Updated 10:30 p.m. Eastern with comments from postlanding briefing.
LONG BEACH, Calif. — Boeing’s CST-100 Starliner safely landed in New Mexico May 25, concluding a six-day uncrewed test flight to the International Space Station and setting the stage for the spacecraft’s first flight with people.
Starliner undocked from the International Space Station at 2:36 p.m. Eastern and maneuvered away from the station. After a one-minute deorbit burn using four Orbital Maneuvering and Attitude Control (OMAC) thrusters at 6:05 p.m. Eastern, the crew capsule jettisoned the service module and reentered the atmosphere over the Pacific Ocean.
The capsule deployed two drogue chutes followed by three main parachutes, jettisoning its heat shield to reveal air bags used to cushion the landing. The spacecraft touched down at 6:49 p.m. Eastern at White Sands Space Harbor in New Mexico.
The landing, immediately deemed successful by NASA and Boeing, wrapped up the Orbital Flight Test (OFT) 2 mission almost exactly six days after its liftoff from Cape Canaveral, Florida. The spacecraft docked with the station a little more than 24 hours after liftoff.
“It was a picture-perfect landing,” Steve Stich, NASA commercial crew program manager, said at a postlanding briefing. “The systems performed great on the vehicle, and once we work through all the data, we’ll be ready to fly the crew on this vehicle.”
OFT-2 was a redo of the original OFT mission in December 2019, which suffered problems immediately after launch that kept the spacecraft from reaching the ISS. Boeing attempted to launch OFT-2 in August 2021 but problems with propellant valves in the spacecraft’s service module postponed the launch.
The company took nearly $600 million in charges to fix the problems from the original OFT and subsequent first OFT-2 launch attempt before it was able to launch the spacecraft last week.
This mission was not without problems. Two OMAC thrusters failed during an orbital insertion burn shortly after separation from the Atlas 5 upper stage, an issue Boeing and NASA continue to investigate. Two reaction control system thrusters also malfunctioned but were later recovered. In both cases, Boeing said the vehicle had sufficient redundancy to continue the mission. The spacecraft also encountered problems with a thermal control loop early in the mission.
Stich said controllers tried firing those two thrusters after undocking. “We saw an interesting signature that looks a little bit like the signatures we saw at shutdown,” he said. That could help narrow down the cause of the problem, he added.
Neither Stich nor Mark Nappi, Boeing’s commercial crew program manager, were worried about the thruster problems. “None of them look to be serious, that they would turn into some kind of design change,” Nappi said. “I’m more optimistic that we’ll be able to explain these and move on.”
The next step in development of Starliner is the vehicle’s first crewed flight, the Crew Flight Test (CFT) mission carrying at least two NASA astronauts. The Starliner spacecraft could be ready for CFT as soon as late this year, although a launch date will depend on what work needs to be done in response to issues found during OFT-2, as well as the schedule of ISS activities. Nappi said it would likely be “several months” before they can set a date for the CFT mission.
“I don’t see any reason why we can’t proceed to the Crew Flight Test next,” Stich said. “We have a few things to work on between now and then but I don’t see any showstoppers this time.” He added the performance of Starliner on OFT-2 was “very similar in lots of ways” to the Demo-1 uncrewed flight test of SpaceX’s Crew Dragon in 2019 in terms of the issues encountered.
“OFT-2 was a test flight, and we expected to learn from this thing, and we did,” Nappi said. Despite the thruster and thermal cooling system anomalies, “the team and the vehicle handled those extremely well, and it was a really good learning experience.”
The valve problem that delayed OFT-2 from last August was not an issue on this flight, but Stich and Nappi said they would examine whether to perform the same mitigations, such as purging the valves with nitrogen gas to remove moisture, for CFT or take other measures that could include redesigning the valves. “We have options for CFT. We still need to look at the longer-term solution,” Nappi said. “I feel confident that we can get an option in place for use on CFT and look at longer-term solutions” for operational missions.
“On a scale of 1 to 10,” he said when asked to rate the OFT-2 mission, “I think I’d give it a 15. This was incredible.”