The Boeing capsule, named Calypso, returned to Earth early this morning (September 7) and landed in the New Mexico desert at 12:01 a.m. ET (04:01 GMT; 23:01 local time on September 6).

“Great landing, Calispo!” NASA astronaut Suni Williams announced on the agency’s webcast. “I don’t think it could have gone any better.”

Initially expected to last more than 3 months, the landing was delayed for a long time, as the orbital mission lasted about 10 days. And although Starliner launched with two NASA astronauts (Williams and Butch Wilmore), no one ever made it home.

A decisive test flight

The newly completed mission, known as Crew Flight Test (CFT), has roots that go back decades. In 2014, NASA awarded multibillion-dollar contracts to SpaceX and Boeing to complete studies of the astronaut taxis Crew Dragon and Starliner capsules.

The agency wanted one or both of those vehicles to begin carrying astronauts to the International Space Station (ISS) by 2017 and regain their own orbital human spaceflight capabilities, something the United States has not had since retiring the space shuttle in 2011.

Neither capsule achieved that ambitious goal. The first mission of SpaceX astronauts, a test flight to the ISS called Demo-2, launched in May 2020. Starliner’s first crewed flight was CFT, which launched on June 5 aboard a United Launch Alliance Atlas V rocket and sent Williams and Wilmore to the orbiting laboratory for a planned eight-day stay.

The CFT was scheduled to fly last year but was delayed to fix problems with the parachute and to remove a large amount of insulation tape from the capsule’s wiring system. (Analysis determined that the tape was flammable and therefore a safety hazard.)

The mission has also been plagued with problems recently. For example, a launch attempt scheduled for May 25 was canceled after crew members noticed a small helium leak in the Starliner’s service module. More helium leaks occurred post-launch as the Starliner chased the ISS into orbit. And more worryingly, the capsule experienced thrust issues, with five of its 28 Reaction Control System (RCS) engines failing shortly after liftoff.

Problems with the thrusters thwarted the first attempt to dock Starliner with the ISS on June 6. The capsule succeeded on its second attempt that day, and crew members eventually recovered four of the five failed thrusters. But the problem loomed over the rest of the mission.

A difficult decision

NASA repeatedly extended the CFT’s stay in orbit, giving mission team members more time to analyze and fix engine issues. Such work included modeling and testing both in space (with the Starliner) and on the ground (with the Starliner RCS engine at NASA’s White Sands Test Center in New Mexico). Ultimately, NASA concluded that bringing Williams and Wilmore home on the Starliner posed an unacceptable safety risk.

“The decision to keep Butch and Suna at the International Space Station and to return the Boeing Starliner home without a crew is a reflection of our commitment to safety: our core value and our North Star,” NASA Administrator Bill Nelson said in a statement on Aug. 2, the same day the agency announced the news.

Williams and Wilmore will remain at the ISS until February, when they will hitch a ride home on SpaceX’s Crew Dragon, which is flying the company’s Crew-9 mission scheduled to launch later this month. To make room for them, Crew-9 will launch with two astronauts instead of the usual four.

Meanwhile, the Starliner had been packed up for a crew-less return to Earth. Among the equipment it had brought home were the Boeing Blue suits Williams and Wilmore had worn in the capsule. The astronauts no longer needed them.

“The suits are incompatible,” Steve Stich, NASA’s commercial crew program manager, said at a press conference on Wednesday, September 4. “So the Starliner suits will not work on Dragon and vice versa.”

Starliner separated from the ISS as scheduled on Friday, September 6 at 18:04 ET (22:04 GMT). A series of burns were performed to prepare for an unmanned landing under parachutes at White Sands Space Center in New Mexico after midnight today.

This was Starliner’s third goal overall. The capsule also completed two unmanned test flights to the ISS: one in December 2019 and another in May 2022. Starliner failed to rendezvous with the orbiting laboratory on its first flight due to several malfunctions. The second uncrewed mission was successful, but Starliner also experienced engine problems on that flight. (This was a different set of issues related to the Starliner Orbital Maneuvering and Control System, not the RCS.)

Foggy future

Boeing and NASA hoped the CFT would pave the way for Starliner certification, which would allow the capsule to launch six-month astronaut missions to the ISS.

The first operational flight of this type, Starliner-1, is scheduled for February 2025. But that launch has already been postponed to no earlier than August 2025. And it’s not clear at this time whether Starliner will be certified by then or what additional testing NASA will need before certification takes place.

“I think what we need to do now is lay out the overall plan, which we haven’t had time to do,” Stich said at a press conference on September 4.

“We didn’t do that because the teams were so focused on this flight, on developing the overall search strategy and the overall amount of work we needed to do,” he added. “And when we do that, will we have a better understanding of when we can certify the vehicle and when we can continue flying?”

Meanwhile, Crew Dragon was certified shortly after the successful completion of Demo-2 in 2020. SpaceX’s vehicle is currently preparing for NASA’s ninth operational flight of astronauts to the ISS. (This would be Crew-9, as its name suggests.)

SpaceX has also flown multiple private crewed missions to the station, as well as the Inspiration4 astronaut flight to Earth orbit that failed to rendezvous with the orbiting laboratory. And it is preparing to launch Polaris Dawn, another commercial free-flight astronaut mission that aims to conduct the first private spacewalk in history.