is another Soyuz-2.1b from Plesetsk on November 3, then a Soyuz ST-B (similar to the Soyuz-2.1b) from Europe’s launch site in French Guiana on November 6, and then the Progress MS-10 cargo launch to the ISS from Baikonur on November 16 using a Soyuz-2.1a.

If all goes well, that should provide some level of assurance that the sensor problem is understood and remedied.

Three crew members are aboard the ISS now: Russian cosmonaut Sergey Prokopyev, NASA astronaut Serena Auñón-Chancellor and European astronaut Alexander Gerst. Ovchinin and Hague were supposed to join them as part of the routine crew rotations that take place every 4-6 months. They were launched on Soyuz MS-09 on June 6, 2018 and expected to return in mid-December.

If Soyuz MS-11 is indeed launched on December 3, they may get to keep that return date. Kirkalev said today the plan is for them to return on December 20.

Soyuz MS-11 will deliver Russian cosmonaut Oleg Kononenko, NASA astronaut Anne McClain, and Canadian astronaut David Saint-Jacques to ISS.

Cargo missions also are on tap over the next five weeks.

Four robotic spacecraft resupply the ISS crews: Russia’s Progress, Japan’s HTV, and the U.S. commercial cargo systems — Northrop Grumman’s Cygnus and SpaceX’s Dragon.

An HTV is already docked at ISS. A Cygnus is scheduled for launch from Wallops Island, VA on November 15. As noted, TASS said today that Roscosmos has set November 16 for the Progress MS-10 launch, just one day after Cygnus. Today NASA announced that the next Dragon launch will occur on December 4.

The rapidity of recovery from the Soyuz MS-10 launch failure is a bit surprising from a U.S. viewpoint where launch failure reviews typically take many months even when no humans are aboard. As Bridenstine said at the Space Council meeting, it is the “most successful failed launch we could have imagined.”