At 19:15 UTC (3:15 p.m. EDT) today, three astronauts stuffed into a Soyuz capsule currently docked to the International Space Station will close the hatch, separating themselves from their three comrades. A little over three hours later (22:33 UTC, 6:33 p.m. EDT) they will undock, move away from ISS, and then at 00:45 a.m. UTC (8:45 p.m. EDT) they will commence their deorbit burn, which will drop them into Earth’s atmosphere and send them down into the fields of Kazakhstan.
The astronauts—Richard Mastracchio, Koichi Wakata, and Mikhail Tyurin—are part of Expedition 39 and have been on the ISS since November. They’re expected to land back on Earth at 01:57 UTC (9:57 p.m. EDT). Mastracchio noted that astronauts Reid Wiseman and Alexander Gerst are likely to live-tweet the de-orbit from ISS, so follow them!
I wonder, too: Will this be visible from the live HD video cameras on the ISS? I can’t be sure, but one of the cameras points right at the docked Soyuz! If it happens over the daylit side of Earth (when the cameras are sending down their feed) we may be in for quite a treat, so I've embedded that stream here as well. Even if these cameras don’t catch the Soyuz on its way down, the view is sure to be stunning anyway, and always well worth watching.
At least some of the undocking and deorbit burn will be over the daylit side of Earth, so here’s hoping we get a live view!