Author Topic: FH Based Mars Architecture  (Read 44062 times)

Offline MP99

Re: FH Based Mars Architecture
« Reply #40 on: 09/27/2015 07:19 pm »
I know SpaceX has no plan for a new US for FH and that they are focused on BFR/MCT for Mars...

http://forum.nasaspaceflight.com/index.php?topic=35529.msg1249513.msg#1249513

Gwynne Shotwell:-

"I'll talk very briefly about Falcon Heavy. So from a commercial perspective Falcon Heavy, it's an over-sized vehicle. Its got more capacity than folks in this room need - unless we wanna put two of the biggest satellites on this vehicle and fly them both to GTO. That would yield a pretty respectable price for folks. But what we are really trying to do is, push the bounds of technology with respect to size of launch vehicles, and see if we can put some really interesting things into the solar system and hopefully land some things on Mars as well. This will be the largest vehicle flying since the Saturn moon rockets. We're sandbagging the GTO-numbers, actually analytically it looks like were gonna take 19 tons to GTO. But we're being conservative, with the 12 metric tons. And this will be - hopefully - a vehicle that takes many things to Mars."
« Last Edit: 09/27/2015 07:20 pm by MP99 »

Offline MP99

Re: FH Based Mars Architecture
« Reply #41 on: 09/27/2015 07:26 pm »
Given that the issues with EDL increase with payload mass, ISTM to make sense to send multiple payloads in FH-sized chunks.

Cheers, Martin

Offline nadreck

Re: FH Based Mars Architecture
« Reply #42 on: 09/27/2015 08:02 pm »
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.

So here below is my "low case" I will do the middle case as well but probably won't get it done till sometime during the week.

The low case

The goal here is the lowest complexity and cost program to put boots and flags on Mars send back selfies with them and bring back some rocks and stuff. Where we go from there is not the concern of this mission architecture. However this is not Mars One, I am not presenting any higher a risk endeavour than I would if long term colonization were the goal. The intention is an architecture that as safely as practical returns astronauts to Earth. The budget here comes out to $8.7 B, and has humans leaving for Mars by 2024, my “high case” had the same date for humans headed for Mars but had spent about $14B by then (though it did charge $4B for taking 4 scientists on its first manned expedition). While my cost estimates are really unlikely to be accurate. I have a 90% confidence in both phase 1 budgets, 70% in the phase 2’s, 65 in the phase 3s,  60% in the low case phase 4 and 50% in the high case phase 4, and 50% in the low case phase 5 and only about 35% in the high case phase 5 and most of you should multiply those confidence rates by whatever confidence rate you have in me. ;)

A one way flight to Mars is relatively easy to contemplate with the FH the way it is expected to appear in the coming spring. Leveraging the moderate capability to launch to TMI and the respectable payload to LEO into the logistics to support a manned expedition to Mars is a relatively straight forward task. The complexity though comes in with trying to come up with an effective and minimal way to put the elements in place needed to take astronauts landed on Mars back to Earth.  In working on my “high case” I conceived of a relatively uncomplicated MAV that used a 7t Dragon 2 and trunk sitting on top of a hydrazine/di-nitrogen tetroxide SSTO massing 33t with 29t of propellant, however to land those 40t on Mars I needed another 35t of heat shield and lander which, even if you refuel the existing Falcon US in LEO the absolute best you can put in TMI is 40t. 

To launch a manned mission to Mars using FH technology with or without a new upper stage seems to me to require a propellant depot and that at that depot you not only refuel either existing upper stages or develop deep space stages that are fueled there too, but that there is “some assembly required” to get the TMI transit environment, manned Mars lander, and Mars Ascent Vehicle and TEI booster all where they need to go.  As with my “high case”, and presumably when I get to my middle case I will present it the same, what follows outlines my best projections for timeline, costs, and rough technical outline of the technologies needed.

So in considering this “low case” minimum architecture I am going to consider the following absolute minimum mission requirements for redundancy in ECLSS, MAV, Transit Hab, TEI return booster, surface Hab (including ECLSS), communications relay, and pressurized wheeled excursion vehicle.  The majority of the 14 months at Mars will be spent with the crew on Mars.  There will be less emphasis on site assessment, there will be no construction of “dug in” habs, no ISRU, a far simpler communications relay satellite system.

So the phases of this architecture are:

2016-2017

1E Development and testing of equipment and technologies for EDL for cargo delivery, relaying communications, avionics/guidance, power generation, support rover.

Phase 1 launches 1 shared to GEO $25M

Phase 1 development budget ($127M):

Mars synchronous orbital satellite development and prototype test in GEO $25
Red Dragon lander development: $50M beyond what is being spent to develop manned D2
Develop hexaped rover: $50M
Develop reels of thin film solar panels to be deployed by rovers: $2M

Total $152M

2018-2019

2E Develop lander capable of EDL of up to 40t of payload on the surface in a direct in approach without capture (mass 35t with hydrazine/di nitrogen tetroxide propellant, jettisonable TPS, and 5 engines of 150 kn thrust each). Develop a Falcon upper stage based ZBF propellant depot using 4 upper stages, a liquid nitrogen based regenerative cooling system,

2M Launch Red Dragon to Mars to prospective landing site, deploy rovers to characterize the site, before EDL of the Dragon the trunk separates and via SEP thrusters, Dracos and judicious Aerocapture and braking sets itself in a synchronous orbit that has a good vantage on the landing site to act as relay. Note that while there are 4 thin film solar panel rolls aboard the Red Dragon and 3 hexaped rovers, it is expected that simply laying the thin film solar panels along the ground will result in gradual degradation so initially 2 rolls are layed out, but a hexaped rover and the remaining two rolls are kept in reserve to be deployed when needed. The initial power budget would be a peak power of 40kw and expected to average 200kwh a day of useable energy which could allow 50kwh use in the day time and 50kwh of night time use under ideal conditions. If there was a 200kwh power storage and a hibernate mode of operations that could allow vital systems to survive (and keep all necessary systems warm enough with 500w of continuous power at the coldest temperatures) then the probe should be able to survive through to the next arrivals and beyond.

Phase 2 Launch budget $125M: 

1FH centre core expendable $75M + Red Dragon $50M

Development budget ($725M)

Develop high thrust (150kn) vacuum optimized hydrazine/di-nitrogen tetroxide engine $25M
Develop lander unit with avionics and berthing mechanism for payload as well as TPS $500M (includes Earth re-entry test to refine accuracy of avionics)
Develop depot module that would berth to 4 upper stages to create the propellant depot and to a 5th that would either be an incoming tanker or outgoing client upper stage being refueled. Requires significant solar power and uses SEP thrusters for station keeping and spin-up/spin-down. Second stages used with it require a layer of insulation in the RP-1 tank at the boundary with the Lox tank as well as a heater. $200M

Total $850M

2020-2021

3E Evaluate performance of landers in 3M and tweek designs, programing as necessary to ensure adequate precision for landers in next launch window. Develop MAV/TEI booster modules 3 engine for MAV, 1 for TEI, mass 33t wet 4t dry(MAV) 3.5t dry(TEI).  Develop 7t dragon 2 variant for use with MAV. Develop a surface hab module with expandable elements that can be landed with the heavy lander include low pressure (100bar) inflatable section with rigid supports that can be used as a hanger/garage work area that can be inflated deflated as needed to move vehicles and other equipment in and out of, hab unit must have ECLSS support for 6 people, and with the supplies from the first lander it would meet the air/water needs of 6 people for 2 years (note 2 will be sent along with a redundant oxygen/water/solar supply craft).  Develop a pressurized vehicle with a 200kwh battery system, deployable & re-spooling thin film solar power supply (same as Red Dragon’s) with ECLSS for 4 people.

3M Launch a Red Dragon and a heavy lander to Mars, heavy lander to arrive first, attempts to approach and land at the same spot as previous Red Dragon location. This lander brings storable logistics supplies, O2 5t + 10t in tank mass and plumbing, water 12t + 3t tanks and plumbing, expedition solar farm equipment 10t. Red Dragon targets landing within 100m of heavy lander as with the first it deploys solar and if possible hooks up power sharing line with heavy lander also trunk separates before EDL and as with previous positions itself in synchronous orbit to provide a redundant relay.

Phase 3 launch budget $715M

1FH centre core expendable $75M + Red Dragon $50M
1FHR with depot module $40M + $10M for modified US (insulation, berthing adapter, plumbing)
3FHR with modified upper stage for depot $150M includes 75t of propellant for the depot.
1F9R with Dragon V2 for depot assembly work (attaching plumbing and support cross bar at tank end opposite berthing connector) supervising a test spin up/down, setting sun shade support structure $100M
4FHR with tanker modified US (stretch and with avionics, thrusters, berthing mechanism, nose cone) $180M
1 FHR with Mars lander unit $40M + $50M for first 40t lander with EDL secure berthing connectors for payload
1 FHR with Payload module for Mars lander unit (rendezvous and berths to lander unit after TMI) $40M + $10M for payload module

Development budget $1.05 B

MAV/TEI boosters $100M
MAV dragon $50M
Hab development $500M
Pressurized vehicle development $350M
Continued refinement of previously developed technology $50M
Total $1.765 B

2022-2023

4E Develop Mars surface lab module with ECLSS for 6 and equipment to analyse atmospheric, surface and core samples. Develop towable single stand drill rig capable of drilling 1000 meters. After the 2022 launches land at Mars determine if the crew of 6 for the 2024 mission will land on two modified Red Dragons or if they will all ride down on the 2nd MAV. Develop modified BA330 transit Hab that can dock with rigid support allowing 2g acceleration, when not expanded, to a dragon and trunk.

4M Launch 1st surface Hab module, 2nd oxygen/water/solar logistics module, 1st pressurized vehicle, 1st food, clothing and other consumables logistics.

Phase 4 launch budget $1.595 B

4 FHR launches with lander modules mated to upper stages to be refueled $300M ($35M per lander)
4 FHR launches with lander payloads $160 + 1x Hab $50M, 1x Oxygen/water/solar payload $10M, 1x MAV $75M, 1x pressurized vehicle (20t including ramp/deployment) and 20t of food and other consumables logistics $100M – sub total $395M all cargos rendezvous with and securely berth to landers after TMI
20 FHR tankers $900M

Development budget $700M

Develop transit hab $200M
Develop surface lab based on Hab ECLSS $200M
Develop mobile Mars Drill rig $200M
Continued refinement of previously developed technologies $100M

Total $2.295 B

2024-2027

5M Launch manned mission with 5 support landers – note while this plans to have all crew return during the 2026 Mars Earth window, a decision to extend the mission, or support the Mars installation as a permanent base could be made and some crew and samples return on one of the MAV’s and with one of the habs/TEI’s in orbit if a second expedition were launched in the 2026 Earth Mars window. Habs with 2 TEI’s and one dragon attached are launched to Mars, one TEI is used to put the transit HAB in a low Mars orbit 2nd to launch it and a dragon back to earth. Splash down of that dragon is in 2027.

Phase 5 launch budget $3.635B

5 FHR launches with lander modules mated to upper stages to be refueled $375M ($35M per lander)
5 FHR launches with lander payloads $160M + 1x surface Hab $50M, 1x Mars surface lab $200M, 1x MAV $75M, 1x pressurized vehicle (20t including ramp/deployment) and 20t of food and other consumables logistics $100M, one mobile drill rig and 1000 meters of drill pipe $50M– sub total $635M
2 FHR launches with transit habs and logistics for 2 years for six people on each. $180M
1 F9R launches with dragon V2 one with 6 crew $100M
6 FHR launches with 6TEI’s each arranged 2 TEI’s rendezvous and berth securely with transit Habs the other 4 TEI’s rendezvous and berth into pairs to leave 2 full TEI’s to rendezvous with transit Habs in Mars Orbit. $420M
45FHR tankers $2.025 B


Edit: missed indicating whether something was Millions or Billions above
« Last Edit: 09/28/2015 03:13 am by nadreck »
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Offline MATTBLAK

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Re: FH Based Mars Architecture
« Reply #43 on: 09/29/2015 09:43 am »
These two attached papers from the 2000s had their mission architectures based on launchers of only 25 metric tons or thereabouts to Low Earth Orbit. Because we are talking about a 50 ton launcher (with possible future upgrades) you might find these as a good reference starting point for drawing up a new Design Reference Mission, building on their basic ideas. This would be for advanced 'Scout' missions, not colonization.

And for what it's worth: I favour a mixed set of Solar, RTG and Stirling units for mission power.
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Offline Lobo

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Re: FH Based Mars Architecture
« Reply #44 on: 09/29/2015 03:30 pm »
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.

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.

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?

Offline Lobo

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Re: FH Based Mars Architecture
« Reply #45 on: 09/29/2015 03:47 pm »
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.


[/quote]

In such a hypothetical, I think a new high energy upper stage would be very plausible.  Either to replace the F9US, or to be on top of it.  It's a modest investment when looking at your workhorse system for a whole Mars architecture, and really helps boost performance to LEO and BLEO.

Also, I think it likely SpaceX wouldn't abandon their stage combustion methalox plans.  Methalox is the propellant of choice to be made on Mars, and it's just a lot easier to deal with than hydrolox, as Elon has said.
So Raptor, or maybe a smaller version of Raptor, I think would become part of the equation. 

I tend to think a mini version of whatever MCT concept SpaceX comes up with, fueled up in LEO, and launched dry to LEO on a reusable FH that can put 50mt into LEO would be the most likely architecture.  It would probably take over services to whatever LEO Space Station(s) there are at that time.

You can drop a bunch of Red Dragons on Mars, but you need a away to get back off of Mars.  Red Dragon cannot do that.  So some sort of Mars Ascent Vehicle will need to be developed anyway.  So just keep the same idea as MCT, but smaller scale.   And Raptor makes a pretty good engine for that task.

Offline guckyfan

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Re: FH Based Mars Architecture
« Reply #46 on: 09/29/2015 03:50 pm »
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?

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.

Offline TomH

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Re: FH Based Mars Architecture
« Reply #47 on: 09/29/2015 04:21 pm »
...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.

Agreed. And launching prop is a low risk way of testing reusable stages. I wouldn't want to put something like JWST on the first Falcon to make its second launch. Having to rebuild an expensive unique machine is hard. Making more prop is not.

Offline Lobo

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Re: FH Based Mars Architecture
« Reply #48 on: 09/29/2015 04:26 pm »
I'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.

Yea, that's kind of what I was thinking.  If SpaceX opted to scrap BFR and just go with FH, and as Tom said it's a hypothetical replacement for SLS, so assume NASA is involved with this too, what would be the likely FH upgrades to better service this?

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.

4) Raptor (1 engine) would have the power and efficiency to be such a heavy lifting reusable upper stage.  As well as to get the MAV...whatever it might look like...off of Mars and back to Earth.  Probably only vacuum-Raptor would be developed, as the booster would be using Merlins.

So these would be some of the assumptions I'd go with when developing a concept for this hypothetical.

 

Offline TomH

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Re: FH Based Mars Architecture
« Reply #49 on: 09/29/2015 04:31 pm »
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.

Offline guckyfan

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Re: FH Based Mars Architecture
« Reply #50 on: 09/29/2015 04:43 pm »

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.

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. ;)

Offline Lobo

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Re: FH Based Mars Architecture
« Reply #51 on: 09/29/2015 04:44 pm »
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?

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.

Ok, if 53mt is the FH number with the Falcon upper stage and full expendability, and more than that with other tweaks, then I think 50mt is a plausible number with RTLS side boosters, expended central core, and reusable large upper stage with a single vacuum Raptor on it.  Probably assuming perfect crossfeed and  some tweaks like RP-1 chilling. 
RTLS side boosters aren't a big performance hit with crossfeed as I understand, as they keep the core full at separation, an they separate fairly quickly and don't need much propellant left in them for boost back.  Trying to get the central core back is a big performance hit though.
Raptor makes both a powerful and efficient upper stage engine, to make up for the reusability performance it.  It could be developed a little smaller than 500klbs if necessary....as it's not yet developed.

So that's why I was assuming a nice, round 50mt as the building block with a mostly reusable high launch rate system.

Offline Lobo

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Re: FH Based Mars Architecture
« Reply #52 on: 09/29/2015 04:52 pm »
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.

Yes, fully agree.  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.

Offline guckyfan

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Re: FH Based Mars Architecture
« Reply #53 on: 09/29/2015 05:13 pm »
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.

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.

Offline nadreck

Re: FH Based Mars Architecture
« Reply #54 on: 09/29/2015 05:15 pm »

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.

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.

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.

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. ;)

Where do you get the carbon for fuel production on Phobos, or do you just produce oxygen there?
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Offline Lobo

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Re: FH Based Mars Architecture
« Reply #55 on: 09/29/2015 05:23 pm »

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.

Yes, good point.  But for those reasons I think LH is better avoided.  LCH4 and LOX are similar to handle and store...but LH2 is another ball of wax.  Especially on Mars.

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.

Yea, I like an integrated concept.  A cylinder with biconic nose stage...maybe 6m in diameter...with an empty volume on the upper half.  That upper volume can be used to house a satellite going to GTO, just be empty when it's used as a tanker, and have a pressurized habitat in it when used as a mini-MCT.  So more than just a new upper stage, but more a whole common platform.  If it's reusable, it will have to do EDL.  The craft the crew and cargo are in will have to do EDL too. 
A new upper stage will need a vacuum engine and tanks, and so will a spacecraft lifting the crew off of Mars.  And going to Mars, unless there's an expendable EDS separate.
Seems to be overlapping needs there that possibly one standard platform could service.

In this case such a mini-MCT would launch full, and get to a LEO empty, where it will refuel prior to departing for Mars.  So it will do the TMI burn, and probably an aerobraking burn, and then enter the Mars atmosphere from some sort of eliptical Mars orbit.  Once it reaches supersonic terminal velocity it will do a deceleration burn prior to landing, where landing thrusters will hover and land it.  (which will be used to land on Earth too, without the main engine deceleration burn thanks to far slower terminal velocity on Earth).
As a satellite launcher, it would have an internal payload bay with a nose that opened (like the Rocketplane Kistler K-1) that could deploy a sat at GTO.  The GTO orbit will take it right back to Earth where it can do a small de-orbit burn and do EDL on Earth.
As a tanker, it launches to a depot and depots all of it's residuals into it, keeping just enough to deorbit and land itself. 
It can even be the depot, using it's tanks.  Loitering in orbit and receiving tanker deliveries until full, where a mini-MCT fills up from it, before heading to Mars.  Then it can deorbit itself and land for refurbishment and relaunch.

It may not be capable enough for direct Earth return. Maybe they could have fuel production on Phobos. One of my pet ideas. ;)

yea, that would be interesting to look at.  Refueling on Phobos would certainly be an option if necessary.  But assuming such a mini-MCT would be lifting off from Mars with no cargo (left on the surface), and only a small crew with just some rock samples and provisions to get them home, and perhaps with a slower, lower energy transit back to Earth, I think it's possible.  It would be preferable, IMO, to having to stop at Phobos for propellant if possible.
Especially since you can make all the propellant you need on Mars.  Just size the platform tanks for the largest dV.  Either Earth ascent to LEO, or Mars ascent home.  Whichever needs the more propellant, size the tanks for that.  They can be short-fueled for other legs


Offline RocketmanUS

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Re: FH Based Mars Architecture
« Reply #56 on: 09/29/2015 05:33 pm »
Falcon Heavy cost and performance

Their site says $90M for 6.4 mt to GTO. Does not list the LEO payload mass for this pricing. I assume this price for booster reuse.

I assume the price is higher for the non cross feed for 45mt to LEO ( performance from their web site ). I assume the price would be around $160M ( three F9's minus two US, price of US based on what was on their site severale years ago ).

For the LEO performance of 45mt non cross feed I assume that is for 185km x 185km. Higher altitude for less air drag on payload would reduce this amount, I assume 40mt would be a better payload mass to use for a higher orbit ( less air drag ). Less air drag means payload can stay in orbit longer without station keeping before another payload meets up with it or before the TMI burn.

As far as upgrades to FH for LEO performance without cross feed we need to wait for SpaceX to announce the new performance and pricing.

My other post on this thread started out with a trans hab. It's mass and volume fits the FH non crossfeed to LEO. Multiple launches are needed to fill the propulsion stage(s) for the needed round trip forthe trans hab. For FH I think it best to brake this down into crew, trans hab, propulsiuon stages, propellant, cargo landers, crew descent/ascent lander. This should give a flexible option between different concepts to be launched by the Falcon heavy ( crew possible on the F9 ).

Offline TomH

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Re: FH Based Mars Architecture
« Reply #57 on: 09/29/2015 05:40 pm »
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.

Those two statements seem to disagree with each other. Anyway, I think that if SLS hasn't already been cancelled previously, the day a manned Red Dragon touches down on Mars would be the day SLS/Orion are both cancelled as unnecessary. NASA might then be directed to work with SpaceX on planetary science of Mars. FH/Red Dragon based research sorties would be doable from technological, financial, and timeline perspectives.

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.

I'm not talking about capturing what drains out. Just like a frozen aquifer that is vertically beneath you, you reach this aquifer by drilling, laterally in this case. You already know the water is in there. Verifying aquifers below level surfaces may be trickier to do. You need a geologist to determine potential danger from landslide, however. Even if you choose a flat location, the discovery of the flowing water is significant because it verifies significant water in the ground.

I did not say choose these sites now for colonization. I prefer all potential sites have sortie visits first by a team of scientists to evaluate their potential for colonization. A rover will not be able to collect nearly as much information as a team of scientists, particularly when you already know a site has a lot of potential.

A good plan might be rovers first to a number of potential sites. Sortie visits by scientists to a handful that seem most promising. Finally, choose the best location for the Mars Prime settlement.
« Last Edit: 09/29/2015 05:51 pm by TomH »

Offline guckyfan

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Re: FH Based Mars Architecture
« Reply #58 on: 09/29/2015 05:53 pm »
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.

Yes, that is what I meant.

Where do you get the carbon for fuel production on Phobos, or do you just produce oxygen there?

I admit this part is just wishful thinking. But not too far fetched. It seems we find both water as ice and CO2 whereever it is cold enough for them to not dissipate.

It is one thing I don't understand. Why have there been no NASA missions to Phobos or Deimos? It would not be too expensive. Too bad as well that the russian Phobos Grund mission failed.

Offline cdleonard

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Re: FH Based Mars Architecture
« Reply #59 on: 09/29/2015 06:10 pm »
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.
How exactly? There is water in the soil but getting useful quantities of hydrogen seems to require processing massive amounts of it. This is why Robert Zubrin's initial proposal involved shipping it from earth.
« Last Edit: 09/29/2015 06:11 pm by cdleonard »

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