A new three-person crew for the International Space Station (ISS) is set to lift off from the Baikonur Cosmodrome in Kazakhstan at 6:31 am Eastern Standard Time tomorrow (Monday). Crew launches have been routine for the 18 years that ISS has been permanently occupied by astronauts rotating on 4-6 month schedules, but that all changed on October 11 when a Soyuz rocket malfunctioned about two minutes after launch. The two-person crew landed safely, but it was a stark reminder about the perils of spaceflight. A return-to-flight so quickly is unusual by U.S. standards, but no one was hurt and NASA and its Russian counterpart, Roscosmos, are confident the problem was identified and fixed. [UPDATE, December 3, 6:50 am ET: The launch was uneventful at 6:31 am ET. Crew is in orbit and on track for docking at ISS at 12:36 pm ET today.]

The three crew members launching on this mission, Soyuz MS-11, are NASA’s Anne McClain, the Canadian Space Agency’s David Saint-Jacques, and Roscosmos’s Oleg Kononenko.

If all goes according to plan, they will lift off at 6:31 am ET tomorrow morning and dock with the ISS just 6 hours and 5 minutes later at 12:36 pm EST after chasing the ISS for four orbits. They will join three crew members already there: NASA’s Serena Auñón-Chancellor, ESA’s Alexander Gerst, and Roscosmos’s Sergey Prokopyev.

Those three arrived in June and are scheduled to return to Earth on December 20.

That is the day the Soyuz MS-11 crew originally was supposed to launch. Instead of delaying the next launch while Russia determined and remedied whatever went wrong on October 11, the launch date was moved up. U.S. launch failure investigations usually take much longer.

Granted, no one was injured. When the Soyuz rocket malfunctioned, automated systems instantly detached the crew capsule and sent it and its occupants away from the rocket. The rocket was destroyed, but Roscosmos cosmonaut Aleksey Ovchinin and NASA’s Nick Hague landed safely. They were quickly picked up by rescue crews who were pre-deployed along the rocket’s projected path just in case something like this happened. They were taken to a nearby town for medical checkups and then returned to the Baikonur Cosmodrome and into the arms of their families and colleagues who had just watched them lift off a couple of hours before. Other than disappointment that they did not get to space, they do not seem to have suffered any ill effects.

The United States has suffered three fatal human spaceflight accidents — the 1967 Apollo 1 fire during a pre-launch test, the 1986 space shuttle Challenger tragedy during launch, and the 2003 space shuttle Columbia tragedy during reentry. In each case, the failure reviews and fixing the technical causes required a great deal of time. It was 19 months from the Apollo fire until the next flight with a crew (Apollo 7). For the space shuttle program, it was 32 months between Challenger and the next shuttle flight (STS-26) and 30 months between Columbia and STS-114.

In this case, however, NASA Administrator Jim Bridenstine, who was at Baikonur for the Soyuz MS-10 launch, expressed confidence the very next day that launches would resume quickly. Russia’s investigation found the technical cause was a separator sensor pin on one of the four strap-on rockets that malfunctioned because it had been bent during booster assembly. The solution was to inspect all the Soyuz rockets that had been already assembled at Baikonur and be more diligent in assembling new ones. Russia conducted four already-scheduled Soyuz launches since October 11 and all went off without a hitch.

The Soyuz rocket has a strong reliability record and it has been 25 years since the Russians had a launch abort on a human spaceflight. In that 1983 case, Soyuz T-10A, the rocket exploded on the launch pad. As with Soyuz MS-10, the crew capsule was ejected and the two-man crew landed safely far from the pad. The Russians had an in-flight abort in 1975 when the Soyuz rocket’s third stage malfunctioned. That crew, Soyuz 18A or the “April 5th Anomaly,” also landed safely near the Chinese border although one of the cosmonauts was injured.

The Russians have suffered two fatal human spaceflights – Soyuz 1 (1967) and Soyuz 11 (1971). In both of those cases they also took more than a year to investigate and resume flights — 18 months after Soyuz 1 and 27 months after Soyuz 11.

Note: The docking time has been updated by one minute. They will dock at 12:36 pm ET.