The Soyuz flown to the International Space Station in March by one-year crewmembers Scott Kelly and Mikhail Kornienko is ready to come home. Under the command of cosmonaut Gennady Padalka, who launched with Kelly and Kornienko in March, Soyuz TMA-16M is scheduled to undock at 5:29 p.m. EDT (21:29 UTC) Friday. It should touch down on the Kazakhstan steppe about three-and-a-half hours later, at 8:51 p.m.
Padalka will become the most experienced spacefarer ever at the end of the trip, racking up a cumulative 879 days in space over the course of five flights. He trades his spot on the station with Sergey Volkov, who arrived Sept. 4 with visiting flight engineers Andreas Mogensen and Aidyn Aimbetov. Volkov will remain on board until next March, returning with Kelly and Kornienko in the Soyuz TMA-18M spacecraft he brought to the orbiting laboratory. Soyuz vehicles have about an on-orbit lifetime of about six months.
According to its current two-line element (TLE) set, the ISS should be near Mongolia at the moment of undocking:
The Soyuz will push back from the station's Zvezda module and drift for three minutes. Once the spacecraft is 20 meters away—far enough to avoid spraying the ISS with thruster exhaust—it will perform a separation burn, easing off at a leisurely two kilometers per hour. The most intense part of the journey home is slated to start at 7:59 p.m. with a four-minute, 45-second de-orbit burn:
If you'd like to learn more about a typical Soyuz reentry, The European Space Agency has you covered: