Author Topic: SpaceX: Mars Colonial Transporter "MCT" -- Speculation (not Raptor)  (Read 695656 times)

Offline modemeagle

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If anyone's good at doing digital editing it might be interesting to see how the minimum size MCT-engined Falcon X and Falcon X Heavy would scale visually against the Saturn V. 
Here is a quick comparison with a 4 Engine Version.  Wish I could find a better Saturn V image to use.

Edit:  Added Shuttle to the picture and rescaled the Saturn V (was a little short)  Can't find a good picture of the Falcon X to scale into it.
« Last Edit: 10/26/2012 01:09 pm by modemeagle »

Offline simonbp

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@FinalFrontier

That's encouraging; I haven't been back to the area since shortly after the spill, but it sounds like things are getting better.

Also IIRC, there are quite a few fab shops inland of the channel, but with access via many-wheeled transporter to water. That could be more convenient that building right on the shore.

@modemeagle

Nice Job! I'm trying to imagine one of those cores coming in for a vertical landing... :D

Offline Kaputnik

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I must admit 'multi chamber' was what popped into my head when I read "MCT" for the first time.
Would it be correct to assume that:
a) the larger the turbopump, the easier it is to build a reliable and robust design
b) the smaller the combustion chamber, the easier it is to avoid instability
"I don't care what anything was DESIGNED to do, I care about what it CAN do"- Gene Kranz

Offline ciscosdad

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Re Tank sizes.
What about using 2 or 4 3.6m Falcon 9s as boosters (but with 1 or 2 of the new engine each booster)? The core stage could be 8.4 or 10m and have 4 or 5 large engines.
Has spacex explicitly said the evolved heavies will all have the same core/booster diameter?

Offline DaveH62

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The discussion in this thread is going nowhere.

1. The fuel is going to be a "light hydrocarbon" which is cheaper than RP-1/LOX (and He as pressurizer). The most likely candidate is methane. This has already been discussed.

2. The paramount design decision is going to be reusability. Or at least a design which can evolve into reusability. The large payloads stated are obviously in expendable mode. In reusable mode you have to count on losing half of that.

3. The engine will most likely be used in a bid for the SLS boosters. And in the F9 replacement. And in the FH replacement. Don't get your hopes up for any ferrying colonialists to Mars.  It also doesn't sound very likely that SLS will go bust and that SpaceX will fill its place for manned NASA missions.

4. They don't need to be in a hurry to build anything. They are already competive with the fleet of rocket that they will soon have (F9 & FH).
3. This would be smart and keeping with SpaceX understanding of the need to make everything financially sustainable. If he builds a rocket that can be a booster for SLS, they have a client to funds their research. Longer term, the 7 meter version could eventually be expanded into a 4-5 engine 8 or 10 meter core to a Super Heavy. With another extension to their core services, they don't need to hurry anything, but have a solid profitable platform family capable of carrying any potential payload.

Question, could they build the move stir wielding and rocket assembly to Florida after testing each engine in Texas?

Offline Dave G

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I should also note the same somewhat applies to Brownsville due to logistics challenges and initial investment. It would probably be slightly cheaper then Houston, but it would still be *ridiculous* from a business perspective.

What logistics challenges?  Brownsville has an international airport, a waterway with access to the Gulf, and potential launch/test site, all very close to each other.  For the engines and other parts necessary to assemble the stages, it's also a fairly direct path from Hawthorne to McGregor to Brownsville to the cape (see picture below).  So logistically, Brownsville looks really good.  Add plentiful and inexpensive real estate, low local labor costs, and low tax rates, and Brownsville seems ideal.

SpaceX has said they're planning an MCT rocket with 7+ meter cores.  Building the cores at Hawthorne or McGregor won't work due to transportation issues.

Remember that SpaceX has a culture that encourages communication between different departments, so the fewer sites the better.  It appears SpaceX is already building a stage integration and launch control facility in Brownsville.  What better choices are there?
« Last Edit: 10/26/2012 03:56 am by Dave G »

Offline Dave G

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Question, could they build the move stir wielding and rocket assembly to Florida after testing each engine in Texas?

Cores that large would probably require new stir welding machines.  In other words, I suspect they would continue to build F9/FH cores in Hawthorne.
« Last Edit: 10/26/2012 04:08 am by Dave G »

Offline A_M_Swallow

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Large parts could be transferred from California to Texas in ships via the Panama Canal.

Offline Dave G

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It also doesn't sound very likely that SLS will go bust ...

That's worth a chuckle ...

Offline Dave G

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Large parts could be transferred from California to Texas in ships via the Panama Canal.

For stuff that can be transported on a truck, that would probably be the cheapest way.

But you can't get a 7m core from Hawthorne to the sea (traffic lights, power lines, etc.)

So I'm not sure why they would want to shiip through the Panama Canal.

« Last Edit: 10/26/2012 04:12 am by Dave G »

Offline Hyperion5

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If anyone's good at doing digital editing it might be interesting to see how the minimum size MCT-engined Falcon X and Falcon X Heavy would scale visually against the Saturn V. 
Here is a quick comparison with a 4 Engine Version.  Wish I could find a better Saturn V image to use.

Thanks a ton, and don't worry about the Saturn V image.  Well this at least does some justice to the saying that a "picture says a thousand words".  I hadn't quite figured on the Falcon 9 v1.1 looking so tiny.  I knew the figures but they don't hit you over the head until you actually see what those mean. With the roughly 30% higher max payload weight and the greater volume, I see little danger the single-core version of this would cannibalize Falcon Heavy sales.   

I've noticed some interesting coincidences if we can use the Merlin 2 concept figures for the MCTs (1.7 million lbf per engine). Four of them would be a near exact match in thrust for a Space Shuttle stack at liftoff (6.8 million lbf on each).  The tank size is also a near match (8.5 vs. 8.4 STS External Tank), as is the payload (67.4 mt vs 70 mt of STS stack).  It's such a good match for the Shuttle stack you might as well put a regular Falcon X and the shuttle stack in a future comparison, modemeagle.  Could you by chance also show the height markers along an entire side? 

Here's what Spacex's portfolio of lifters would look like if they added this 4-MCT Falcon X and its variants. 

Falcon 1----Thrust (SL): --Thrust (SL): 102,000 lbs--Payload: .67 mt 
Falcon 9 v1.0--Thrust (SL): 855,000 lbs--Payload: 9.9 mt
Falcon 9 v1.1--Thrust (SL): 1.323 million lbs--Payload: 13.15 mt
Falcon Heavy--Thrust (SL): 3.8 million lbs--Payload: 53 mt
Falcon X--Thrust (SL): 6.8 million lbs--Payload: 67 mt
Falcon X Heavy--Thrust (SL): 19.52 million lbs--Payload: 229 mt w/o crossfeed (270 mt with cross-feed)
Falcon X Ultra Heavy--Thrust (SL): 32.538 million lbs--Payload: 381 mt w/o cross-feed (450 mt with cross-feed)

*-I assumed Heavy variants would feature 95.7% of three and five cores' worth of thrust and also see similar payload percentage jumps seen in Falcon Heavy compared to Falcon 9 v1.1. 

Just look at how well this scales for Spacex.  Using upgrades of the Falcon 1's engine, they went from 670 kg to orbit to 53 mt to orbit in 5 years (assuming the Falcon Heavy flies next year).  The MCT would enable a rocket with a huge fairing (up to around 13-14 m) and 65-70 mt of payload.  That same rocket core can then be used in modular fashion to cover all potential launch needs from 65 mt to 450 mt.  With a big 13 m fairing this really is looking like Elon's dream "colony rocket" in its potential heavy and ultra heavy variants. 

Interesting thing I noticed--a 67 mt heavy lifter would feature almost exactly 100X the payload of the original Falcon 1. 




« Last Edit: 10/26/2012 04:32 am by Hyperion5 »

Offline DaveH62

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Question, could they build the move stir wielding and rocket assembly to Florida after testing each engine in Texas?

Cores that large would probably require new stir welding machines.  In other words, I suspect they would continue to build F9/FH cores in Hawthorne.
What I'm trying to understand is if they can continue primary manufacturering in California shipping and testing individual engines in Texas and then assembling complete rockets at a launch site for final testing. Texas or Florida could work. Avoid investing in new production line for engines. New stir wielding facility won't be cheap, but fraction of a new complete production facility and keeps your main production staff under one roof with your engineers.

Offline go4mars

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So you think it'll be cheaper to build all-new than use the VAB and shuttle pads?
Yes.
We're all fans of reusability, but this rocket has to be commercially viable without it at the beginning. 
Disagree.  If it isn't reusable, I doubt the price will be compelling to any customers.  I expect to see a sub-scale demonstrator first.  And judging by what I've heard of the grasshopper program, so does the main man.

You think ILS or Intelsat or Iridium or even Bigelow would want to risk half billion dollar amounts on a single launch?
No.  I don't think it will cost half a billion dollars per launch.  Lower costs opens up a lot of other doors, even if it is overpowered for most missions.

Elon and Shotwell were mentioning 150-200 metric tons, and the minimum size considered (7 meters) hints that it'll be modular to hit that figure.  Modularity...
I don`t agree with your "logic".  If the eventual goal is landing 50 tonne infrastructure pieces on Mars in a single launch, then the heavy (modular/crossfeeding) version should be a hekuvalot bigger than 150-200tonnes to LEO. 
The original TAN patent expires in <9 years, so it could also be that they just don’t plan on production until then.
An interesting point.  Might be they'll at have a design that can allow for it as a future upgrade, but who knows... I doubt they'll sit still in the intervening 9 years.
I had heard that hydraulics were limited in how heavy of stuff they could push up, ...Is that possible using the horizontal approach with hydraulic lift to get it to vertical? 
Yes.
How hard would it be to protect such a low-lying launch complex from hurricanes' winds and storm surges?
A worthwhile question.  Hard.  You takes your chances.  Minimizing impact is certainly a worthwhile consideration (whether through insurance or my preference: threat minimization).  Cost tradeoffs should be examined and probably will be...  SpaceX needs a solitary consultant geologist for that.
Has spacex explicitly said the evolved heavies will all have the same core/booster diameter?
Not that I know of.
I suspect they would continue to build F9/FH cores in Hawthorne.
Plusso Uno.  Until/if the follow-on systems obselesce the current/near-term iterations.
« Last Edit: 10/26/2012 05:13 am by go4mars »
Elasmotherium; hurlyburly Doggerlandic Jentilak steeds insouciantly gallop in viridescent taiga, eluding deluginal Burckle's abyssal excavation.

Offline Halidon

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Has spacex explicitly said the evolved heavies will all have the same core/booster diameter?
SpaceX hasn't explicitly said much, actually. This is a speculation thread, people are spinning theories. So feel free to spin away.

Offline ciscosdad

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OK, anyone ready to speculate on how they might use falcon 9's as boosters (with or without the new engines). My maths-fu is not up to this!

Offline Dave G

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Question, could they build the move stir wielding and rocket assembly to Florida after testing each engine in Texas?

Cores that large would probably require new stir welding machines.  In other words, I suspect they would continue to build F9/FH cores in Hawthorne.
What I'm trying to understand is if they can continue primary manufacturering in California shipping and testing individual engines in Texas and then assembling complete rockets at a launch site for final testing. Texas or Florida could work. Avoid investing in new production line for engines. New stir wielding facility won't be cheap, but fraction of a new complete production facility and keeps your main production staff under one roof with your engineers.

Right.  I'm also assuming primary manufacturing would continue in Hawthorne.

Building huge cores and assembling huge stages can be done anywhere with access to the sea.  As an example, Saturn V stages were shipped down the Mississippi, through the Gulf to the cape.


Offline Dave G

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SpaceX hasn't explicitly said much, actually.

During an April interview, SpaceX president Gwynne Shotwell discussed a project with similar characteristics, describing engines with "more than 1.5 million pounds" of thrust.

"We've looked at a number of different architectures, we haven't honed in on one just yet," said Shotwell. "I think we're still considering vehicle diameter. But the vehicle diameter is large, 7m minimum, multiple engines. These are big rockets."


---

In the past, SpaceX has said that the F9/FH core of 3.6 meters is the maximum diameter that can be transported over land, using a special low-bed truck.

It also seems obvious that you can't transport a 7+ meter core from Hawthorne to the sea.  That would be about 25 feet tall on a truck.  Traffic lights and power lines would seem to make this impossible.

So by deduction, it appears SpaceX is intending to create a new production facility to build these huge new cores.  The question is: Where?

Offline apace

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Amazing thread, but you're talking about a company which has launched two (2) rockets in the medium size this year... and other companies need billions of dollars to develop such a big new rocket from parts which already exists. So, nice talks but for the next years, only wishful thinking.

Offline modemeagle

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It's such a good match for the Shuttle stack you might as well put a regular Falcon X and the shuttle stack in a future comparison, modemeagle.  Could you by chance also show the height markers along an entire side?
Edited and inserted a new picture above with the shuttle.
http://forum.nasaspaceflight.com/index.php?topic=30103.msg972407#msg972407

Offline Hyperion5

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We're all fans of reusability, but this rocket has to be commercially viable without it at the beginning. 
Disagree.  If it isn't reusable, I doubt the price will be compelling to any customers.  I expect to see a sub-scale demonstrator first.  And judging by what I've heard of the grasshopper program, so does the main man.

Well reusability from the beginning would be nice, but I think it's probably going to require some sort of Grasshopper program for the big Falcon X as well.  Spacex's Falcon 9 would not scale well for any mega Falcon with fewer than 8-9 engines.  A single engine on any 3-4 MCT Falcon X would be too much to land on barring the ability to do deep throttling.  As Elon's company hasn't yet developed deep throttling rockets or a fully-functioning Grasshopper, I think a little skepticism is healthy.  If he can pull off the Grasshopper naturally I'll be much less skeptical. 

You think ILS or Intelsat or Iridium or even Bigelow would want to risk half billion dollar amounts on a single launch?
No.  I don't think it will cost half a billion dollars per launch.  Lower costs opens up a lot of other doors, even if it is overpowered for most missions.

I don't think it would cost Spacex half a billion dollars to launch either, sorry I didn't clarify that.  It's just that I remembered there's more than launch costs in getting a satellite to orbit.  You actually have to build the satellite. If you were to build satellites big enough to take advantage of Spacex's payload capacity it wouldn't be the rocket that would be primarily driving costs.  However you could probably overcome this issue by just launching a ton of smaller satellites as primary and secondary payloads.  That'd be my fallback plan if I were Elon until the satellite makers' got big satellite construction costs down. 

Elon and Shotwell were mentioning 150-200 metric tons, and the minimum size considered (7 meters) hints that it'll be modular to hit that figure.  Modularity...
I don`t agree with your "logic".  If the eventual goal is landing 50 tonne infrastructure pieces on Mars in a single launch, then the heavy (modular/crossfeeding) version should be a hekuvalot bigger than 150-200tonnes to LEO.

Sorry if I offended you but can we please just leave the questioning of the others' logic elsewhere?  Let's just have fun speculating.  I've been enjoying many of your other points anyways. 

I agree 150-200 mt is not enough to launch 50 mt infrastructure pieces to Mars.  Elon to me would be under-sizing the Falcon X Heavy if that's the target he's aiming for.  All you have to do is scale up the Falcon Heavy math to see that. 
 
13 mt(Mars capacity)/53 mt =24.5% of LEO capacity
A 150-200 mt launcher would be pushing its limits to put 50 mt on Mars.
50 mt/200 mt=25% of LEO capacity

The 7 m Falcon X Heavy I estimated would peak out at 210 mt to LEO with cross-feed, meaning it would have almost no margin of error to get 50 mt to the Martian surface. 

A 4 MCT Falcon X on the other hand would enable far bigger fairings and a much larger Heavy variant.  Big enough in fact it has room for error setting 50 mt down on the martian surface.  I've assumed Falcon Heavy-like LEO:Mars ratios for payloads.  Methane may however allow even bigger Mars payloads due to higher Isp. 

Falcon X Heavy-229.14 mt to LEO (56 mt to Mars likely)
Falcon X Heavy with cross-feed-270 mt to LEO (56 mt+ likely)
Falcon X Ultra Heavy-382 mt to LEO (93 mt to Mars likely)
Falcon X Ultra Heavy with cross-feed-450 mt to LEO (93 mt+ likely)

You see you wouldn't need a single-stick core with 300 mt of launch capacity.  A 4-MCT Falcon X would be much more commercially viable and you could simply use modularity to scale the payloads from 67-450 mt as needed.  This would allow you to build more cores and more engines, essentially decreasing the flight rate needed to keep the per unit costs down.


Has spacex explicitly said the evolved heavies will all have the same core/booster diameter?
Not that I know of.

Technically a Falcon X with two Falcon 9 boosters would give Spacex a nice, easy way to scale up payloads.  It'd enable customers to order something heavier than the regular Falcon X could fly but too light to justify the overkill of the Heavy variant.  It would however require a second set of propellant lines at the pad. 

My only concern would be that Spacex's flight rate is already going to be rather spectacular in the coming years.  They might prefer building more MCT cores to keep that production line humming rather than stretching Falcon 9 core production to the limits. 
« Last Edit: 10/26/2012 02:27 pm by Hyperion5 »

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