Stranded Starliner Spacecraft’s Thrusters Have Been Overheating, NASA Admits

Thrust of the Matter

The thrusters on Boeing's cursed Starliner space capsule keep overheating — and NASA is hard at work on a fix for the issue that's led, in part, to its astronauts being stranded on the International Space Station.

As Ars Technica reports, NASA officials admitted during a press conference earlier this week that the agency has been quietly testing out one of the spacecraft's errant thrusters here on Earth for the past month.

After having issues docking with the ISS due to its thrusters malfunctioning at the beginning of June, NASA apparently began investigating the issue at its White Sands, New Mexico test facility to get to the bottom of the problem. As its engineers discovered, the craft's four propulsion devices appear to be overheating.

Starliner's four thrusters are, as Ars explains, situated around the circumference of the rocket in propulsion pods that agency officials refer to as "doghouses." Due to a design flaw that appears to have been discovered during those tests, the doghouses result in a thermos-like insulation that keeps heat in, which in turn causes them to overheat.

Hot Dog

Along with the discovery of the hot doghouse issue, NASA also learned during the White Sands tests that the thrusters were, well, thrusting too much.

"What we have found in this flight is we have fired the thrusters more than expected, and I would say more frequently," explained Steve Stich, NASA's commercial crew program manager. "When I say frequently, I’m talking about how close you fire an individual thruster pulse to the next pulse of that thruster."

"What we’re trying to do at White Sands is really replicating exactly what those pulses were that those thrusters saw, and then understand the heating effects from those pulses, and then make sure there’s no unintended consequences of those pulses," Stich continued.

By testing the thruster out on the ground, NASA hopes, as Ars explains, to determine whether it was damaged from the additional stress it experienced.

If agency engineers can prove that the thruster wasn't too harmed to fly, it could help them determine whether Starliner is safe to return the stranded astronauts back home — and given that the flight that was supposed to last only eight days has now stretched to a month, those tests couldn't wrap soon enough.

More on Starliner: Stranded Astronauts "Absolutely Confident" in Boeing's Leaky Starliner