Fireplace, fed by leaking engines, destroyed ABL House Programs rocket

WASHINGTON — ABL House Programs stated it misplaced its second RS1 rocket after a static-fire take a look at when a hearth broke out underneath the car fed by leaking gas that would not be extinguished by pad programs.

The corporate launched Aug. 26 particulars about the July 19 incident that led to the lack of the car throughout one of many last exams earlier than the car’s second launch at Pacific House Advanced – Alaska on Kodiak Island.

In a assertion, ABL House Programs stated it ignited the E2 engines within the first stage of the RS1 rocket within the take a look at, however aborted the take a look at after simply half a second due to a low strain studying in a single engine that the corporate stated was brought on by a defective strain sensor.

The engines shut down, however a hearth then broke out underneath the bottom of the car, fed by gas leaks from two engines. That fireplace was contained however couldn’t be extinguished by both water or inert fuel programs, and the corporate began offloading kerosene and liquid oxygen propellants from the car.

The launch pad the corporate makes use of at Kodiak doesn’t have its personal water provide, with the corporate as an alternative utilizing cellular tanks that ran out of water 11 and a half minutes after ignition. That brought about the hearth to unfold “and a progressive lack of pad programs,” the corporate said, together with the shortcoming to proceed detanking the rocket and ultimately telemetry from the rocket.

“At T+ 23:24, the hearth exceeded the thermal functionality of the construction and RS1 buckled to the pad,” the corporate said. That broken a “majority” {of electrical} and plumbing connections on the launch mount, though the construction of the launch mount itself and different floor assist gear survived.

An investigation of the 2 engines that had the gas leaks that fed the hearth confirmed “vital erosion” of their propellant injectors and liners that the corporate stated is an indication of failure linked to combustion instability. “Our present main principle is that variations within the Block 2 Stage 1 propellant feed system led to a better vitality startup than on the take a look at stand, triggering an instability in 2 of 11 engines,” it said.

ABL added that in additional than 300 exams of the E2 engine, it had seen that phenomenon solely as soon as, which it attributed to a special situation. The corporate added, although, that it had little expertise with this particular configuration and was beginning a collection of exams at its Mojave Air and House Port take a look at website in California to see if that rationalization is appropriate and to search for different potential causes.

The corporate didn’t provide a timeline for finishing that work or for making an attempt one other launch. ABL stated it’s returning the bottom assist gear to Lengthy Seashore, California, for repairs whereas the following RS1 rocket is “properly into manufacturing.”

The pad fireplace came about slightly greater than 18 months after ABL’s first launch of the RS1. That car misplaced energy 10 seconds after liftoff and crashed again on the launch pad. The corporate later concluded that the design of the launch mount contributed to a hearth within the rocket’s engine compartment that led to the lack of energy, and redesigned the mount.

The car destroyed within the July fireplace was a revised Block 2 model of the RS1. It options 20% larger thrust and 20% extra propellant, and the addition of two engines to the unique nine-engine first stage.

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