After a gorgeous and 100% successful launch atop the Atlas V rocket from United Launch Alliance, Boeing’s uncrewed Starliner crew capsule suffered a mission-shortening failure just 30 minutes into its inaugural flight.
A Mission Event Timer issue resulted in Starliner burning a significantly larger amount of propellant than planned and forced Boeing and NASA to abort the planned rendezvous and docking with the International Space Station and opt instead for a landing at White Sands Missile Range, New Mexico, No Earlier Than Sunday morning (22 December) roughly 48 hours after launch.
The issue came as a blow to Boeing after a wonderfully successful liftoff of Starliner on its inaugural, uncrewed Orbital Flight Test mission to the International Space Station.
Per the pre-launch timeline, Starliner was supposed to execute an Orbit Insertion Burn 31 minutes after liftoff from the Cape Canaveral Air Force Station to finish placing itself into a stable and circular orbit after being initially dropped off in a planned sub-orbital trajectory by the Atlas V rocket.
However, for reasons Boeing engineers do not yet understand, Starliner’s Mission Event Timer clock malfunctioned, causing the vehicle to think it was at a different point in the mission and at a different time in its mission that it actually was.
Because #Starliner believed it was in an orbital insertion burn (or that the burn was complete), the dead bands were reduced and the spacecraft burned more fuel than anticipated to maintain precise control. This precluded @Space_Station rendezvous.
— Jim Bridenstine (@JimBridenstine) December 20, 2019
This resulted in Starliner’s Reaction Control System thinking the Orbit Insertion Burn was underway and executing a series of burns to keep the vehicle oriented in the insertion burn attitude; however, the Orbit Insertion Burn was not actually occurring.
When mission controllers realized the issue, they sent manual commands to Starliner to perform an Orbit Insertion Burn in a backup window that came roughly eight minutes after the planned maneuver.
However, a known and brief gap in NASA satellite communications caused a further delay.
By the time Starliner was finally able to burn its engines and get into a stable orbit, it had burned 25% more propellant than anticipated.
That, coupled with the fact that a major software issue occurred so early in flight prompted NASA and Boeing to significantly alter the mission’s timeline and abort the planned Saturday morning rendezvous and docking with the International Space Station.
Instead of an eight-day mission that would have seen the return of biological science samples from the Station, Starliner will now come back to Earth after just 48 hours in orbit and having not performed some of its critical flight test objectives such as rendezvous, proximity operations, and automated docking to the International Space Station.
Starliner in orbit. (Credit: Boeing)
Unfortunately for the Boeing company as a whole, this is yet another major software malfunction in a year that has plagued the company with such issues.
While NASA and Boeing related that a great deal of the flight test objectives will still be completed, significant portions will not.
At a post-launch news conference, NASA Administrator Jim Bridenstine stated it was too early to say whether NASA would make Boeing repeat the uncrewed Orbital Flight Test before allowing people to fly on the Crew Flight Test.
The Administrator said that while he would not rule out the possibility of a second, uncrewed Orbital Flight Test, he would also not commit to such a proposal at this time, noting that Boeing and NASA will have to review the cause of the software issue and evaluate the impact the fix to that software might have on Starliner’s overall certification for flight thus far.
At the same press conference, a Boeing representative was confident that Starliner will return safely to Earth for landing at White Sands Missile Range, New Mexico, on Sunday morning, but he acknowledged that a significant amount of work has to occur for Boeing to be comfortable that the Mission Event Timer issue will not repeat during entry and landing.
NASA astronaut Nicole Mann – who is assigned to fly the Crew Flight Test of Starliner – related in the same post-launch news conference that had a crew been onboard Starliner, they very likely could have taken manual control of the craft and successfully completed the Orbit Insertion Burn as planned.
The software issue does rather dramatically highlight a Commercial Crew mandate that crews be able to take manual control of a spacecraft at any point in the flight sequence despite the high levels of automation in both Starliner and its counterpart, Crew Dragon from SpaceX.
Despite no longer being able to reach the International Space Station, NASA and Boeing are hopeful that Starliner will still be able to demonstrate some of its fine-tune maneuvering capabilities while on orbit.
The hope from Boeing – at this point – is that Starliner would be able to demonstrate enough automated rendezvous system capability to convince NASA that a repeat of the uncrewed Orbital Flight Test is not necessary before proceeding to crew flights.
Regardless of the issues with Starliner, United Launch Alliance has much to be proud of, with the Atlas V demonstrating all of its new configuration changes and functioning perfectly in flight.
The Atlas V and its Dual Engine Centaur upper stage – flying for the first time in 15 years – successfully delivered Starliner into its intended suborbital trajectory.