NASA
At around 11:27 p.m. ET Tuesday night, Kelly is scheduled do something he hasn't done in 340 days: Walk on solid ground.
For nearly a year, Kelly has been floating in space, 249 miles above Earth's surface, on board the International Space Station (ISS).
During that time he shattered the record for the longest consecutive days spent in space by any NASA astronaut. The previous record was 215 days, held by NASA astronaut Michael López-Alegría.
Kelly's return marks an important milestone in NASA's One-Year-Mission, dedicated to studying the human body's response to long-term stays in zero gravity. Once Kelly returns, scientists will thoroughly evaluate him by analyzing everything from his vision, to his physical performance, metabolism, and mental health.
Right now, Kelly is getting ready to board a Russian Soyuz capsule with his one-year-mission partner, Russian cosmonaut Mikhail Kornienko.
Kornienko also spent 340 days in space, though he didn't break the cosmonaut (the word used to refer to a Russian astronaut) record for the longest stay in space. That world record of 437 days is still held by cosmonaut Valeri Vladimirovich Polyakov, who achieved it in the mid-90s.
The Soyuz capsule is scheduled to undock with the ISS and begin its 3.5-hour trip back to Earth at approximately 7:45 p.m. ET Tuesday. But NASA will begin streaming live coverage of the event at 4 p.m. ET, shortly before Kelly and Kornienko officially leave the ISS for the Soyuz and close the ISS hatch behind them.
People often wonder what it's like to go to space, but if you've ever wondered what it's like to return from space, this is your chance. Plus, you'll be seeing history in the making! Here's a breakdown of the major events:
| 4:00 - 7:30 p.m. ET | Farewell and hatch closure coverage |
| 8:02 p.m. ET | Soyuz undocks with the ISS |
| 10:32 p.m. ET | Soyuz burns its engines to prep for re-entry |
| 11:27 p.m. ET | Landing near Dzhezkazgan, Kazakhstan |
You can watch it all on NASA TV, or on the livestream below: