Today, Russian space agency Roscosmos blamed a bend in a sensor for last month’s dramatic failure of a Soyuz rocket launch, which forced two astronauts to make a harrowing emergency landing.

After the launch failure on October 11th, Roscosmos promptly started looking into the cause. Initial speculation focused on the rocket’s boosters, one of which didn’t seem to separate properly from the rest of the spacecraft.

Roscosmos just released new information from the investigation, which concluded this week. Russian news agency TASS reports that investigators found that a sensor — which monitors the separation of the boosters from the rocket — was deformed, bent by about six degrees. Six degrees isn’t a lot, but it was enough to keep the lid of a nozzle on one of the boosters from opening. That booster then hit the fuel tank of the central part of the rocket, lurching it violently off course.

The investigation concluded that the issue occurred while the rocket was being assembled at the Baikonur Cosmodrome, the site in Kazakhstan where the Russian rockets are launched. Speaking at a news conference today, the head of the investigation, Oleg Skorobogatov, told reporters that two additional Soyuz rockets could have the same problem.

Roscosmos also released video from the exterior of the rocket that shows the moment when one of the boosters doesn’t quite manage a flawless separation.

The next launch of the Soyuz rocket in the same configuration is tentatively scheduled for November 16th when it is set to carry an uncrewed Progress supply ship to the International Space Station. Since the space shuttle program ended in 2011, the Russian Soyuz rocket system has been the only way for astronauts to access the ISS. NASA is working on alternatives with Boeing and SpaceX, but the test flights for those commercial crew spacecraft aren’t scheduled to take place until 2019.

The next crewed launch of the Soyuz is scheduled for December 3rd.