The astronauts will be checked out by flight surgeons as they adjust to gravity, officials said, and should be allowed to go home after a day or two. However, their condition will be monitored for long after that.

Everything from walking, to wearing clothes, to smelling food and other odors terra firma will require getting used to for Williams and Wilmore, 59 and 62, experts say.

The NASA astronauts splashed down on Tuesday in a SpaceX capsule after problems with a Boeing vehicle set in motion a nine-month stay on the International Space Station.