This was a critical International Space Station crew launch ferrying three people to the outpost. When the Soyuz MS-10 in-flight failure occurred two months earlier, it left the ISS in a precarious position: the three crew on the outpost had to come home by late-December or they would exceed the on-orbit time limit for their Soyuz MS-09 craft. That meant this mission's planned late-December launch had to be advanced to early-December, and teams back on the ground had to quickly discover and fix the cause of the Soyuz MS-10 failure or they'd risk having to de-crew the entire ISS. A fix was identified, implemented, and tested within six weeks, allowing this mission to fly early.