Recently, NASA and Boeing representatives published preliminary results of an investigation into the causes of the failures, which caused the Starliner CST-100 spacecraft to interrupt its flight and return to Earth ahead of schedule during the first Orbital Flight Test (OFT) mission. The joint investigation team found such serious errors in the spacecraft software that only the timely intervention of specialists from the ground-based Control Center saved the spacecraft from an imminent crash.

On December 22, 2019, the unmanned spacecraft CST-100 Starliner Crew Module made a controlled soft landing at the White Sands Missile Range military training ground in New Mexico, which was the completion of the OFT mission, which lasted only 48 hours.

During the first orbital test of the Starliner spacecraft, a comprehensive check of the ship’s automated systems was required before this ship could take on board the crew of astronauts. The spacecraft was launched on December 20, 2019 from the cosmodrome at Cape Canaveral in Florida and almost immediately after the separation of the ship from the upper stage of Centaur, a specialized timer failed.

Because of this, the ship’s engines were not promptly turned on and it entered a far orbit far from the calculated one. In the automatic landing procedure, such an option was not provided, and NASA and Boeing engineers had to lead the ship to Earth in manual mode.

The NASA and Boeing investigation team began work in early January 2020, and its experts immediately discovered three errors that led to the OFT mission crashing. The first two errors were found in the spacecraft software. The main mistake was the failure of the Mission Elapsed Timer (MET), the value of which jumped by 11 hours in one second, which caused the untimely separation of the Service Module from the capsule of the spacecraft Crew Module.

Boeing Starliner CST-100 spacecraft

In addition to program errors, during the launch of the OFT mission, there was a communication system failure through which control commands could be transmitted to the spacecraft. This, in turn, did not allow specialists to timely identify and correct the consequences of the failure of the MET timer.

And, it should be noted that any of the detected errors could lead to the crash of the CST-100 spacecraft if experts from the Mission Control Center did not intervene in a timely manner.

Despite the fact that all the errors that led to the failure of the OFT mission have already been identified and eliminated, NASA experts have developed a program of 11 additional tests that should identify errors not yet found, if any, in the spacecraft software. And the investigation team will continue to work, and by the end of this month, a detailed report on the reasons for the mission’s failure should be ready with recommendations on how to avoid repeating this in the future.