NASA and Boeing are sharing more details about the issues that were encountered during the Boeing CST-100 Starliner crew spacecraft uncrewed demo mission in December, and their progress on investigating the causes and implementing fixes. In a new blog post, NASA lays out the three different specific issues that occurred, and notes that for two of them, the spacecraft would’ve been lost without direct intervention by the ground crew.

The first issue identified is the mission timer issue that Boeing and NASA were very transparent about during the actual mission itself. This led to the spacecraft’s automated navigation systems believing it was in a different part of the mission later than it actually was. That then incurred thruster firing which used fuel and necessitated ground control stepping in to manually position the spacecraft in a different orbit than planned to ensure it could continue flying.

The second issue detailed in this new post was a software issue in the part of the launch where the Service Module attached to the capsule is discarded prior to re-entry and landing, which resulted in another propulsion issue and another case where to save the spacecraft the ground crew had to step in and execute corrective action roughly two hours ahead of its planned de-orbit.

“Regarding the first two anomalies, the team found the two critical software defects were not detected ahead of flight despite multiple safeguards,” NASA explains in the post. “Ground intervention prevented loss of vehicle in both cases. Breakdowns in the design and code phase inserted the original defects. Additionally, breakdowns in the test and verification phase failed to identify the defects preflight despite their detectability. While both errors could have led to risk of spacecraft loss, the actions of the NASA-Boeing team were able to correct the issues and return the Starliner spacecraft safely to Earth.”

As for what this means for the Boeing commercial crew program, NASA continues that these defects finding their way all the way through design and development to flight can be attributed to “no simple cause,” and instead will “require systemic corrective actions” starting with 11 “top-priority” ones already identified by the investigation team, with more to follow as the investigation continues.

NASA also said that it’s too early to definitely identify either the root causes of the problems, or all the fixes that will be required for Boeing’s Starliner system prior to future flights. The agency does say it expects that it will reach that point by the end of February, however. It’s holding a press conference with Boeing later this afternoon (at 3:30 PM EST) to discuss these findings and its progress in more detail.