Author Topic: MCT Speculation and Discussion Thread 4  (Read 610341 times)

Offline Lobo

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Re: MCT Speculation and Discussion Thread 4
« Reply #880 on: 10/21/2015 10:23 PM »
I really suspect that SpaceX will be doing just BFR development over the next decade while the actual vehicle to mars will continue to be studied and refined without a firm mission architecture until they actually have to cross that bridge.

Even if there is a separate BFR and MCT vehicle, and they aren't integrated like STS, I think they'll need to have some degree of working concept of the MCT vehicle, because it's requirements are what will drive BFR's design.  It will need to be big enough to get MCT to LEO, it can't be any smaller, and it probably won't be any bigger.  So they'd need at least a certain amount of design on the MCT vehicle before they could finalize a BFR design.  But as you say, the BFR could fly first while they are still refining MCT, where the oribiter had to pretty much be finalized before STS could ever fly it's first launch as they were integrated.

Offline Lobo

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Re: MCT Speculation and Discussion Thread 4
« Reply #881 on: 10/21/2015 10:48 PM »
Things do change and I can't wait for the great reveal. I like MCT going all the way and back for a simple reason, not only because Elon Musk said so. It is operationally simple, straightforward and elegant. Making MCT ready for the next flight is a lot simpler down on earth than in space. Getting the weight back up into orbit is not an expensive problem given the capability of BFR.

I agree, with a proviso:

As you add more and more little things to make it work, a straightforward plan can have terrible complexities. Many refueling dockings, transferring people from several Dragons to the MCT, etc... there will be a point where making an easy system work isn't easy.

But otherwise yes... if they can make it work in the simple way envisaged it will make the trip cheaper (which is ultimately the SpaceX goal). And 20 Synods later they'll have a different vision for higher numbers.

That is true, and the MCT vehicle will be complex obviously.  But I don't think it's quite as daunting to have those various roles as many think...if they are related and not opposing.

So, lets start first with the basic MCT vehicle.  What does it need to do at a minimum, from what we know/can plausibly speculate from EM's comments.

1)  It will need to get itself from some sort of Earth orbit to Mars, or else there'd need to be an expendable stage, which wouldn't be reusable, so unlikely I think.
2)  It will need to be capable of atmospheric EDL on Mars...in order to take off against from Mare (unless we are assuming a lander is left like Mars Direct, but then it wouldn't be reusable...so that seems unlikely).
3)   It will need to be a SSTO vehicle for taking off from Mars. 

I think most here agree mostly with those basic functions.

So what what else would we perhaps like it to do?

1)  EDL on Earth, so the whole vehicle comes home.  That's advantageous for many reasons, including refurbishment on the surface rather than in space.  MCT will already be capable of EDL on Mars, and Earth is not too different.  The atmosphere supplies much more dV to decelerate than Mars atmosphere, so no main engine retro propulsion needed.  The atmosphere will slow it down to around 120 MPH.  Only a small amount of retro propulsion needed.  However, the TPS will take more heat, so essentially, to make it capable of Earth EDL, you just need to make sure the TPS can withstand EArth EDL after doing a Mars EDL.  A little thicker layer of PICA-X tiles, for example.  I don't think too difficult....check.

2)  TEI without Mars orbit refueling.  Since MCT already needs to be capable of TMI, TEI is no more difficult.  It a matter of getting it to Mars orbit with enough propellant for TEI.  So mainly a matter of making sure the propellant tanks and propulsion system is of size enough to get that extra propellant off the surface and to Mars orbit, so it can do TEI.  I don't think too difficult.  Larger tanks and thrust...Check.

3)  In the case of an integrated design, MCT gets itself from booster staging to LEO.  But MCT will alrady be a SSTO vehicle to get off Mars.  It's really not different on Earth, but the dV is larger because of Earth's deeper gravity well.  So we put a reusable booster under it to supply that extra dV...I don't think anyone assumed any different anyway...Check.

4)  Using one common MCT hab for transit both ways and on the surface.  Well, if the rest of the above is true, MCT will get itself to Mars, land itself, stay on Mars, then get itself back off MArs, and get itself back to Earth.  So no need for a second hab, the primary hab will service the crew for the entire trip.  It needs to be designed for zero-g operation and Mars gravity operation.  That's not a given, but I don't think it too hard either.  Especially for a smaller crew of 6-7 for the early exploration missions.  Once there's a colony, then the colonists will use the facilities already on the surface when they get there and not need to habitate in MCT.
So, a hab designed to support 6-7 astronauts in gravity as well as in zero-g...shouldn't be a big issue...so check.

People like to look at the compromise design of the shuttle as an example of trying not to do too much.   But remember, those were competing design criteria it had to deal with, not complementing design criteria like MCT. 

Where with the shuttle, as I understand...NASA, USAF, and politicians all had some quite different requirements that STS had to do if it was going to get joint support and funding.  Many of which didn't really have anything to do with what NASA needed STS to do.    MCT won't really have that problem, as it can focus only on what EM wants it to do without anything competing with that.
It's not going to have big companies like LM and ATK causing political pressure for certain hardware to be used, they won't have USAF requiring things like on-pad payload change out and a excessive cross range to to enable single polar orbit spy satellite deployment/capture in there pressuring the design to vary from it's primary goals.  It won't need features and hardware just so a politician can bring political pork back do their district.

So, most of these things are just a little in addition to a primary function MCT will need to do already, rather than competing with a primary function.  So I don't think it necessarily will had huge amounts of complexity to MCT, and it can add a lot of mass and economic efficiency to it by reducing the number of different vehicles and systems required to develop and maintain overall.

IMHO.
« Last Edit: 10/21/2015 10:57 PM by Lobo »

Offline Impaler

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Re: MCT Speculation and Discussion Thread 4
« Reply #882 on: 10/21/2015 11:18 PM »
Has anyone considered the possibility that the upcoming reveal will just be the Rocket, aka BFR, and not in fact the whole system?  I really suspect that SpaceX will be doing just BFR development over the next decade while the actual vehicle to mars will continue to be studied and refined without a firm mission architecture until they actually have to cross that bridge.

That is precisely my thinking.
The BFR is congruent with SX's core competency and is a necessary precursor. Even it will undergo changes after hopefully SX succeeds in recovering and re-flying F9 cores. 

I think Musk will speak to the MCT issue, but still in vague terms.  Even were he somewhat specific I don't think many observers here would expect the details to hold true during what I expect would be a longer than a decade gestation for the Block One MCT, which I expect to be quite different from its folllow-on.
There are too many outside SX technology developments ongoing* to fixate and spend R&D $ on a MCT in this decade, and probably for the early part of the next.

*SEP panels & engines, plasma propulsion, magneto aero capture, life support systems tech, etc. 
Never mind extreme wildcards like one of the myriad small fusion projects actually working.

I sure we will get some nice video of a giant rocket taking off.  It might just have some totally ambiguous payload-fairing on it leaving everything beyond the launch unspecified much the way Vulcan was introduced, this would be a clear sign that they are shopping BFR around to commercial customers, but even I would find that a bit conservative given the hype that has been built up.

More likely were shown some kind of large mars vehicle reaching LEO on top of the BFR.  But then the video might just cut to said vehicle landing on mars with all the details of refueling, trajectory, aerocapture, entry etc etc left out.  Or on the opposite end of the spectrum we could see a nearly full 'architecture' which covers all these steps and Musk will be open with the numbers.

But even the most minimal video will give some ideas as to what the present preferred architecture is and one of the three camps of 'Super Dragon', 'Integrated Bi-conic' and 'Separate Bi-conic' will likely get to crow, despite the fact that the shown architecture is still in flux, given the kind of 'Holy writ' that people ascribe to offhand statements of Musk their will be no point arguing with a video. 

The speculation would then narrow down to other operational details of how the vehicle actually dose the mission and what the ultimate cost will be, how fast if at all SpaceX can put the vehicle into service, if SLS is doomed and when first landing on mars might happen.

Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #883 on: 10/21/2015 11:36 PM »
Has anyone considered the possibility that the upcoming reveal will just be the Rocket, aka BFR, and not in fact the whole system?  I really suspect that SpaceX will be doing just BFR development over the next decade while the actual vehicle to mars will continue to be studied and refined without a firm mission architecture until they actually have to cross that bridge.

That is precisely my thinking.
The BFR is congruent with SX's core competency and is a necessary precursor. ...
You seem to forget that Dragon is clearly also SpaceX's core competency. Dragon is at least as impressive as F9 is. And what will the second stage of BFR be? MCT and BFR's second stage are solving almost all the same problems. The ones that are left are ones that Dragon is helping to solve.
Quote
...
There are too many outside SX technology developments ongoing* to fixate and spend R&D $ on a MCT in this decade, and probably for the early part of the next.

*SEP panels & engines, plasma propulsion, magneto aero capture, life support systems tech, etc. 
Never mind extreme wildcards like one of the myriad small fusion projects actually working.
Um, SpaceX is absolutely working SEP panels/engines/plasmapropulsion and life support systems tech right now. Magneto aerocapture is a totally unproven idea that is only really being pursued by one company (with nearly no funding), and it will remain to be seen if it's either practical or worthwhile. Regardless, evangelists for the tech (mainly Jon Goff here ;) ) seem to emphasize its ability to allow /existing/ tech to utilize it, so SpaceX need not put off developing MCT even if it's a totally real thing. And I would put even less faith in the small fusion projects.


...and anyway, developing BFR first doesn't make ANY sense. There's nothing for them to launch with it! And then they have to pay for the upkeep of that expensive infrastructure. That's exactly the sort of senseless thing that NASA would do (ahem), not SpaceX.

And I guarantee you that whenever Elon gets around to announcing this, it's not going to merely be BFR. SpaceX has a much more solid grasp on this stuff than folks like you and Impaler, who insist on handicapping the architecture in weird ways.
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Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #884 on: 10/21/2015 11:37 PM »
Developing BFR first wouldn't make any sense. It'd be a total waste of resources.
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Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #885 on: 10/21/2015 11:38 PM »
MCT need not be more "complex" than a combination of what we've seen for SpaceX's reusable F9 upper stage (now obsolete) and crew Dragon. Just bigger and using Methane. Don't overthink it.
« Last Edit: 10/21/2015 11:40 PM by Robotbeat »
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Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #886 on: 10/21/2015 11:50 PM »
Has anyone considered the possibility that the upcoming reveal will just be the Rocket, aka BFR, and not in fact the whole system?  I really suspect that SpaceX will be doing just BFR development over the next decade while the actual vehicle to mars will continue to be studied and refined without a firm mission architecture until they actually have to cross that bridge.

That is precisely my thinking.
The BFR is congruent with SX's core competency and is a necessary precursor. Even it will undergo changes after hopefully SX succeeds in recovering and re-flying F9 cores. 

I think Musk will speak to the MCT issue, but still in vague terms.  Even were he somewhat specific I don't think many observers here would expect the details to hold true during what I expect would be a longer than a decade gestation for the Block One MCT, which I expect to be quite different from its folllow-on.
There are too many outside SX technology developments ongoing* to fixate and spend R&D $ on a MCT in this decade, and probably for the early part of the next.

*SEP panels & engines, plasma propulsion, magneto aero capture, life support systems tech, etc. 
Never mind extreme wildcards like one of the myriad small fusion projects actually working.

I sure we will get some nice video of a giant rocket taking off.  It might just have some totally ambiguous payload-fairing on it leaving everything beyond the launch unspecified much the way Vulcan was introduced, this would be a clear sign that they are shopping BFR around to commercial customers, but even I would find that a bit conservative given the hype that has been built up.

More likely were shown some kind of large mars vehicle reaching LEO on top of the BFR.  But then the video might just cut to said vehicle landing on mars with all the details of refueling, trajectory, aerocapture, entry etc etc left out.  Or on the opposite end of the spectrum we could see a nearly full 'architecture' which covers all these steps and Musk will be open with the numbers.

But even the most minimal video will give some ideas as to what the present preferred architecture is and one of the three camps of 'Super Dragon', 'Integrated Bi-conic' and 'Separate Bi-conic' will likely get to crow, despite the fact that the shown architecture is still in flux, given the kind of 'Holy writ' that people ascribe to offhand statements of Musk their will be no point arguing with a video. 

The speculation would then narrow down to other operational details of how the vehicle actually dose the mission and what the ultimate cost will be, how fast if at all SpaceX can put the vehicle into service, if SLS is doomed and when first landing on mars might happen.
What Musk says isn't "holy writ." You don't have to like it, but if you're going to discuss MCT, you have to actually discuss /MCT/ (which means what little we have to go on), not make up your favorite architecture in its place. You can do that in the Mars subsection of the more general forum.
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Offline GregA

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Re: MCT Speculation and Discussion Thread 4
« Reply #887 on: 10/22/2015 12:52 AM »
Yes EM's said it. I think it was something like "you need a really big f'ing rocket, a BFR". But if that memory is correct, then he wasn't really calling it a BFR at the time... just describing it.

If that was the only mention of it, then the context still doesn't seem to indicate differentiation between a launch vehicle and a spacecraft  f he was saying to land 100mt on Mars, you need a really big f'ing rocket...for example...there's nothing in that to indicate a stand alone rocket, and a separate spacecraft. 

I'm more saying, was there a reference to "BFR" and "MCT" being referred to separately in the same comment, like how "Dragon" and "Falcon" are referred to differently in the same comment.  If so, then there could be a reasonable chance EM will just be announcing the LV.  Although even then, it's main purpose would be to loft MCT to space, just like the main purpose of the Saturn V was to loft the Apollo CSM and LEM through TLI.  The spacecraft were in the "unveilings" from the beginning.  Even when it was originally Direct Ascent instead of LOR. 
So I would expect something like that for this unveiling.  At least a working concept for the spacecraft, even if there is a stand alone LV.

But good to know that EM actually did use the term.  I'd not been aware of that.  :-)

He has used the term BFR several times I'm sure, but the whole area has been vague and I think his early comments were of a generic sense (a big rocket) - slowly converting to his own code name (given his naming of the barges, "Insane" mode on Tesla's and volume going up to 11, I think the name might stick - especially if it has a legitimate interpretation too).

I don't think I've heard him use the terms MCT and BFR when spelling it out but someone here must remember better. He has spoken about "landing the whole thing" which I've interpreted as MCT, as well as needing a BFR to get to orbit, so I think it's a fairly safe assumption that we've made.

Offline GregA

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Re: MCT Speculation and Discussion Thread 4
« Reply #888 on: 10/22/2015 12:55 AM »
This might be useful Lobo

[Question about getting to Mars.] I don't think the Moon is a necessary step, but I think if you've got a rocket and spacecraft capable of going to Mars, you might as well go to the Moon as well - it's along the way. That's like crossing the English Channel, relative to Mars. So, it's like, if you have these ships that could cross the Atlantic, would you cross the English Channel? Probably. It's definitely not necessary, but you'd probably end up having a Moon base just because, like, why not, ya know. It terms of the key technologies, obviously it would be great to have some sort of fundamental new thing that's never existed before and pushes the boundaries of physics, that'd be great, but as far as the physics that we know today, I actually think we've got the basic ingredients - they're there. I mean, if you do a densified liquid methalox rocket with on-orbit refueling, so like you load the spacecraft into orbit and then you send a whole bunch of refueling missions to fill up the tanks and you have the Mars colonial fleet - essentially - that gets built up during the time between Earth-Mars synchronizations, which occur every 26 months, then the fleet all departs at the optimal transfer point. I think we have - we don't need any sort of thing that people don't already know about, I believe. I believe we've got the building blocks, but the mass efficiency is extremely important. So, having better heat shields, that obviously are reusable.

http://shitelonsays.com/transcript/elon-musk-at-mits-aeroastro-centennial-part-2-of-6-2014-10-24

and this from 2005:

In past talks Musk has hinted at the development of something called the “BFR” (where B stands for “big” and R for “rocket”), a heavy-lift vehicle far larger than the Falcon family of vehicles. At SpaceVision2005 Musk disclosed that the BFR, in its current iteration, would use “multiple” Merlin 2 engines. The BFR would be able to place 100 tons in low Earth orbit, putting it in competition with NASA’s planned shuttle-derived heavy-lift launcher. The BFR is so big, Musk said, that it’s too large for the BFTS at their Texas test site...

http://www.thespacereview.com/article/497/1
« Last Edit: 10/22/2015 01:04 AM by GregA »

Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #889 on: 10/22/2015 03:08 AM »
This might be useful Lobo

[Question about getting to Mars.] I don't think the Moon is a necessary step, but I think if you've got a rocket and spacecraft capable of going to Mars, you might as well go to the Moon as well - it's along the way. That's like crossing the English Channel, relative to Mars. So, it's like, if you have these ships that could cross the Atlantic, would you cross the English Channel? Probably. It's definitely not necessary, but you'd probably end up having a Moon base just because, like, why not, ya know. It terms of the key technologies, obviously it would be great to have some sort of fundamental new thing that's never existed before and pushes the boundaries of physics, that'd be great, but as far as the physics that we know today, I actually think we've got the basic ingredients - they're there. I mean, if you do a densified liquid methalox rocket with on-orbit refueling, so like you load the spacecraft into orbit and then you send a whole bunch of refueling missions to fill up the tanks and you have the Mars colonial fleet - essentially - that gets built up during the time between Earth-Mars synchronizations, which occur every 26 months, then the fleet all departs at the optimal transfer point. I think we have - we don't need any sort of thing that people don't already know about, I believe. I believe we've got the building blocks, but the mass efficiency is extremely important. So, having better heat shields, that obviously are reusable.

http://shitelonsays.com/transcript/elon-musk-at-mits-aeroastro-centennial-part-2-of-6-2014-10-24

and this from 2005:

In past talks Musk has hinted at the development of something called the “BFR” (where B stands for “big” and R for “rocket”), a heavy-lift vehicle far larger than the Falcon family of vehicles. At SpaceVision2005 Musk disclosed that the BFR, in its current iteration, would use “multiple” Merlin 2 engines. The BFR would be able to place 100 tons in low Earth orbit, putting it in competition with NASA’s planned shuttle-derived heavy-lift launcher. The BFR is so big, Musk said, that it’s too large for the BFTS at their Texas test site...

http://www.thespacereview.com/article/497/1
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Online MikeAtkinson

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Re: MCT Speculation and Discussion Thread 4
« Reply #890 on: 10/22/2015 09:05 AM »
Has anyone considered the possibility that the upcoming reveal will just be the Rocket, aka BFR, and not in fact the whole system?  I really suspect that SpaceX will be doing just BFR development over the next decade while the actual vehicle to mars will continue to be studied and refined without a firm mission architecture until they actually have to cross that bridge.

SpaceX are in a unique position where they can design several things in parallel:

1. Rocket engines - Raptor
2. Booster - BFR
3. Spacecraft - MCT (crew/cargo + tankers)
4. Mission architecture(s) - Mars (+perhaps Moon and others)
5. Ground infrastructure (factories, test and launch facilities)

This is a big advantage in both time and money. It is almost the exact opposite to SLS/Orion used for Mars where the engines, rocket and spacecraft are already designed (and based on earlier versions) and the mission architecture has to adapt to those.

At some point things have to be nailed down: e.g. rocket thrust and Isp, booster size and payload - and this then allows more detailed design of the other elements. It is not necessary, and probably not a good idea, for the final architecture and supporting mission elements to be created initially, just a reasonable stab at it and the flexibility to change things in reaction to changing circumstances.

But I see no reason for SpaceX to give up one of their big advantages - the ability to design and evolve all elements in parallel. The idea that they will create a BFR over the next decade and only then firm up the MCT and mission architecture is silly. NASA have done this with SLS/Orion and we've seen how it limits them as the cost of maintaining the capability is so high. SpaceX can probably maintain BFR capability much cheaper than NASA with SLS, but SpaceX have far more limited resources and so creating a BFR with no near-term missions is just as unaffordable.


Offline Semmel

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Re: MCT Speculation and Discussion Thread 4
« Reply #891 on: 10/22/2015 10:45 AM »
Lobo is on the right track here. Before jumping to design solutions, we need to find the requirements for BFR and MCT first. Thats like engineering 101. That hasn't been happening to the extend needed to define an MCT or BFR. Lobo just started that process and I am very glad he did it.

Offline symbios

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Re: MCT Speculation and Discussion Thread 4
« Reply #892 on: 10/22/2015 01:05 PM »
Lobo is on the right track here. Before jumping to design solutions, we need to find the requirements for BFR and MCT first. Thats like engineering 101. That hasn't been happening to the extend needed to define an MCT or BFR. Lobo just started that process and I am very glad he did it.

This discussion has been ongoing on and of since the first post of the first thread of the MCT. the problem is that there is as many version of the requirements as there is people posting. Especially since not one can even agree what the MCT should be able to do.

So if you can nail that down I would recommend you for the Nobel peace price.
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Offline GregA

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Re: MCT Speculation and Discussion Thread 4
« Reply #893 on: 10/22/2015 01:06 PM »
Lobo is on the right track here. Before jumping to design solutions, we need to find the requirements for BFR and MCT first. Thats like engineering 101. That hasn't been happening to the extend needed to define an MCT or BFR. Lobo just started that process and I am very glad he did it.
Agree that's necessary - but I believe he and a few others with the appropriate knowledge have been getting into those requirements for quite some time - and from that trying to ascertain what could work that still fits within what EM has said.

(Or did I miss some new approach?)


Offline Lobo

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Re: MCT Speculation and Discussion Thread 4
« Reply #894 on: 10/22/2015 05:02 PM »
Lobo is on the right track here. Before jumping to design solutions, we need to find the requirements for BFR and MCT first. Thats like engineering 101. That hasn't been happening to the extend needed to define an MCT or BFR. Lobo just started that process and I am very glad he did it.
Agree that's necessary - but I believe he and a few others with the appropriate knowledge have been getting into those requirements for quite some time - and from that trying to ascertain what could work that still fits within what EM has said.

(Or did I miss some new approach?)

That's mainly what I've been trying to do anyway.  :-)
Ironically, SpaceX's actual concept may not have much to do with EM's previous comments if the design work leads them in other directions.  But for us, it's all we have to go on.  heh.

I think the booster (whether that is one stage or two stages) will be wholly dictated by the needs of MCT and it's design.  If it's an integrated design, the booster will be just one piece.  If it's a non integrated design, then the booster will need to be two pieces.  That's pretty important to know for booster design.
Then depending on what MCT's payload really needs to be (100mt assumed at this point), the dry mass of MCT will be dictated by what's needed to get that to Mars in a reusable vehicle, pluswhatever other features you want to have.  After you have a reasonable idea of all of that, only then can you really start designing the booster. 
So I have a hard time seeing the booster design first, and then MCT's design to be just whatever the booster ends up being able to lift.  I don't think they'd want to risk that the booster ended up being too small...or overly large (which can mean more expensive and complex and difficult than necessary). 

Whatever system -that- ends up being, then may have an unmanned payload delivery capability of X tonnes, which will probably be quite a bit more than any current systems next to SLS.  So it could readily compete for payload that would otherwise need a D4H or a fully expendable FH (or SLS).  But that will be more a secondary objective that will be a result rather than a design criteria.  Just as the Apollo Program's requirements drove the Saturn V's design, the resultant design would have then been a pretty capable LV for launching unmanned payloads...like whole space stations.  :-)
I would think similar for MCT.  Having a non integrated MCT might be better for that purpose, but again, I think that will be a resultant, rather than a design driver.  They'll design MCT and the booster for the most efficient way to send cargo and crew to Mars.  And whatever else it can do, is just bonus.


« Last Edit: 10/22/2015 05:08 PM by Lobo »

Offline philw1776

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Re: MCT Speculation and Discussion Thread 4
« Reply #895 on: 10/23/2015 02:13 PM »
Musk has worked out just enough about potential "MCT" approaches that he has a generic requirement for his BFR launcher.  I am certain that he has explored the solution space for Mars transport and wants a launch capability that can support solutions from all chemical solution to SEP/chemical hybrid transport and other possible more exotic solutions.  Technology over a >10 year timeframe does not stay still.  The 1st and  2nd stage need only be able to get the 100mT cargo plus MCT dry weight into appropriate LEO.  If all his broad brush Mars transport solution space fits within these parameters and their evolutionary improvements (e.g.Merlin to Merlin FT), he's good to go.

Assuming that this time he really does give us more insight into his plans as promised for later this year, I am certain that the MCT portion of the architecture vs what actually flies a decade or more from now will have substantial differences.  SX has yet to fly a single crewed Dragon mission and yet to learn the lessons necessary to demonstrate a core competence in this area.  So, the Block One MCT will likely again be different from the MCT that lands the first crew on Mars June 2033 following the un-crewed MCT bringing the ISRU equipment May 2031.
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline TrevorMonty

Re: MCT Speculation and Discussion Thread 4
« Reply #896 on: 10/23/2015 06:28 PM »

Offline JasonAW3

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Re: MCT Speculation and Discussion Thread 4
« Reply #897 on: 10/23/2015 07:30 PM »
Sleeping your way to mars.

http://www.parabolicarc.com/2015/10/23/snooze-mars/

Yeah, only problem I'd have is that I snore.
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Offline Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #898 on: 10/23/2015 11:37 PM »
Musk has worked out just enough about potential "MCT" approaches that he has a generic requirement for his BFR launcher.  I am certain that he has explored the solution space for Mars transport and wants a launch capability that can support solutions from all chemical solution to SEP/chemical hybrid transport and other possible more exotic solutions.  Technology over a >10 year timeframe does not stay still.  The 1st and  2nd stage need only be able to get the 100mT cargo plus MCT dry weight into appropriate LEO.  If all his broad brush Mars transport solution space fits within these parameters and their evolutionary improvements (e.g.Merlin to Merlin FT), he's good to go.
But why build BFR first? BFR has the most infrastructure requirements. Additionally, you're making the implicit assumption that MCT isn't essentially BFR's second stage. I really, REALLY don't expect SpaceX to make the same mistake NASA is currently making by building a super-expensive-to-develop-and-maintain launch vehicle without really anything to launch.


Quote
... So, the Block One MCT will likely again be different from the MCT that lands the first crew on Mars June 2033 following the un-crewed MCT bringing the ISRU equipment May 2031.
I have no doubt MCT will evolve, but your timeline is not the same as SpaceX's timeline. They expect crewed missions much earlier. Which makes sense, as it doesn't make sense to develop a capability and then essentially just let it languish, sucking up money while nothing is accomplished (another mistake NASA is making, though this is mostly Congress's fault).
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Offline philw1776

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Re: MCT Speculation and Discussion Thread 4
« Reply #899 on: 10/24/2015 01:43 AM »
Musk has worked out just enough about potential "MCT" approaches that he has a generic requirement for his BFR launcher.  I am certain that he has explored the solution space for Mars transport and wants a launch capability that can support solutions from all chemical solution to SEP/chemical hybrid transport and other possible more exotic solutions.  Technology over a >10 year timeframe does not stay still.  The 1st and  2nd stage need only be able to get the 100mT cargo plus MCT dry weight into appropriate LEO.  If all his broad brush Mars transport solution space fits within these parameters and their evolutionary improvements (e.g.Merlin to Merlin FT), he's good to go.
But why build BFR first? BFR has the most infrastructure requirements. Additionally, you're making the implicit assumption that MCT isn't essentially BFR's second stage. I really, REALLY don't expect SpaceX to make the same mistake NASA is currently making by building a super-expensive-to-develop-and-maintain launch vehicle without really anything to launch.

philw1776:  No, I see the MCT as the BFR stage 2.  Just its specifics beyond engines & tankage at TBD.  I see several cargo refueler MCTs as does Musk to fuel up the transit MCT.

Quote
... So, the Block One MCT will likely again be different from the MCT that lands the first crew on Mars June 2033 following the un-crewed MCT bringing the ISRU equipment May 2031.
I have no doubt MCT will evolve, but your timeline is not the same as SpaceX's timeline. They expect crewed missions much earlier. Which makes sense, as it doesn't make sense to develop a capability and then essentially just let it languish, sucking up money while nothing is accomplished (another mistake NASA is making, though this is mostly Congress's fault).

Musk NEVER meets schedule, hence my timeline.  I see him as cash flow limited for R&D for BFR and MCT.
« Last Edit: 10/24/2015 01:44 AM by philw1776 »
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

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