NASA to Say If Boeing Starliner Astronauts Will Stay Longer on Space Station

Will they stay or will they go?

On Saturday, NASA is scheduled to finally announce its decision for how two of its astronauts, who went to orbit in June on Starliner, a spacecraft built by Boeing, will come home from the International Space Station.

The agency has announced a news conference for 1 p.m. Eastern time on Saturday to reveal its decision. Here’s a look at what will be discussed.

What is the problem with Boeing’s Starliner?

Suni Williams and Butch Wilmore arrived at the space station on June 6. If everything during the mission had proceeded perfectly, Starliner would have been docked for just eight days. But this is a test flight for Starliner, the first with people aboard, and it was not a surprise that some problems might pop up.

But problems with the Boeing spacecraft’s propulsion system turned out to be more than minor glitches.

As Starliner approached the space station, several of its thrusters malfunctioned, putting out diminished thrust. All but one were brought back into operation, and the docking was successful. Starliner also experienced several leaks of helium.

NASA and Boeing officials initially said that they needed to study the problems but that they expected Ms. Williams and Mr. Wilmore to be able to safely return to Earth in the spacecraft that had taken them to the station.

“The vehicle at station is in good shape,” Steve Stich, the manager of the commercial crew program at NASA, said during a news conference on June 28. “I want to make it very clear that Butch and Suni are not stranded in space. Our plan is to continue to return them on Starliner and return them home at the right time.”

The right time may turn out to be never.

The problems remained perplexing after weeks of analysis. Even after ground tests, the engineers could not say what had caused the thrusters to malfunction. At least some NASA engineers expressed worries that uncertainties could point to a more serious underlying problem and that NASA should not risk the lives of the astronauts.

Boeing has said it believes the extensive analysis and testing show that its vehicle is safe enough for the journey.

What are NASA’s choices for getting Willians and Wilmore home?

Leaders at the space agency including Bill Nelson, the administrator, are meeting in the Johnson Space Center in Houston to assess whether the Starliner is safe enough for Ms. Williams and Mr. Wilmore.

If they decide it is not, the astronauts would hitch a ride on a vehicle built by a competitor: SpaceX’s Crew Dragon.

If NASA leaders choose the SpaceX option, two of the astronauts scheduled to launch on the next Crew Dragon mission will be bumped off to make room for Ms. Williams and Mr. Wilmore on the return trip, and the two astronauts will have their stay extended a further half a year, becoming full-fledged crew members of the space station. They would finally return around February.

Starliner would still return to Earth in September, but flying autonomously without the astronauts.