NASA astronauts Butch Wilmore and Suni Williams, who rode Boeing's crew capsule to the ISS last year, splashed down on Tuesday in SpaceX's Dragon capsule amidst a lengthy effort by Boeing to fix Starliner's faulty propulsion system, which had caused their eight-day test mission to stretch into a nine-month stay in space.
The technical issues on Starliner's debut crewed mission were the latest setback - and most visible so far - in Boeing's thorny development of a spacecraft that has cost the aerospace giant more than $2 billion. Starliner would compete with the dominant Crew Dragon capsule from Elon Musk's SpaceX and provide NASA a second U.S. ride to low-Earth orbit for its astronauts.
But before clinching a long-sought NASA certification for routine flights, the craft may need an extra uncrewed test mission that would be its fourth overall, after it flew two uncrewed tests in 2019 and 2022.
"We're ... looking at some options for Starliner, should we need to, of flying it uncrewed," Steve Stich, chief of NASA's Commercial Crew Program that oversees Starliner development, told reporters Tuesday night. "When we look forward, what we'd like to do is that one flight, and then get into a crew rotation flight."
"We'll kind of weigh all those things as we get the testing and analysis behind us," Stich said.
Boeing did not return requests for comment.
Stich said Starliner's crewed flight last year checked off some key testing milestones related to how astronauts command and fly the vehicle. The purpose of an extra uncrewed test, he said, would be to validate that its thrusters can perform as designed in space, an environment impossible to simulate in tests on Earth.
Starliner's first crewed mission was to be its final test before it could begin routine astronaut flights for NASA, which relies on SpaceX's Crew Dragon craft.
STARLINER'S COMPETITIVE FUTURE
Boeing is also eyeing Starliner as a taxi to and from privately built space stations that are in early development - the kind of non-government revenue that SpaceX has brought in with fully private Dragon missions.
But Starliner's future was thrown into uncertainty when it suffered five thruster failures during its flight to the ISS last year, as well as leaks of helium that is used to pressurize the thrusters. NASA made Starliner return to Earth without its crew in September, deeming it too risky for astronauts to ride.
A NASA safety advisory panel in January said the agency and Boeing were making "significant progress" in their post-flight technical investigations but that the propulsion system issues remain unresolved.
Stich said Boeing is planning a ground test this summer of propulsion system components aimed at validating the company's fixes.
On top of Boeing's $2 billion in Starliner charges since 2016, the ceiling of the company's fixed-price $4.2 billion NASA contract for Starliner development and missions has grown by $326 million since being awarded in 2014, according to a Reuters analysis of contract data. The company has received half of that so far during development, roughly $2.2 billion.
SpaceX's Crew Dragon meanwhile has flown 11 astronaut missions for NASA, including a crewed test flight in 2020.
The total value of SpaceX's initial $3 billion NASA contract, also awarded in 2014 and similar to Starliner, has grown to nearly $5 billion, largely due to extra missions NASA has added amid Starliner's development delays.
