Space Launch Delta 30 terminated the Firefly Aerospace Inc., Alpha rocket over the Pacific Ocean at 7:01 p.m. Pacific Time after a successful lift off at 6:59 p.m. Pacific Time from Space Launch Complex-2 at Vandenberg SFB Sept. 2.
So, according to these initial reports it appears as though telemetry indicated a slight tilt of the rocket as it went supersonic and Space Force Range Safety immediately destroyed the vehicle some miles out over the Pacific Ocean.
Wonder what would have happened if USSF had been in charge during the recent Astra launch attempt up in Alaska where the rocket danced sideways a couple of hundred meters before going up, would there have been a pad explosion?
Robert Pearlman Editor
Posts: 50369 From: Houston, TX Registered: Nov 1999
posted 09-03-2021 12:21 PM
As this video shows, Firefly's Alpha did more than just slightly tilt, it tumbled almost 180 degrees before it was destroyed by range safety.
posted 09-07-2021 05:47 AM
OK, that video clarifies the situation. The vehicle appears to lose forward momentum and starts wallowing at about the 2:25 mark. The flight had to be terminated at that point. The company's post-flight analysis here explains what happened.
From Firefly:
About 15 seconds into the flight, engine 2 (there are four Reaver engines on the first stage) shut down. It was an uneventful shutdown – the engine didn't fail -- the propellant main valves on the engine simply closed and thrust terminated from engine 2.
The vehicle continued to climb and maintain control for a total of about 145 seconds, whereas nominal first stage burn duration is about 165 seconds. However, due to missing the thrust of 1 of 4 engines the climb rate was slow, and the vehicle was challenged to maintain control without the thrust vectoring of engine 2.
Alpha was able to compensate at subsonic speeds, but as it moved through transonic and into supersonic flight, where control is most challenging, the three engine thrust vector control was insufficient and the vehicle tumbled out of control.
NukeGuy Member
Posts: 105 From: Irvine, CA USA Registered: May 2014
posted 05-03-2023 12:04 PM
Here is a slow motion test of Firefly's rocket done by one of the "Slo-Mo Guys" which was pretty interesting.
posted 09-03-2021 12:17 PM
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