The Boeing CST-100 Starliner spacecraft is seen after it landed in White Sands, New Mexico, Sunday, Dec. 22, 2019. NASA/Bill Ingalls
Boeing’s Starliner spacecraft safely returned from orbit on Sunday morning, landing at White Sands Space Harbor in New Mexico before sunrise. The capsule very nearly hit its bullseye, and initial reports from astronauts on the scene say the vehicle came through in “pristine” condition.
The company will now spend several days preparing Starliner for transit, before shipping it from New Mexico back to Boeing’s processing facility at Kennedy Space Center in Florida. Then, engineers will spend most of January reviewing data captured by on-board sensors. What happens after that is the big question.
Mission Elapsed Time anomaly
After the spacecraft launched on board its Atlas V rocket, but before it separated from the booster, the capsule needed to figure out what time it was. According to Jim Chilton, Boeing’s senior vice president of the Space and Launch division, the way this is done is by “reaching down into” the rocket and pulling timing data out. However, during this process, the spacecraft grabbed the wrong coefficient. “We started the clock at the wrong time,” Chilton said. “The spacecraft thought she was later in the mission and started to behave that way.”
The net effect of this is that Starliner’s service module thrusters began consuming a lot of propellant to keep the vehicle in a very precise attitude with respect to the ground. When flight controllers realized the error, it took time to establish a communications link because the spacecraft was not where they thought it was.
With the on-board propellant remaining, Starliner did not have sufficient reserves to approach the International Space Station and perform a rendezvous and docking with the orbiting laboratory—a key objective of this flight test before NASA allows its astronauts to fly on the capsule into space.
Much of the rest of the flight went very well, however, once flight controllers diagnosed and corrected the mission elapsed time error. (The clock was off by 11 hours.) The vehicle flew smoothly in orbit, its life support systems kept the spacecraft at good temperatures, and it made a safe and controlled landing on Sunday morning. Chilton said he believes the vehicle will meet 85 to 90 percent of the test flight’s objectives.