An artistic rendering of Boeing’s Starliner spacecraft
 Image: Boeing

Boeing’s new passenger spacecraft suffered a second major software bug during its debut flight to space in December — one that would have ended in a “catastrophic spacecraft failure” had it not been corrected. Fortunately, Boeing patched the issue before it became a problem, but the issue has safety experts worried about the company’s ongoing oversight of its space vehicles.

The spacecraft under close scrutiny is Boeing’s new Starliner capsule, a vehicle designed to take crews to and from the International Space Station for NASA. Boeing launched the Starliner on its first test flight on December 20th, without any people on board. The flight was meant demonstrate the vehicle’s ability to get to space, dock with the International Space Station, and then return to Earth — all the major things it will have to do when astronauts are inside.

But the mission didn’t go quite as planned. A software glitch during the launch prevented Starliner from firing its main engines at the right time, and the capsule got into the wrong orbit as a result. The vehicle never made it to the space station and had to land much earlier than expected. Now it seems that there was a second software glitch that Boeing caught while the Starliner was in orbit, according to NASA’s Aerospace Safety Advisory Panel, which had a public meeting today. While the details are fuzzy, the glitch would have caused the Starliner’s thrusters to needlessly fire while it descended to Earth, and the capsule would have moved uncontrollably.

NASA and Boeing disclosed the first software bug during the launch, but both organizations have kept quiet on this second issue. It was only made public today during the safety panel’s meeting.

In a statement, Boeing tells The Verge it “investigated a valve mapping mapping software issue, which was diagnosed and fixed in flight.” The company says the “error in the software would have resulted in an incorrect thruster separation and disposal burn,” adding that “what would have resulted from that is unclear.” NASA has not responded to multiple requests for comment.

Both Boeing and NASA are investigating the causes behind these software issues, according to the panel. But panel members are worried about Boeing’s testing processes, and they want NASA to look into the company’s protocols surrounding management and handling of Starliner. “The panel has a larger concern with the rigor of Boeing’s verification processes,” Paul Hill, a member of ASAP, said during the meeting.

In the meantime, NASA is still trying to figure out if it wants Boeing to repeat the uncrewed test flight of Starliner, since the vehicle never reached the space station. It’s possible NASA may not require Boeing to do another test flight and instead let the company proceed with putting astronauts on board the vehicle. That decision will be made in the coming weeks.