WASHINGTON — A software glitch prevented the upper stage of Firefly Aerospace’s Alpha rocket from completing a second burn during a December launch, stranding its payload in a low orbit.
In a Feb. 20 statement, Firefly said an error with the guidance, navigation and control (GNC) software for the upper stage of the Alpha on the company’s “Fly the Lightning” mission Dec. 22 kept the upper stage from firing as planned to circularize its orbit. That left the upper stage and its payload, a Lockheed Martin technology demonstration satellite, in an orbit with a low perigee.
The investigation, which included the company’s own mishap team as well as an independent review, found that the error in the GNC software algorithm “prevented the system from sending the necessary pulse commands to the Reaction Control System (RCS) thrusters ahead of the stage two engine relight.” Firefly didn’t elaborate on the issue, but the RCS thrusters likely would have been used to ensure the stage was in the proper orientation and to settle its tanks so propellant would flow from them into the engine.
“We’re proud of the combined team’s ability to work together to achieve this positive outcome,” Bill Weber, chief executive of Firefly, said in a statement about the investigation. “Looking ahead, the important long-term outcome is the rapid, thorough maturation of Alpha as the dependable one-metric-ton-class rocket the market is demanding.”
Firefly said that it is both correcting the GNC software error and implementing other “process changes” to better detect similar problems in the future. The company said Alpha will be ready for its next launch in the “coming months” but was not more specific.
The mishap stranded the Lockheed Martin satellite in an orbit with an initial perigee of only about 215 kilometers. Lockheed accelerated the tests of the satellite’s antenna technology in what a company executive called a “dramatically…
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