NASA astronauts returning to Earth: All you need to know | Space News

Two NASA astronauts are on their way back to Earth after spending nine months stranded in space.

Sunita Williams and Barry Wilmore departed the International Space Station (ISS) early on Tuesday morning and are expected to splash down off the coast of Florida in the evening. Boeing’s Starliner, their original return spacecraft, was deemed unsafe for the journey home, forcing the astronauts to stay in space much longer than planned.

Here’s all you need to know about their extended stay and long-awaited return:

Who are the two astronauts who are stuck in space?

The two astronauts stranded on board the International Space Station (ISS) are 59-year-old Sunita “Suni” Williams and Barry “Butch” Wilmore, 61, both veteran NASA-trained space travellers.

Williams, the current commander of the ISS and a retired US Navy officer, joined NASA in 1998. Over her career, she has spent 322 days in space and completed nine spacewalks. She previously held the record for the most spacewalks by a female astronaut, until 2017 when the title went to Peggy Whitson, who completed 10.

Wilmore first flew to space in 2009 on board the Space Shuttle Atlantis. Before the Boeing Starliner mission, he had logged 178 days in space. He has served as a flight engineer and commander on previous ISS missions, conducting research on plant growth in space, the effects of microgravity on the human body, and environmental changes on Earth.

In the Boeing mission, Wilmore served as the commander and Williams was the pilot.

When and how are they coming back to Earth?

The SpaceX Crew Dragon carrying Wilmore and Williams undocked from the ISS at 1.05am ET (05:05 GMT) on Tuesday. It is expected to splash into the Atlantic Ocean just before 6pm ET (22:00 GMT).

Late on Monday night, the process for Williams and Wilmore to return started. Hatch closure preparations began at 10:45pm ET (02:45 GMT).

NASA is livestreaming the departure and return journey of the astronauts.

They will return on board a SpaceX Crew Dragon capsule, which has been docked at the station since September 2024. This capsule originally brought NASA astronaut Nick Hague and Russian astronaut Aleksandr Gorbunov to the ISS, with two empty seats left for Wilmore and Williams’ return.

The four could not return on the same capsule until an additional crew carrying four other astronauts arrived to replace them.

That has now happened. Crew-10, which docked at the ISS on Sunday at 12:04am ET (04:04 GMT), consists of NASA astronauts Anne McClain and Nichole Ayers, Japanese astronaut Takuya Onishi, and Russian astronaut Kirill Peskov. They launched from Kennedy Space Center in Florida, US, on Friday.

Why did they get stuck?

Williams and Wilmore got stuck after technical issues with the spacecraft meant to bring them home.

They had travelled to the ISS on board Boeing’s CST-100 Starliner as part of its first crewed test flight. The mission, under NASA’s Commercial Crew Program, aimed to develop private spacecraft for transporting astronauts to and from the station. By outsourcing low-Earth orbit missions, NASA has said it aims to focus on deep space exploration, including the Artemis missions to the Moon and future human missions to Mars.

During the 25-hour flight to the ISS, Starliner experienced helium leaks and a malfunctioning thruster, which helps steer and control reentry. When it arrived on June 6, four more of the 28 thrusters failed, delaying docking with the station.

Although engineers restored four out of five failed thrusters, NASA deemed the spacecraft too risky for human travel and sent it back emptyleaving Williams and Wilmore stranded on the ISS.

In August 2024, NASA decided to bring them back on a SpaceX vehicle. Crew Dragon-9, which launched on September 29, 2024, has been docked at the ISS since, but bringing them home earlier would have left only one US astronaut on the space station, limiting research and emergency response.

Now, with their replacement members arriving on Crew-10, Williams and Wilmore can finally head home.

How long have the two astronauts been stuck in space?

Williams and Wilmore have been in space since June 5, 2024, meaning they will have spent more than nine months in orbit by the time they return.

After blasting off from Cape Canaveral, Florida, in June, they were originally scheduled to stay in space for just eight days.

The standard ISS rotation for astronauts is roughly six months.

How did they survive in space for so long?

Despite the unexpected extension of their stay, Williams and Wilmore have remained in good health and even conducted a spacewalk together in January.

Life on board the ISS follows a structured routine with exercise, work and leisure. This includes regular routines on both the treadmill and resistance machine in order to maintain their bone and muscle strength.

Throughout the year, several space agencies and private companies also scheduled missions to resupply the space station with food, water and oxygen, regularly replenished by cargo missions.

Over Christmas, the two even enjoyed a festive dinner that included smoked oysters, crab, duck foie gras, cranberry sauce, Atlantic lobster, and smoked salmon, according to The Times newspaper in London.

Williams and Wilmore have also been able to maintain contact with their families through email and telephone.

In an interview with Lester Holt on NBC Nightly News in November, Williams said she and Wilmore were “feeling good, working out, eating right”.

“We have a lot of fun up here too,” she added. “People who are worried about us, really, don’t worry about us … We’re a happy crew up here.”

Have astronauts been stuck in space before?

Williams and Wilmore are not the first astronauts to face an extended stay in space due to unforeseen circumstances. There have been previous cases where astronauts had to remain in orbit longer than planned due to technical problems or geopolitical events.

The longest single spaceflight by a US astronaut was Frank Rubio’s 371-day mission on board the ISS, from 2022 till 2023, extended due to issues with the Soyuz spacecraft that brought him to orbit. He ultimately returned on a different Soyuz capsule.

In 1991, Soviet astronaut Sergei Krikalev was stranded on board the now-decommissioned Mir space station for 311 days due to the dissolution of the Soviet Union.

Political turmoil and funding shortages delayed his return, forcing him to remain in orbit far longer than planned. When he finally landed in March 1992, he returned not to the Soviet Union, but to a newly independent Russia.