After 286 days in space, two American astronauts who've been stuck on the International Space Station since last spring are finally on their way back down to Earth ... and we're live-streaming their spacecraft's arrival.

Butch Wilmore and Sunita "Suni" Williams are expected to splash down off the coast of Florida today at about 5:50 PM ET, following a 19-hour journey in a SpaceX spacecraft, alongside astronauts Nick Hague and Aleksandr Gorbunov.

A relief crew arrived at the ISS Sunday, giving Butch and Suni the green light to head home after 9 months spent in space. NASA even bumped up their return by a day to dodge some unfavorable weather later this week.

Wilmore and Williams, both test pilots, were only supposed to be in space for 8 days ... they flew the Boeing Starliner up to the ISS in June last year, but due to thruster issues and helium leaks, NASA decided to return the spacecraft to Earth completely empty -- forcing the unexpected staycation in space for Butch and Suni. They’ve been stuck on the International Space Station ever since.

To be clear ... they were never actually "stranded" -- Butch and Suni had arrived at the ISS prepared for an extended stay in the event something on the mission went sideways ... as it did. NASA was considering whether the two could fly back on the Boeing Starliner, but NASA vetoed them getting on that return trip over safety concerns.

Then they had the opportunity to return in September, but they opted to stay, since the SpaceX craft sent up at the time kept 2 crew members off the flight, to give Buch and Suni seats for the ride back ... but that would have left no replacements on the ISS if they had departed. So they stayed.

The two are now finally about to be back on the ground. Welcome home!