Kathy Lueders, who was recently appointed associate administrator of the agency’s human exploration and operations directorate, said that NASA, as part of efforts to reduce costly bureaucratic overhead, had not asked Boeing or SpaceX for a high-level management plan for how complex pieces of engineering would be put together and tested.
But that lack of knowledge meant that NASA did not fully understand how Boeing was designing the Starliner’s software and the testing process for verifying that it would work as intended. “We thought we understood it, but we ended up finding out that over time, that kind of changed,” Ms. Lueders said.
She also said that for the December test flight, NASA had focused on the highest priorities, in particular ensuring that Starliner did not pose any danger to the space station as it approached, and that might have caused software engineering to receive less attention.
“Where do you apply the resources to make sure that you’re getting kind of the biggest bang for your buck, to be able to really flesh out where you have problems in your systems?” she said.
NASA is now overseeing software development more closely at both SpaceX and Boeing.
The Starliner spacecraft, launched on top of an Atlas 5 rocket on Dec. 20, encountered two major software problems during its flight. The first occurred minutes after the spacecraft had separated from the rocket, because the capsule’s clock had been set wrong. That caused the spacecraft to squander its propellant, and a planned docking at the International Space Station was called off.
Starliner also experienced a communications problem that prevented mission controllers from quickly regaining control. An investigation revealed that the spacecraft’s radio receiver had been listening to too wide a swath of frequencies, which led to interference from other transmissions from Earth. Boeing engineers have added a filter to limit the frequencies.
The second software flaw would have fired the wrong thrusters as Starliner was preparing for re-entry. As Boeing engineers hastily combed through the Starliner software in the aftermath of the clock problem, they found that problem and fixed it. If it had not been fixed, two pieces of Starliner — the capsule that returns to Earth and the service module, which is discarded — might have collided. The capsule might have tumbled and burned up in the atmosphere instead of landing safely in White Sands, N.M.
Article source: https://www.nytimes.com/2020/07/07/science/boeing-starliner-nasa.html