Yet another Mars architecture

RobertDyck · 2013-11-18 16:09:20

My criteria for site selection was/is:

close to the equator: warm (for Mars), no winter, lots of sunlight for greenhouse(s) and solar panels
low altitude: below the datum, sufficient atmosphere to protect against heavy ion Galactic Cosmic Radiation
relatively flat smooth ground: safe to land
lots of water

There's only one area that meets all this: Elysium Planitia. But that's a big Plain. The frozen pack ice is located there.
And it's 3km below the Datum! Yea!

(nitpicking is Ok. That's how we work out the mission killing bugs.)

JoshNH4H · 2013-11-20 05:05:45

(nitpicking is Ok. That's how we work out the mission killing bugs.)

Captain Nitpick reporting for duty

I question the necessity of your requirement that the location be below the datum. Firstly, because the change in elevation isn't equivalent to a very significant change in the amount of shielding required to offer sufficient radiation protection from whatever source, and secondly because the datum is (as we all know) an entirely arbitrary point. Why not restrict yourself to -1 km, -2 km?

In the context of a colony, water is of course the most important resource to be located near, and not just water-rich dirt but actual water-ice (An aquifer would be even better, but we've yet to find any of those). Of course it's also of primary importance to be located near good deposits of Iron (Common, probably, even if you hold out for rocks with Fe content above 50%--More on this at the bottom of my post) and good sources of Silicon Dioxide for glassmaking, which will be vital to the greenhouse. These are presumably less common, though also presumably still extant.

Other goodies on the wishlist include Aluminium ores, Fluorine ores, Nitrates, Sulfur, Phosphorus, Copper (Aluminium can substitute in any application if not available), Chlorides, and Chromium for alloying to make stainless steel. This kind of steel is stronger than plain carbon steel, so even without oxygen atmospheres it is still useful.

Other items that could be useful would be the catalyst metals, Ni, Ag, Pt, Au, Os, Ir, etc.

Tungsten might find some use in lightbulbs, although I would expect noble-gas based lights to be used more in the early days (and probably the later ones too) because they're more efficient and don't required you to do anything with Tungsten. It's possible that gases like Argon and CO2 have sufficiently white-ish emission spectra to be used in lighting; I'd hope so.

My point is that it'll take a bit to even get the basics down. A lot of rovers but also humans. I'd say that once we established the Iron and Silica ore we'd be ready to go, given the stuff we already know is in the atmosphere.

With regards to Iron ore, it's not enough that those blueberries exist. You want stuff that exists on more than a surface layer. The blueberries on Mars are quite small-- About 3 mm in diameter. That's just not enough to mine for ore. The Iron content has to be in the dirt and in the rocks to be usable.

RobertDyck · 2013-11-20 10:01:59

All valid points. The reason I said "below the datum" is protection against heavy ion Galactic Cosmic Radiation. That's very difficult to protect against. Light shielding will cause radiation particles to split, each having lower energy (speed) and lower mass, but greater number of body cell hits. It turns a bullet into a shotgun blast. Radiation shielding that makes radiation worse? That's nasty! You can shield with a large tank of liquid hydrogen, which gradually slows the heavy ion without splitting it. But we don't have a lot of that, and it has to be very thick to be effective. There have been proposals to use propellant tanks as shielding, but as soon as you use propellant you get rid of your shielding. Again, nasty. Water is effective because it has so much hydrogen, but again the tank has to be very thick, and heavy. Plastic rich in hydrogen, such as polyethylene and polypropylene, can also be used, but again it has to be very thick. If the heavy ion strikes an oxygen atom in water or carbon atom in plastic, it could still split. The most effective shielding by far is the atmosphere of a planet. Mars atmosphere may be thin, and not effective against proton or light ion radiation, but it is very effective against heavy ion GCR. And since proton and light ion radiation doesn't have the "split" problem, it can be shielded with regolith.

I'm getting this from this chart:

This is from a paper by the science team for the MARIE instrument on Mars Odyssey. They published 4 papers; I posted a copy on the local chapter website:
http://chapters.marssociety.org/winnipeg/radiation

Legend: Particle Type = proton, alpha, light, medium, heavy

JoshNH4H · 2013-11-20 12:29:07

My understanding of the radiation situation is rather different than that. It's really quite confusing. My understanding was that solar protons were relatively simple to block, because they had lower energies and therefore were less penetrating. Think about it this way: It's safe to touch an alpha emitter, even though it emits alpha particles at several MeV (Higher even than the range of solar radiation for the most part) they are stopped quickly by your skin. I've heard that the same holds true for low-energy protons. This would mean that both are blocked easily by the atmosphere, and the radiation issue would stem from X-rays or super-high energy protons produced in a solar flare and the drizzle of GCR.

Meanwhile, (and that graph and I agree on that), it was my understanding that GCR particles heavier than protons were quite rare.

I've seen a lot of conflicting information on the issue. It would helpful if someone who's involved in radiation could publish a unified guide to the different types.

GW Johnson · 2013-11-20 12:49:33

A unified guide? Aw, you didn't expect things to make sense, did you?

You can use regolith as a GCR shield even in space, if you make it thick enough to capture the secondary showers. That's several meters thick. On a surface, that's just bulldozer work, it can be done. So, there's no reason you have to settle only at lower elevations on Mars. A roof of regolith several meters thick would be effective even atop Olympus Mons. Although, for the life of me, I don't see that as a particularly attractive place to settle.

On the blueberries as an iron source, aren't those about as high-grade an ore as some types we mine here? Their presence on an eroded surface suggests that the rocks in that vicinity might be full of them, just not eroded yet. You could bulldoze up the loose surface and sieve it for blueberry ore particles. Whether digging up the rocks would be practical would depend upon whether the blueberries were harder or softer than the rocks in which they formed. If harder, release them by crushing, and then sieve. If softer, probably not practical.

GW

RobertDyck · 2013-11-20 13:15:22

Opportunity found the matrix rock at Meridiani Planum was soft sedimentary rock. I expect (hope) that Elysium Planetia is too. After all, it's part of the bottom of the dryed up ocean. The part that extends farthest south, and actually crosses the equator.

JoshNH4H · 2013-11-20 22:12:32

GW-Don't forget about the added benefit that comes from piling meters of regolith atop a pressurized structure There's also no reason why it can't be liquid water or water ice.

The blueberries are about as good as it gets in terms of iron concentration. But there's no way to pick up blueberries and nothing else. You're going to get impurities (for example the sedimentary rocks they're embedded in) that means another separation step. It would be worth it to see if there are orebodies more like the ones we user on earth. These are large rocks or patches of dirt made of iron oxides. Given that Mars is Mars I'd expect us to find some.

The only benefit that occurs to me regarding Olympus Mons is the higher survival rate of asteroids and the material contained therein. That might be our only source of nickel and manganese for a while.

By the way, manganese is an important alloying element for steel too. That should be on the list.

JoshNH4H · 2013-11-20 22:15:01

When I have some free time, though, I'll figure out who to email and then email them about the radiation question. Somebody knows this, or at least has a self consistent guess and is qualified to say what we do and don't know.

RGClark · 2013-11-21 07:37:39

RobertDyck wrote:

Bob Clark: Wouldn't your goal be achieved with artificial gravity? We don't need a magical, yet-to-be-invented propulsion technology. We can do it now.
Do you have a porkchop plot showing characteristic energy (C3) for transit time to Mars in weeks?

Apparently doing artificial gravity is not as trivial a technical problem as portrayed, at least NASA doesn't think so. I looked at several of the NASA Mars Design Reference Missions and none of them contain artificial gravity despite the fact NASA has known about the problem of long zero-g exposure for decades:

Human Exploration of Mars: The Reference Mission of the NASA Mars Exploration Study Team.(NASA Mars DRM 3.0)
July, 1997
Shorter transit times reduce the time spent by
the crew in zero g to the length of typical
tours of duty for the International Space
Station. (Thus, the Mars Study Team chose
not to use artificial gravity spacecraft designs
for the Reference Mission.)
http://www.nss.org/settlement/mars/1997 … ission.pdf

Human Exploration of Mars Design Reference Architecture 5.0.
July, 2009
The current Mars DRA 5.0 study efforts considered “thrust-only” NTR engines, zero-gravity
crewed MTV designs, and photovoltaic arrays (PVAs) to supply spacecraft electrical power.
http://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf

It is notable these both use nuclear propulsion and the transit time is still several months. Also the effects of long stays at zero-g at the ISS actually shows some of the astronauts will likely be incapacitated for days to weeks on arrival.

A discussion on this other forum showed for departing from HEO, or from the Moon or L2, a delta-V in the range of 10 to 11 km/s would allow a travel time of about 35 days:

Math needed for 5-week flight from Earth to Mars.
http://orbiter-forum.com/showthread.php … stcount=17

This would result in a high arrival speed at Mars and it also assumes aerobraking/aerocapture is used so no or minimal propellant is required to slow down on arrival.

But 11 km/s is about the delta-v the Saturn V launcher needed to send 45 metric tons (mT) to translunar injection. Then if we had a Saturn V size rocket departing from the Moon or L2 we could send about 45 mT to Mars for a one-way trip time of about 35 days.
But remember almost all the mass of the rocket is just propellant, which we can get from the Moon. You would not need to send the entire 3,000 mT mass of a Saturn V size vehicle to the Moon or L2, only the dry mass components. And probably with 3d-printing even the dry mass components that needed to be sent from Earth could also be reduced.

This is for a one-way flight. For the return flight, you would have the dry mass components for the return vehicle already sent to Mars beforehand on a slow flight so not needing as large a departure rocket. The propellant for the return flight would be obtained at Mars by ISRU.

Bob Clark

Last edited by RGClark (2013-11-21 07:39:06)

JoshNH4H · 2013-11-21 10:36:14

I'd be pretty interested to hear their reasoning for that,actually. It's not something you would expect to be of consequence, but NASA acts like it is.

I would think that it would be trivial to design a damped spring mass system at the end of a tether, then bringa rocket engine for spin up and spin down. The delta V for a complete spin up/spin down would be around 25 m/s.

JoshNH4H · 2013-11-21 10:52:19

With respect to 11 Km per second launch trajectories I would say it's completely infeasible to either launch a Saturn V class rocket into space or build facilities to build it on the Moon. That is, for a couple decades at least.

Terraformer · 2013-11-21 12:02:13

Still, that would let you beat NASA. But still, it's mainly fuel, and it's been shown before that it requires a 3.2 (or 3.6?) km/s delta-V to get to Mars in 3 months, departing from EML1. That craft could be built on Terra, launched dry, fueled in LEO refueled in L1, and sent on it's way. Or docked together in LEO, if you want a bigger one. Of course, you need to stop again. Maybe if you cannibalise parts from your upper stage, or even build your ship *as* the upper stage (why not? Built in shroud, and significant delta-V capacity...), you can get yourself a large craft that can launch to Mars and then hang around in orbit, maybe refueling from Phobos or possibly fuel sent from Mars. If you're going to be retaining fuel for decelerating at whichever planet, you might as well build the hab so that it's surrounded by full hydrogen fuel tanks, so you've got plenty of radiation shielding. No artificial gravity, but if your trip is only 3 months, can you get by without it?

Launch it as a bare hull upper stage, just engines, tanks, and structure, and you can outfit it on orbit. If we're using an expendable Falcon Heavy, your ship will be at least 50 tonnes like that, if not more (because it's an integrated stage). By the time you're ready to launch, you might have something that's 100 tonnes (but then, that cuts your delta-V down). Or you could fit several such craft together on orbit. Maybe even 8 of them, and a big hab in the center. That should get you a decent ship (after all, the launches would put over 400 tonnes into orbit to outfit the ship with). Total cost for building such a monster might be a couple of billion dollars. Penny change, really. You could have a decent crew size with that, and a proper hanger full of several scout landers, and a few drones to fly around the ship and inspect it. Crew size maybe of 20? With a big iron chair for the captain to sit on? Oooh, I'm liking this big ship. You could use it for multiple missions to multiple planets. Rotate ground crews, make sure everyone gets enough exercise in a gravitational field.

Remember - we go big, or we don't go.

RGClark · 2013-11-21 13:36:01

JoshNH4H wrote:

With respect to 11 Km per second launch trajectories I would say it's completely infeasible to either launch a Saturn V class rocket into space or build facilities to build it on the Moon. That is, for a couple decades at least.

That depends on how difficult you view it to have propellant production facilities on the Moon, which is very dependent on how difficult you view it to have a manned base on the Moon.
The evidence is that there are vast stores of ice at the poles of the Moon. Turning this into hydrolox propellant is a simple electrolysis procedure that even appears in children's toys.
Note that most plans for Mars missions now include ISRU propellant production on Mars. So you already need this technology anyway. And by producing these facilities on the Moon first you can also test its viability in a real world situation, as well as actually using the propellant thus produced for your Mars mission.

Bob Clark

JoshNH4H · 2013-11-21 15:57:53

Terraformer and Bob-

I'm not arguing that fuel depots are a bad choice when it comes to colonization. What I am saying is that it's nonsensical to argue that it makes sense to build an extensive lunar infrastructure as a prerequisite to a Mars mission. The initial mission should be cheap and fairly quick; infrastructure comes later, once feasibility has been proven.

Lunar ISRU is not a prereq for martin ISRU. The technologies and environments are very different. As Zubrin likes to say, if you want to go to Mars, go to Mars.

Terraformer · 2013-11-21 17:35:03

Well, that depends on whether you're focused on colonising the solar system or a flags and footprint mission. Also, if, like me, you see Luna as being a valid first target... well, we might as well postpone the first mission by a few years and do it properly. It's not like Lunar settlement is dependent on a launch window that comes around every few years...

GW Johnson · 2013-11-21 18:26:44

Re post 134 above: I'm sorry, NASA is just wrong about how difficult artificial gravity might be. If you are afraid to go, you have a vested interest in playing up how difficult something is. That's what's going on with NASA regarding both artificial gravity and radiation protection. Neither is very difficult.

They (NASA) have evolved toward a no-risk posture. Which means they really do not want to go to Mars, since that is always high risk, as was Apollo in the 1960's.

I've posted here before on both artificial gravity and radiation protection. No need to belabor those points again. Suffice it to say that cable-connected spinning modules have way too many failure modes to suit my taste. I favor the slender baton spinning end-over-end. 56 m at 4 rpm seems eminently doable, just not something you can fling t orbit with a single SLS launch.

Brings up another point. Having 100 ton payload capability with SLS is nice, but not required, to go to Mars. We built ISS out of 15 ton modules. Atlas 5 and Delta-4 (in their respective "heavy" configurations) can fling modules 15 to 20 tons. They are far cheaper than shuttle was, and far cheaper than SLS will ever be! If we had to do it again, we could build ISS for about 10 times less, counting prices and learning-curve effects. That's the price of a proper Mars manned vehicle.

GW

JoshNH4H · 2013-11-21 18:31:09

GW-

Can you point me to where you discuss the difficulties associated with the spinning tether system? I've considered the issue at some length and I don't see there to be many issues with it, so I'd appreciate your input.

RobertDyck · 2013-11-21 19:46:43

Launch a Saturn V from the Moon or L2? Alllllll righty then! Saturn 1C was the first stage, empty mass 135,218 kg. Even SLS with a full-size upper stage and new yet-to-be-developed SRBs will only be able to lift 130 metric tonnes to 185 km orbit at 27° inclination. You might be able to lift it to a lower orbit, but remember you also have to add a fairing on top. Just to deflect air during launch. Orbit stability would be measured in weeks. Then another launch to lift another stage to push your empty Saturn 1C to a stable orbit. This second stage would require rendezvous and docking equipment: radar, maneouvring thrusters, docking collar.

You want to update that? SLS core stage will use LH2/LOX instead of RP1/LOX. If it's completed, empty mass will be 85,270 kg. That's still too big for SLS Block 1: existing SRBs, interim upper stage. It could be launched with SLS using existing SRBs and the full-size upper stage. But you would still only get to LEO. It would still require another stage, launched separately, to dock and push it to a fuel depot. Or an assembly point with fuel tankers to ferry propellant.

Note: Wikipedia lists Block 1 with an "interim cryogenic propulsion stage" that is a modified Delta Cryogenic Second Stage that has one RL10 engine, while the "SLS fact sheet" on NASA's website has a new stage with a single J-2X engine. Either way it's rated for 70 metric tonne to LEO. And I should add, I keep saying "existing SRBs", but NASA's "SLS fast facts" documents lists 5-segment SRBs.

So even if a fuel depot existing, such a vehicle would be a monster.

The viability of a fuel depot? First you build the customer, then you build the provider. If you expect a lunar mine to provide fuel for a mission to Mars, then you will be waiting for ever. That requires mining, refining, transport, and depot services including storage and delivery to a customer. None of that will be built until *AFTER* a customer exists. If you want all that, then first go to Mars via direct launch. Then build the fuel depot.

Note: My architecture calls for TMI & TEI stages to be replaced by a single reusable stage. It would be docked instead of an orbit assembled expendable TMI stage. This allows for complete flexability, the future stage could be anything: LH2/LOX, solid core nuclear thermal, gas core nuclear thermal, Ion/solar-electric, MPD/solar-electric, MPD/nuclear-electric, VASIMR/nuclear-electric. Whatever becomes available, and whatever propellant is available. If you want a depot, this architecture creates a customer, so therefor this architecture supports your depot.

Actually I doubt any form of solar-electric propulsion will ever be as fast as chemical, certainly not faster. Solar-electric has low thrust but high Isp; distance necessary to build up speed requires a Jupiter at minimum, Pluto/Kuiper Belt preferably. Solar-electric is great for low speed, low mass cargo missions, but will not deliver anything to Mars quickly.

RobertDyck · 2013-11-21 19:54:16

RGClark wrote:

The evidence is that there are vast stores of ice at the poles of the Moon.

That's contraversial. There is lots of hydrogen, but how concentrated and is it ice? A significant portion could be clay or other hydrated minerals. Remember the source is believed to be carbonaceous chondrite asteroids that impacted. In fact, we're learning the difference between comets and carbonaceous chondrite asteroids is a matter of degree, a continuum. Even comets have a lot of non-ice solid material. Even if a lot is ice, is it sufficiently concentrated to be worth harvesting? The contraversy won't be settled until a rover lands on a Lunar pole and starts digging.

JoshNH4H · 2013-11-22 00:29:25

It was my understanding that there was still a lot of question with regards to what portion of the hydrogen-containing material at the lunar poles comes from the solar wind vs. cometary impacts vs. asteroidal impacts. Certainly if the impacts that left the material there were chondritic we would expect there to be more Carbon lying around than there is.

Given that we're talking about a cold trap situation, wouldn't it make sense that the hydrogen to be found there is primarily in the form of water? Other than Water, Ammonia, and Methane, most other things would have either never migrated their way to the poles or would have long since escaped.

LCROSS results were consistent with large amounts of water ice in craters.

Tom Kalbfus · 2013-11-22 07:48:06

Terraformer wrote:

Well, that depends on whether you're focused on colonizing the solar system or a flags and footprint mission. Also, if, like me, you see Luna as being a valid first target... well, we might as well postpone the first mission by a few years and do it properly. It's not like Lunar settlement is dependent on a launch window that comes around every few years...

Well we did land on it first! Why do you act as if the Apollo missions didn't happen? Probably if we contracted it out to private business, we could do both. There are economic reasons for going to the Moon, if we give the right subsidy and take it away later, then businesses will have incentive for establishing bases on the Moon, because they will be investing some of their money and would be seeking a return on their investment. The problem with Apollo is that no one was seeking a return on taxpayer's investment, and Apollo was not sustained! The first step to establishing a base on the Moon is establishing a business plan, then the government extends a subsidy to make sure it happens, the subsidy should be less than paying for the entire mission and having astronauts play golf. Nothing the Apollo Astronauts brought back from the Moon ever paid for subsequent missions, that is why Congress could pull the plug

RobertDyck · 2013-11-22 09:04:05

Also look at it from the perspective of congress. On 20 July 1989, President George H. W. Bush stood on the steps of the Air and Space museum and announced "We will go to Mars." NASA produced the 90 day report that called for a space station, base on the Moon, mines on the Moon, fuel depot in Earth orbit, and nuclear powered spacecraft for Mars. The price for everything was $450 billion! Congress said "You want what!?!?!" and that was the end of that.

Martin Marieta had 3 teams of engineers produce alternate plans, to reduce the cost, one team was Dr. Zubrin and his partner. NASA priced Mars Direct at $20 billion for the first mission, plus $2 billion for each mission thereafter. One mission every 26 months, in 1990 dollars. But Congress believed the contractors would create excuses to increase the price back to $450 billion (in 1989 dollars), so said No.

Since then the station has been built. Many calculate the cost, including missions to the station, at $100 billion. Now you're asking for a permanent base on the Moon, lunar mines, a fuel depot in Earth orbit, and a nuclear powered spacecraft for Mars. That's the full 90-Day report. Apply inflation from 1989 to today, then deduct $100 billion for the station. How much does that work out to?

This is how Congress sees it. They already said "NO!" Why would you think they'll ever say yes?

Terraformer · 2013-11-22 09:59:34

I don't think they'll ever say yes. Why are you thinking they'll ever say yes to a Martian flags and footprints mission, when they haven't so far?

It's undeniable that Lunar fuel will make Mars missions easier, and we're going to be needing that fuel anyway. Why waste resources, just to get to Mars a few years earlier? That's short term thinking, that will set back colonisation.

I don't think a Mars mission, at the moment, could be done privately and make money. But Lunar fuel changes that, and I think there's a viable business case for setting up cis-Lunar infrastructure. Not necessarily with fuel as the main focus, but it'll be a required part of it, and once you've got that you can boost your production to provide for a Mars mission.

RobertDyck · 2013-11-22 10:09:06

You're stuck in a circle. Congress said no to the 90-Day report. We get nothing as long as we demand the 90-Day report. So you're demanding the 90-Day report.

JoshNH4H · 2013-11-22 10:17:49

I'd add that nobody had ever put a mission of the Mars Direct type before Congress in any meaningful way. By Mars direct type, I mean an emphasis on simply going to Mars. It's not flags and footprints but it doesn't require a preexisting, massively expensive space infrastructure. Not yet, at least.

New Mars Forums

Announcement

#126 2013-11-18 16:09:20

Re: Yet another Mars architecture

#127 2013-11-20 05:05:45

Re: Yet another Mars architecture

#128 2013-11-20 10:01:59

Re: Yet another Mars architecture

#129 2013-11-20 12:29:07

Re: Yet another Mars architecture

#130 2013-11-20 12:49:33

Re: Yet another Mars architecture

#131 2013-11-20 13:15:22

Re: Yet another Mars architecture

#132 2013-11-20 22:12:32

Re: Yet another Mars architecture

#133 2013-11-20 22:15:01

Re: Yet another Mars architecture

#134 2013-11-21 07:37:39

Re: Yet another Mars architecture

#135 2013-11-21 10:36:14

Re: Yet another Mars architecture

#136 2013-11-21 10:52:19

Re: Yet another Mars architecture

#137 2013-11-21 12:02:13

Re: Yet another Mars architecture

#138 2013-11-21 13:36:01

Re: Yet another Mars architecture

#139 2013-11-21 15:57:53

Re: Yet another Mars architecture

#140 2013-11-21 17:35:03

Re: Yet another Mars architecture

#141 2013-11-21 18:26:44

Re: Yet another Mars architecture

#142 2013-11-21 18:31:09

Re: Yet another Mars architecture

#143 2013-11-21 19:46:43

Re: Yet another Mars architecture

#144 2013-11-21 19:54:16

Re: Yet another Mars architecture

#145 2013-11-22 00:29:25

Re: Yet another Mars architecture

#146 2013-11-22 07:48:06

Re: Yet another Mars architecture

#147 2013-11-22 09:04:05

Re: Yet another Mars architecture

#148 2013-11-22 09:59:34

Re: Yet another Mars architecture

#149 2013-11-22 10:09:06

Re: Yet another Mars architecture

#150 2013-11-22 10:17:49

Re: Yet another Mars architecture

Board footer