XCOR and the Lynx rocket

[Robotbeat]

If/when this engine flies, it will be a huge deal. XCOR is dead-serious about rapid-turnaround, fully reusable orbital human spaceflight. They know how to make a highly reusable engine, let's see them do it!

[QuantumG]

If/when this engine flies, it will be a huge deal. XCOR is dead-serious about rapid-turnaround, fully reusable orbital human spaceflight. They know how to make a highly reusable engine, let's see them do it!

That won't be relevant to their deal with ULA, but yeah.

Lynx is gunna be one sweet hot rod.

[Robotbeat]

It is relevant. They're doing the smart thing by finding customers for the big parts they need for orbital flight. ULA really needs a better/cheaper RL-10, and XCOR knows how to help them. They also need a hydrolox engine for their orbital work.

[QuantumG]

Yes... but it's not relevant to ULA. They'll be throwing it away with every flight.

[guckyfan]

I wonder about the "low mass" claim.

I do see how it would be reliable and relatively cheap to build for low to medium thrust engines. But can a piston engine/pump with its pistons, cylinders and non rotating masses be lightweight compared to turbines?

For reuse with very long life cycles it may be worth some weight increase though. Especially on orbital tugs with expected very long lifetime.

[jongoff]

Yes... but it's not relevant to ULA. They'll be throwing it away with every flight.

Actually it's relevant in a not-so-obvious way. I had been talking with some ULAers a few years ago about this. One of the big challenges with an RL-10 replacement is that building up enough heritage with an expendable rocket engine that people are willing to trust $1B+ satellites on it is hard. The RL-10 was having its bugs wrung-out in parallel with flight development of Centaur and Atlas way back in the day. For a new engine that was completely replacing the flight-proven RL-10, they'd want a ton of flights and as much data as possible. A reusable RL-10 replacement from XCOR flown on a suborbital or orbital vehicle that happened to rack up a ton of flights would be *very* interesting to them. At the time they were so desperate for a way to rack up the mileage on some engines that they offered to build us a free Centaur stage if we could wrap it into some sort of reusable vehicle design that could realistically get them at least 20-50 flights worth of engine time on the engine. Don't know if that's still on offer though. :-)

~Jon

[Garrett]

Thanks for that great explanation Jon! Very interesting indeed.

Makes me wonder if the biggest contribution the suborbital industry will make to the orbital/BEO industry will be what you just talked about, i.e. racking up hundreds/thousands of rocket flight hours (and the training of hundreds of rocket engineers ...)

[jongoff]

Thanks for that great explanation Jon! Very interesting indeed.

Makes me wonder if the biggest contribution the suborbital industry will make to the orbital/BEO industry will be what you just talked about, i.e. racking up hundreds/thousands of rocket flight hours (and the training of hundreds of rocket engineers ...)

Yeah, I'm not sure. With how much longer it's taken for companies like XCOR and Masten to get to a critical mass of talent, technology, and money, it's not as clear what role they'll play. That said, I'm willing to bet that an RLV orbital stage built by XCOR will likely be a lot more maintainable and long-lived than a SpaceX stage, assuming XCOR gets to that point (fingers crossed). So maybe, if things pick up from here, they may also be lending experience with high flight-rate reusability.

~Jon

[simonbp]

Well, Greason did say that their eventual orbital vehicle's second stage would be both reusable and hydrogen powered, so presumably that's what he has in mind for this eventually. But getting ULA to pay for development and maybe buy some engines in the meantime doesn't hurt.

I wonder how much impulse a Lynx with a hydrogen engine would have... Probably not as much as the kerosene version, but maybe enough to rack up some flight hours.

[RanulfC]

Got to be asked/wondered: The RL-10 has been run on cryo-propane, which when "chilled" store into about the same volume as RP-1 with a much better ISP. I wonder if everyone would consider using it instead of LH2 in order to fit into a smaller, less expensive hull?

Randy

[BrightLight]

I don't know the weight of the piston pump or the weight of a full-up engine or the ISP but 25,000lbf of thrust ain't so bad (the XLR-99 was about 59,000lbf).  It might be useful to have a couple of them on a sub-orbital aircraft, say flying at Mach 10 and be able to fly it 10 times in 10 days.

[Joel]

I didn't see this linked anywhere.


http://www.airspacemag.com/space-exploration/The-Lynxs-Leap-223968551.html

[Joel]

If the first stage of the future orbital vehicle is HTHL, why not make it a three-stage-to-orbit architecture?


The first stage takes off flying west gaining altitude but not much speed. After staging, the first stage then glides back (eastward) to the launch site. The second stage, which is not lifting body, takes off towards the east and is sized so that it can land vertically at the launch site without any boost-back needed. The third stage continues to orbit.

[sublimemarsupial]

If the first stage of the future orbital vehicle is HTHL, why not make it a three-stage-to-orbit architecture?

Isn't that exactly what XCOR is already planning? From the article: "Greason won’t say much about more about the orbital vehicle than that it is planned as two rocket-powered stages launched from a carrier aircraft"

3 stages, just the first one is air breathing.

[Joel]

Isn't that exactly what XCOR is already planning? From the article: "Greason won’t say much about more about the orbital vehicle than that it is planned as two rocket-powered stages launched from a carrier aircraft"

3 stages, just the first one is air breathing.

Yeah, you're right. I misread that quote.

[Garrett]

I didn't see this linked anywhere.
http://www.airspacemag.com/space-exploration/The-Lynxs-Leap-223968551.html

Good article. Some nice info about the RCS engines.

Twelve of these engines, designated 3N22, will go on the spaceship that’s coming together elsewhere on the shop floor. Six of them will give the pilot pitch, yaw, and roll control at the apex of the ship’s suborbital flight, outside the atmosphere, where aerodynamic flight controls have no effect. Six more are backups, there in case something goes wrong with any of the first six.

[Lurker Steve]

Isn't that exactly what XCOR is already planning? From the article: "Greason won’t say much about more about the orbital vehicle than that it is planned as two rocket-powered stages launched from a carrier aircraft"

3 stages, just the first one is air breathing.

Yeah, you're right. I misread that quote.

I thought I read that sub-orbital Lynx starts out with a air breathing engine as well.
If they "launch" Lynx from a carrier aircraft, that would actually make 2 air breathing stages, right ?

Or they just drop the jet engine from Lynx, and increase the fuel for the rocket engine in Lynx, going back to a 2-stage launcher.

[kch]

I thought I read that sub-orbital Lynx starts out with a air breathing engine as well.

Hmmm ... don't remember anything about a jet engine for Lynx ... don't see it here, either:



 

[Joel]

3 stages, just the first one is air breathing.

Does the "carrier aircraft" really need to be air breathing? Could it not simply be a scale-up of the Lynx?

[sublimemarsupial]

3 stages, just the first one is air breathing.

Does the "carrier aircraft" really need to be air breathing? Could it not simply be a scale-up of the Lynx?

Suppose that it could be a scaled-up lynx, nothing to rule that out.  In my opinion, though, lynx is prototyping systems for the second and third stages, and the "carrier aircraft" is just that, a traditional air-breathing plane.