Vast/Launcher

[tater]

These guys are pretty interesting. The number of smaller LVs that survive can't end up being too high, but this has a little more payload mass, which might make them attractive.

https://launcherspace.com/

 

(if they already have a thread, let me know, I'll delete this, I'd not bogart someone else's thread, that would be a crappy thing to do)

Edited February 21, 2023 by tater

[MaverickSawyer]

Huh. LOX-cooled engine? That's... kind of an odd choice. Wonder why?

[sh1pman]

Another small sat launcher? Aren't  there, like, 15 of them in dev/flying already? Market big enough?

Would be nice to see more startups with super-heavy rockets.

Edited February 27, 2019 by sh1pman

[Ozymandias_the_Goat]

2 minutes ago, sh1pman said:

Would be nice to see more startups with super-heavy rockets

You know, the kind you can fly out of your garage.

[tater]

27 minutes ago, sh1pman said:

Another small sat launcher? Aren't  there, like, 15 of them in dev/flying already? Market big enough?

Would be nice to see more startups with super-heavy rockets.

The investment required for that is vastly higher, and there are not really any payloads.

[sh1pman]

Just now, tater said:

The investment required for that is vastly higher, and there are not really any payloads.

Yea, I wasn't really serious about it 

That rocket looks like Falcon 1. Or baby Falcon 9 B5.

[sevenperforce]

2 hours ago, MaverickSawyer said:

Huh. LOX-cooled engine? That's... kind of an odd choice. Wonder why?

Yeah that's an odd choice. What are they using for their fuel? The flame looks like kerolox but that's just a guess. 

LOX is so corrosive that it's almost never used for regenerative cooling.

Edited February 27, 2019 by sevenperforce

[Cunjo Carl]

19 minutes ago, sevenperforce said:

Yeah that's an odd choice. What are they using for their fuel? The flame looks like kerolox but that's just a guess.

Nice- It is in fact LOX/RP1!

 

Also, they seem to be getting along well with their town officials and have good safety measures in place, which says at least to me that they intend to be trying at this long-term.

https://riverheadlocal.com/2018/04/04/town-issues-violation-notice-to-rocket-engine-company-at-luminati-site/

[sevenperforce]

37 minutes ago, Cunjo Carl said:

Nice- It is in fact LOX/RP1!

 

Also, they seem to be getting along well with their town officials and have good safety measures in place, which says at least to me that they intend to be trying at this long-term.

https://riverheadlocal.com/2018/04/04/town-issues-violation-notice-to-rocket-engine-company-at-luminati-site/

That link says it is staged combustion. 

Presumably that means ORSC which is huge for any American rocket engine, let alone a tiny smallsat engine like this.

[Barzon]

Can someone ELI5 what staged combustion is, and how it is different from full flow combustion, and what full flow combustion even is?

[Cunjo Carl]

4 hours ago, MaverickSawyer said:

Huh. LOX-cooled engine? That's... kind of an odd choice. Wonder why?

I have a couple random guesses. One of them is that if the chamber pressure is above 50 bar, the 'warm' compressed liquid Oxygen will have dramatically better viscosity than RP1, making it easier to pump through the channels, so the channel(s) can be made simpler/smaller. Also, when warmed, pressurized liquid Oxygen can go supercritical effectively removing its surface tension and probably allowing for simpler injectors and better propellant mixing in the chamber, and so better combustion efficiency in a smaller chamber.

The downside is they're more constrained on materials choice... it looks like they originally tried an inconel chamber (expensive and chemically resistant) and now they're apparently trying Copper! As long as they're very careful to keep it Dry, copper can be surprisingly Oxygen resistant. I certainly wouldn't have guessed it though!

 

25 minutes ago, sevenperforce said:

That link says it is staged combustion. 

Presumably that means ORSC which is huge for any American rocket engine, let alone a tiny smallsat engine like this.

That'd sure be awesome! They apparently line their chambers with copper, but the rest of the engine/throat is apparently an enormous single hunk of 3D printed inconel, which would be a good material for the job!

Some more articles with interviews and pretty pictures:

https://3dprintingindustry.com/news/launcher-space-race-largest-single-piece-3d-printed-rocket-engine-149500/

https://3dprint.com/220518/launcher-a-space-start-up-making-3d-printed-rocket-engines/

Edit: Image is a direct link from the 3dprint.com interview, which has a lot of juicy technical details on the fabrication of the engine:

Launcher Inc.'s E-1 engine, and two injectors. Apparently all 3d printed

Edited February 27, 2019 by Cunjo Carl

[sevenperforce]

Just now, Barzon Kerman said:

Can someone ELI5 what staged combustion is, and how it is different from full flow combustion, and what full flow combustion even is?

https://en.wikipedia.org/wiki/Liquid-propellant_rocket#Engine_cycles

Full flow combustion is a form of staged combustion.

All pump-fed rocket engines have to get energy to turn the turbopump that pumps them. If they don't have a pump, they're pressure-fed from tanks that hold higher pressure than the combustion chamber. Pressure-bearing tanks are heavy AF so high-performing architectures use pumps to force low-pressure propellant into a high-pressure combustion chamber.

Most pump-fed engines historically have been "gas generator" engines, where a small amount of propellant is burned in what is essentially a small internal combustion engine, turning the pump. This wastes propellant but in the end it's a pretty good equation. Common GG engines include RS-68, Merlin, and F-1.

You can use an electric pump, which wastes no fuel but requires you to carry heavy batteries all the way up. The Electron by Rocketlab makes an end-run around this by jettisoning batteries as they are spent.

Another option, pioneered by Blue Origin in the BE-3, is the "combustion tap-off" engine, where a small amount of chamber gases are rerouted out of the chamber to spin the turbine. This is hard to do with kerolox because it doesn't burn very cleanly so you get a lot of soot and coking in the turbopump.

And then you have staged combustion.

Staged combustion is like a gas generator cycle, except that you burn the propellant in an off-ratio, ending up with either fuel-rich or oxygen-rich exhaust. Then, rather than dumping the exhaust, you route it into the chamber. This means all the propellant ends up getting pushed through the engine. It's called "staged combustion" because the combustion occurs in stages. The SSME used fuel-rich staged combustion (FRSC); they burned a lot of hydrogen with a tiny amount of LOX, then routed that fuel-rich exhaust into the main chamber along with the rest of the LOX to burn. The Russians pioneered oxygen-rich staged combustion (ORSC) with engines like the RD-180, burning a lot of oxygen with a tiny amount of kerosene, and then routing that hot oxygen-rich exhaust into the chamber along with the rest of the kerosene to burn. Oxygen-rich staged combustion is challenging because superheated oxygen gas basically eats anything it touches, but the Russians figured it out, and that's the design for the BE-4 (although it's using methane not kerosene) and this new startup engine as well.

Full flow staged combustion (FFSC) is the big guy. That's where you have two different miniature engines running two different turbopumps. One preburner burns a bunch of fuel with a tiny amount of oxidizer, and one preburner burns a bunch of oxidizer with a tiny amount of fuel. Each preburner spins a different turbopump. You end up with two exhaust flows: one of oxygen-rich gas, one of fuel-rich gas. Those two gas flows are routed together into the main chamber using turbine force. The advantage here is that both turbopumps are smaller and lighter (since each one is pumping only one type of propellant) than using a single turbopump, and ALL of the propellant is "staged". Having all that propellant flow means that the turbopumps have way more power and can create much higher chamber pressure. Also, gas-gas reactions are far more complete, which means more efficiency.

So there you have it. Idk if that was ELI5 but maybe ELI9?

[Barzon]

Thank you so much @sevenperforce ! That has certainly cleared things up for me!  

[sevenperforce]

15 hours ago, Barzon Kerman said:

Thank you so much @sevenperforce ! That has certainly cleared things up for me!  

No problem!

A little more ELI9 rocket science, just for fun....

Rocket engineers generally prefer that the propellant exhaust flows out of the combustion chamber and through the nozzle, rather than out of the chamber and through the valves back into the tank. This would be bad, and you would not go to space today (or maybe ever).

But of course this is intrinsically challenging. Suppose you have two tanks, one that is pressurized to 200 psi and another pressurized to 50 psi. If you hook them up and open a valve between them, the contents will flow from the 200 psi tank to the 50 psi tank, without exception. If you want the process to work in reverse, you will need to replace the valve with some machine (like a displacement pump) and add energy to the system. Perhaps with a little effort and elbow grease, you can force one tank up to 210 psi while dropping the other to 45 psi or so.

The energy you used to make this change is now stored in that system. You can extract that energy, if you like, by placing a turbine or piston shaft at the valve. And this is how a rocket cycle works.

Gas generator engines are less challenging because you take a small amount of propellant at low pressure, burn it at medium pressure, and then use its pressure drop along with a turbine to operate the pump. The pump does the work of forcing the rest of the propellant into the high-pressure chamber; it also steps up pressure from the low-pressure tanks into the medium-pressure gas generator. You can dump that gas exhaust overboard (Merlin 1D on the Falcon 9), or you can use it for roll control thrust vectoring like a vernier motor (Merlin 1A), or if you really want to be creative you can inject it down near the end of the nozzle where the nozzle's expansion has lowered the flow pressure (Merlin 1D Vacuum, F-1). Adding gas gen exhaust at the end of the nozzle allows it to mix with the rest of the exhaust gases, which lowers their speed slightly but improves overall efficiency. 

You can also build a "gas generator" which uses a completely separate loop for generating gas and spinning the turbine. The RD-107 multichamber engines which power the Soyuz launch vehicles are connected to a completely separate tank of high-test hydrogen peroxide; this is catalytically decomposed and the exhaust is used to spin the turbine. I don't know where the exhaust is dumped but it probably goes overboard.

One type of engine cycle I did not mention yesterday is the "expander cycle". If you have a propellant with a ridiculously high heat capacity, like liquid hydrogen, you can actually skip the gas generator step altogether. Simply by pushing cryogenic fuel through channels around the nozzle and chamber, the hydrogen absorbs heat, boils, and expands. The expanding gas, now at higher pressure, can be used to turn a turbine that pumps the rest of the propellants into the chamber. The low-pressure hydrogen gas can be dumped or routed back into the tank to provide autogenous pressurization, injected into the end of the nozzle, or even injected into the main combustion chamber using turbine force. Of course this cycle is limited to a small number of propellants (liquid hydrogen in current vehicles; liquid oxygen in some theoretical designs) and it tends not to work for large engines. The larger a rocket engine becomes, the less heat-generating surface area it has proportional to the amount of propellant being pushed through it. The Vinci engine being designed for the Ariane 6 attempts to get around this problem by using a very very long, narrow, cylindrical combustion chamber, but that rapidly becomes a tradeoff in terms of combustion efficiency and engine mass. For more far more detailed info on expander cycles, I recommend this resource.

But I digress. Where were we? Ah, yes; staged combustion.

With a gas-generator engine, the gas generator can operate at a lower pressure than the main combustion chamber so long as it has a sufficient pressure drop across the turbine. But that's not the case with staged combustion. In a staged combustion engine, the low-pressure propellant is pushed by the turbopump into a ridiculously high-pressure preburner. The fuel-rich or oxidizer-rich exhaust from the preburner is passed through a turbine to run the turbopump, losing pressure, and it is this lower-pressure exhaust which is then routed into the main combustion chamber.

This means that you never have to pump anything into the combustion chamber itself, because the flows into the combustion chamber are coming from regions with much higher pressure. The pressure drop across the turbine between the preburner and the chamber is used to drive the pump for the preburners themselves. Elon Musk said that in order to reach a pressure of 300 bar in the combustion chamber, they have to run the oxygen preburner at a whopping 700 bar or higher. The 400-bar drop from the preburner to the chamber is what is used to turn the turbine to force propellant out of the low-pressure tanks and into the preburner.

[tater]

 

[StrandedonEarth]

Looks like they mounted the test rig in a shipping container. Always nice to see new controlled-explosion startups coming along

[Ultimate Steve]

1 hour ago, StrandedonEarth said:

Looks like they mounted the test rig in a shipping container. Always nice to see new controlled-explosion startups coming along

How many are there at this point? Some are more real than others, but the smallsat scene has exploded. We've got:

• Rocket Lab
• Vector
• Virgin Orbit
• Launcher
• Arca
• Firefly
• Astra
• Landspace
• Ispace
• Expace
• Orbex
• PLD?
• RocketStar?
• Zero2Infinity?

[tater]

A few can likely survive, but not all.

[tater]

 

[Cheif Operations Director]

Seems like a scaled down non-reusable falcon 9

[NSEP]

On 7/5/2019 at 5:17 AM, Cheif Operations Director said:

Seems like a scaled down non-reusable falcon 9

Thats pretty much what most smallsat launchers are. Its simple and it works.

[Cheif Operations Director]

6 hours ago, NSEP said:

Thats pretty much what most smallsat launchers are. Its simple and it works.

Nice if people had some imagination. Like perhaps not always using 7-9 engines on the first stage and 1 on the second. I have nothing against simple designs but if you could tell them apart it would be nice

 

[tater]

6 hours ago, Cheif Operations Director said:

Nice if people had some imagination. Like perhaps not always using 7-9 engines on the first stage and 1 on the second. I have nothing against simple designs but if you could tell them apart it would be nice

I suppose the goal is a certain ability to deal with engine out events.

[Cheif Operations Director]

1 hour ago, tater said:

I suppose the goal is a certain ability to deal with engine out events.



Then use 11 engines with some fins( I know I make it sound Kerbal(y) when it is not) Its just annoying that you can not tell any of them apart excluding logos

[tater]

8 hours ago, Cheif Operations Director said:

Then use 11 engines with some fins( I know I make it sound Kerbal(y) when it is not) Its just annoying that you can not tell any of them apart excluding logos

Falcon 9 is the one that lands