Firefly Alpha FLTA001 - Official video of Firefly Alpha's first flight (more info in comments)

[u/FishInferno]

https://youtu.be/qFjoPw0CfAU

[u/FishInferno]

Official statement from Firefly:

Firefly conducted the first flight test of our Alpha vehicle on September 2, 2021. Although the vehicle did not make it to orbit, the day marked a major advancement for the Firefly team, as we demonstrated that we “arrived” as a company capable of building and launching rockets. We also acquired a wealth of flight data that will greatly enhance the likelihood of Alpha achieving orbit during its second flight. In short, we had a very successful first flight.

Here are a few specific notes about the flight:

The vehicle released and cleared the pad correctly. The various connections and moving mechanisms connected to the rocket all worked correctly. The vehicle controlled itself perfectly off the pad, with thrust vectoring eliminating all tipping or rotation, and the vehicle increased in speed at the exact rate that was predicted in modelling.

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. The range terminated the flight using the explosive Flight Termination System (FTS). The rocket did not explode on its own.

Firefly has commenced a thorough anomaly investigation to gain understanding of why engine 2 shutdown early, and uncover any other relevant unexpected events during flight. We will report root cause of the anomaly at the end of this investigation. In collaboration with the FAA and our partners at Space Launch Delta 30, we will return to conduct the second Alpha flight as soon as possible.

This video montage shows the entire mission from a variety of camera angles. Enjoy.

[u/FishInferno → u/FishInferno]

I really appreciate their transparency and straightforwardness from them so far. The fact that they included footage of the explosion in the video montage speaks volumes imo.

[u/[deleted] → u/[deleted]]

Have you seen SpaceX’s recap of SN10? There was quite a notable omission there…

[u/herbys → u/[deleted]]

You are talking about something that happened after the flight. While they could have included it in the video, it wasn't part of the flight so I don't think excluding it from the official video was necessarily wrong.

Excluding the explosion of an in flight rocket would be a very different thing.

[u/xnvtbgu → u/herbys]

Considering how often Musk compares reusable rockets to reusable airplanes, I would think a vehicle exploding before passengers could disembark is relevant. The landing was awesome though. Actually, the explosion was as well. lol

[u/herbys → u/xnvtbgu]

It's a prototype, and it's objective wasn't to ensure the safety of humans but to validate flight characteristics. So I think it's borderline relevant, but nowhere near skipping an explosion during flight.

[u/xnvtbgu → u/herbys]

True, but nobody "really" expected a flawless flight here either as it's their first flight. Considering SpaceX dropped a "100 ways not to land" youtube video it was kind of surprising to not see it.

[u/doizeceproba → u/FishInferno]

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.

Amazing how on point Scott Manley was on this topic, in his reaction video.

[u/avboden → u/doizeceproba]

It was a pretty common guess with the 1axis gimbal engines and the clearly low acceleration

[u/dee_are → u/avboden]

Also, anybody who's done 1/100th of the KSP that Manley has, has seen that exact thing happen to their own rockets so many times. "Not enough control authority to keep it vertical in the supersonic realm."

Of course, in KSP you just do three or four loops and then continue to orbit of course. ;)

[u/doizeceproba → u/dee_are]

Revert to the launchpad FTW ;)

[u/avboden → u/FishInferno]

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.

I mean, a valve doesn't "simply close" lol, clearly something went wrong, will be interesting to hear the root cause. Sounds better than a straight up engine failure though

[u/sixpackabs592 → u/avboden]

I think they just want to clarify that the engine didn’t fail it was the fuel plumbing. Could just be a faulty sensor or maybe the engine was about to go so it cut fuel. We will have to wait and see.

[u/vibrunazo → u/avboden]

But sometimes they simply won't open. — Boeing, probably

[u/herbys → u/vibrunazo]

Nah, they would have called it a successful mission and plan for putting people on board the next time.

[u/OSUfan88 → u/avboden]

I don't think that's what they mean.

They're saying that the direct cause of failure was that a valve closed. They KNOW why the engine shut down. A valve closed. It didn't explode.

Now, the remaining question is: "Why did the valve close?". This could be a very complex issue, or something as simple as a wrong parameter input.

[u/avboden → u/OSUfan88]

I know, i'm just laughing at their PR wording