Sunita Williams' return: What happens after NASA astronauts' landing on Earth?

Two NASA astronauts, Sunita Williams and Butch Wilmore, are about to return to Earth after spending nine months aboard the International Space Station (ISS), a protracted mission that has been hampered by politics, timetable changes, and technical difficulties. Sunita Williams, 59, and Butch Wilmore, 62, had been stuck on the ISS after their faulty Boeing Starliner craft upended what was to be a roughly week-long test mission.

Formally a member of NASA's Crew-9 astronaut rotation mission, the four-person crew is set to splash down off the coast of Florida later Tuesday at 5:57 p.m. ET (Wednesday at 3:27 a.m. India time).

Long-term space travelers suffer from nausea, vertigo, and an unsteady walk upon returning to Earth due to the lack of gravity. The eight-day trip for Williams and Wilmore, test pilots for Boeing's new Starliner capsule, lasted more than nine months because their spacecraft had to return empty in September due to a string of helium leaks and thruster malfunctions.