• NASA and Boeing are further extending the first Starliner crewed flight but are not yet setting a new target date for returning the capsule to Earth.
• Officials say the Starliner team is conducting additional testing on the ground that will be completed before the spacecraft leaves the International Space Station.
• Boeing's crew flight test represents the first time Starliner is carrying people, flying NASA astronauts Butch Wilmore and Suni Williams.

NASA and Boeing are further extending the first Starliner crewed flight but are not yet setting a new target date for returning the capsule to Earth, the organizations announced Friday.

Boeing's Starliner capsule "Calypso" will stay at the International Space Station into next month while the company and NASA conduct new testing back on the ground. Boeing's crew flight test represents the first time Starliner is carrying people, flying NASA astronauts Butch Wilmore and Suni Williams.

Officials say the Starliner team is starting a test campaign of the spacecraft's thruster technology at White Sands, New Mexico — testing that will be completed before Starliner returns to Earth.

"We think the testing could take a couple of weeks. We're trying to replicate the inflight conditions as best we can on the ground," NASA's Commercial Crew manager Steve Stich said during a press conference.

Before launching on June 5, Boeing and NASA planned for Starliner to be in space for nine days. As of Friday, the Starliner flight has tallied 24 days and counting.

Despite the extended stay at the ISS, officials emphasized that Starliner is safe to return at any point in case of an emergency. NASA and Boeing say the delay for testing is solely to gather more data about the spacecraft's performance, in particular its thruster system.

"I want to make it very clear that Butch and Suni are not stranded in space," Stich said.

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The Starliner crew flight test represents a final major step before NASA certifies Boeing to fly crew on operational, six-month missions. Yet, similar to the previous two spaceflights that were uncrewed, Starliner is running into several problems during the mission.

Starliner was once seen as a competitor to SpaceX's Dragon, which has made 12 crewed trips to the ISS over the past four years. However, various setbacks and delays have steadily slipped Starliner into a backup position for NASA, with the agency planning to have SpaceX and Boeing fly astronauts on alternating flights.

Testing in New Mexico

Despite NASA and Boeing's assurances that Calypso is safe to return at any point, Starliner teams want to try to replicate thruster issues that occurred when the spacecraft was approaching the ISS. Officials said the goal of the ground testing is to "make sure that there's nothing that's unusual" about the thruster's performance.

The White Sands ground tests are expected to begin as early as Tuesday.

"This will be the real opportunity to examine the thruster, just like we've had in space, with on-the-ground detailed inspection. Once that testing is done, then we'll look at the plan for landing," Stich said.

"We're not going to target a specific date [for return] until we get that testing completed," he added.

Officials noted their rationale for keeping Starliner at the ISS while the White Sands testing is conducted: Boeing and NASA say their teams can perform thruster tests more frequently on the ground, as well as physically inspect the thrusters after test firings.

While Starliner will now spend far longer than anticipated in orbit, NASA's Stich noted that the spacecraft is designed for missions as long as 210 days.

Agency and company representatives repeatedly expressed confidence in the Boeing spacecraft's safety. Officials said delaying the return to Earth is an optional choice to study Starliner more during an experimental mission, rather than a necessary decision to fix a risky problem.

"We're not stuck on ISS. The crew is not in any danger, and there's not increased risk when we decide to bring Suni and Butch back to Earth," Boeing's Starliner program Vice President Mark Nappi said.