I know SpaceX has no plan for a new US for FH and that they are focused on BFR/MCT for Mars...
Hmm, I think I want to answer this with a high, low, and middle case.The low case is the FH based minimum architecture to put people on Mars and return them safely either as a precursor and to drum up interest (the HSF equivalent of the Musk terrarium on Mars), or as a one shot, this is all we may ever be able to do.
Quote from: TomH on 09/26/2015 06:47 pmQuote from: ssnitrousoxide on 09/26/2015 09:47 amTo some serious aerospace engineers on this site this thread looks like a carnival for Lego rockets, and I think they will have heart attacks reading these posts. Without the depth of the simulations made by experts like Dimitry at least try to support the performance claims with some basic graduate-level calculations. What about we stay away from designing the "dream FH" and use a generic term like "a rocket that is capable of delivering 50mt to LEO", or stick to "vanilla FH" instead? Let SpaceX figure out how they want to evolve FH; I think people here are smart enough to design an architecture without reinventing FH themselves.How about you follow the parameters outlined in the opening post limiting this hypothetical exercise to a Falcon Heavy with new high energy upper stage, rather than trying to hijack the thread and tell us that "we" should use the term generic rocket. This is what...your third post on the forum, but you assume you get to tell us all how someone else's thread has to flow? I don't think so.And here's the irony of it all. Dimitry and Hyperion5 did perform calculations which found Falcon Heavy capable of delivering more than 53 mT to LEO. That was with cross feed, but may not have included super cryo prop. It surely did not include a new US. With a high energy US, the masses being discussed are not unrealistic.The info's all locked up in L2, but if you've got membership, head here: http://forum.nasaspaceflight.com/index.php?topic=37599.msg1375593#msg1375593. We pulled those sims off before Spacex announced the official launch mass figures, so they're a little off. However what I can say is that regardless of whether you use the mass figures we did or the new official ones, the Falcon Heavy is almost exactly as mass-efficient a lifter as a Saturn V was to LEO (you can do the math). There should be little doubt that it will hit the payload figures on their site. It's a very impressive feat for an all-kerolox rocket, and is only beaten by the Delta IV Heavy (RS-68A) and Energia in terms of % of launch mass delivered to LEO. Our sims featured chilled RP-1 & oxygen, whereas I believe Spacex have only recently mentioned using super cryogenic oxygen. Since the Falcon Heavy has slightly more thrust than we initially expected and less launch mass, you can easily get more payload to LEO if you simply chill the RP-1. If you want to get an idea of just how much more potent the rocket might be with a higher-energy methalox upper stage, I suggest you read this thread: http://forum.nasaspaceflight.com/index.php?topic=35533.msg1249705#msg1249705. Most of the performance gain came from the 3rd stage, not the other 2 stages. Thus I would not be terribly shocked to see a 70 tonne payload to LEO IF you added that methalox 3rd stage and chilled the core & booster stages' RP-1. However as this thread is focused on an architecture of the possible, it's probably a mistake to focus too much on hypothetical FH upgrades.
Quote from: ssnitrousoxide on 09/26/2015 09:47 amTo some serious aerospace engineers on this site this thread looks like a carnival for Lego rockets, and I think they will have heart attacks reading these posts. Without the depth of the simulations made by experts like Dimitry at least try to support the performance claims with some basic graduate-level calculations. What about we stay away from designing the "dream FH" and use a generic term like "a rocket that is capable of delivering 50mt to LEO", or stick to "vanilla FH" instead? Let SpaceX figure out how they want to evolve FH; I think people here are smart enough to design an architecture without reinventing FH themselves.How about you follow the parameters outlined in the opening post limiting this hypothetical exercise to a Falcon Heavy with new high energy upper stage, rather than trying to hijack the thread and tell us that "we" should use the term generic rocket. This is what...your third post on the forum, but you assume you get to tell us all how someone else's thread has to flow? I don't think so.And here's the irony of it all. Dimitry and Hyperion5 did perform calculations which found Falcon Heavy capable of delivering more than 53 mT to LEO. That was with cross feed, but may not have included super cryo prop. It surely did not include a new US. With a high energy US, the masses being discussed are not unrealistic.
To some serious aerospace engineers on this site this thread looks like a carnival for Lego rockets, and I think they will have heart attacks reading these posts. Without the depth of the simulations made by experts like Dimitry at least try to support the performance claims with some basic graduate-level calculations. What about we stay away from designing the "dream FH" and use a generic term like "a rocket that is capable of delivering 50mt to LEO", or stick to "vanilla FH" instead? Let SpaceX figure out how they want to evolve FH; I think people here are smart enough to design an architecture without reinventing FH themselves.
Quote from: Hyperion5 on 09/27/2015 02:05 am Thus I would not be terribly shocked to see a 70 tonne payload to LEO IF you added that methalox 3rd stage and chilled the core & booster stages' RP-1. However as this thread is focused on an architecture of the possible, it's probably a mistake to focus too much on hypothetical FH upgrades.I know SpaceX has no plan for a new US for FH and that they are focused on BFR/MCT for Mars. I am interested primarily in a SLS alternative for NASA. The new SLS DRM recently posted is complex, expensive, far into the future, and IMHO faces great obstacles in coming to fruition. I started this thread as a means to examine a realistic alternative based on FH. In that the US is the weak link in terms of FH's utility for deep space, I allowed for the consideration of a new high energy US in the defining parameters. Though I know political considerations are a reality, I wanted to examine solely the technical and financial considerations of such an architecture, initially ignoring politics. If SLS goes down, and BFR/MCT turns out to be Musk having bitten off more than he can chew, I am interested in a realistic alternative of HSF to Mars by NASA and/or SpaceX.
Thus I would not be terribly shocked to see a 70 tonne payload to LEO IF you added that methalox 3rd stage and chilled the core & booster stages' RP-1. However as this thread is focused on an architecture of the possible, it's probably a mistake to focus too much on hypothetical FH upgrades.
Hyperion,Is the 53mt to LEO on SpaceX's website, and your calculations with more with chilled RP-1 (or a high energy upper stage) assuming any booster reusability? Or all boosters expended?I'm assuming that's a fully expended performance number?
...a FH based architecture can use a mix. Where large single pieces are needed a FH can be expended. But there should be a number of architecture pieces that can be cost efficiently launched with at least booster recovery. Would that be up to 30t? Launching fuel might be most efficient with recovery of all 3 first stage cores.
Quote from: Russel on 09/27/2015 05:48 amI'd be perfectly happy with a FH with the 1st stage fully reusable and a decent methalox upper stage.I would be happy with that too.But I would be even more happy with reusable sideboosters but expendable center core for the heavy components. Plus a fully reusable launch vehicle with methalox upper stage for refuelling and lighter components of the architecture and capable of being refueled for earth departure. And once you have that methalox upper stage this would not be too far of a stretch to have.
I'd be perfectly happy with a FH with the 1st stage fully reusable and a decent methalox upper stage.
1) No hydrolox for various SpaceX reasons. Even if NASA is willing to foot the bill for that, I think Elon works to steer them towards methalox, for the main reason of in-situ production if nothing else. 2) Reusable upper stage, and reusable (preferably fully) boosters as there will be a high launch rate, and you don't want to be throwing away a lot of rocket states if you don't have too. High launch rates help make the economics of reusability work. Even if they are only reusable side boosters returning to the launch site and an expended core (or recovered downrange on a barge?)3) Some sort of Mars Ascent Vehicle will be needed to get crews off the Mars surface...and possibly back home too. Red Dragon can only get them to the surface.
Quote from: Lobo on 09/29/2015 03:30 pmHyperion,Is the 53mt to LEO on SpaceX's website, and your calculations with more with chilled RP-1 (or a high energy upper stage) assuming any booster reusability? Or all boosters expended?I'm assuming that's a fully expended performance number?I think that is a safe assumption. Still a FH based architecture can use a mix. Where large single pieces are needed a FH can be expended. But there should be a number of architecture pieces that can be cost efficiently launched with at least booster recovery. Would that be up to 30t? Launching fuel might be most efficient with recovery of all 3 first stage cores.
I personally think a number of sorties should be undertaken before any colonization plan is executed. The confirmation yesterday of flowing water just made the case much more viable. Having groundwater hydrologists, geologists, and biologists examine a number of sites firsthand before determining the best location for Mars Prime seems reasonable. I think a FH based architecture would be the best way to do that scouting before any colonization efforts begin. The latest SLS DRM supports a total of 2 Mars surface missions for untold cost into the 2040s. That's nuts.I would support NASA abandoning SLS/Orion to work with SpaceX on this initial exploration phase with FH, Red Dragon, and a new high energy US. Then let SpaceX continue with less NASA involvement when it moves to BFR/MCT colonization efforts.
I know in the various MCT speculation threads, people want to jump right to the 100 person colonization speculation. But there's going to be probably 2 decades or more of just exploration with smaller 4-7 person crews. NASA would be on board partnering with SpaceX certainly, as they aren't going to let a mission go to Mars without their Astroanuts on it. And Elon has always been eager to work with NASA. NASA will want to do a lot of exploration, for the sake of science and knowledge.SpaceX will want to do a lot of exploration for the sake of locating promising locations to start an outpost which will grow into a base, and then maybe a colony.But for both parties, there will be a lot of sites to check out. And with 1 mission, and maybe later 2 missions per synoid, it'll take awhile to visit various interesting locations around the globe. So this be going on for some time before anyone needs to worry about a number of colonists.
Quote from: Lobo on 09/29/2015 04:26 pm1) No hydrolox for various SpaceX reasons. Even if NASA is willing to foot the bill for that, I think Elon works to steer them towards methalox, for the main reason of in-situ production if nothing else. 2) Reusable upper stage, and reusable (preferably fully) boosters as there will be a high launch rate, and you don't want to be throwing away a lot of rocket states if you don't have too. High launch rates help make the economics of reusability work. Even if they are only reusable side boosters returning to the launch site and an expended core (or recovered downrange on a barge?)3) Some sort of Mars Ascent Vehicle will be needed to get crews off the Mars surface...and possibly back home too. Red Dragon can only get them to the surface.1) Actually production of LH is even easier. It is needed for methane production too. What is more difficult would be handling, storage and reliably reusable engines without refurbishment.
2+3) Similar to MCT concept a reusable upper stage could serve as Earth departure stage after refuelling in LEO and Mars lander and ascent vehicle. It may not be capable enough for direct Earth return. Maybe they could have fuel production on Phobos. One of my pet ideas.
1) Actually production of LH is even easier. It is needed for methane production too. What is more difficult would be handling, storage and reliably reusable engines without refurbishment.
2+3) Similar to MCT concept a reusable upper stage could serve as Earth departure stage after refuelling in LEO and Mars lander and ascent vehicle.
It may not be capable enough for direct Earth return. Maybe they could have fuel production on Phobos. One of my pet ideas.
It is not what people want. It is what Elon Musk has announced. He will settle for a Falcon based architecture only when he fails in building BFR/MCT. And we just happily go along with it.For precursor missions for surveying sites Falcon Heavy + Red Dragon will do with little development effort. I do agree they will be necessary.
I don't believe the discovery of high concentrate brines on the surface has a major impact on settlement or bases. They are seasonal and with a small amount of water. For water supply subsurface ice shields or glaciers are of more importance IMO. Those brine locations may be of some importance for concentrated salt deposits, another resource likely needed long term.
Can I presume you meant "production of hydrogen is even easier" the only reason for liquid hydrogen is to store it in great volume if you were using it as propellant.
Where do you get the carbon for fuel production on Phobos, or do you just produce oxygen there?