Author Topic: FX, FXH, FXX, Merlin 2  (Read 50014 times)

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
FX, FXH, FXX, Merlin 2
« on: 11/11/2011 05:03 AM »
Discuss the possibility of a Falcon X, Falcon X Heavy, Falcon XX, and Merlin 2 engine.

Their possible configurations or something in between.

Also any changes that might make them better including reusability.


Offline tigerade

  • Full Member
  • ****
  • Posts: 718
  • Low Earth Orbit
  • Liked: 50
  • Likes Given: 36
Re: FX, FXH, FXX, Merlin 2
« Reply #1 on: 11/11/2011 05:05 AM »
I believe this are all paper rockets, or more accurately powerpoint rockets.  I've never heard anything about them except that one presentation last year.

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #2 on: 11/11/2011 05:36 AM »
Yes a concept they had.

Some info on them at:
http://nextbigfuture.com/2010/08/spacex-talks-falcon-x-heavy-for-125.html

I believe the FXH can be made reusable and lift up to 140k kg to LEO.
So that their would not be a need for the FXX.
The FX ( reusable ) for payloads up to 38k kg to LEO.

They could need to be a little wider to hold the extra fuel needed for return.

The Merlin 2 as I understand it was to have two settings, 1.2Mlb or 1.7Mlb at launch. The 1.2Mlb was for FX,FXH and the 1.7Mlb setting for the FXX. So the Merlin 2 would have plenty of thrust for a reusable Falcon.

thread on SpaceX's Grasshopper RLV
http://forum.nasaspaceflight.com/index.php?topic=26884.0

thread on SpaceX 1st and 2nd stage reusability
http://forum.nasaspaceflight.com/index.php?topic=21923.0

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 7109
  • A spaceflight fan
  • London, UK
  • Liked: 634
  • Likes Given: 743
Re: FX, FXH, FXX, Merlin 2
« Reply #3 on: 11/11/2011 08:24 AM »
I woulod say that FX can be considered a competitor to the equally paper-only Atlas-V P2/3A and FXX to the Atlas-V P3B.

Both FXX and Atlas-V P3B could be considered commercial alternatives to the SLS as they both fall into the same performance category (70-150t IMLEO and >25t through escape).  Both FX and A-V P2/3A fit in my 'General Purpose Launch Vehicle' concept that can be optimised for any HSF application from CLV to heavy CaLV (20-100t+ IMLEO).  I believe that it could be possible to have fully-reusable CCBs for both FX and A-V P2/3A; SpaceX have outlined one way to make the upper stage reusable too.

But, as tigerade rightly points out, neither are seriously in development.  They're just concepts right now and, with NASA and its Congressional supporters politically and ideologically committed to SLS, they are not likely to move into serious development any time soon.
« Last Edit: 11/11/2011 08:26 AM by Ben the Space Brit »
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline Kaputnik

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 2822
  • Liked: 466
  • Likes Given: 432
Re: FX, FXH, FXX, Merlin 2
« Reply #4 on: 11/11/2011 10:40 AM »
It's hard to say what SpaceX are up to, but it's an interesting thought experiment to try and guess.
From what we know of Grasshopper and from the RTLS reusable Falcon video, they seem to be planning on landing first stages using a single Merlin 1. Therefore any switch to a Merlin 2, with significantly higher thrust, would go completely against this plan.
My guess would be that Merlin 1 is the way ahead, with the only forseeable big change being the 'Raptor' development (whether that is an engine or a whole stage, and whether it is LH2 or CH4 fuelled). However I cannot see Raptor being significantly greater thrust than Merlin, since it is intended for upper stages anyway.

As an aside, SpaceX seem to think that they can land a 10t Dragon on Mars, using its standard 3.6m heatshield. Nobody really knows how they plan on meeting this claim, but if we suspend reality for a moment and give them the benefit of the doubt, that means that even with a standard Falcon or FH fairing, they could be landing over 20t in one go. Applying the same hammerhead configuration to a FX would yield more than 50t. So the need for monolithic BFRs like FXX goes away, and a modular approach makes more sense.
But, then again, I don't believe that they can actually land a Dragon on Mars so this is all moot.
Waiting for joy and raptor

Offline apace

  • Full Member
  • ****
  • Posts: 810
  • Liked: 3
  • Likes Given: 1
Re: FX, FXH, FXX, Merlin 2
« Reply #5 on: 11/11/2011 10:59 AM »
What happened to the trade studies from SpaceX and others for the HLV?

Offline jabe

  • Regular
  • Full Member
  • ****
  • Posts: 1119
  • Liked: 81
  • Likes Given: 4
Re: FX, FXH, FXX, Merlin 2
« Reply #6 on: 11/11/2011 11:01 AM »
my 2 cents..they proposed to give options other then SLS..
I'm guessing that Spacex is hoping for depots to developed.  Possibly gives a much larger launch rate for F9 and if FH is successful, combining depots with FH it will be fun to watch without the need to build a FXH..and cheaper..
jb

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #7 on: 11/11/2011 02:32 PM »
I think F9 and FH are technology & production test beds for larger systems.  They will use this system (that pays for itself along the way) to improve their methods until they have a solid characterization of the challenges associated with reusable hardware architectures.  This step-wise approach to their sub-scale demonstrator fleet might culminate in something that demonstrates staged combustion, different fuels, cross-feed, characterization of reentry forces, 1st stage avionics, landing software, re-entry materials and hardware, etc.  They might even eventually test M2 on an expendable version before scaling up to a rapidly reusable crossfeeding BFR that can deliver 50 tonne chunks of payload to the surface of Mars in a fully reusable architecture (implies methane engines will factor in at some point).  Remember, the BFR isn't trying to be competition for SLS.  It is for enabling large-scale Mars colonization at a price point of roughly the cost of an average home in California.  That's the big untapped market that requires reusable big falcon rockets.  The timeframe for developing the reusable Mars architecture will (I think) necessarily be after the IPO, and the optimal timing for an IPO will be some time after FH has had success and ISS resupply has commenced.  That timing might be at odds with mid-term prospects for the global economy.  Hopefully not, and time will tell. 

The other thing that might play in here, is the prospect of just the first stage of a rapidly reusable BFR being developed first, and instead of a second stage, a sub-orbital passenger vehicle could provide fast intercontinental mass-transit.  Which would ideally help with development costs for the Mars architecture. 

Without an IPO, an arch-angel investor could fund a lot of this (like Buffet/Gates/Saudi etc. or income from Tesla and Solar city might play in. 

This of course is all over a long timeframe. 
« Last Edit: 11/11/2011 02:46 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #8 on: 11/11/2011 02:35 PM »
And everyone will get a pony too.

Offline beb

  • Full Member
  • **
  • Posts: 264
  • Liked: 3
  • Likes Given: 7
Re: FX, FXH, FXX, Merlin 2
« Reply #9 on: 11/11/2011 02:59 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #10 on: 11/11/2011 03:07 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.
When was the last time you saw Musk talking about those? Musk wasn't the one really pushing FX, FXX, Merlin 2 etc. That's pretty much just SpaceX fanbois, plus a couple powerpoints from SpaceX. Musk has been pushing crewed Dragon, reusable Falcon 9, and Falcon Heavy. Ambitious enough.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #11 on: 11/11/2011 04:18 PM »
First you need an engine development. The only new engine development is the SC engine of unknown thrust and unknown prop type. With a 300-500klbf RP-1/LOX engine using the same 9:1 configuration a vehicle with the same length and 5-6m diameter which can be launched initially on the same pads as F9, a greater than double performance of the F9/FH or 30-35MT/105-125MT can be achieved at roughly the same prices or up to 50% more as that of the F9/FH. This would drop LEO $/kg rates by about 30% or to $3,500/$1,800 for single/heavy. This approach would use the experience gained from the F9 and FH and just scale up those designs including being able to use the RLV concepts being explored for the F9. A 1+mlbf engine as the next engine just does not seem to be in the near future plans.

Such a vehicle would replace the FH usage completely leaving the F9 as the small sat launcher then the X vehicle as the large GEO sat launcher and then the XH vehicle as a BEO or tanker launcher.

Offline Lurker Steve

  • Full Member
  • ****
  • Posts: 1420
  • Liked: 35
  • Likes Given: 9
Re: FX, FXH, FXX, Merlin 2
« Reply #12 on: 11/11/2011 04:56 PM »
First you need an engine development. The only new engine development is the SC engine of unknown thrust and unknown prop type. With a 300-500klbf RP-1/LOX engine using the same 9:1 configuration a vehicle with the same length and 5-6m diameter which can be launched initially on the same pads as F9, a greater than double performance of the F9/FH or 30-35MT/105-125MT can be achieved at roughly the same prices or up to 50% more as that of the F9/FH. This would drop LEO $/kg rates by about 30% or to $3,500/$1,800 for single/heavy. This approach would use the experience gained from the F9 and FH and just scale up those designs including being able to use the RLV concepts being explored for the F9. A 1+mlbf engine as the next engine just does not seem to be in the near future plans.

Such a vehicle would replace the FH usage completely leaving the F9 as the small sat launcher then the X vehicle as the large GEO sat launcher and then the XH vehicle as a BEO or tanker launcher.


How about they finish the development of the FH first ? Any idea on how much SpaceX has committed to the development of the FH, before you go and obsolete it before the first flight ?

How much was spent to develop the F1, only to halt production after 5 flights ?

Eventually, you need to launch production rockets enough times to pay for the development costs. NASA and/or the DOD will not be funding this development.

Offline Jason1701

  • Senior Member
  • *****
  • Posts: 2238
  • Liked: 70
  • Likes Given: 39
Re: FX, FXH, FXX, Merlin 2
« Reply #13 on: 11/11/2011 05:02 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.
When was the last time you saw Musk talking about those? Musk wasn't the one really pushing FX, FXX, Merlin 2 etc. That's pretty much just SpaceX fanbois, plus a couple powerpoints from SpaceX. Musk has been pushing crewed Dragon, reusable Falcon 9, and Falcon Heavy. Ambitious enough.

Musk actively downplayed the concepts. NSF posters are echoing him when they call FX/XX a single guy's idea that never went anywhere.

The trade studies went into the RACs, which (I think likely) had GR&As biased in favor of SD.

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #14 on: 11/11/2011 05:24 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.
Uh, didn't Musk actually come out and say specifically they weren't building an FX, FXH or FXX, and that he was annoyed they'd been publicly discussed at all?

So this isn't something Musk said that we should take with a grain of salt, this is something Musk specifically denied that fans and detractors alike have taken way too seriously.

Discuss the possibility of a Falcon X, Falcon X Heavy, Falcon XX, and Merlin 2 engine.
Musk has specifically said they aren't building any of these vehicles, and Merlin 2 as it's been discussed seems unlikely since Merlin 1D already exceeds the 2's claimed T/W ratio.

Whatever this new staged combustion engine is, that'll tell us more about SpaceX's future direction than previous disclosures. Specifically whether there's a first stage version, and how big it is.
« Last Edit: 11/11/2011 05:25 PM by ArbitraryConstant »

Offline manboy

  • Senior Member
  • *****
  • Posts: 2082
  • Texas, USA, Earth
  • Liked: 127
  • Likes Given: 539
Re: FX, FXH, FXX, Merlin 2
« Reply #15 on: 11/11/2011 05:30 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.
Uh, didn't Musk actually come out and say specifically they weren't building an FX, FXH or FXX, and that he was annoyed they'd been publicly discussed at all?

So this isn't something Musk said that we should take with a grain of salt, this is something Musk specifically denied that fans and detractors alike have taken way too seriously.
Than he probably shouldn't have said this

Quote
“we’re confident we could get a fully operational vehicle to the pad for $2.5 billion—and not only that, I will personally guarantee it,” Musk says. In addition, the final product would be a fully accounted cost per flight of $300 million, he asserts. “I’ll also guarantee that,” he adds, though he cautions this does not include a potential upper-stage upgrade.
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #16 on: 11/11/2011 05:33 PM »
I totally agree on finishing F9, FH, Dragon cargo and crew first.

Some good points have been said.

That said, I,m looking for any specs that might have been published on the FX,FXH,FXX.

Their posted specs on the Merlin 2 was to be able to launch on F9-FXX. I believe the Merlin 2 on the F9 was to test the M2 and for customers that only want a single engine on the first stage ( read some place DoD might have wanted a single engine only on the first stage ).

My point of this thread is for info and a possible future with a bigger Falcon rocket, not meant that we should have it now but maybe start R and D around 2015 to 2017.

Is there any info on a new SpaceX first stage engine other than the Merlin 1d?

Note:
Yes I am for fuel depots. The fuel is the biggest part of mass needed in LEO for BEO missions. I do hope that SpaceX gets it's FH and red Dragon ( Mars cargo version )
Red Dragon thread
http://forum.nasaspaceflight.com/index.php?topic=26269.0
« Last Edit: 11/13/2011 05:17 AM by RocketmanUS »

Offline Jason1701

  • Senior Member
  • *****
  • Posts: 2238
  • Liked: 70
  • Likes Given: 39
Re: FX, FXH, FXX, Merlin 2
« Reply #17 on: 11/11/2011 05:35 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.
Uh, didn't Musk actually come out and say specifically they weren't building an FX, FXH or FXX, and that he was annoyed they'd been publicly discussed at all?

So this isn't something Musk said that we should take with a grain of salt, this is something Musk specifically denied that fans and detractors alike have taken way too seriously.
Than he probably shouldn't have said this

Quote
“we’re confident we could get a fully operational vehicle to the pad for $2.5 billion—and not only that, I will personally guarantee it,” Musk says. In addition, the final product would be a fully accounted cost per flight of $300 million, he asserts. “I’ll also guarantee that,” he adds, though he cautions this does not include a potential upper-stage upgrade.

Musk saying that they can build something if given a fat government contract in no way means they are pursuing it in lieu of that.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #18 on: 11/11/2011 06:17 PM »
Here is the possible NET timelines for any new next gen vehicle:
1) 3-4 years development for new SL engine - ~ 2015
2) At least 18-24 months from final design engine testing start to first launch. ~ 2017-2018

It’s not something that would happen soon and this timeline also assumes fast development with full spending. With the several other projects already being started any next gen booster development will be a slow start making an in earnest start of development years away, sometime after first successful FH flight and after as well as the first 1st stage recovery. Any next gen booster would get funds for development after FH, RLV development and CCDev. There is not likely to be much funds left other than for the SC engine development. FH has been projected to cost $300+M for pad, development and first test flight or about $100M per year of spending. RLV spending during the next few years will probably be for the test flights of the Grasshopper at <$10M, and CCDev spending (SpaceX funded portion) in the order of $20-50M. The revenue for the projected 6 flights next year ~$600M  (1 COTS and 3CRS with 2 sat). That’s ~$120M in profit that can be applied to new development projects. In other words there are not sufficient funds next year or for the next few years until 2014 or later for any significant next gen booster development. Making 2020 the earliest you would see a next gen SpaceX booster fly, with FH having been operational for 7 years, unless they are contracted by NASA or DOD to develop such a booster prior to 2015 something which has a very low probability.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #19 on: 11/11/2011 06:57 PM »
I agree with that in general, but the timeline could be upset by a sudden infusion of fresh dollars (IPO).  But I suspect IPO will be along your predicted timeframe (2014ish).  Although Elon has mentioned 2012.  Well, if the contract arrangement for big gov't sats gets figured out, reuse looks more likely, FH goes up at least once (preferably crossfed), ISS resupply happens, LAS hardware seems to be working, and the plans for future markets and hardware are laid out, then sure.  IPO in 2012.  I'll be surprised if it happens by then.
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #20 on: 11/11/2011 07:16 PM »
With IPO money also comes a greater fiduciary responsibility. That means expensive projects with little reason and little chance of real payback ever will be actually less likely for SpaceX to take on than they are now. I can imagine IPO money being used for Merlin 2 MAYBE, but not the other vehicles beyond Falcon Heavy, since there's really no market need, not even close.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #21 on: 11/11/2011 07:25 PM »
With IPO money also comes a greater fiduciary responsibility. That means expensive projects with little reason and little chance of real payback ever will be actually less likely for SpaceX to take on than they are now. I can imagine IPO money being used for Merlin 2 MAYBE, but not the other vehicles beyond Falcon Heavy, since there's really no market need, not even close.

This is why I say 2020 would be the date for a SpaceX next gen booster giving sufficient time for FH’s capability and low price to have created its own 30+MT market.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #22 on: 11/11/2011 08:47 PM »
With IPO money also comes a greater fiduciary responsibility. That means expensive projects with little reason and little chance of real payback ever will be actually less likely for SpaceX to take on than they are now. I can imagine IPO money being used for Merlin 2 MAYBE, but not the other vehicles beyond Falcon Heavy, since there's really no market need, not even close.
Not exactly.  If Elon still holds a controlling interest (majority of voting shares), and firmly believes in his plan for SpaceX, then he can pretty much do what he wants.  He doesn't even need to disclose exactly how the money is being allocated beyond broad categories (all justifiable by "competition sensitive").  For example, if I invest in some random oil company where the management has built up and sold successfully 4 times by buying up acreage in strategic fairways, testing a well, then selling, then I sure don't want them telling all the shareholders exactly what they are going to do with the money before it is spent.  There is lots of precedent. 
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Eric Hedman

  • Full Member
  • ****
  • Posts: 818
  • Liked: 214
  • Likes Given: 205
Re: FX, FXH, FXX, Merlin 2
« Reply #23 on: 11/11/2011 09:18 PM »
And everyone will get a pony too.
Jim,

What color pony can I get?  ;D ;D 8) 8)

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #24 on: 11/11/2011 11:00 PM »
After reading article
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awst/2010/11/29/AW_11_29_2010_p28-271784.xml

That is if the FXX were ever built, could a clean 39A or 39B pad handle the FXX on it's own MLP? (I assume that RP-1 fuel tanks would be there)

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #25 on: 11/12/2011 03:54 AM »
After reading article
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awst/2010/11/29/AW_11_29_2010_p28-271784.xml

That is if the FXX were ever built, could a clean 39A or 39B pad handle the FXX on it's own MLP? (I assume that RP-1 fuel tanks would be there)

Of course.  Imaginary launch vehicles work on imaginary pads.

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #26 on: 11/12/2011 01:00 PM »
After reading article
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/awst/2010/11/29/AW_11_29_2010_p28-271784.xml

That is if the FXX were ever built, could a clean 39A or 39B pad handle the FXX on it's own MLP? (I assume that RP-1 fuel tanks would be there)

Of course.  Imaginary launch vehicles work on imaginary pads.
Serious answer please.
Based on expected size of FXX ( diameter ) and fueled and unfueled could the pad handle it? The flame trench would it work with such a vehicle?

Edit: using this example
at Launch complex 39 (LC-39)

With a launch vehicle with a 10 meter diameter
8.5Mlb max weight at lift off
10.2Mlb max thrust at lift off ( RP-1/LOX engines )

Can the pad handle the weight?
Can the flame trench handle that much exhaust?
« Last Edit: 11/13/2011 05:24 AM by RocketmanUS »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #27 on: 11/12/2011 01:18 PM »

Serious answer please.
Based on expected size of FXX ( diameter ) and fueled and unfueled could the pad handle it? The flame trench would it work with such a vehicle?

These vehicles are only notional and only exist as ideas not true projects.
They aren't defined enough to make an assessment, hence my original answer is applicable.

that is why this thread is meaningless.
« Last Edit: 11/12/2011 01:25 PM by Jim »

Offline Tcommon

  • Full Member
  • *
  • Posts: 146
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #28 on: 11/12/2011 03:33 PM »
This is becoming a farcical, predicting all these wild SpaceX projects when the company is still a long way off from supporting themselves by launching payload. SpaceX has done some remarkable things, but they haven't shown they can launch time and time again reliably. Just a couple of failures could imperil the young company.

And everyone will get a pony too.
:D
« Last Edit: 11/14/2011 05:33 AM by Tcommon »

Offline apace

  • Full Member
  • ****
  • Posts: 810
  • Liked: 3
  • Likes Given: 1
Re: FX, FXH, FXX, Merlin 2
« Reply #29 on: 11/12/2011 03:57 PM »
2012 will be the year SpaceX has to show that they can fire more than 1 rocket a year...

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #30 on: 11/12/2011 04:18 PM »
Basically ask this thread’s question again after FH flies

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #31 on: 11/12/2011 06:53 PM »
Than he probably shouldn't have said this

Quote
“we’re confident we could get a fully operational vehicle to the pad for $2.5 billion—and not only that, I will personally guarantee it,” Musk says. In addition, the final product would be a fully accounted cost per flight of $300 million, he asserts. “I’ll also guarantee that,” he adds, though he cautions this does not include a potential upper-stage upgrade.
That quote relates to their NASA heavy lifter concept. It no longer obtains since they weren't selected. At no point did they say they were going to build anything like that out of pocket.

There's no need to take promises with a grain of salt for stuff that was never promised.

The Merlin 2 as I understand it was to have two settings, 1.2Mlb or 1.7Mlb at launch. The 1.2Mlb was for FX,FXH and the 1.7Mlb setting for the FXX. So the Merlin 2 would have plenty of thrust for a reusable Falcon.
I don't think it would have a low enough throttle setting for landing.

I don't think the Merlin 2 concept as has been discussed by SpaceX is ever going to happen. The Merlin 1D already exceeds its performance in T/W, and probably ISP.

If you want insight into their aspirations, wait for more details on the staged combustion engine they've been talking about. What fuel it uses, how big it is, and whether there's a first stage version will greatly shape what vehicles it would be useful in.

Eg:

-Something with thrust of say 2-5x compared to Merlin, with a first stage version, implies a larger vehicle that that they don't want to rule out flyback reusability for.

-Something with thrust similar to Merlin with no initial first stage version implies an updated US engine for F9 for improved performance particularly to GTO.

-Hydrogen implies US, methane or kero could be used for both.

etc...

Basically the basic stats on this engine will be worth more in nailing down SpaceX's future plans than any amount of speculation on FX, FXH, FXX, etc, which we're fairly certain won't be built at all.
« Last Edit: 11/12/2011 07:00 PM by ArbitraryConstant »

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #32 on: 11/12/2011 08:02 PM »
If you want insight into their aspirations, wait for more details on the staged combustion engine they've been talking about.
Well said. 

This is becoming a farcical, predicting all these wild SpaceX projects, when the company is still a long way off from ...
True.  But it can be interesting to imagine how the challenge might be met.  You know Elon's end goal, and you know (roughly) where SpaceX is today.  How to best get from B to Z? 



2012 will be the year SpaceX has to show that they can fire more than 1 rocket a year...
  I thought that about 2011 as well (in fact there are still five 2011 flights on the manifest).   
« Last Edit: 11/12/2011 08:03 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #33 on: 11/12/2011 08:30 PM »
2012 will be the year SpaceX has to show that they can fire more than 1 rocket a year...
 
I thought that about 2011 as well (in fact there are still five 2011 flights on the manifest).   
Actually ORBCOM does not have a dedicated 2011 F9 flight and C2 and C3 have been combined so the remaining 2011 F9 flights is actually 3. When added to the flights likely to occur in 2012 list as 2012 which is 2 CRS flights (CRS2 & CRS3) a max number of launches for 2012 is 5. They are able to produce the hardware to support this rate, actually they have several F9’s ready to go already so an increase in production rate is not required. Now if they can do the pad processing and NASA and range interactions smoothly enough to not slip too many launch opertunities.
« Last Edit: 11/12/2011 08:31 PM by oldAtlas_Eguy »

Offline majormajor42

  • Full Member
  • ****
  • Posts: 525
  • Liked: 43
  • Likes Given: 221
Re: FX, FXH, FXX, Merlin 2
« Reply #34 on: 11/13/2011 02:41 AM »
Silly thread. Most of the FX, FXH, FXX, M2 speculation talk was before Elon announced their plans for a Crossfed FH, M1d, and the Grasshopper project, leading to full reusability. So I don't know why we would go back to discussing these old ideas, especially when these new technologies, when deployed, will then shape what any new bigger rocket will look like (if it is even necessary). So I think that is enough for now considering the current flight rate (or lack of). I don't expect Elon to make any more new technology announcements till after we get another flight or two, with the exception of this SC engine.

The cool thing about what they are doing right now is that much of it is being developed within their current manifest. I'd like to see how far they can go sticking to that philosophy.

« Last Edit: 11/13/2011 04:49 PM by majormajor42 »
...water is life and it is out there, where we intend to go. I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man or machine on a body such as the Moon and harvest a cup of water for a human to drink or process into fuel for their craft.

Offline grr

  • Full Member
  • *
  • Posts: 162
  • Highlands Ranch, Colorado
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #35 on: 11/14/2011 10:31 PM »
It's important to remember than Elon Musk is a dot-com billionaire. He comes from an industry where vaporware is not only endemic but most required as a business plan. So all this talk about future rockets FX, FXH and FXX is just that: talk.

As for the Merlin2. Right now the DOD is interested in a 500K rocket engine. I think that's what we're going to see a 500K (possibly methane) engine.

But people should take the things Musk says with a grain of salt.

First off, Musk was never a billionaire. He was a millionaire.

Secondly, while there has been plenty of vaporware in silicon valley, I would have to say that aviation/astronautics are no stranger to that. How many ideas are proposed around here, let alone at L-Mart, ULA, Boeing, ATK, etc that were pure vaporware?
Far far more than I have ever seen out of Silicon valley. 
In general ideas that get talked about in Silicon valley are already being worked on (disregard companies like MS).
Finally, what examples do you have from Musks in which he spoke about something, but it was not being worked on?
Paypal? IIRC, announcements out of them were items being worked on.
Then you have Tesla. What items were there that was pure vaporware?
None.
Likewise, I recall when musk first talked about doing space, and laid out the plan for doing F1 and F5. Then it was changed from F1 and F9. Yet, how many ppl screamed that he could not do it? Loads. they all said that it was vaporware and that the would never be able to put a small rocket in space, let alone a 9 engine one.
And yet, here he is.

Likewise, he stated that he would do the FH. Again, many are running around screaming that it is vaporware. However, as has been pointed out by himself and others, it was designed in from the gitgo.

I would say that if he brought this up, that it is very likely that he has ppl actively working on this.  Probably only a couple, but I would be amazed if he does not have any. Heck, from his POV, he will want to take away business from SLS. The only way to do that, is be well ahead of the launch curve.

Offline grr

  • Full Member
  • *
  • Posts: 162
  • Highlands Ranch, Colorado
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #36 on: 11/14/2011 10:46 PM »
First you need an engine development. The only new engine development is the SC engine of unknown thrust and unknown prop type. With a 300-500klbf RP-1/LOX engine using the same 9:1 configuration a vehicle with the same length and 5-6m diameter which can be launched initially on the same pads as F9, a greater than double performance of the F9/FH or 30-35MT/105-125MT can be achieved at roughly the same prices or up to 50% more as that of the F9/FH. This would drop LEO $/kg rates by about 30% or to $3,500/$1,800 for single/heavy. This approach would use the experience gained from the F9 and FH and just scale up those designs including being able to use the RLV concepts being explored for the F9. A 1+mlbf engine as the next engine just does not seem to be in the near future plans.

Such a vehicle would replace the FH usage completely leaving the F9 as the small sat launcher then the X vehicle as the large GEO sat launcher and then the XH vehicle as a BEO or tanker launcher.


How about they finish the development of the FH first ? Any idea on how much SpaceX has committed to the development of the FH, before you go and obsolete it before the first flight ?

How much was spent to develop the F1, only to halt production after 5 flights ?

Eventually, you need to launch production rockets enough times to pay for the development costs. NASA and/or the DOD will not be funding this development.


FH?
I think that they have to get F9 in active production.
Doing what they have done so far is more than admirable.
However, in many ways, they are heading for some of the most difficult work yet: Making it repeatable.

I have been a strong private space supporter, however, when I heard one of them speak about their software being bug-free is, well, that has the making of another  bill gates type idiot.

That shows that at least one top person there does not have a good grasp of QA issues.

So, until they get F9 into active production, I would not worry too much about FH.

And until F9 has a record behind it, one mishap could destroy that company.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #37 on: 11/14/2011 10:59 PM »
F9 is already in active production... it's launch operations that is lagging.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline grr

  • Full Member
  • *
  • Posts: 162
  • Highlands Ranch, Colorado
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #38 on: 11/15/2011 10:45 AM »
F9 is already in active production... it's launch operations that is lagging.


Is it active production?
Or is it still in development with patches and regular modifications occurring between each launch?

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6746
  • Spokane, WA
  • Liked: 551
  • Likes Given: 339
Re: FX, FXH, FXX, Merlin 2
« Reply #39 on: 11/15/2011 04:44 PM »
I woulod say that FX can be considered a competitor to the equally paper-only Atlas-V P2/3A and FXX to the Atlas-V P3B.

Both FXX and Atlas-V P3B could be considered commercial alternatives to the SLS as they both fall into the same performance category (70-150t IMLEO and >25t through escape).  Both FX and A-V P2/3A fit in my 'General Purpose Launch Vehicle' concept that can be optimised for any HSF application from CLV to heavy CaLV (20-100t+ IMLEO).  I believe that it could be possible to have fully-reusable CCBs for both FX and A-V P2/3A; SpaceX have outlined one way to make the upper stage reusable too.

But, as tigerade rightly points out, neither are seriously in development.  They're just concepts right now and, with NASA and its Congressional supporters politically and ideologically committed to SLS, they are not likely to move into serious development any time soon.

Here's a scenario I could see for FX.  Since it is just a Powerpoint rocket at this point, it really could be made in a 5 or 5.5m diameter, rather than 6, with a pair of Merlin 2's, instead of 3.  With performance downscaled accordingly.  The reason that would be useful, is if SpaceX wants to bid on the LRB's for SLS, it sounds like 5-5.5m is the widest the LRB's could be and still fit into the flame trench.  AVP2 would be 5m diameter, so they'd be ok.  FX would basically be a competator to AVP2 anyway, just a little wider and with a little more capacity. 
Looks like the SLS Block II with LRB baseball cards have 3 X 1m lb engines, and 5m diameter LRB's (but I'd heard the trenches could actually accomodate up to 5.5m). 
So a 5.5m FX LRB core, with 2 X 1.5Mlb Merlin 2's, or perhaps 3X 1.0Mlb derated/throttled Merlin 2's, (don't know why NASA wouldn't allow 2 engines instead of 3 if it could do the 3Mlb thrust), designed from the beginning to be an SLS booster, with all the appropriate connection points and structure built into it, could basically be a clean sheet booster, but also SpaceX's new MLV.  3 could be strapped together for an FXH, although it'd have a little less performance than the 6m core. 
It'd be optimixed to be SLS's LRB, and then it would be a stand alone LV with that performance.

The advantage to SpaceX if they could land that contract is significant, because they could lock in a big contract, and pay for the development of their MLV.  The FX and M2 engine would both be US-built, so no issues there.  And who knows, maybe NASA might consider using FX as a single stick stand alone launcher for Orion to LEO, rather than SLS, and then they could go back to a 1.5 launch system for a lunar mission.  Or if they want to send Orion to the ISS for some reason. 
And since M2 is supposed to be up to 1.7Mlb, then two if them could actually do 3.4Mlb, improving SLS's performance some if you have a real heavy load.   You have some wiggle room there. 

Without something like an SLS LRB booster bid and award, I doubt we'd see FX any time soon, if ever.  They'd just stick with F9 and FH, as that would serve any potential commercial/DoD market for the forseeable future.

Conversely, that might be the only way we'd see an 5m AVP2 core any time soon.   If ULA were to be able to bid it for SLS LRB booster and win.  With perhaps 3 X US-Bilt RD180's, tweaked up it get 1Mlb each.
« Last Edit: 11/15/2011 04:55 PM by Lobo »

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6746
  • Spokane, WA
  • Liked: 551
  • Likes Given: 339
Re: FX, FXH, FXX, Merlin 2
« Reply #40 on: 11/15/2011 04:49 PM »
And everyone will get a pony too.

@Wheeeee!  A Pony!

Offline chrisking0997

  • Full Member
  • **
  • Posts: 279
  • NASA Langley
  • Liked: 84
  • Likes Given: 210
Re: FX, FXH, FXX, Merlin 2
« Reply #41 on: 11/15/2011 05:13 PM »
And until F9 has a record behind it, one mishap could destroy that company.

which is a disappointing point of view.  If you wanna make an omlet, ya gotta break some eggs. 

I really havent heard anyone point out fundamental flaws with F9, so I fail to see how one failure could destroy SpaceX.  That would imply spaceflight is so easy a caveman could do it, which runs against what so many here espouse.
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

Offline RobLynn

  • Full Member
  • **
  • Posts: 245
  • Per Molestias Eruditio
  • London
  • Liked: 27
  • Likes Given: 25
Re: FX, FXH, FXX, Merlin 2
« Reply #42 on: 11/17/2011 11:16 AM »
I doubt that the FX, FXH, FXX, Merlin 2 make sense any more.

Learning curves for mass production of Merlin 1D mean that SpaceX will reap huge engine cost and reliability gains over time.  But on top of that given their goal of rocket powered re-entry and landing they need to have a relatively low thrust engine on the recovered stage, something not achievable with a throttled Merlin 2.

Also with propellant cross feed they have growth capacity from 3 to 5, 7 or even 9 parallel stages by simply beefing up center stage structure.  That gives LEO capacity of up to 150 tonnes (higher than FXX), while lower initial staging velocities for 5-9 stage variants makes recovery of at least some of those stages even easier.
I'm a "glass is twice as big as it needs to be" kinda guy

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #43 on: 11/17/2011 12:05 PM »

Also with propellant cross feed they have growth capacity from 3 to 5, 7 or even 9 parallel stages by simply beefing up center stage structure.  That gives LEO capacity of up to 150 tonnes (higher than FXX), while lower initial staging velocities for 5-9 stage variants makes recovery of at least some of those stages even easier.

That make less to no sense.  The pad infrastructure and operations would be a unwieldy kludge.

 FX, FXH, FXX, Merlin 2 make way more sense..
« Last Edit: 11/17/2011 12:06 PM by Jim »

Offline spectre9

  • Senior Member
  • *****
  • Posts: 2403
  • Australia
  • Liked: 36
  • Likes Given: 67
Re: FX, FXH, FXX, Merlin 2
« Reply #44 on: 11/17/2011 01:01 PM »
If SpaceX can make Merlin 2 they can put everybody out of business.

If they can sustain their cost cutting either the competition gets involved in the battle or they will die.

Aerojet and ATK will be no chance at the booster comp and they wont be giving away any Merlin 2s for others to beat them.

Where do they get the money?

They crush the market share of ULA. Cut costs or lose business, that's just the reality of it.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #45 on: 11/17/2011 02:11 PM »
If SpaceX can make Merlin 2 they can put everybody out of business.
Not so.  Only reusability could do that.  Even then, everyone would start trying to design reusable systems.  Plus, a lot of space companies get a lot of their revenue from inherently expendable purposes (weapons).  It sounds like Merlin 2 is on the back-burner anyways (usurped by staged combustion).
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Ben the Space Brit

  • Senior Member
  • *****
  • Posts: 7109
  • A spaceflight fan
  • London, UK
  • Liked: 634
  • Likes Given: 743
Re: FX, FXH, FXX, Merlin 2
« Reply #46 on: 11/17/2011 02:28 PM »
If SpaceX can make Merlin 2 they can put everybody out of business.

Not so.  Only reusability could do that.

FWIW, I believe propulsive reusability is incompatible with M2's enormous thrust (1.7Mlbf target, IIRC).  So, the fact that SpaceX is going down the propulsive reusability route suggests that they're going to stick with M1d for now.

Should large commercial payloads that need the 'grunt' of an HLV emerge, it may be commercially viable to develop a EHLV.  As matters stand, though, I think that the Falcon-9R is their current 'fully evolved' objective.  Falcon-X and Atlas-V Phase 2/3A, even with recoverable common core boosters, really only make sense as a product to sell to NASA as a one-size-fits-all HSF-support launcher.
"Oops! I left the silly thing in reverse!" - Duck Dodgers

~*~*~*~

The Space Shuttle Program - 1981-2011

The time for words has passed; The time has come to put up or shut up!
DON'T PROPAGANDISE, FLY!!!

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #47 on: 11/17/2011 02:30 PM »
If SpaceX can make Merlin 2 they can put everybody out of business.

Not so.  Only reusability could do that.

FWIW, I believe propulsive reusability is incompatible with M2's enormous thrust (1.7Mlbf target, IIRC). ...
Why the heck would you think that?

I mean don't get me wrong, I don't think SpaceX is going down the Merlin 2 road, there's just no reason large thrust would mean no reusability.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8639
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1111
  • Likes Given: 241
Re: FX, FXH, FXX, Merlin 2
« Reply #48 on: 11/17/2011 02:34 PM »
Why the heck would you think that?

I mean don't get me wrong, I don't think SpaceX is going down the Merlin 2 road, there's just no reason large thrust would mean no reusability.

The M2 has to much thrust for boost back. You would need a secondary (more weight) propulsion system to do the landing at a lower thrust setting.
If you're happy and you know it,
It's your med's!

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #49 on: 11/17/2011 04:35 PM »
Each core generation in the presentation (FX, FXX) represents an increase in thrust of a factor 2-3. So a new engine with ~300klbf would fit well with this generational step and still reuse tech learned on the F9. In fact almost all of the electronics and software of the F9 could be reused with little change (the stability and moment algorithms would be different though but that is only a small part of the overall software pakage) if the number of engines on the first stage remained at a count of 9.

Offline RobLynn

  • Full Member
  • **
  • Posts: 245
  • Per Molestias Eruditio
  • London
  • Liked: 27
  • Likes Given: 25
Re: FX, FXH, FXX, Merlin 2
« Reply #50 on: 11/17/2011 04:41 PM »

Also with propellant cross feed they have growth capacity from 3 to 5, 7 or even 9 parallel stages by simply beefing up center stage structure.  That gives LEO capacity of up to 150 tonnes (higher than FXX), while lower initial staging velocities for 5-9 stage variants makes recovery of at least some of those stages even easier.

That make less to no sense.  The pad infrastructure and operations would be a unwieldy kludge.

Why would do think that?  You have effectively a single linked fuel a nd oxidiser system through all of the cross feeds (Assuming each engine has shut off valves in case of failure), load bearing connections between stages that can take axial loads of up to 400 tonnes, and so substantial lateral loads as well.  It would not be hard to make a cradle to allow horizontal transport and errection even for 9 linked stages if there was demand.

I also can't see how supporting the fueled stack weight before liftoff would present any difficulties and while there are other electrical systems and fluids that need to be topped off, most of those will be accessible from the bottom of the stack.
I'm a "glass is twice as big as it needs to be" kinda guy

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #51 on: 11/17/2011 05:09 PM »

Also with propellant cross feed they have growth capacity from 3 to 5, 7 or even 9 parallel stages by simply beefing up center stage structure.  That gives LEO capacity of up to 150 tonnes (higher than FXX), while lower initial staging velocities for 5-9 stage variants makes recovery of at least some of those stages even easier.

That make less to no sense.  The pad infrastructure and operations would be a unwieldy kludge.

Why would do think that?  You have effectively a single linked fuel a nd oxidiser system through all of the cross feeds (Assuming each engine has shut off valves in case of failure), load bearing connections between stages that can take axial loads of up to 400 tonnes, and so substantial lateral loads as well.  It would not be hard to make a cradle to allow horizontal transport and errection even for 9 linked stages if there was demand.

I also can't see how supporting the fueled stack weight before liftoff would present any difficulties and while there are other electrical systems and fluids that need to be topped off, most of those will be accessible from the bottom of the stack.

Where do I start.

9 stages in a row?  It won't know where to fly

81 engines on a first stage is ido itic.

The hangar and launch mount?

And if you meant parallel staged and a circular vehicle, see #2 and forget horizontal processing.
« Last Edit: 11/17/2011 05:11 PM by Jim »

Offline RobLynn

  • Full Member
  • **
  • Posts: 245
  • Per Molestias Eruditio
  • London
  • Liked: 27
  • Likes Given: 25
Re: FX, FXH, FXX, Merlin 2
« Reply #52 on: 11/17/2011 06:53 PM »
9 stages in a row?  It won't know where to fly

81 engines on a first stage is ido itic.

The hangar and launch mount?

And if you meant parallel staged and a circular vehicle, see #2 and forget horizontal processing.

Ah I think I see what you mean, I figure 9 laid out in a grid to keep load paths short - 5 = X, 7 = might be H or O.  9 really no worse for control than 3 in terms of moments created by individual engines.

As for 81 engines, so what?  They're supposedly designed to fail safe without damaging other engines.  That being the case and given their low manufacturing price (1-2million at a guess) it seems like a pretty cheap way to get the heavy lift job done compared to an expensive new billion dollar Merlin 2 that is almost certainly going to cost more per kN of thrust forever given larger tooling, lower production rates and costs of new development.  The Merlin 1D also allows cost reducing reusability through controlled re-entry and landing using one of the 9 engines in the core - can't do that with the Merlin 2 approach.

Horizontal integration is harder, but still pretty straight forward given a few simple platforms to walk around on.

I guess if you don't like it we'll just have to agree to disagree and see how spaceX's plans evolve over next 5 years.
I'm a "glass is twice as big as it needs to be" kinda guy

Offline dunderwood

  • Full Member
  • *
  • Posts: 156
  • Liked: 4
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #53 on: 11/17/2011 07:07 PM »
Quote
It would not be hard to make a cradle to allow horizontal transport and errection even for 9 linked stages if there was demand.

I would hate to see what you think is a hard project.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #54 on: 11/17/2011 09:10 PM »

1.  They're supposedly designed to fail safe without damaging other engines. 

2.  Horizontal integration is harder, but still pretty straight forward given a few simple platforms to walk around on.

3.  I guess if you don't like it we'll just have to agree to disagree and see how spaceX's plans evolve over next 5 years.


1.  Not proven

2. Not for that many cores. 

3.  No need to wait.  They are not going to use more than 3 cores.  Your opinion is wrong.

Offline starsilk

  • Full Member
  • ****
  • Posts: 644
  • Denver
  • Liked: 226
  • Likes Given: 46
Re: FX, FXH, FXX, Merlin 2
« Reply #55 on: 11/17/2011 10:21 PM »
Why the heck would you think that?

I mean don't get me wrong, I don't think SpaceX is going down the Merlin 2 road, there's just no reason large thrust would mean no reusability.

The M2 has to much thrust for boost back. You would need a secondary (more weight) propulsion system to do the landing at a lower thrust setting.

that depends on the size of the booster.. a truly huge rocket (I believe SpaceX call them BFRs  ;)) using nine M2s would have the same thrust/weight ratio as the current F9, presumably.

Online butters

  • Full Member
  • ****
  • Posts: 1724
  • Liked: 361
  • Likes Given: 112
Re: FX, FXH, FXX, Merlin 2
« Reply #56 on: 11/18/2011 01:06 AM »
They are not going to use more than 3 cores.

Probably, but 5 might not be inconceivable, integrated in an X configuration like Soyuz with the strongback supporting the central stage only. It's unlikely, though. If SpaceX had any inclination to support a five-core X configuration at some point, then one would expect them to account for that during their refurbishment of SLC-4E.

I think that SpaceX likes the economics of cranking out lots of M1 engines on a high-rate production line. I'm not sure we'll see a Falcon 16 or anything like that, but I doubt we'll see less than 4 engines on any future first stage from SpaceX.

I also suspect that SpaceX is eyeing NOFBX. Probably for Dragon, but possibly also for future LV stages.

Offline spectre9

  • Senior Member
  • *****
  • Posts: 2403
  • Australia
  • Liked: 36
  • Likes Given: 67
Re: FX, FXH, FXX, Merlin 2
« Reply #57 on: 11/18/2011 01:30 AM »
If Space X want a BFR they're not going to do it with 50-100 Merlin 1D engines.

I just don't think they will anyway  :-\

Offline ChefPat

  • Full Member
  • ****
  • Posts: 1051
  • Earth, for now
  • Liked: 123
  • Likes Given: 1020
Re: FX, FXH, FXX, Merlin 2
« Reply #58 on: 11/18/2011 11:41 AM »
It may be possible to cluster 5, 7 or 9 F9 bodies for a HLV. Or maybe not. The heavier lift of a possible FX or FXX is not just the lift, but the vastly larger faring size as well.
Playing Politics with Commercial Crew is Un-American!!!

Offline Lars_J

  • Senior Member
  • *****
  • Posts: 6161
  • California
  • Liked: 665
  • Likes Given: 195
Re: FX, FXH, FXX, Merlin 2
« Reply #59 on: 11/18/2011 05:37 PM »
Practically it becomes very difficult to cluster more than 3 cores for them, though. Look at an F9 roll-out video, and look at how the 1st stage is held down. Quite an elaborate mechanism on all four sides.

For FH, they'll have to modify this hold-down arrangement such that the cores are only held on two sides.

But to do this for 5, 7, or 9 cores quickly becomes very difficult. Theoretically possible, sure, but certainly not practical.


Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #60 on: 11/18/2011 06:16 PM »
If the SLS goes bust, maybe SpaceX can purchase the 8.4m tooling for scrap, including the barge to transport, and build a 52 M1D engined HLV using a LOX/LH2 US which could do about 95MT in the single stick configuration with a 10m faring or 380MT in the heavy configuration. Talking about BFRs!! Although managing 150+ number of engines maybe a little too much. 52 M1D’s is 7.28mlbf.

Offline grr

  • Full Member
  • *
  • Posts: 162
  • Highlands Ranch, Colorado
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #61 on: 11/18/2011 07:29 PM »
They are not going to use more than 3 cores.

Probably, but 5 might not be inconceivable, integrated in an X configuration like Soyuz with the strongback supporting the central stage only. It's unlikely, though. If SpaceX had any inclination to support a five-core X configuration at some point, then one would expect them to account for that during their refurbishment of SLC-4E.

I think that SpaceX likes the economics of cranking out lots of M1 engines on a high-rate production line. I'm not sure we'll see a Falcon 16 or anything like that, but I doubt we'll see less than 4 engines on any future first stage from SpaceX.

I also suspect that SpaceX is eyeing NOFBX. Probably for Dragon, but possibly also for future LV stages.

Every part of me (as a software engineer) says that a 5, 7 or 9 core system, using 9 engines per core will never happen. But then I remember Seymour cray saying that massively parallel computers will never happen nor win the day.

Offline Zed_Noir

  • Senior Member
  • *****
  • Posts: 2374
  • Canada
  • Liked: 327
  • Likes Given: 536
Re: FX, FXH, FXX, Merlin 2
« Reply #62 on: 11/18/2011 07:49 PM »
If the SLS goes bust, maybe SpaceX can purchase the 8.4m tooling for scrap, including the barge to transport, and build a 52 M1D engined HLV using a LOX/LH2 US which could do about 95MT in the single stick configuration with a 10m faring or 380MT in the heavy configuration. Talking about BFRs!! Although managing 150+ number of engines maybe a little too much. 52 M1D’s is 7.28mlbf.

How do you come up with 52 Merlin and how they would be configured?

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #63 on: 11/18/2011 08:09 PM »
I think if there were a market worth pursuing SpaceX could do better than a 9-core Falcon 9.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3341
  • Florida
  • Liked: 1741
  • Likes Given: 199
Re: FX, FXH, FXX, Merlin 2
« Reply #64 on: 11/18/2011 08:25 PM »
If the SLS goes bust, maybe SpaceX can purchase the 8.4m tooling for scrap, including the barge to transport, and build a 52 M1D engined HLV using a LOX/LH2 US which could do about 95MT in the single stick configuration with a 10m faring or 380MT in the heavy configuration. Talking about BFRs!! Although managing 150+ number of engines maybe a little too much. 52 M1D’s is 7.28mlbf.

How do you come up with 52 Merlin and how they would be configured?


The number 52 is the number of engines you could squeeze in based on the area of a 8.4m diameter core vs a 3.6m diameter core. Its a 6x6 central block of engines with four additional on each side for a total of 52 engines.

Online butters

  • Full Member
  • ****
  • Posts: 1724
  • Liked: 361
  • Likes Given: 112
Re: FX, FXH, FXX, Merlin 2
« Reply #65 on: 11/18/2011 10:30 PM »
If they sized the engine around 650-700klbf, then they could do two engines on the 3.6m Falcon and 16 engines on a hypothetical 10m BFR delivering over 10Mlbf of thrust in a single-core configuration. I see no reason to make the engine any bigger than that.

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #66 on: 11/19/2011 12:52 AM »
I doubt that the FX, FXH, FXX, Merlin 2 make sense any more.

Learning curves for mass production of Merlin 1D mean that SpaceX will reap huge engine cost and reliability gains over time.  But on top of that given their goal of rocket powered re-entry and landing they need to have a relatively low thrust engine on the recovered stage, something not achievable with a throttled Merlin 2.

Also with propellant cross feed they have growth capacity from 3 to 5, 7 or even 9 parallel stages by simply beefing up center stage structure.  That gives LEO capacity of up to 150 tonnes (higher than FXX), while lower initial staging velocities for 5-9 stage variants makes recovery of at least some of those stages even easier.

Thread on this is ( should find some good answers there )
Falcon Super Heavy
http://forum.nasaspaceflight.com/index.php?topic=21867.0

As far as reusability ( FX or FXH ), a means to recover would need to be found when using a Merlin 2 or similar sized engine. Possibly add some Merlin 1's to offset the added mass needed for recovery and use them for the lower thrust that might be needed for powered landing. For the possible Falcon reuse we will have to see what SpaceX comes up with their Grasshopper.

Grasshopper RLV
http://forum.nasaspaceflight.com/index.php?topic=26884.0

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #67 on: 11/19/2011 04:47 AM »
If they sized the engine around 650-700klbf, then they could do two engines on the 3.6m Falcon and 16 engines on a hypothetical 10m BFR delivering over 10Mlbf of thrust in a single-core configuration. I see no reason to make the engine any bigger than that.
Yeah, the intermediate sizes make a lot of sense, particularly now that SpaceX is better at throttling. I don't think you even need to assume an engine size compatible with a 10 Mlbf monster. If there were demand for something that size and SpaceX was positioned to provide the launcher, designing the engine would be a very nice problem to have.

The intermediate size works great over a range of scenarios:

-F9/FH upgrades.
-A new core that works for GTO launches even if new payloads aren't available.
-Can probably be sold to other providers even if SpaceX's own vehicles aren't successful.
-Very optimistic scenarios including large flyback boosters in the EELV to FH to low end SLS range.

While I don't think SpaceX will bet the farm on reusability, I don't think they're willing to rule it out for future vehicles at this point.

If one day there's enough demand for SpaceX to build anything remotely that size and they need a bigger engine... that's a very nice problem for them to have.

Offline Hauerg

  • Full Member
  • ****
  • Posts: 719
  • Berndorf, Austria
  • Liked: 334
  • Likes Given: 1111
Re: FX, FXH, FXX, Merlin 2
« Reply #68 on: 11/19/2011 05:54 AM »
I think if there were a market worth pursuing SpaceX could do better than a 9-core Falcon 9.
But when the "market" is something like 1 flight every 2 years ......

Offline MikeAtkinson

  • Full Member
  • ****
  • Posts: 1716
  • Bracknell, England
  • Liked: 489
  • Likes Given: 61
Re: FX, FXH, FXX, Merlin 2
« Reply #69 on: 11/19/2011 07:11 AM »
If we take the published performance of F9 and FH with Merlin 1D and make guesses about loss of performance with reusuable 1st and second stages, we get something like the table below (SpaceX quote lower prices for 80% of maximum payload, which is what I'm taking as LEO typical).

launcherLEO maxLEO typicalGT0 max
Falcon 9 (Merlin 1D)16000128007200
Falcon 9 (Merlin 1D) reusable 1st stage13000104005850
Falcon 9 (Merlin 1D) reusable 1st & second stages1000074002800
Falcon Heavy (Merlin 1D)530004500016000
Falcon Heavy (Merlin 1D) reusable 1st stage370003000011200
Falcon Heavy (Merlin 1D) reusable 1st & second stages32000250006200

Note the massive drop in GTO performance caused by the reusable second stage.

For full reusuability there is a big payload gap for LEO and the largest GEO satellites are too big for a FH with both 1st and 2nd stages reusable.

It looks like there is a gap of for a reusuable single core launcher of 20-25 tonnes payload to LEO which would have about 60-75 tonnes in a 3 core configuration and up to 130 tonnes in a non-reusable version.


Another thing to consider is that Merlin 1D is unlikely to be the last in the Merlin 1 line. I think they are likely to be able to squeeze another 20% thrust and another 1-2 s of Isp out of it by the end of the decade.

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #70 on: 11/19/2011 02:28 PM »
I think if there were a market worth pursuing SpaceX could do better than a 9-core Falcon 9.
But when the "market" is something like 1 flight every 2 years ......
It may not be worth servicing at all.

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #71 on: 11/21/2011 08:50 PM »
I think if there were a market worth pursuing SpaceX could do better than a 9-core Falcon 9.
But when the "market" is something like 1 flight every 2 years ......
It may not be worth servicing at all.
That is why I like the FX and FXH and not the FXX.
With F9 for crew and small cargo, FH for small diameter but heavier load with the FX to handle the wider loads to the FXH for the biggest cargos.

If they can all use the same pad that would be good for the economics.

For BEO crew missions I see the need for many flights for the FX and FXH with crew delivered by the F9.

The FX,FXH eliminates the need for a Saturn V launcher while still giving us a Saturn IB class launcher ( FX, wide body but with some extra lift ).

Offline Tcommon

  • Full Member
  • *
  • Posts: 146
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #72 on: 01/04/2012 07:24 PM »
fun picture

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #73 on: 01/04/2012 07:40 PM »
fun picture
Maybe that's what the huge underground test stand is really for.
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #74 on: 01/04/2012 07:49 PM »
If we were not to have the FXX and only have the FX and FXH for the near future ( at least through the 2020's ) then with what has been stated on this thread use 9 engines with SL thrust at around 400,000lb instead of the 3 Merlin 2 engines for core as a possibility.

So how could that change things-
Added pluming?
Dry mass of first stage?
Engine out?
Total payload mass to orbit?
Any thing else to add?

Looks like 3 of the possible ~400,000lb engines could be exchanged for the Merlin 1D engines on  the F9 or FH?

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #75 on: 01/04/2012 07:50 PM »
fun picture
Maybe that's what the huge underground test stand is really for.
Do you have any link(s) to the underground test stand for us?

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #76 on: 01/04/2012 08:28 PM »
Do you have any link(s) to the underground test stand for us?
http://www.wacotrib.com/wacotoday/135938808.html

A little snippet from this article:

"To fire all 27 engines at the same time, which is required to lift the massive rocket, a test stand will be built deep into the earth.

“We are, in fact, looking at digging a very deep flame trench so that instead of firing Falcon Heavy engines on elevated test stands, they fire into the ground, reducing noise levels,” said Kirstin Brost Grantham, SpaceX spokeswoman.

The new test stand will be connected to the tallest water tower in America. The tower will be 280 feet high and hold 500,000 gallons of water that can be emptied in less than 90 seconds via 6-foot-wide tubes. Rocket engine tests require water to buffer sound; a test of this magnitude will require a lot of water to minimize the noise."


500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 
« Last Edit: 01/04/2012 08:29 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline mrhuggy

  • Full Member
  • ***
  • Posts: 319
  • East Yorkshire, UK
  • Liked: 73
  • Likes Given: 1
Re: FX, FXH, FXX, Merlin 2
« Reply #77 on: 01/04/2012 09:26 PM »
Do you have any link(s) to the underground test stand for us?
http://www.wacotrib.com/wacotoday/135938808.html

A little snippet from this article:

"To fire all 27 engines at the same time, which is required to lift the massive rocket, a test stand will be built deep into the earth.

“We are, in fact, looking at digging a very deep flame trench so that instead of firing Falcon Heavy engines on elevated test stands, they fire into the ground, reducing noise levels,” said Kirstin Brost Grantham, SpaceX spokeswoman.

The new test stand will be connected to the tallest water tower in America. The tower will be 280 feet high and hold 500,000 gallons of water that can be emptied in less than 90 seconds via 6-foot-wide tubes. Rocket engine tests require water to buffer sound; a test of this magnitude will require a lot of water to minimize the noise."


500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 

Sounds like they are building in extra capacity at the new stand for bigger things like Merlin 2.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #78 on: 01/05/2012 01:14 PM »
The Texas test stand is rated for 15MN. Almost for two Merlin 2, if those are ever to be developed. So if they actually wanted to design such an engine, they already have the test stand for it.

http://www.popularmechanics.com/science/space/rockets/elon-musk-on-spacexs-reusable-rocket-plans-6653023?src=rss

It seems to me that due to the payload loss from reusable stages (I think this article implies 40% for just the first stage reusability alone but he might have meant including the effect of both stages), a BFR will certainly be required in the grand scheme (making life multi-planetary). 

If Elon intends to make a fully reusable BFR for this purpose, would this test stand be sufficient?
 
500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 

Is there a rule of thumb for gallons per second per unit thrust? 
 
« Last Edit: 02/08/2012 01:48 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #79 on: 01/05/2012 02:14 PM »
500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 

Sounds like they are building in extra capacity at the new stand for bigger things like Merlin 2.
Is there a rule of thumb for gallons per second per unit thrust? 

no, you are not going to find indirect proof that Merlin 2 is being developed

Offline aameise9

  • Member
  • Posts: 46
  • Potsdam, Germany
    • Cognitive Biology
  • Liked: 9
  • Likes Given: 51
Re: FX, FXH, FXX, Merlin 2
« Reply #80 on: 01/05/2012 02:43 PM »

Sounds like they are building in extra capacity at the new stand for bigger things like Merlin 2.

Wouldn't this stand be required in order to test cross-feeding in FH?

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #81 on: 01/05/2012 02:54 PM »

Sounds like they are building in extra capacity at the new stand for bigger things like Merlin 2.

Wouldn't this stand be required in order to test cross-feeding in FH?
Not necessarily.  It could be tested on the fly with a dummy payload.  To reduce risk to the pad, cross-feeding might begin at some point after takeoff. 
« Last Edit: 01/05/2012 02:56 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #82 on: 01/05/2012 03:18 PM »
Now this is a little off-topic (I really don't think SpaceX will be developing FX anytime soon), but if they're going to build a test stand capable of firing Falcon Heavy at once (not counting the upper stage, which will, of course, have to be test-fired separately), I see no reason they wouldn't test cross-feeding on the stand.

Testing on a stand before flight is almost always a good idea if you can afford it. (Falcon 9 upper stage was not vacuum-fired before being launched on Falcon 9 flight 1, and although it reached orbit quite successfully, it did mean the restart didn't work... But since it was a demo flight and orbit was still achieved, I'd still say that it was still a reasonably good decision not to do the very expensive vacuum test for that stage... though for smaller stuff, it probably is worth testing in a vacuum on the ground first.) That's the real reason the Soyuz N-1 project failed to reach orbit, IMHO... They failed to ever test the whole first stage on the ground, thus they blew up 4 N-1 rockets before even getting past the first stage.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #83 on: 01/05/2012 03:33 PM »
if they're going to build a test stand capable of firing Falcon Heavy at once, I see no reason they wouldn't test cross-feeding on the stand.
Agreed.  Most likely. 

Unless timeframe is a big factor:  For example, some customer might need a cross-feeding FH demo by a certain date that is sooner than the test stand completion date.  I have no idea if that's the case though. 
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32120
  • Cape Canaveral Spaceport
  • Liked: 10764
  • Likes Given: 321
Re: FX, FXH, FXX, Merlin 2
« Reply #84 on: 01/05/2012 03:50 PM »
if they're going to build a test stand capable of firing Falcon Heavy at once, I see no reason they wouldn't test cross-feeding on the stand.
Agreed.  Most likely. 

Unless timeframe is a big factor:  For example, some customer might need a cross-feeding FH demo by a certain date that is sooner than the test stand completion date.  I have no idea if that's the case though. 

There are no customers

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27987
  • Minnesota
  • Liked: 7796
  • Likes Given: 5198
Re: FX, FXH, FXX, Merlin 2
« Reply #85 on: 01/05/2012 04:08 PM »
It's true. Nobody has a payload (or is building one) that needs a Falcon Heavy with cross-feed right now. Every payload that would need the extra boost is still conceptual right now.

You might talk about putting a Dragon on a Falcon Heavy, but that's still conceptual right now. Without cross-feed (and with vertical payload integration....), they should be able to launch just about anything out there.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #86 on: 01/05/2012 08:20 PM »
go4mars  thanks for the underground test stand link.


If they can test 27 Merlin 1d engines at the same time , then they could most likely test a 1.7Mlb engine at the Texas site as a future possibility if they wanted to.

As for the FX,FXH that would be for after the F9/Dragon and FH are flying and the FH was not enough or the FXH would be cheaper for BEO missions.

I think SpaceX should look into their FX,FXH design now a little bit to see how they might work it into their plans now and the near future ( infrastructure ).

Offline ArbitraryConstant

  • Full Member
  • ****
  • Posts: 1761
  • Liked: 435
  • Likes Given: 245
Re: FX, FXH, FXX, Merlin 2
« Reply #87 on: 01/05/2012 10:55 PM »
Maybe that's what the huge underground test stand is really for.
Sounds like it's intended to reflect the sound upwards, otherwise it would be too loud for the surrounding communities.

Offline baldusi

  • Senior Member
  • *****
  • Posts: 7437
  • Buenos Aires, Argentina
  • Liked: 1442
  • Likes Given: 4499
Re: FX, FXH, FXX, Merlin 2
« Reply #88 on: 01/06/2012 11:12 AM »
The Texas test stand is rated for 15MN. Almost for two Merlin 2, if those are ever to be developed. So if they actually wanted to design such an engine, they already have the test stand for it.

Offline grr

  • Full Member
  • *
  • Posts: 162
  • Highlands Ranch, Colorado
  • Liked: 0
  • Likes Given: 0
Re: FX, FXH, FXX, Merlin 2
« Reply #89 on: 01/07/2012 04:00 PM »
if they're going to build a test stand capable of firing Falcon Heavy at once, I see no reason they wouldn't test cross-feeding on the stand.
Agreed.  Most likely. 

Unless timeframe is a big factor:  For example, some customer might need a cross-feeding FH demo by a certain date that is sooner than the test stand completion date.  I have no idea if that's the case though. 


I would think that the ground-based test would not only be cheaper, but also faster. If any serious anomalies are going to show up, it would be better on the ground. Then that just leaves one test flight, fix minor bugs and away you go.

Offline mrhuggy

  • Full Member
  • ***
  • Posts: 319
  • East Yorkshire, UK
  • Liked: 73
  • Likes Given: 1
Re: FX, FXH, FXX, Merlin 2
« Reply #90 on: 01/07/2012 05:23 PM »
500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 

Sounds like they are building in extra capacity at the new stand for bigger things like Merlin 2.
Is there a rule of thumb for gallons per second per unit thrust? 

no, you are not going to find indirect proof that Merlin 2 is being developed

Building excessive capacity  in the test stand only future proofs the stand, so you don't have to upgrade it later.

And no i wasn't jumping on "oh my god they doing merlin 2"

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #91 on: 02/08/2012 01:50 PM »
The Texas test stand is rated for 15MN... So if they actually wanted to design such an engine, they already have the test stand for it.

http://www.popularmechanics.com/science/space/rockets/elon-musk-on-spacexs-reusable-rocket-plans-6653023?src=rss

I think this article implies 40% for just the first stage reusability alone but he might have meant including the effect of both stages.

It seems to me that due to the payload loss from reusable stages, when a BFR is required eventually (making life multi-planetary), that to get 50 tonne chunks to Mars' surface (a stated goal) will require something pretty impressive at lift-off (especially since the rocket needs to be about 40% more potent than its expendible version). 

So perhaps a BFR who would in non-expendible version be 400+ tonnes to LEO or so (240 tonnes to LEO in reusable version to get 50 tonnes to the surface of Mars)?  Seems to me a cross-fed version would be the most likely.  So assuming a scale-up of FH, 54 tonnes to 400, they need a Merlin 2 to be just over 1 million pounds of thrust.  Since SpaceX is talking about 1.6 million, maybe the BFR will have less engines per stage or will be bigger than my guess. 

If Elon intends to make a fully reusable BFR for this purpose, will this new test stand be sufficient to test a BFR engine? 
 
500000 divided by 90 seconds.  That's 5555 gallons per second.  Does that sound excessive for 27 merlin 1D's? 

Is there a rule of thumb for gallons per second per unit thrust? 
 
« Last Edit: 02/08/2012 02:29 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #92 on: 02/08/2012 02:20 PM »
Is there a rule of thumb for gallons per second per unit thrust? 
 
Just discovered that the sound suppression system for Saturn V was 15000 gallons per second.

If that scales the same, then this new test stand should be able to handle a 2.8 million pound thrust engine. 
« Last Edit: 02/08/2012 02:24 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline bulkmail

  • Member
  • Posts: 72
  • Liked: 16
  • Likes Given: 4
Re: FX, FXH, FXX, Merlin 2
« Reply #93 on: 02/08/2012 05:38 PM »
Can somebody calculate the LEO lift capacity of a hypothetical Falcon XX Heavy (three 10m cores with cross feeding - with 6? Merlin2 engines each) with Merlin2 and/or Raptor upper stages?

Are there any fundamental technical issues preventing such configuration?

Offline baldusi

  • Senior Member
  • *****
  • Posts: 7437
  • Buenos Aires, Argentina
  • Liked: 1442
  • Likes Given: 4499
Re: FX, FXH, FXX, Merlin 2
« Reply #94 on: 02/08/2012 06:07 PM »
Can somebody calculate the LEO lift capacity of a hypothetical Falcon XX Heavy (three 10m cores with cross feeding - with 6? Merlin2 engines each) with Merlin2 and/or Raptor upper stages?

Are there any fundamental technical issues preventing such configuration?
If you copy the FH equation (3.3 times the 16tonnes of the F9b2), you'd get somewhere around 500tonnes.
I guess that you should start thinking differently. You should start with a desired mission, then decide a vehicle that can do the mission in one or two launches.
Let's say that you make it a two launches mission, where first you send the return vehicle and some exploration vehicle plus a surface habitat. On the second launch you send the crew with a space habitat, the Mars descent vehicle and the Earth return capsule.
You've got to calculate some mass at Trans Mars Insertion orbit. That's what you should optimize then. LEO is not a good benchmark if you're going with straight launches, since low energy and high energy orbits require very different optimizations.

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #95 on: 02/08/2012 06:30 PM »
If you copy the FH equation (3.3 times the 16tonnes of the F9b2), you'd get somewhere around 500tonnes.

to get 50 tonne chunks to Mars' surface (a stated goal)
   

I'm pretty confident there's an Elon quote out there somewhere that talks about a desire for direct throw to get 50 tonnes at a time to the surface of Mars in a fully reusable architecture. 

I assume that represents the heaviest need of the colonists (nuclear power plant maybe)? 

Anyway, with your 500 tonne rocket, that drops by some percent for reuse (40% for single stick apparently).  Say a cross-fed version only drops by 20%.  Would a 400 tonne to LEO rocket be likely to get 50 tonnes to the surface of Mars?   
« Last Edit: 02/08/2012 06:37 PM by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline bulkmail

  • Member
  • Posts: 72
  • Liked: 16
  • Likes Given: 4
Re: FX, FXH, FXX, Merlin 2
« Reply #96 on: 02/08/2012 06:35 PM »
Can somebody calculate the LEO lift capacity of a hypothetical Falcon XX Heavy (three 10m cores with cross feeding - with 6? Merlin2 engines each) with Merlin2 and/or Raptor upper stages?

Are there any fundamental technical issues preventing such configuration?
If you copy the FH equation (3.3 times the 16tonnes of the F9b2), you'd get somewhere around 500tonnes.
I guess that you should start thinking differently. You should start with a desired mission, then decide a vehicle that can do the mission in one or two launches.
Let's say that you make it a two launches mission, where first you send the return vehicle and some exploration vehicle plus a surface habitat. On the second launch you send the crew with a space habitat, the Mars descent vehicle and the Earth return capsule.
You've got to calculate some mass at Trans Mars Insertion orbit. That's what you should optimize then. LEO is not a good benchmark if you're going with straight launches, since low energy and high energy orbits require very different optimizations.

OK, so the mission I'm thinking about is Moon outpost/base and Moon cargo delivery on a big scale.

But, WOW, 500mT to LEO...  this is more than the whole ISS - in a single launch! Aren't there any problems with that? Maybe 3x6 engines configuration doesn't fit, maybe there is no fairing big enough for 500mT, maybe a much more powerful upper stage is needed?

Offline go4mars

  • Senior Member
  • *****
  • Posts: 3747
  • Earth
  • Liked: 147
  • Likes Given: 3062
Re: FX, FXH, FXX, Merlin 2
« Reply #97 on: 02/08/2012 06:38 PM »
OK, so the mission I'm thinking about is Moon outpost/base and Moon cargo delivery on a big scale.
The mission Elon is thinking of is Mars colonization.

Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline bulkmail

  • Member
  • Posts: 72
  • Liked: 16
  • Likes Given: 4
Re: FX, FXH, FXX, Merlin 2
« Reply #98 on: 02/08/2012 06:50 PM »
Anyway, with your 500 tonne rocket, that drops by some percent for reuse (40% for single stick apparently).  Say a cross-fed version only drops by 20%.  Would a 400 tonne to LEO rocket be likely to get 50 tonnes to the surface of Mars?   

I would assume yes - if Falcon Heavy can deliver a Red Dragon, then ~10 times more lift to LEO should be capable to deliver ~10 more at Mars?

Offline Tass

  • Full Member
  • ***
  • Posts: 361
  • Liked: 76
  • Likes Given: 153
Re: FX, FXH, FXX, Merlin 2
« Reply #99 on: 02/13/2013 03:09 PM »
Hi. I have this (quite possibly hare-brained) idea that I would like to see discussed.

As you all know SpaceX is planning the Falcon Heavy rocket, which is basically three Falcon 9 first stages strapped together with a stage on top. What is special is that it is going to use propellant cross feed, using up the propellant from the side stages first and then dropping them when empty. Thus they become better than the "half stage" strap on boosters that many rockets use in that they leave what is basically a full falcon 9 which is all ready moving fast. And they have an advantage over a full stage in that the engines of the center stage have been working the whole time rather than being dead weight.

Now this seems to suggest an obvious further step, if we ever needed a super heavy lift rocket. What if you strapped nine cores together basically three falcon heavy first stages side by side, then cross fed from the two outer rows with a total of six cores first, followed by regular falcon heavy cross feed.

Would it even need a top stage to achieve orbit then? How much could it lift? Since it is in a way just a repeated application of the original falcon heavy technology could it be done with *relatively* limited extra development cost (still expensive, everything in this field is).

Now I know we don't need it for the foreseeable future. I know SpaceX are not planning to do it. It is still interesting to discuss the possibility though.

Offline spectre9

  • Senior Member
  • *****
  • Posts: 2403
  • Australia
  • Liked: 36
  • Likes Given: 67
Re: FX, FXH, FXX, Merlin 2
« Reply #100 on: 02/13/2013 04:01 PM »
Difficult to find maybe so you can be forgiven.

Edit : thanks Chris.

This is the nine core Falcon Heavy thread - posting that so I can find it later.

I find Jim's post reply #51 quite relevant  :)
« Last Edit: 02/13/2013 04:11 PM by spectre9 »

Online Chris Bergin

Re: FX, FXH, FXX, Merlin 2
« Reply #101 on: 02/13/2013 04:04 PM »
Merged.
« Last Edit: 02/13/2013 04:05 PM by Chris Bergin »

Offline R7

  • Propulsophile
  • Senior Member
  • *****
  • Posts: 2738
    • Don't worry.. we can still be fans of OSC and SNC
  • Liked: 948
  • Likes Given: 662
Re: FX, FXH, FXX, Merlin 2
« Reply #102 on: 02/13/2013 04:22 PM »
81 engines on a first stage is ido itic.

But it might be eventful!

Say monsterHeavy's 1D has 0.999 reliability, probability for boring flight (0.999)81 = 0.92
AD·ASTRA·ASTRORVM·GRATIA

Offline Tass

  • Full Member
  • ***
  • Posts: 361
  • Liked: 76
  • Likes Given: 153
Re: FX, FXH, FXX, Merlin 2
« Reply #103 on: 02/13/2013 04:31 PM »
Difficult to find maybe so you can be forgiven.

Edit : thanks Chris.

This is the nine core Falcon Heavy thread - posting that so I can find it later.

I find Jim's post reply #51 quite relevant  :)

Ah. Didn't think to look outside of advanced concepts for that.

Offline HMXHMX

  • Full Member
  • ****
  • Posts: 1437
  • Liked: 1073
  • Likes Given: 300
Re: FX, FXH, FXX, Merlin 2
« Reply #104 on: 02/13/2013 04:33 PM »
Hi. I have this (quite possibly hare-brained) idea that I would like to see discussed.

As you all know SpaceX is planning the Falcon Heavy rocket, which is basically three Falcon 9 first stages strapped together with a stage on top. What is special is that it is going to use propellant cross feed, using up the propellant from the side stages first and then dropping them when empty. Thus they become better than the "half stage" strap on boosters that many rockets use in that they leave what is basically a full falcon 9 which is all ready moving fast. And they have an advantage over a full stage in that the engines of the center stage have been working the whole time rather than being dead weight.

Now this seems to suggest an obvious further step, if we ever needed a super heavy lift rocket. What if you strapped nine cores together basically three falcon heavy first stages side by side, then cross fed from the two outer rows with a total of six cores first, followed by regular falcon heavy cross feed.

Would it even need a top stage to achieve orbit then? How much could it lift? Since it is in a way just a repeated application of the original falcon heavy technology could it be done with *relatively* limited extra development cost (still expensive, everything in this field is).

Now I know we don't need it for the foreseeable future. I know SpaceX are not planning to do it. It is still interesting to discuss the possibility though.

Just for historical interest, we proposed something similar for the NASA MSFC HLV study effort in mid-2010.  SpaceX won one of the contracts (t/Space didn't) but I never saw any reports on any work performed; the study seems to have disappeared into the mists.  Our architecture was based around clustering standard modules as described in the second graphic below.

In the first graphic below, the "Class Three" engine is an RD-170 equivalent, or about 1.8Mlbf.  So the module it is attached to is slightly larger than a F9v1.1, more along the lines of a Zenit first stage.  But the enabling assumption we made was that you could build stages/modules with the Delta propellant Mass faction (PMF) on the oder of 0.95.  F9v1.1 should be close to that if not better.

Offline R7

  • Propulsophile
  • Senior Member
  • *****
  • Posts: 2738
    • Don't worry.. we can still be fans of OSC and SNC
  • Liked: 948
  • Likes Given: 662
Re: FX, FXH, FXX, Merlin 2
« Reply #105 on: 02/14/2013 10:27 AM »
Just for historical interest, we proposed something similar for the NASA MSFC HLV study effort in mid-2010.

Unstaged = the whole cluster is SSTO vehicle? Impressive final acceleration or deep throttling?
Staged = green cores drop early? Cross feed?
AD·ASTRA·ASTRORVM·GRATIA

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2438
  • Claremore, Ok.
  • Liked: 395
  • Likes Given: 11
Re: FX, FXH, FXX, Merlin 2
« Reply #106 on: 02/15/2013 05:33 AM »
And everyone will get a pony too.

OOOOHHH Can I have oner too Jim?
My God!  It's full of universes!

Offline HMXHMX

  • Full Member
  • ****
  • Posts: 1437
  • Liked: 1073
  • Likes Given: 300
Re: FX, FXH, FXX, Merlin 2
« Reply #107 on: 02/15/2013 05:41 AM »
Just for historical interest, we proposed something similar for the NASA MSFC HLV study effort in mid-2010.

Unstaged = the whole cluster is SSTO vehicle? Impressive final acceleration or deep throttling?
Staged = green cores drop early? Cross feed?

We did propose that, given the high t/w of the reference powerplants, coupled to high delivered Isp, and using dense propellant (LOX-kerosene), expendable SSTO was indeed feasible.  It's mainly valuable for certain inclinations where you don't want to be overly constrained by azimuth considerations late in the burn.  The engines had throttle capability that allowed the trajectory to close.  That's not theoretical...we talked with the manufacturers, but I can't go into detail.  I limited burnout G to 7, much like Gemini-Titan.

Yes, the green cores drop as stage one.  We considered cross-feed, but none of the concepts shown employ it as I recall (maybe the 1-1 did).  In the case of the 6-1, the six modules of the first stage had fixed inter-module exchange of fluids to minimize residuals, but no cross-feed to the central core.  No reason one couldn't go with universal cross-feed, however.  Just adds development cost and risk.

What I was really trying to show is that common modules, built with high performance engines and lightweight tanks, can be clustered economically to provide heavy lift, thus obviating the need for a specialized HLV like NASA wanted.  I knew in advance that it wouldn't be accepted but was making a point.

Offline spectre9

  • Senior Member
  • *****
  • Posts: 2403
  • Australia
  • Liked: 36
  • Likes Given: 67
Re: FX, FXH, FXX, Merlin 2
« Reply #108 on: 02/15/2013 07:43 AM »
A specialised heavy lifter with a large diameter tank uses less metal and gets a better mass fraction.

It's launch rate that skews the price.

Medium boosters that launch by themselves and can be clustered as a heavy lifter are cheaper because you get the overall launch rate of the booster and not the big rocket.

The problem with putting everything on big rockets is that payloads all go to different orbits.

SpaceX doesn't have a market for a heavy lifter before there is a colony on Mars.

1. Put colony on Mars
2. Build MCT
3. Profit

Step 1 just doesn't make sense because it's so expensive that nobody wants to do it. The motivation is just too weak.

Life is simply too comfortable on planet Earth in the 21st century, especially for those countries that have the technology to do space exploration.

Right now it's wanting to go because we think it might be cool to live and die on Mars

In the 22nd century there will be a need to go because the planet is overcrowded and resources are running thin.

If colonies were to magically appear in space (LEO is fine for starters) HLLVs might make sense. People are going to need goods, services and transport from the surface.

Building those colonies in the cheapest way possible should be the goal of people today not pushing technology so hard trying to stumble upon some sort of "magic" that makes everything possible such as SSTO or RLV.

Offline R7

  • Propulsophile
  • Senior Member
  • *****
  • Posts: 2738
    • Don't worry.. we can still be fans of OSC and SNC
  • Liked: 948
  • Likes Given: 662
Re: FX, FXH, FXX, Merlin 2
« Reply #109 on: 02/15/2013 12:22 PM »
What I was really trying to show is that common modules, built with high performance engines and lightweight tanks, can be clustered economically to provide heavy lift, thus obviating the need for a specialized HLV like NASA wanted.  I knew in advance that it wouldn't be accepted but was making a point.

*sigh* Makes one want to believe there are numerous alternate universes where your proposal fell to more fertile ground.

Itching to ask your opinion why the proposal was doomed to fail, but knowing it's OT and probably mostly policy related must digress. Thanks anyway for interesting info.
AD·ASTRA·ASTRORVM·GRATIA

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6746
  • Spokane, WA
  • Liked: 551
  • Likes Given: 339
Re: FX, FXH, FXX, Merlin 2
« Reply #110 on: 02/16/2013 12:06 AM »

Just for historical interest, we proposed something similar for the NASA MSFC HLV study effort in mid-2010.  SpaceX won one of the contracts (t/Space didn't) but I never saw any reports on any work performed; the study seems to have disappeared into the mists.  Our architecture was based around clustering standard modules as described in the second graphic below.

In the first graphic below, the "Class Three" engine is an RD-170 equivalent, or about 1.8Mlbf.  So the module it is attached to is slightly larger than a F9v1.1, more along the lines of a Zenit first stage.  But the enabling assumption we made was that you could build stages/modules with the Delta propellant Mass faction (PMF) on the oder of 0.95.  F9v1.1 should be close to that if not better.

That's very interestings.  Coincidentally, I speculated on something like this recetly on this thread, but on a larger scale:

http://forum.nasaspaceflight.com/index.php?topic=30773.15

After going back and reading more of the ESAS report.  In particular why they discounted the ET-sized inline LV's with 4-seg STS boosters (Direct-like), and why they discounted Atlas Phase 2-heavy, and Atlas Phase 3a, I think I understood better why they went the way they did, instead of some of the more obviously better ways.
They seemed dead-set on 1.5 architecture, so anything that didn't provide a small crew launcher just big enough for the Orion CSM, and then a really big HLV with 125mt or more to LEO, they discounted.  Even if two 70-90mt LV's would have gotten them there, that was "2" launches rather than "1.5" launches.
But, another reason they seemed to discount Atlas Phase 3a, and why they didn't consider any other multi-booster HLV, like something like AJAX or your proposal here, is the amount of interfaces the LV would need.  All of those separation events drives reliablitly down (at least in the metrics that NASA was going with at the time of ESAS).   I wondered why they showed LV's with just two Atlas V boosters, or two Delta IV boosters, but not four or six or eight Atlas V boosters?  But I think it was the amount of interfaces.  They wanted to keep the HLV at no more than two boosters.

Then I was talking to a NASA guy on PM who posts on L2, and who worked on the RAC-2 monolithic LV concept in 2010.  He said it beat the shuttle derived in every way, but politics were such that Shuttle derived was chosen.  He said the RAC-3 team, which looked at using existing EELV's, gave it a good try, but their LV's had 6 and 7 boosters, and the interfaces were a nightmare.  It just couldn't be done with existing EELV's to get 130mt to LEO, which was the goal of the three RAC teams.  (although certainly a multiple launch architecure using EELV's could have been used...but that wasn't in the scope of the RAC teams).

So, I guess that's a long explaination to get to the point that, while I really like your concept, the heavier versions might suffer from these issues with multiple interfaces.  And even if it wasn't a -real- problem, NASA probably wouldn't go with it for the same reason they didn't really consider any HLV with more than 2 boosters, because they thought it would be.

So my idea was sort of like a large Atlas Phase 2.  Maybe call it Atlas Phase 2-b?  Go with cores that are 5-6m wide (depending on what's easiest to make with existing tooling assets), and put four RD-180's on the bottom, and a new ACES/wide-body common Centaur upper stage on top of it, and that should get about 50mt to LEO. 
But 3 of them together in a tri-core heavy configuration and now you should have over 125mt to LEO.  150-175t to LEO in a "1.5" launch architecrure, and your HLV only has two boosters, so you don't run into the interface issue.
(I suppose this would be effectively the FX and FXH LV's, but Atlas Derivatives instead of SpaceX)
ULA would retain Atlas V for smaller payloads and switch to the ACES/WBC common upper stage on it as they already want to do.  The Delta IV line is retired complately and all heavy payload fly on Atlas Phase 2.5, but the Delta IV tooling could be used for Atlas PHase 2.5.  I think that tooling can make cores of at least 5.4m wide.  That would work if it can't go to 6m wide, the cores will just need to be taller.
But Atlas Phase 2 is siginificantly shorter than Delta IV, so Atlas Phase 2.5 might be closer to Delta IV in hight, and maybe a bit wider.  So Atlas Phase 2.5-heavy might be very close in size to Delta-IV heavy, rather than the shorter Atlas Phase 2 heavy.
So that shouldn't be a problem.

However, you make a pretty good point about the RD-170. The single core migth look a lot like the Dynetics F-1A booster, but with a pair of RD-170's that would protrude on the bottom on two sides like the F-1A's would.  But two outboard cores could be strapped on to the other sides where the engines don't stick out.

If not, they could just stick with four RD-180's.

The other thing about your concept, is the central core would probably be a very different animal than the booster cores, because to standardize on a design, you need 6 booster interfaces on each central core no matter how many booster you are putting on, otherwise you will have several versions of the core, which means less commonality.  But you don't want your boosters to have all of those interfaces.  No need for that extra expense for booster that only need one set of interfaces.  So you make two different cores, a central core with 6 booster interfaces, and a booster core with 1 booster interface.
In my concept, you make make just a single core with two booster interfaces.  Then a single core LV flies with just two interfaces that aren't being used.  The heavy flies with a central core with two interfaces being used, and two boosters that one one of their two booster interfaces.  So that seems like a more feasible way to make just one single standard core accross the board.

But, if the booster interfaces weren't a problem, then your concept scales better than mine, and could replace the entire range of EELV's up to heavy lift.
:-)


Offline RocketmanUS

  • Senior Member
  • *****
  • Posts: 2226
  • USA
  • Liked: 71
  • Likes Given: 31
Re: FX, FXH, FXX, Merlin 2
« Reply #111 on: 03/25/2013 06:55 PM »
A SpaceX version of the Sat INT-21, however all RP-1/LOX.

1st stage to use 9 Merlin 2's thrust rated for two engine out.
2nd stage to use multiple Marlin 1D vacuum engines.

Use shuttle VAB and launch pad.

Three developments are the Merlin 2's, the ~10m cores, and large fairing.

Offline mlindner

  • Software Engineer
  • Full Member
  • ****
  • Posts: 1937
  • Space Capitalist
  • Silicon Valley, CA -- previously in Ann Arbor, MI
  • Liked: 532
  • Likes Given: 212
Re: FX, FXH, FXX, Merlin 2
« Reply #112 on: 03/25/2013 08:09 PM »
A SpaceX version of the Sat INT-21, however all RP-1/LOX.

1st stage to use 9 Merlin 2's thrust rated for two engine out.
2nd stage to use multiple Marlin 1D vacuum engines.

Use shuttle VAB and launch pad.

Three developments are the Merlin 2's, the ~10m cores, and large fairing.

What is Sat INT-21?
Internal combustion engine in space. It's just a Bad Idea.TM - Robotbeat

Offline baldusi

  • Senior Member
  • *****
  • Posts: 7437
  • Buenos Aires, Argentina
  • Liked: 1442
  • Likes Given: 4499
Re: FX, FXH, FXX, Merlin 2
« Reply #113 on: 03/25/2013 08:19 PM »
A SpaceX version of the Sat INT-21, however all RP-1/LOX.

1st stage to use 9 Merlin 2's thrust rated for two engine out.
2nd stage to use multiple Marlin 1D vacuum engines.

Use shuttle VAB and launch pad.

Three developments are the Merlin 2's, the ~10m cores, and large fairing.

What is Sat INT-21?
Basically just the first two stages of the Saturn V. It would have need to have the instrument unit moved from the top of the third stage to the top of the third. Almost the same as the one that put the Skylab on orbit. But since Skyelab itself was the third stage repurposed, there was no need to move the instrument unit. The instrument unit was 6.6m wide (as the SV-IVB), but the first and second stages were 10m.
« Last Edit: 03/25/2013 08:58 PM by baldusi »

Offline Lars_J

  • Senior Member
  • *****
  • Posts: 6161
  • California
  • Liked: 665
  • Likes Given: 195
Re: FX, FXH, FXX, Merlin 2
« Reply #114 on: 03/25/2013 08:39 PM »
Basically just the first two stages of the Saturn V. It would have need to have the instrument unit moved from the top of the third stage to the top of the third. Almost the same as the one that put the SpaceLab on orbit.

Skylab

Offline deltaV

  • Full Member
  • ****
  • Posts: 1538
  • Change in velocity
  • Liked: 165
  • Likes Given: 480
Re: FX, FXH, FXX, Merlin 2
« Reply #115 on: 03/25/2013 08:53 PM »
Just for historical interest, we proposed something similar for the NASA MSFC HLV study effort in mid-2010.  SpaceX won one of the contracts (t/Space didn't) but I never saw any reports on any work performed; the study seems to have disappeared into the mists.  Our architecture was based around clustering standard modules as described in the second graphic below.

If I'm reading those charts right the "32/40" means all cores to orbit (SSTO) gives 32 mt and all but one core dropping off part way through (TSTO) gives 40 mt. Is that right? I though staging gave a lot more benefit than that.

Edit: it looks like all of those numbers are 25% more payload for TSTO than SSTO. It seems like a remarkable coincidence that 2 core and 7 core would have the exact same staging bonus. Are these numbers supported by individual trajectory optimizations?
« Last Edit: 03/25/2013 08:57 PM by deltaV »

Tags: