Progress MS-21, Russian production No.451, identified by NASA as Progress 82P, was a Progress spaceflight launched by Roscosmos to resupply the International Space Station (ISS). It was the 174th flight of a Progress spacecraft.

Soyuz-2 is a modernised version of the Soviet Soyuz rocket. In its basic form, it is a three-stage launch vehicle for placing payloads into low Earth orbit. Compared to the previous versions of the Soyuz, the first-stage boosters and two core stages feature uprated engines with improved injection systems. Digital flight control and telemetry systems allow the rocket to be launched from a fixed launch platform, whereas the launch platforms for earlier Soyuz rockets had to be rotated as the rocket could not perform a roll to change its heading in flight.