The astronauts on the I.S.S. — including two who were scheduled to return months ago — held a zero-gravity cookie-decorating contest and built a reindeer from storage bags.
In June, two NASA astronauts, Suni Williams and Butch Wilmore, set out for what was expected to be an eight-day trip to the International Space Station.
On Wednesday — around six months and several spacecraft malfunctions later — they donned Santa Claus hats and wished their families the best from hundreds of miles above sea level as their tenure, which is likely to keep them in Earth’s orbit for at least two more months, stretched on.
Ms. Williams, 59, and Mr. Wilmore, 61, docked at the space station during a test flight of Boeing’s Starliner, which was intended to be a commercial option for ferrying people to and from the station.
But after a spate of malfunctions called the safety of the return flight into question, NASA leaders decided to bring the Starliner to Earth uncrewed, leaving the two astronauts behind until another aircraft can take them back.
So Ms. Williams and Mr. Wilmore had a chance to participate in the long, strange tradition of celebrating the holidays in space, which began in 1968 when the Apollo 8 astronauts read verses from the Book of Genesis while broadcasting a video of the lunar surface to roughly one billion viewers.