Tying up hair can be unnecessary when maintaining it is already challenging. In microgravity, washing hair requires a different technique, often using no-rinse shampoo and a towel. Since there is no shower on the ISS, astronauts avoid the need for elaborate hairstyling.

The US astronauts stranded on the International Space Station are home at last — more than nine months after their days-long jaunt into orbit turned into a headline-grabbing space odyssey.

Butch Wilmore and Suni Williams have nearly half a century of combined experience as astronauts. But this is just their third time in space. Ms. Williams was born in Ohio but grew up in Massachusetts. She was a test pilot in the U.S. Navy and has spent more than 3,000 hours flying 30 different aircraft. She was selected as a NASA astronaut in 1998.