by Douglas Messier
Late in the evening of Dec. 21, Boeing engineers discovered a software glitch that could have caused its uncrewed Starliner capsule to become unstable or enter the Earth’s atmosphere with a damaged heat shield. The result could have been the loss of the vehicle.
Engineers transmitted new software to the capsule at 5 a.m. the next morning. Less than three hours later, Starliner landed safely at White Sands Missile Range a two-day orbital flight test.
Boeing officials admitted at a press conference on Friday that they would have never discovered the problem if it had not been for a nearly catastrophic software glitch that occurred right after launch. That error resulted in Starliner limping into a low orbit and failing to rendezvous and dock with the International Space Station (ISS) as planned.
During the abbreviated flight test, ground controllers also had intermittent problems communicating with the spacecraft during part of its orbit because they were using a frequency close to one utilized by terrestrial cell phone networks, Boeing officials said.
NASA and Boeing officials discussed the anomalies with Orbital Flight Test 1 (OFT-1) at a press conference on Friday afternoon. The officials provided updates on an on-going investigation being conducted by an independent team composed of space agency and company experts.
The anomalies are signs of what NASA Associate Administrator for Human Exploration Douglas Loverro said are systemic problems in developing software at Boeing. Those problems need to be solved before NASA places its astronauts on a Starliner for flights to the space station, he added.
Loverro said that Boeing’s processes broke down at several points, resulting in software errors not being caught and corrected prior to launch. Officials are working to identify why and put corrective actions in place.
Loverro mentioned press reports about other problems at Boeing. The aerospace giant has been struggling with the grounding of its 737 MAX aircraft after two fatal crashes. Those accidents have been blamed on design and software flaws.
Boeing Vice President John Mulholland will need to retest and re-verify all of Starliner’s software, which totals about one million lines of code.
Starliner was supposed to start its mission elapsed timer just prior to launch by obtaining the time from its Atlas V booster. However, that action was not written into the software, resulting in the timer being off by 11 hours, Mulholland said.
On the morning of Dec. 20, the Atlas V placed Starliner in a suborbital trajectory as planned. However, the timer error prevented the spacecraft from firing its engine to reach an orbit where it could rendezvous and dock with the space station. A shortened two-day flight test was conducted.
Mulholland said engineers began an immediate review of all of Starliner’s software afterthe anomaly to make sure there were no additional errors. On the evening of Dec. 21, they identified a “valve mapping error” in the service module’s thrusters. The glitch could have caused the service module to bump into the crew capsule after separation.
OFT-1 was the first of two planned Starliner flight tests prior to certifying the vehicle to carry astronauts to the station on a commercial basis.
NASA Administrator Jim Bridenstine said no decision has been made on whether to require Boeing to repeat the mission without a crew before placing astronauts aboard for the second flight test to ISS.