The saga of the Starliner’s first crewed mission may soon be coming to an end. On Saturday July 20, engineering teams with NASA and Boeing completed a hot fire test of the spacecraft’s thrusters. The positive results suggest that the spacecraft’s first voyage to the International Space Station with astronauts on board may finally conclude in the coming days.
The Starliner CST-100 spacecraft has been docked at the ISS since June 6, a day after it finally blasted off atop an Atlas V rocket. The launch came days after an earlier attempt had been scrubbed. Ground teams detected a helium leak before that launch, with two more appearing after liftoff and another two identified once the ship had parked at the ISS. The docking process itself was far from flawless, with five thrusters failing during the first docking attempt.
Originally scheduled to return to Earth on June 14, the Starliner’s crew has been aboard the ISS far longer than planned. NASA and Boeing officials have insisted that Starliner is capable of safely returning the astronauts at any time, and that the lengthy delay is to take advantage of an opportunity to do tests that are impossible on Earth. Accordingly, the space agency maintains that the astronauts are not stranded.
In a statement released Tuesday, NASA said the two astronauts who had come aboard the ISS via the Starliner, Butch Wilmore and Suni Williams, entered the spacecraft and tested 27 of its 28 thrusters one at a time. The tests were aimed at measuring thruster performance and helium leak rates. NASA said the preliminary results were encouraging and were within the margins necessary for the crew to finally return home aboard the ship.
Wilmore and Williams have conducted several other tests since the dry fire, including a check of its water systems and internal pressure. The data from the thruster tests is being reviewed. Once that analysis is done, NASA said it will release a target return date for the two crew members.
In its own statement, Boeing said a flight test readiness review will occur at some point late this week. The two astronauts will also take part in two simulations of the undocking procedure this week.
The Starliner, part of a $4.3 billion Boeing contract with NASA’s Commercial Crew Program, has had a rocky run since its inception, running into numerous delays, cost overruns, and technical issues. The problems got so bad that NASA administrator Bill Nelson took shots at Boeing during a 2022 interview, chastising the company for falling so far behind rival SpaceX in its development of a reusable crew capsule.