FAILURE: Firefly Alpha 1st flight - Vandenberg SLC-2W - 3 Sep 2021 (01:59 UTC)

[Navier–Stokes]

Rehost of the full video:

[FutureSpaceTourist]

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.

[JEF_300]

It cannot be overstated how much I enjoy that Alpha makes a Titan-esque startup squeal.

That video is excellent, because you can actually see the engine shutdown at 54 seconds into the video.

[TrevorMonty]

Note that the above has a typo of "values" for "valves."

If that is accurate, I'm taking it as good news for the Reaver engines at least. No reason was given for the valves closing prematurely, but that could be a wiring problem, or sensor or software or some other "easily" correctable issue.

Better to have a plumbing problem than to find at this late stage the engine cannot do a full burn reliably.

Hopefully its easy fix and they are back on pad soon.

Sent from my SM-G570Y using Tapatalk

[Danderman]

What is the heritage of the Reaver engine?

[russianhalo117]

What is the heritage of the Reaver engine?

In house but with design help from Aerojet Rocketdyne applied from development knowledge collected during the ongoing multiple decade fully additive manufactured Bantam (RS-88) engine family programme. AR also manufacturers some of the parts for the completed Reaver(-1) engine. Yuzhnoye Design Bureau were also involved in a similar roll and metallurgy knowledge for engines during the prototyping phase. Full production of Firefly's engine was previously stated as to be fully/near fully inside the company after the first few flights. The regular general Firefly thread discusses all of this.


Bantam history:
What morphed into the Bantam engine family started out as an Atlas engine proposal that lost out to RD-180. The proposed successor version of the RS-56-OSA (LR-105-9) sustainer engine was to be the RS-88-OSA (LR-105-11). The RS-56-OSA predecessor was the LR-105-7. The proposed successor version of the RS-56-OBA (LR-89-9) booster engine was to be the RS-88-OBA (LR-89-11). The RS-56-OBA predecessor was the LR-89-7. Rocketdyne made several modernisations during its ongoing merger and acquisition life to Bantam (RS-88) with the most recent use being the RS-88-LAE  (short LAE) used on Starliner for launch aborts et al. Further higher thrust class versions, propellant types and engine cycles are planned to be tested by AR under future follow on contracts.

[Steven Pietrobon]

The new video clearly shows one engine has shut down.

[Senex]

Deeply impressed by their transparency and professional presentation of the event.  It speaks well of their culture.  It reassures me that they will be able to quickly resolve the issues and move forward.

Congratulations!

[gaballard]

Video also shows the engine tried to relight at T+39s and flames out about ~5 seconds later, although a small flame is visible out the bell for the rest of the flight.

Edit: Although they use TEA-TEB, don't they, so I'm not sure that's a "relight" proper...

[FutureSpaceTourist]

https://twitter.com/free_space/status/1434962338378039296

Prelim analysis: @Firefly_Space Alpha rocket engine #2 shut down about 15 sec. after liftoff when prop valve closed due to loss of electrical signal, CEO Tom Markusic tells @AviationWeek. Engines survived FTS destruct, fall from 50,000 ft & were recovered. Photo credit: Firefly

[JEF_300]

Prelim analysis: @Firefly_Space Alpha rocket engine #2 shut down about 15 sec. after liftoff when prop valve closed due to loss of electrical signal, CEO Tom Markusic tells @AviationWeek. Engines survived FTS destruct, fall from 50,000 ft & were recovered. Photo credit: Firefly

This would seem to suggest that the problem was purely electrical. That's a good sign.

[kdhilliard]

https://twitter.com/Free_Space/status/1434969410062725120

How did this hardware come down on land? After length of flight, shouldn’t it have been many miles down range? Or did it depart the launch trajectory significantly because of the underthrust to the point where it climbed far more vertically because trying to get back on course?

Truss, engines landed about 3/4 mi. from SLC-2 in the desert. Don't know why there.

[Targeteer]

amidst all those "system X nominal" calls how is "shutdown, engine 2" not called out?

[ulm_atms]

I'm going to ask something that is probably a stupid question.....

Wouldn't you want to use valves/servos that only move when power is supplied to keep something like this from happening?  This sounds like a power must be applied to keep open kinda system.  If their FTS was engine shutdown based I could see it(small charge to blow the power board and all engines then shut off for example)....but since it is explosive termination based...what's the point of having valves that can electrically fail closed?

There is probably good reason....I just don't see it.  Any insights?

[kdhilliard]

amidst all those "system X nominal" calls how is "shutdown, engine 2" not called out?

I know, right?  Specifically:

T+0:00  Ignition.
T+0:03  The vehicle has lifted off.
T+0:05  Liftoff time is 1:59:01.00 Zulu.
T+0:10  RC transition operation procedures to PRC LP 14-35.  IT commence LP 14-57.  Report anomalies.
T+0:19  Please confirm I have no fires on the pad.  I have no visual.  Please confirm no fires on the pad.  Moving to ground.
T+0:34  Stage two pressure's up.
T+0:35  Prop call?
T+0:39  Prop is nominal.
T+0:46  GNC?
T+0:48  I'm seeing a dip in V_Mag.
T+0:54  There's no fires on the pad.
T+0:56  Avionics?
T+0:59  Responding AVI.
T+1:08  S1 pressure profile nominal.
T+1:11  Avionics / Power nominal.
T+1:15  Telemetry is nominal.
T+1:24  Plus 1:30.
T+2:15  Vehicle is supersonic.
T+2:32  Anomaly.
T+2:33  V class anomaly.
T+2:34  Move the anomaly team to procedure MLP 1499.

Link to T+0:30  ("Prop" = Propulsion.)

[tleski]

This video has slightly different callouts than the one livestreamed by Tim Dodd. For example there was a callout "not yet supersonic" at 1:48 in the stream which was pointed out by Scott Manley. This is not present in the video posted later by Firefly. So, most likely they were aware of the situation but the callouts were "sanitized" in the official video.

[Firehawk153]

I'm going to ask something that is probably a stupid question.....

Wouldn't you want to use valves/servos that only move when power is supplied to keep something like this from happening?  This sounds like a power must be applied to keep open kinda system.  If their FTS was engine shutdown based I could see it(small charge to blow the power board and all engines then shut off for example)....but since it is explosive termination based...what's the point of having valves that can electrically fail closed?

There is probably good reason....I just don't see it.  Any insights?

One guess would be on-pad scenarios?  Having the valve close by default might encourage a more benign failure scenario or shutdown in case the vehicle has not left the pad.  It might prevent an on pad failure which might take the rocket and ground equipment with it.  Again, just a guess though

[Robert Thompson]

I'm going to ask something that is probably a stupid question.....

Wouldn't you want to use valves/servos that only move when power is supplied to keep something like this from happening?  This sounds like a power must be applied to keep open kinda system.  If their FTS was engine shutdown based I could see it(small charge to blow the power board and all engines then shut off for example)....but since it is explosive termination based...what's the point of having valves that can electrically fail closed?

There is probably good reason....I just don't see it.  Any insights?

The principle reminds me of a safety design. I work with a telescope that has unpowered spring breaks that, by default, when the telescope is not powered, clamp down onto the structure to prevent movement. Only when the telescope is under power (magnetic drives) are the brakes hydraulically pushed into an open position (commanded open) to allow movement (commanded movement). This prevents uncommanded movement of 11 tons.

[NaN]

I'm going to ask something that is probably a stupid question.....

Wouldn't you want to use valves/servos that only move when power is supplied to keep something like this from happening?  This sounds like a power must be applied to keep open kinda system.  If their FTS was engine shutdown based I could see it(small charge to blow the power board and all engines then shut off for example)....but since it is explosive termination based...what's the point of having valves that can electrically fail closed?

There is probably good reason....I just don't see it.  Any insights?

The principle reminds me of a safety design. I work with a telescope that has unpowered spring breaks that, by default, when the telescope is not powered, clamp down onto the structure to prevent movement. Only when the telescope is under power (magnetic drives) are the brakes hydraulically pushed into an open position (commanded open) to allow movement (commanded movement). This prevents uncommanded movement of 11 tons.

This is what "fail safe" means -- when a component fails, it should do so in the least dangerous manner possible.

Having a propellant valve fail closed is safer than failing open -- the valve doesn't know whether it's in flight or is sitting on the ground, and having it close upon an electrical failure is safer than sticking in whatever the last commanded position was.

[NaN]

amidst all those "system X nominal" calls how is "shutdown, engine 2" not called out?

I know, right?  Specifically:

T+0:00  Ignition.
T+0:03  The vehicle has lifted off.
T+0:05  Liftoff time is 1:59:01.00 Zulu.
T+0:10  RC transition operation procedures to PRC LP 14-35.  IT commence LP 14-57.  Report anomalies.
T+0:19  Please confirm I have no fires on the pad.  I have no visual.  Please confirm no fires on the pad.  Moving to ground.
T+0:34  Stage two pressure's up.
T+0:35  Prop call?
T+0:39  Prop is nominal.
T+0:46  GNC?
T+0:48  I'm seeing a dip in V_Mag.
T+0:54  There's no fires on the pad.
T+0:56  Avionics?
T+0:59  Responding AVI.
T+1:08  S1 pressure profile nominal.
T+1:11  Avionics / Power nominal.
T+1:15  Telemetry is nominal.
T+1:24  Plus 1:30.
T+2:15  Vehicle is supersonic.
T+2:32  Anomaly.
T+2:33  V class anomaly.
T+2:34  Move the anomaly team to procedure MLP 1499.

Link to T+0:30  ("Prop" = Propulsion.)

There were people making lengthy broadcasts for over 20 seconds during a critical period of T+10s to T+32s - the engine shutdown happening early in that time range. They should have been on a ground channel (per 'moving to ground') but may have stomped on or prevented flight-related callouts that people were trying to make. It didn't affect any outcome but they will definitely want to tighten this up in the future.

There are a few callouts missing in the Firefly video that you were looking at. From Tim Dodd's you can hear these additional:

T+0:25: I'm looking [garbled] the sweep... cameras are sweeping the pad
T+0:32: plus 32 seconds
T+1:47: Not yet supersonic