Starliner astronauts to return after Crew-10 launch: What to know about SpaceX mission

An upcoming routine SpaceX mission to send a crew of astronauts to the International Space Station bears a little more significance this time around.

When a mission known as Crew-10 launches as early as Wednesday, its arrival in orbit will pave the way for the crew of the Boeing Starliner to finally come home. Those two astronauts, Butch Wilmore and Suni Williams, have unexpectedly remained at the space station since June after NASA determined that the troubled Starliner spacecraft wasn't up to the task of transporting them back.

Wilmore and Williams were instead months ago folded into the Crew-9 mission when its spacefarers docked at the orbital outpost in September on the SpaceX vehicle selected for their return.

But Williams and Wilmore weren't able to travel back to Earth right away for two critical reasons: The Crew-9 astronauts had a six-month mission of their own to complete before departing the space station. And, per NASA protocol, the team would have to wait on their successors to arrive.

Now, that could happen in a matter of days if the spacefarers of Crew-10 are able embark on a short trip to the space station on a SpaceX Dragon capsule.

Here's everything to know about the Crew-10 mission, including its role in ending the Starliner saga.

What is the SpaceX Crew-10 mission?

As the name suggests, Crew-10 is SpaceX's tenth science rotation mission to the International Space Station.

The missions, most of which last about six months, are contracted under NASA's commercial crew program. The program allows the U.S. space agency to pay SpaceX to launch and transport astronauts and cargo to orbit aboard the company's own vehicles, freeing up NASA to focus on its Artemis lunar programand other deep space missions, including future crewed expeditions to Mars.

SpaceX uses its Falcon 9 rocket – one of the most active in the world – to launch the crew missions from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Once in orbit, the astronauts aboard a SpaceX Dragon capsule then seperate from the rocket to continue onto the space station.

The Boeing Starliner was meant to one day become a second operational vehicle for NASA under the program, though its status remains unclear after its botched inaugural crewed flight test. In September, the Starliner vehicle undocked from the space station without its crew for a parachute-assisted landing in New Mexico.

Meet the astronauts of Crew-10

The Crew-10 mission includes four spacefarers:

• NASA astronaut Anne McClain, of Spokane, Washington, mission commander;

• NASA astronaut Nichole Ayers, of Colorado, mission pilot;

• Japanese astronaut Takuya Onishi of the Japan Aerospace Exploration Agency (Jaxa), a mission specialist;

• Roscosmos cosmonaut Kirill Peskov, a mission specialist.

When will the Crew-10 mission launch for ISS?

As of Monday, Crew-10 was expected to board the Dragon for a launch at 7:48 p.m. EST Wednesday, with an anticipated arrival at the ISS the next morning.

The upcoming potential launch comes after NASA twice delayed the Crew-10 mission, originally anticipated to get off the ground in February.

NASA initially announced in December that the launch had been pushed to late March to give SpaceX more time to prepare a new Dragon capsule for liftoff. The launch date was then moved back up to mid-March – most likely due to pressure from President Donald Trump and SpaceX CEO Elon Musk – when NASA decided to instead use a "previously flown" Dragon named Endurance.

When will Starliner astronauts return with Crew-9?

If Crew-10 launches as scheduled, the Starliner crew could return to Earth as early as Sunday, March 16, a NASA spokesman told USA TODAY.

The tentative return date would allow for a few days of handover activities when Crew-10 arrives at the space station – a crucial process for the outgoing astronauts to help the arriving spacefarers familiarize themselves with their new home.

Williams and Wilmore, the two astronauts of the Starliner crew, would then depart the station with Crew-9. That mission included a truncated crew of two – NASA astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov – in order to leave two extra seats on its Dragon capsule for the Starliner crew.

Once Crew-9 undocks on the Dragon, they would make a splashdown landing off the Florida coast.

Crew-10 astronauts arrive at Kennedy Space Center, address media

The Crew-10 spacefarers arrived Friday at the Kennedy Space Center in Cape Canaveral and have since participated in a dress rehearsal ahead of the launch, donning their SpaceX space suits.

SpaceX has also conducted a static fire test of the Falcon 9 rocket, which as of Sunday is upright on the launch pad.

McClain, the mission's commander, told media Friday that Crew-10 has been in constant contact with the Crew-9 astronauts, including the Starliner crew.

"We are going to take a little bit of an adventure," McClain told media on Friday.