Astra, a small launch vehicle business, has found the cause of a launch failure in August and says it will try again as early as late this month. Astra stated the August 28 launch of the Rocket 3.3 vehicle, classified LV0006, failed because propellants escaped from a delivery system and ignited, crippling one of the rocket’s 5 first-stage engines just under one second after liftoff, according to a statement released on October 12.
In a blog post detailing the inquiry, Benjamin Lyon, who works as the executive vice president as well as the chief engineer of Astra, said, “The issue we uncovered was something we hadn’t seen before.” The propellants leaked into an enclosed region between the rocket as well as its launch platform due to a quick-disconnect device that was supposed to seal shut when lines delivering RP-1 fuel as well as liquid oxygen into this rocket disconnected during liftoff.
“The engine exhaust burned those propellants, triggering an over-pressure event that destroyed the link to the electronics which control the fuel system, closing down the engine just under one second after blastoff,” he wrote.
The rocket hovered barely off the ground with only four engines firing, floating away from a launch tower until enough propellant had been burnt off to make it light, sufficient to ascend under its decreased thrust. The vehicle reached maximum dynamic pressure or max-Q, but the mission ended soon after.
Astra claims to have implemented several improvements to address the issue in future launches. It adjusted the locations of propellant interfaces to prevent fuel and oxidizer from mixing even if there are leaks, and it updated the propellant connections to limit the chance of leakage. In addition, the company’s verification procedures were upgraded. “We believe that these adjustments, taken together, considerably minimize the likelihood of a similar occurrence occurring in the future,” Lyon wrote.
With all those changes implemented, Astra stated that it is now ready to launch its next vehicle, the LV0007. That launch, codenamed STP-27AD2 and the second of 2 under a US Space Force contract, will take place in one of two windows. The first window goes from October 27 to October 31, while the second window is from November 5 to November 12. The deployment will actually occur from Kodiak Island, Alaska, where the corporation has attempted three orbital launches previously.
The Federal Aviation Administration issued a temporary flight restriction (TFR) on October 7 limiting airspace in the region of the Kodiak launch site for “space operations,” sparking speculation that Astra was gearing for a new launch attempt. That TFR, however, extends from October 19 to October 29 and is set up differently than TFRs for past Astra launches in the area.
The forthcoming flight will be Astra’s fourth orbital launch attempt; the first three failed to reach orbit, while the second, in December 2020, came near. According to Lyon, the August launch validated adjustments made after the second launch, such as a closed-loop propellant control mechanism to better control propellants and prevent an early engine shutdown such as the second launch.