Three months after Boeing’s Starliner departed Earth with two astronauts aboard, the spacecraft will be returning home without them, in a decision that NASA has acknowledged caused “tension” with Boeing. 

The Starliner is set to depart the International Space Station around 6:00 p.m. EST on Friday night, if weather allows, and will land at White Sands Space Harbor at New Mexico right after midnight, as long as NASA’s plan goes smoothly. The spacecraft’s flight to the station in June was plagued with helium leaks and malfunctioning thrusters, leaving astronauts Suni Williams and Butch Wilmore in space for months longer than the expected eight-day journey. Now, they aren’t set to return until February 2025, on a SpaceX Dragon capsule.

“It was a tough decision to make,” NASA’s commercial crew program manager, Steve Stich, said in a conference ahead of the departure. “It was really hard to determine whether to be uncrewed or not. I would say the teams were very split,” he said about the uncertainty surrounding the thrusters, adding that it was NASA that chose to keep its two astronauts in space. 

The last meeting between Boeing and Nasa wasn’t quite “heated,” he said, but there was “tension in the room.” 

“Boeing believed in the model that they had created, that tried to predict thruster degradation for the rest of the flight,” he said. “I would say the NASA team looked at the model and saw some limitations.” 

NASA has indicated that it’s optimistic and confident about the Starliner’s return trip being a success.

“We have confidence in the vehicle,” Mr. Stich said when asked how NASA felt about the Starliner’s landing given that it wasn’t deemed safe enough for the crew to be on board. “We’ve had two good landings with Starliner so far, and we’re expecting another one Friday.”

As the two astronauts are staying in space for months longer than anticipated, they’ve had to adapt to new exercise routines to combat the challenges of extended stays in space. Their families on the ground have also had to adapt to the long space duration — both astronauts are married and Mr. Wilmore has two daughters. Mr. Wilmore has expressed that missing out on his daughter’s senior year of high school is one of his greatest challenges of being in space, his pastor told the Sun, as Mr. Wilmore’s family and church community await his return to Earth.

Ahead of the flight, Boeing tells the Sun that it’s focusing on the safety of the crew and Starliner “first and foremost.”

“We are executing the mission as determined by NASA,” a representative says, “and we are preparing the spacecraft for a safe and successful uncrewed return.”

NASA is planning to hold a post-landing news conference at 1:30 a.m. on Saturday.