Roscosmos also released dramatic video footage from the onboard camera this morning, showing a calm ascent into space interrupted by a booster separation and sudden tumbling motion.
During the conference, officials said that the abnormal separation of one of the rocket's four strap-on boosters, which hit the core booster, was caused by a nozzle cover on the oxidizer tank failing to open. According to the press statement, that impact occurred because the separation contact sensor was deformed during assembly at its Baikonur Cosmodrome launch site in Kazakhstan. [Soyuz Space Crew Launch Failure 2018: Full Coverage]
Just now, @roscosmos released an official cause of the emergency landing of Soyuz-2! The reason turned to be operational, due to a failed opening of the cap of the block D on 118th second. Soyuz-FG with cosmonauts on board will be launched on 3rd of December from Baikonur. #GK pic.twitter.com/9U82yOJt8Q— GK Launch Services (@gk_launch) November 1, 2018
"The launch ended up with a launcher failure caused by abnormal separation of one of the strap-on boosters (Block D) that hit with its nose the core stage (Block A) in the fuel tank area," Oleg Skorobogatov, chair of the investigation committee, confirmed in the translated statement. "It resulted in its decompression and, as a consequence, the space rocket lost its attitude control."
During the aborted launch Oct. 11, the crew capusle carrying NASA astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin was able to safely separate from the rocket after getting a warning signal during separation, firing engines to gain distance from the booster, according to NASA spokesperson Reid Weisman. The two took about a half hour to parachute down to Earth, where they were met by a search-and-rescue team.
Russian officials said during the press conference that they'd created measures to avoid the issue happening again, and that resuming Soyuz launches was a priority.
They added that the uncrewed Progress MS-10 cargo ship, which launches on a Soyuz-FG rocket, will fly to the space station Nov. 16, and that the next crew launch, Soyuz MS-11, will fly Dec. 3. That flight is scheduled to carry three more crewmembers to the space station, bringing the total back up to six.
The three crewmembers currently on the station will return to Earth Dec. 20, a week later than originally scheduled, Roscosmos officials said.