Possible SpaceX Vehicle Configurations based on recent (10/23) Raptor information

[Chris Bergin]

So basically, we don't know what Raptor is for? Not even confirmed it's for Falcon X?

We don't.  There were several options that I counted.   
a) a high energy upper stage for FH
b) a single engine replacement for first stage of F9, (the "Merlin 2" scale)
c) a large engine for a BFR, with a similar (7-9) engine count
d) a Mars ascent stage

The ~300 ton number, if correct, narrows it down.

It's too large for option A.
It's too small for option B.
It works well for option C.
It could work for option D.

Much will depend on what MCT turns out to be.  The easy guess is a 4x up-scaled F9 and F9H, but remember Tinker's diagram from a while back?  It had several flaws, but some aspect of it got a nod from Elon.   So a combined US/EDS is possible too.

That's a good post! Thanks. Now to squeeze some more people I know

[a_langwich]

4) by doing business in Mississippi, they get 2 more senators and some congressman on their side, besides helping NASA keep their facilities utilized.

I would think the press release from the Mississippi congressman supports the "getting members of the Mississippi delegation on their side" angle.  Somebody brought this work to the attention of the Mississippi delegation.  On the flip side, those members of Congress may be eager to find non-partisan happy stories after the shutdown, may be looking to hedge their bets as SpaceX's accomplishments grow, and may be sniffing around to see if SpaceX wants to share the Texas love and build something in their state.

One interesting thing to me is that Stennis actually had to refit a test stand to support this.  Hasn't there been a fair amount of work done on methane engines in the past?  Perhaps previous tests were much smaller, and/or done onsite at manufacturer's locations.  I guess the day is far off when Stennis can compete with the local brewpub for how many fuels it has on tap.

[Jcc]

A new class of LV deserves a new name, Falcon X won't do. In keeping with the bird of prey theme, how about:

SpaceX Eagle!

[JBF]

A new class of LV deserves a new name, Falcon X won't do. In keeping with the bird of prey theme, how about:

SpaceX Eagle!

[Zed_Noir]

A new class of LV deserves a new name, Falcon X won't do. In keeping with the bird of prey theme, how about:

SpaceX Eagle!

Nah. In keeping with the SpaceX media theme naming of their equipment. Maybe Thunderbird 9 from the Gerry Anderson TV series, which should be on-air again in it's new incarnation in few years. 

[Mongo62]

Well, if the Falcon was named after the "Millennium Falcon" from Star Wars, then perhaps another Star Wars vessel? To tie into the SpaceX corporate name, how about "X-wing"?

Of course, I suppose that "Death Star" is out of the question. Although it would give Elon the opportunity to tell the world, "Now witness the power of this FULLY FUELED AND OPERATIONAL heavy lift launch vehicle!"

[Chris Bergin]

Stay focused guys....or we might end up with 50 pages of name suggestions

PS: SpaceX BFR

[NovaSilisko]

PS: SpaceX BFR

Beastly Fantastic Rocket! 


A martian ascent engine with 300 tons of thrust seems kinda insane. That'd be one hell of an ascent stage (and even more of a... hell of a descent stage)

remember Tinker's diagram from a while back?  It had several flaws, but some aspect of it got a nod from Elon.

I can't say I remember that, not been the most active person. Someone refresh my memory?

[QuantumG]

Last I heard, they are hush-hush until they get the launch pad.

[meekGee]

PS: SpaceX BFR

Beastly Fantastic Rocket! 


A martian ascent engine with 300 tons of thrust seems kinda insane. That'd be one hell of an ascent stage (and even more of a... hell of a descent stage)

remember Tinker's diagram from a while back?  It had several flaws, but some aspect of it got a nod from Elon.

I can't say I remember that, not been the most active person. Someone refresh my memory?

Well some parts of it made more sense than others, and some were too generic to be meaningful, but I think the point made was that there'd be no in-orbit assembly, not sure even about in-orbit refueling, and the upper stage was also the Earth-departure stage, lander, and ascent stage (so no Mars-orbit shenanigans either)

But take that with a huge grain of salt.  It was a partial response to a partial diagram...  FWIW.

(I'd call it "SISO" - Simple In, Simple Out.)

[simonbp]

PS: SpaceX BFR

Beastly Fantastic Rocket! 

Bovine Flatulation Rocket...

[Hyperion5]

Stay focused guys....or we might end up with 50 pages of name suggestions

PS: SpaceX BFR

Looks like we need to get the Off-Topic Sheriff in here and keeping the mayor on-topic.  He's clearly going to need a rocket-grade arsenal, say in the 300 tf class, to get this thread back to launch vehicles.   

My prediction is that the Falcon X or whatever it ends up being called will have only one of two possible configurations.  Both will have a single Raptor up top, while the 1st stage will feature either 7 or 9 Raptor booster engines. 

[simonbp]

Or maybe 2x Raptor on the second stage.

But either way, the larger point may be that this will be a rocket designed from the ground up to be reusable, using lessons learned from Falcon. That will mean lower performance numbers than just scaling Falcon performance.

[gin455res]

So basically, we don't know what Raptor is for? Not even confirmed it's for Falcon X?

We don't.  There were several options that I counted.   
a) a high energy upper stage for FH
b) a single engine replacement for first stage of F9, (the "Merlin 2" scale)
c) a large engine for a BFR, with a similar (7-9) engine count
d) a Mars ascent stage

The ~300 ton number, if correct, narrows it down.

It's too large for option A.
It's too small for option B.
It works well for option C.
It could work for option D.

Much will depend on what MCT turns out to be.  The easy guess is a 4x up-scaled F9 and F9H, but remember Tinker's diagram from a while back?  It had several flaws, but some aspect of it got a nod from Elon.   So a combined US/EDS is possible too.

and b ii)
a smaller 'Falcon 4 equivalent' single-raptor engine, light launcher.
by shrinking the length of the F9 tankage to match the raptor's thrust (using
the existing F9 upper stage and a reduced payload) you can more quickly flight test the raptor.
No need to wait for the larger tank tooling. Plus you now have a presence in the
lower-mass payload market. 1 engine per stage gives you simplicity.

The upper stage always seemed a little under-powered to me before
the switch to boost back. The 300 tonf sizing seems like a good call
for expanding SpaceX's launch capabilities on both sides of the market
wrt payload size.

[john smith 19]

I'll note that after all the speculation that Raptor was some kind of small upper stage engine this is a whole different item. 

We know Spacex likes a)Common propellant on both stages b) Common engines on both stages c)Minimal divergence (consider how they phased out F1) d)Like small(ish) upgrades by engine tweaks, big ones by side mount boosters.

So as meekgeek notes the obvious routes are a upsized F9 and FH sized to the new engine. That's roughly a 2.7 million lbf takeoff thrust.  So double the payload as a baseline? That puts the Raptor FH version (or whatever) about the Saturn V capability (in expendable mode). That should be big enough to carry a 2nd stage as a payload. Handy if you're looking for an EDS. A creative option would be to leverage the cross feed tech being developed for FH to the  upper stage and create an on orbit vehicle of multiple upper stages attached together to delivery a very big delta v, useful for planetary probes or crewed launches to other planets.

But note, to maintain their business Spacex has a tricky choice. Either it maintains 2 lines (Merlin F9/FH for its existing commercial launches, and Raptor F9/FH) or phases out the Merlin F9/FH lines and creates a new design, an F9 payload size with Raptor engines. That keep them in their core market, gives them plenty of stretch and (if they vary tank length rather than diameter) and lets them retain the common tooling / common engine approach they have used very successfully so far.

Spacex has grown a lot over the years. It'll be interesting to see if they feel the 2 parallel lines, retaining RP1 as a propellant, work out cheaper than standardizing around Methane and developing a new LV to fit in the F9 hole.

[TrevorMonty]

One possible scenario is a 7 engine  70mt core. Recoverable 1st and 2nd stages up to 30mt, recoverable 1st stage for 30-50mt, fully expendable for 50-70mt. Plus option of 3core 210mt monster which maybe paritially recoverable upto 150mt. Pricing would depend on the scenario. This would allow one core to cover the 15- 210mt range. By the time they build it SpaceX should have had recovery of the F9R sorted.

[smoliarm]

So basically, we don't know what Raptor is for? Not even confirmed it's for Falcon X?

We don't.  There were several options that I counted.   
a) a high energy upper stage for FH
b) a single engine replacement for first stage of F9, (the "Merlin 2" scale)
c) a large engine for a BFR, with a similar (7-9) engine count
d) a Mars ascent stage

The ~300 ton number, if correct, narrows it down.

It's too large for option A.
It's too small for option B.
It works well for option C.
It could work for option D.

Much will depend on what MCT turns out to be.  The easy guess is a 4x up-scaled F9 and F9H, but remember Tinker's diagram from a while back?  It had several flaws, but some aspect of it got a nod from Elon.   So a combined US/EDS is possible too.

Let me add a dime:
A.   “The E-Complex supports testing of small engine and single/multiple components” – wiki.
      Also, it was noted in another thread that E-2 stand has max limit of 100,000 lbf thrust:
http://arc.aiaa.org/na101/home/literatum/publisher/aiaa/books/content/6.jpc/2005/mjpc2005/6.2005-4419/staging/6.2005-4419.fp.png_v01
B.   The article at seattlepi.com
      http://www.seattlepi.com/news/article/SpaceX-to-test-methane-rocket-engine-in-Miss-4919628.php
      “…Mississippi will spend $500,000 and NASA will spend $600,000 to help upgrade a rocket test stand
      so it can use methane to fuel SpaceX's Raptor engine…”
C.   Finally, the same article says:
      “...The testing could support a handful of jobs, but officials said it's important because
      it could make Stennis more attractive to other private users...”

So, this is a small project in all three dimensions – the money, the workforce, and the equipment involved. Therefore, I would not rule out any of options meekGee listed. I guess, Spacex themselves do not know what is the goal: will this project result in Big Engine for the BFR, or will it yield just Meth-LOX U/S.
But – they invest their money in upgrade of NASA equipment, so they have some confidence.
We just do not know – how much

[IRobot]

But note, to maintain their business Spacex has a tricky choice. Either it maintains 2 lines (Merlin F9/FH for its existing commercial launches, and Raptor F9/FH) or phases out the Merlin F9/FH lines and creates a new design, an F9 payload size with Raptor engines.

The only excuse for them to replace F9 would be if the new Raptor could increase re usability, for example allowing S2 fly back while maintaining a good payload capability.

[john smith 19]

But note, to maintain their business Spacex has a tricky choice. Either it maintains 2 lines (Merlin F9/FH for its existing commercial launches, and Raptor F9/FH) or phases out the Merlin F9/FH lines and creates a new design, an F9 payload size with Raptor engines.

The only excuse for them to replace F9 would be if the new Raptor could increase re usability, for example allowing S2 fly back while maintaining a good payload capability.

Well let's not get too concerned. Raptor (AFAIK) has not even gotten on a test stand yet, yet alone into a stage design. 

I expect Merlin V 1.1 (or .2 or .3) will be launching a good few payloads yet.

But from past experience with F1 we know that Spacex don't like to keep "legacy" systems in production. If Raptor follows the F9/FH approach then at some point the senior Spacex management will be getting round a table to make a decision on this. By that point F9 (and hopefully FH) will have racked up a fair flight record and be a well known quantity. With both a Raptor F9/FH and a Merlin F9/FH they will be a 4 product company. Given a Raptor is 2x a Merlin 1.1 it would seem you'd have as much of a job designing a new thrust structure  to retro fit Raptor to F9/FH as you would designing a whole new vehicle (which of course would draw on the lessons learned from F9/FH by this time).

Keep in mind that a Raptor FH would be in the SLS class payload which, if you're not NASA or planning to run your own exploration programme is a big payload. Sure in theory there are payloads that could use that kind of mass level, but AFAIK no one who is interested in those sorts of payloads has cut any metal for them. You could launch quite a large space hotel in 1 go if you were minded, for example.

At the bottom it's a production engineering problem. The team to build a Raptor based F9/FH would likely be as big as that needed to build Merlin based F9/FH's, but with a lot fewer launches to spread the cost over.  unless the HLV "market" expands a lot. Basically a Raptor F5 (to be on the safe side) is equal to an F9.

I can see pro and con on both sides. My guess is it depends on how many staff to mfg both vehicles and engines and if you can share the between the two designs and what the production costs will be, all very closely held information.

I expect we'll hear when Musk is ready to announce it. 

[Elmar Moelzer]

I am wondering whether they might do a 5 raptor engine first stage and single engine second stage.
IIRC, 5 engines is a bit of a sweet spot and was what they had originally planned (Falcon5). A 5 engine (with 300 tonnes each) first stage would have a combined 1500 tons of trust. 2.2 (?)times the thrust of the F9 first stage. Combined with the larger second stage this should roughly double their payload to orbit and make reusability less of an issue. I think that it would have to throttle to much lower levels than Merlin 1D though in order to allow propulsive landing.