Firefly Space : Company and Development General Thread

[Pueo]

An old photo from their twitter appears to show an yellow core material in the lox tank barrel section.
https://twitter.com/Firefly_Space/status/1091480640132767744
There's also this tweet that shows significant frost on the tank bulkhead and no frost on the barrel.
https://twitter.com/Firefly_Space/status/1012377726903377920

This photo of the 1^st stage kerosene tank also shows a mess of material at the transition between the barrel and bulkhead sections. 

I think they are using the sandwich construction solely for the cylindrical section, it being easier to form as a developable surface, and somehow attaching the single CFRP shell caps.  That would be pretty clever, you increase the stiffness on the section of the tank that experiences compressive loads holding up rest of the structure and insulate the majority of your surface area.  The bulkheads, being entirely in tension, wouldn't have been been benefited by the sandwich design and would be more difficult to produce with their compound curvature.  The tricky part is finding a method of attaching your bulkheads to the cylindrical wall that will survive cryogenic temperatures.

[TrevorMonty]

I didn't see anyone else point this out, but they've updated the page on their site talking about Firefly Beta: https://firefly.com/launch-beta/

Firefly Beta is an evolutionary design based on Firefly Alpha technology. Beta is a 2-stage launch vehicle capable of delivering 8,000 kg to a 200 km (125 mile) Low Earth Orbit and has the capability of achieving Geosynchronous Transfer Orbits. The Beta vehicle utilizes technologies such as all carbon composite tanks, heritage LOx/RP-1 liquid fueled engines and builds on other elements of the existing Alpha architecture. Firefly Beta will have lowest cost per kg to orbit of all launch vehicles in the 8,000 kg and under class.

Propulsion: Stage 1
ENGINE
5X Reaver 2
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
5
THRUST (VAC)
4,261 kN 957,910 lbf
ISP (VAC)
334 sec

Propulsion: Stage 2
ENGINE
1x Reaver 1 Vac
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
1
THRUST (VAC)
194 kN 43,613 lbf
ISP (VAC)
325 sec

Dimensions
STAGE 1 DIAMETER
3.7 m 12 ft
STAGE 2 DIAMETER
3.7 m 12 ft
PAYLOAD FAIRING DIAMETER
4.7 m 15.3 ft
OVERALL LENGTH
46.7 m 151.8 ft

It looks like they've decided to build a new engine themselves rather than using the AR1. Otherwise, it's generally what you'd expect.

Edit: Of note, the fairing has a diameter of 4.7m, which should be plenty big enough to fit a Cygnus or vehicle of equivalent size.

Edit Again: Also, that Reaver 2 engine will have a thrust of (4,261/5=) ~852 kN, so it's fairly similar to the modern Merlin. But they claim a vacuum isp of 334, which is around 20s better than the Merlin. That's a significant enough increase in isp to suggest to me that it may be a staged combustion engine.

Likely to be few years away, need to develop Reaver 2 first. May need to be RLV, as ELV will be getting close to F9R in price.

[Steven Pietrobon]

The Isp's for Beta don't make sense. 334 s vac on the first stage, which is more than the 325 s on the second stage! They are using different engines, with 852.2 kN on Reaver 2 and 194 kN for Reaver 1. Still, 325 s for a vacuum kerolox turbopump fed engine seems pretty low. The RD-180 gets 338 s vac, so that would seem to indicate staged combustion for Reaver 2.

[Gliderflyer]

The Isp's for Beta don't make sense. 334 s vac on the first stage, which is more than the 325 s on the second stage! They are using different engines, with 852.2 kN on Reaver 2 and 194 kN for Reaver 1. Still, 325 s for a vacuum kerolox turbopump fed engine seems pretty low. The RD-180 gets 338 s vac, so that would seem to indicate staged combustion for Reaver 2.

The specs for Reaver 2 are pretty close to the RD-870 (the nozzles in the render are also similar): https://www.yuzhnoye.com/en/technique/rocket-engines/steering/rd-870/

[AstroWare]

I didn't see anyone else point this out, but they've updated the page on their site talking about Firefly Beta: https://firefly.com/launch-beta/

Firefly Beta is an evolutionary design based on Firefly Alpha technology. Beta is a 2-stage launch vehicle capable of delivering 8,000 kg to a 200 km (125 mile) Low Earth Orbit and has the capability of achieving Geosynchronous Transfer Orbits. The Beta vehicle utilizes technologies such as all carbon composite tanks, heritage LOx/RP-1 liquid fueled engines and builds on other elements of the existing Alpha architecture. Firefly Beta will have lowest cost per kg to orbit of all launch vehicles in the 8,000 kg and under class.

Propulsion: Stage 1
ENGINE
5X Reaver 2
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
5
THRUST (VAC)
4,261 kN 957,910 lbf
ISP (VAC)
334 sec

Propulsion: Stage 2
ENGINE
1x Reaver 1 Vac
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
1
THRUST (VAC)
194 kN 43,613 lbf
ISP (VAC)
325 sec

Dimensions
STAGE 1 DIAMETER
3.7 m 12 ft
STAGE 2 DIAMETER
3.7 m 12 ft
PAYLOAD FAIRING DIAMETER
4.7 m 15.3 ft
OVERALL LENGTH
46.7 m 151.8 ft

It looks like they've decided to build a new engine themselves rather than using the AR1. Otherwise, it's generally what you'd expect.

Edit: Of note, the fairing has a diameter of 4.7m, which should be plenty big enough to fit a Cygnus or vehicle of equivalent size.

Edit Again: Also, that Reaver 2 engine will have a thrust of (4,261/5=) ~852 kN, so it's fairly similar to the modern Merlin. But they claim a vacuum isp of 334, which is around 20s better than the Merlin. That's a significant enough increase in isp to suggest to me that it may be a staged combustion engine.

I'm confused. If I follow that link to the Beta page, I see a 2.8m fairing listed. Where do you see a 3.7m stage diameter or a 4.7m fairing diameter listed?

[moddedLimes]

Ok that's weird it looks like the mobile website hasn't been updated yet but the desktop one has.

I didn't see anyone else point this out, but they've updated the page on their site talking about Firefly Beta: https://firefly.com/launch-beta/

Firefly Beta is an evolutionary design based on Firefly Alpha technology. Beta is a 2-stage launch vehicle capable of delivering 8,000 kg to a 200 km (125 mile) Low Earth Orbit and has the capability of achieving Geosynchronous Transfer Orbits. The Beta vehicle utilizes technologies such as all carbon composite tanks, heritage LOx/RP-1 liquid fueled engines and builds on other elements of the existing Alpha architecture. Firefly Beta will have lowest cost per kg to orbit of all launch vehicles in the 8,000 kg and under class.

Propulsion: Stage 1
ENGINE
5X Reaver 2
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
5
THRUST (VAC)
4,261 kN 957,910 lbf
ISP (VAC)
334 sec

Propulsion: Stage 2
ENGINE
1x Reaver 1 Vac
PROPELLANT
LOX/RP-1
PROPELLANT FEED
Turbopump
COMBUSTORS
1
THRUST (VAC)
194 kN 43,613 lbf
ISP (VAC)
325 sec

Dimensions
STAGE 1 DIAMETER
3.7 m 12 ft
STAGE 2 DIAMETER
3.7 m 12 ft
PAYLOAD FAIRING DIAMETER
4.7 m 15.3 ft
OVERALL LENGTH
46.7 m 151.8 ft

It looks like they've decided to build a new engine themselves rather than using the AR1. Otherwise, it's generally what you'd expect.

Edit: Of note, the fairing has a diameter of 4.7m, which should be plenty big enough to fit a Cygnus or vehicle of equivalent size.

Edit Again: Also, that Reaver 2 engine will have a thrust of (4,261/5=) ~852 kN, so it's fairly similar to the modern Merlin. But they claim a vacuum isp of 334, which is around 20s better than the Merlin. That's a significant enough increase in isp to suggest to me that it may be a staged combustion engine.

I'm confused. If I follow that link to the Beta page, I see a 2.8m fairing listed. Where do you see a 3.7m stage diameter or a 4.7m fairing diameter listed?

[TrevorMonty]

The Isp's for Beta don't make sense. 334 s vac on the first stage, which is more than the 325 s on the second stage! They are using different engines, with 852.2 kN on Reaver 2 and 194 kN for Reaver 1. Still, 325 s for a vacuum kerolox turbopump fed engine seems pretty low. The RD-180 gets 338 s vac, so that would seem to indicate staged combustion for Reaver 2.

The specs for Reaver 2 are pretty close to the RD-870 (the nozzles in the render are also similar): https://www.yuzhnoye.com/en/technique/rocket-engines/steering/rd-870/

Makes sense a modernized version of RD870 developed in Ukraine but built in USA.

[TrevorMonty]

We used it at Rotary on the Jet A fuel tank and I got Scaled to quote a honeycomb-cored composite tank for QuickReach (for the DARPA-AirLaunch FALCON program) but that program ended before we could implement it.

(Edit: added a photo of the Rotary Roton fuel tank fabrication.)

I did not know that. I don't have any sort of feel for relative cost in this area. Skin-and-core sounds expensive. How do you wrap a honeycomb around a relatively low radius? The easiest way I can figure to use this sort of construction is actually foam core. That seemed a lot more forgiving, but I'm not sure the property increases you get are worth the mass and complexity. 

Did you use the design freedom of using different thickness skins on inside and outsider?

We used foam on the LOX tank and Nomex core on the fuel tank, and definitely did use differing densities of core materials as well as skin thickness.  The typical cost was about $150/lbm of finished structure using the hand layup prototyping techniques that were available to us – but that was over 20 years ago, and some things are cheaper to do and some things more expensive these days.

looks like there is a new article up from composites world at least from this tweet https://twitter.com/CompositesWrld/status/1318567874701778946?s=19

https://www.compositesworld.com/articles/the-alpha-launch-vehicle-designing-performance-in-cost-out

Looking at Ingersol Machine videos on Youtube, these are composite 3D printers. Firefly are 3D printing most of LV much same as what Relativity keeps publicizing, but Firefly have flight ready LV.
Ingersol are definitely expertise in there field and have worked with lot of large aerospace companies.

[edzieba]

We used it at Rotary on the Jet A fuel tank and I got Scaled to quote a honeycomb-cored composite tank for QuickReach (for the DARPA-AirLaunch FALCON program) but that program ended before we could implement it.

(Edit: added a photo of the Rotary Roton fuel tank fabrication.)

I did not know that. I don't have any sort of feel for relative cost in this area. Skin-and-core sounds expensive. How do you wrap a honeycomb around a relatively low radius? The easiest way I can figure to use this sort of construction is actually foam core. That seemed a lot more forgiving, but I'm not sure the property increases you get are worth the mass and complexity. 

Did you use the design freedom of using different thickness skins on inside and outsider?

We used foam on the LOX tank and Nomex core on the fuel tank, and definitely did use differing densities of core materials as well as skin thickness.  The typical cost was about $150/lbm of finished structure using the hand layup prototyping techniques that were available to us – but that was over 20 years ago, and some things are cheaper to do and some things more expensive these days.

looks like there is a new article up from composites world at least from this tweet https://twitter.com/CompositesWrld/status/1318567874701778946?s=19

https://www.compositesworld.com/articles/the-alpha-launch-vehicle-designing-performance-in-cost-out

Looking at Ingersol Machine videos on Youtube, these are composite 3D printers. Firefly are 3D printing most of LV much same as what Relativity keeps publicizing, but Firefly have flight ready LV.
Ingersol are definitely expertise in there field and have worked with lot of large aerospace companies.

Not remotely the same sort of composite. Ingersoll themselves show the Masterprint being used to print the tooling used for creating CFC parts, not for those parts themselves.
Specifically, they print bulk thermoplastic with embedded short fibres (the same technique as used on desktop FFF machines), which have the limitation in that fibre orientation is determined by print plane. The bulk of the material by volume and by mass is plastic, with the fibre providing some isotropic reinforcement in effectively one plane.
Firefly's rocket body (and other CFC aerospace parts) use multiple layers of carbon fibre woven in multiple orientations, with the 'fibre plane' effectively normal to the surface of the part. The goal is to maximise the mass that is the carbon fibre itself, and use as little epoxy as possible. The plastic used is thermoset, not thermosoftening.

'3D printing' high performance CFCs in free air is a non-trivial task that I do not think I have seen anyone accomplish yet. However, computer-controlled fibre layup onto tooling is not a new technique: Northrop were early adopters for the B2 manufacture, so the technique is at least 3 decades old. Most oft the time that sort of fibre placement is not necessary, so for cylindrical rocket bodies (and COPVs) much simpler fibre laying robots like those used by Rocketlab are all that is needed.

[FutureSpaceTourist]

twitter.com/thesheetztweetz/status/1319271727566901248

Firefly Aerospace is targeting no earlier than Dec. 22 for the maiden launch of its Alpha rocket, CEO Tom Markusic tells me – and he's feeling confident:

"I think it's very reasonable for us to expect complete success on the first launch."

https://twitter.com/thesheetztweetz/status/1319272419891228673

Only a handful of tests remain until Alpha’s first launch. Firefly conducted a final engine test with the rocket’s first stage two weeks ago, with a second stage engine test up next.

https://www.cnbc.com/2020/10/21/firefly-aerospace-aims-for-first-rocket-launch-in-late-december.html

[FutureSpaceTourist]

Fighting talk! I guess Firefly think Electron payload mass is bit low for the market? But RocketLab don’t seem short of customers so far.

https://twitter.com/thesheetztweetz/status/1319284541580738561

Firefly’s target market is shared by several other rocket companies – Rocket Lab, Astra, Virgin Orbit, & Relativity, to name a few – but Markusic expects that "Alpha is going to be the only rocket left in the small launcher class."

[Davidthefat]

I wonder how fast they can churn out these engines. Based on what I've read about the Firefly engines is that their liners are machined from forgings, and the jacket is electrodeposited on. That electrodeposition process isn't necessarily a fast process or a common place process. I'd think they need to go to specialized vendors to do that electrodeposition process and that they don't have that capability in house.

They need to get forgings from forges that are probably serving other customers as well; I don't think many forges do the near net shape forgings of the copper alloy they need. It seems like they are tapping off the combustion gasses at the top of the combustion chamber head end in the injector assembly. Not sure if they are printing their injector, but if it's machined, machining those tap off holes in the injector and injector orifices, potentially coating with a ceramic coating, and subsequently sealing the assembly to the rest of the chamber seems like places that can be difficult to get consistent. Making sure quality is consistent through all those processes.

At least Rocket Lab and Relativity has the advantage of 3d printing their engines.

http://www.michman.org/resources/Documents/4%20-%20Kovacs%20-%20Firefly%20MAMA.pdf

[trimeta]

http://www.michman.org/resources/Documents/4%20-%20Kovacs%20-%20Firefly%20MAMA.pdf

The third slide in that deck confuses me, specifically their comparison with Relativity Space. I know that this forum tends to be skeptical about Relativity in general, but the claimed capabilities of the Terran 1 are strictly greater than those of the Firefly Alpha: more payload (898kg vs. 630kg to 500km SSO), larger fairing (2.54m x 3.16m vs. 2m x 2.5m diameter x height of cylindrical section), cheaper ($12M vs. $15M). Firefly is at least a year ahead of Relativity, so if their argument is "we'll actually be profitable, and learning from real missions, and that will let us accelerate past Relativity," I'd buy that, but saying "Relativity can barely put satellites into MEO, while we can go to the surface of the Moon" seems without validity. Unless they're implicitly taking into account a future "Block 2" of the Alpha, or the Beta? Relativity has no public plans for a "Terran 2," but their architecture does put them in a good position to build one, if the market went in that direction.

[TrevorMonty]

GEO and beyond is meant to use SEP 3rd stage which isn't in slides. If they updated it would show RL capable of lunar orbit and deep space missions.

No mention of ABL their main competitor at present.

[Stan-1967]

I wonder how fast they can churn out these engines. Based on what I've read about the Firefly engines is that their liners are machined from forgings, and the jacket is electrodeposited on. That electrodeposition process isn't necessarily a fast process or a common place process. I'd think they need to go to specialized vendors to do that electrodeposition process and that they don't have that capability in house.

Are you saying that the jacket is electroplated over the waxed liner that is shown on slide 7 in the attachment?   I do know that other methods would electroform the jacket on a machined mandrel, remove from the mandrel & then selectively electrodeposit brazing metals ( or alloys ) and mate/bond the jacket & liner in a brazing furnace.  This was done in house the the rocket engine mfg. I know of. 

Modern high speed acid copper electrodeposition can deposit metal in excess of 10 microns per minute, so even a thick jacket ( or liner) can be electroformed in a relatively short time if the electroplating tool is optimized for the geometry of the part.

[FutureSpaceTourist]

https://twitter.com/thesheetztweetz/status/1319389738797846530

Firefly Aerospace on Saturday conducted a successful separation test of the fairing for its first Alpha rocket launch:
https://www.cnbc.com/2020/10/21/firefly-aerospace-aims-for-first-rocket-launch-in-late-december.html

[Davidthefat]

I wonder how fast they can churn out these engines. Based on what I've read about the Firefly engines is that their liners are machined from forgings, and the jacket is electrodeposited on. That electrodeposition process isn't necessarily a fast process or a common place process. I'd think they need to go to specialized vendors to do that electrodeposition process and that they don't have that capability in house.

Are you saying that the jacket is electroplated over the waxed liner that is shown on slide 7 in the attachment?   I do know that other methods would electroform the jacket on a machined mandrel, remove from the mandrel & then selectively electrodeposit brazing metals ( or alloys ) and mate/bond the jacket & liner in a brazing furnace.  This was done in house the the rocket engine mfg. I know of. 

Modern high speed acid copper electrodeposition can deposit metal in excess of 10 microns per minute, so even a thick jacket ( or liner) can be electroformed in a relatively short time if the electroplating tool is optimized for the geometry of the part.

AFAIK, they aren't deposited all in one go, but in many passes. I don't have direct experience with fully electrodeposited jackets, so no idea on the actual timeframe. It seems like days at a time just for a jacket. Where printed chamber is days for a chamber.

Real cool video of the Vulcain engine being fabbed (electrodeposited jacket @ 24 min): 

3D printed chambers are usually just printed, cleaned out, heat treated, then machined.

Copper liners do get nickel plated prior to brazing, but it's your typical nickel plating process with only thicknesses in the order of 10s of microns. In a hip brazed chamber, it's still a lot of manual processes like close out welds and leak tests, ect prior to the actual braze then a lot of machining away of metal. Lots of touch labor going into that part. I could be wrong, but looking at the finished chamber, the Firefly engines do not look like a HIP Brazed chamber, but more like an electrodeposited one. Like the lack of a throat support makes me think it's not HIP Brazed, but electro deposited.

Either way, both those are labor intensive processes to do a close out. Printed chambers are just a lot faster turn around time than both those methods.


edit: Makes me think if they are already bothering with traditional manufacturing methods, why don't they go for a single engine or dual engine system. Wonder if it's due to the limitations of the turbopump Ukraine is allowed to export. I'd think just a single Merlin class engine would save them weight, complexity in plumbing, and time by just making a single engine. The upper stage and first stage engines are already different, so it's not about keeping commonality of the engines.

Also let me rethink about the chamber manufacturing technique used. They also can be just vacuum brazing the chamber as well.

edit 2: Confirmed they are electrodeposited jackets. Found a Powerpoint on google that confirmed that they are "Copper / nickel plated thrust chamber"

[trimeta]

edit: Makes me think if they are already bothering with traditional manufacturing methods, why don't they go for a single engine or dual engine system. Wonder if it's due to the limitations of the turbopump Ukraine is allowed to export. I'd think just a single Merlin class engine would save them weight, complexity in plumbing, and time by just making a single engine. The upper stage and first stage engines are already different, so it's not about keeping commonality of the engines.

One possible reason could be the Beta, the second stage of which uses a single vacuum-optimized version of the Alpha's first-stage engine. So between the two rockets, Firefly is only designing three engines, rather than four. Maybe if the Alpha had a one-and-one dissimilar engine design, they couldn't use its first-stage engine as the second-stage engine of their larger-but-not-Falcon-9-sized Beta.

[intelati]

https://twitter.com/Firefly_Space/status/1321094434457608194?s=09

Big milestone for Firefly’s Vandenberg launch site team – successful rotation testing of the strongback! Testing included verification of the launch pad hydraulic lift system and command and control from the blockhouse control room consoles. #Firefly #MakingSpaceForEveryone[/quoute]

[FutureSpaceTourist]

https://twitter.com/firefly_space/status/1321457373198848001

Firefly’s fairing separation system was designed and manufactured in-house. It is “operationally resettable” so we are able to fully test each fairing prior to launch. Alpha Flight 1 fairing passed the test and is ready to fly!

Edit to add: