The Cost of Going to Mars - A cost estimate of Colonization

srmeaney · 2005-06-29 22:28:20

Martian Colonization Project
Human transfer + forward deployed systems Cost

item.............................................qty.........itempurchase&deploy
colonist & 1 years food...........10,000,000.....$20,000,000,000.00
subtotal.......................................................................................$200,000,000,000,000,000.00

aerodrome/stormshelter............1,000...........$20,000,000,000.00
Ceramics processing plant.........5,000...........$20,000,000,000.00
colonist habitat.........................5,000...........$20,000,000,000.00
Electric cable (1 Km)..................1,000..........$20,000,000,000.00
electric smelter.........................5,000...........$50,000,000,000.00
Garage (rover&fuelplant)............5,000..........$20,000,000,000.00
Gas processing plant .................5,000..........$20,000,000,000.00
hydroponics&aquaculture............5,000..........$20,000,000,000.00
Ice mining equipment..................5,000...........$20,000,000,000.00
Lge. Ceramic object Kiln.............5,000............$50,000,000,000.00
Manual Factory...........................5,000............$20,000,000,000.00
Mars Aeroplane factory...............1,000............$20,000,000,000.00
mars ev suit factory.....................1,000..........$20,000,000,000.00
mars rover plant........................1,000.............$20,000,000,000.00
medical lab module....................1,000.............$20,000,000,000.00
mine/tunnel equipment...............5,000.............$50,000,000,000.00
Nuclear reactor (10 MWh)............1,000............$100,000,000,000.00
Power cable Mfg. plant................1,000............$20,000,000,000.00
Solar Array (30 KWh)................5,000...............$20,000,000,000.00
subtotal........................................................................................$1,790,000,000,000,000.00

UN comitments.............................1...............$20,000,000,000,000,000.00
Science, R&D fund........................1...............$10,000,000,000,000,000.00
subtotal........................................................................................$30,000,000,000,000,000.00

total.............................................................................................$231,790,000,000,000,000.00

The expense is in the human colonist. To send 10 million people to mars at 200 million billion dollars, this will be the area we need to reduce systems cost and improve colonist transfer efficiency. It will need to reduce to about 18 million billion dollars.

SpaceNut · 2005-06-30 05:18:55

All for 23 billion per person, now if that was a more realistic 23 million for the elite or even as low as 23 thousand for the common person then the journey could start today.

RobS · 2005-06-30 07:50:35

Where do these cost estimates come from? The air?

Example: why would you fly a thousand 10-megawatt reactors to Mars? It'd be cheaper to build large reactors there, and ten million people will need more than ten million kilowatts. That's not even the peak need for a North American, who get only a quarter or so of their energy from electricity. Marsians will probably need about 10 kilowatts per capita because they'll need electricity to power transportation and life support.

-- RobS

Fledi · 2005-06-30 19:10:29

Welcome back, srmeaney, I already missed your crazy postings.

Yes, the list looks very realistic, as always, just one detail that I don't understand.

You have 5,000 colonist habitats for the same price as 1000 x 1km electric cable. Do you suggest a habitat for 2000 people will cost the same as 200 meters of electric cable?

srmeaney · 2005-06-30 22:07:12

Hi Fledi,

The expense is the purchase and deloyment of a single item cargo block in a generic lander package. It wasnt convenient to tally the rows, thats why you get a subtotal at the bottom of each section.
The idea of a generic lander came as an idea that the internal cargo volume could be used to define the limit and in the case of cargo, the presurized storage Cylinder would need to be opened leaving in many cases a lander engine platform and its cargo. In certain cases the contents would be emptied on to the martian surface, in others it would remain an intact system.

As to the cost estimate query raised by Robs, it is based on the NASA reference mission ($50,000,000,000.00/mission) and magnified up for ten million colonists, subjected to a realization that we couldnt afford that, swapped out for equipment needed to manufacture habitats and other industrial infrastructure on Mars, and subjected to the fact that this will be contracted out to private industry on a sacle of activity yet to be achieved. The result is a very expensive colonization program which would be reduced if we terraformed Mars first, developed an ecosystem and food chain and then sent people to tool up from the stone age. I settled for a somewhat easier version where the resupply of food from Earth (a real requirement) for ten million people will be in the area of 200 million billion dollars.

As to Spacenut,
What did you think the Colonization of Mars would cost? It's going to cost fifty million billion dollars to send ten million colonists to Mars over a hundred years (and only if we can improve crew transfer efficiency to a hundred thousand people a year as Heavylift systems will leave a debris field in Earth orbit thick enough to cast a shadow) because a greater cost would be a waste of money and to achieve anything less would be unacceptable.

The Space Commonwealth financing the Colonization of it's Martian Territories seems as inevitable as the Mountain bowing before the Wind.

Yang Liwei Rocket · 2005-07-10 06:56:53

where did this list come from ?

SpaceNut · 2005-07-11 10:44:44

As for cost to colonize space if it costs more than a shuttle mission to get there and keep those that are there alive it is costing to much. As for the cost to go if it is more than a taxi ride from a soyuz to back and forth then it also is more than we can afford.
Space need not be expensive and nor should it be to go to colonize it.
Probably anything costing 100's of million billions will never be started if presented all at once.
So do this as a piece meal building block process at reasonable costs and before you know it we have started to do what we wanted to do from the start, which is to colonize space.

srmeaney · 2005-08-02 02:06:50

Space need not be expensive and nor should it be to go to colonize it.
Probably anything costing 100's of million billions will never be started if presented all at once.
So do this as a piece meal building block process at reasonable costs and before you know it we have started to do what we wanted to do from the start, which is to colonize space.

Fine, an annual colonization contract of five hundred thousand billion dollars...As long as Mars gets the ten million colonists in the next hundred years and the equipment it needs to survive and prosper and every last one of them are citizens of the Space Commonwealth (and not one of the miriad earth prison camps passing themselves off as a democracy).

Yang Liwei Rocket · 2005-08-02 06:20:48

Who will do such a mission in the near future ? The scientists of India are looking at the Moon, ESA have the Aurora plan for Mars In comparison with NASA's budget of sixteen billion dollars (€13 billion), ESA's budget of €3 billion superficially looks considerable less but the Europeans do have manned mission plans and the Russians will soon lift off from French Guiana and there will be a Russian mission Phobos-Grunt. Considerable costs are incurred by NASA in maintaining the ageing Space Shuttle. A single Space Shuttle launch costs more than $600 million and during the last decades up to one third of NASA's budget had to be invested in the Shuttle to keep it flying and NASA's offical word is that it can go back to the Moon in 2018, Chinese are looking at the Moon and manned flights. EU has big GNP but is divided French and Germans are in the Euro but swedish and England have not joined Euro zone currency.
calculate GDP 1 EU $10,800,200,000,000 - 2 U S $ 10,300,100,000,000
3 China $ 5,800,500,000,000 - 4 Japan $ 3,350,400,000,000
CIA lists China even higher [6 trillion]
Right now the Chinese space plans are very young and China does not have the capacity to build spaceships to Mars, but China says it is planning to establish a base on the Moon to exploit its mineral resources. ESA have also many missions planned, we recently heard Germany joined the Aurora Exploration Programme.

TwinBeam · 2005-08-03 10:22:36

Cost savings #1 - don't send so many colonists - send about 300K young colonists, give them strong incentives to have big families (such as per-capita land grants), and you'll have your 10M colonists after a century.

Savings factor: 1/33rd the original estimate, or about $7 million billion.

Realism: even 300K is impossible at current prices. At current prices, with a high level of commitment by multiple governments, we might be able to send as many as 1000 over the course of a century, creating a population of ~15000 within a century. That's not bad considering where we're at now, but it's not great. Cost per person must be drastically reduced.

Grypd · 2005-08-03 11:46:29

Or go completely SciFi. Invent an artificial womb that works at least 99.9% then send 10 people and a sperm and ova bank. Build your bases facilities to increase population just cook up a 1000 at a time.

Train them using AI computers and the original 10 people as "parent" figures and soon you will get your 10 million.

Of course the computer AI will probably convince your citizens of your new civilisations standards as they go along and voila the Commonwealth of Mars with a very "loyal" population. :twisted:

TwinBeam · 2005-08-03 13:24:37

Cost savings #2: The original estimate at $20B per person seems a bit excessive, probably because it's based on the reference mission, which includes a lot of NASA overhead beyond construction and launch - design, big profits for the cost-plus contractors, bureaucracy.

They also foolishly emphasize reducing launch mass (a relatively small cost) at the same time as trying to get extremely high reliability. That makes every component cost about 50x as much as it might if you just made every system redundant and easy to maintain and repair in flight. After all, there are people on board - might as well keep them busy and get some value from them.

A reasonable assumption for long term operation would be that the design costs are only a minor factor to costs. Figure a generous 50 tons to LEO per person carried, including all supplies, ship, H2 fuel (but not O2 for the rockets - get that from the moon for a lot less), and launch costs to LEO should be on the order of $300M / person. Maybe another $50M/person for construction - assuming multiple Mars ships of the same design. So $350M/person.

Figure the same ship gets re-used for 10 trips before it has to be scrapped, so launch costs become $35M/person. Add $15M/person to get them to LEO. Add $50M/person for O2 from the moon, and $50M/person for fuel and supplies from Mars for each round trip. So $150M/person, or 1/133 of the original estimate ($20B/person).

Still way too pricey for private exploitation. I could see governments spending $15B/year to send 100 people a year (on average). I doubt they'd continue that for much more than 30 years before the political will fell apart - so you might get 3000 colonists delivered, which could swell to 100K within a century. Not bad.

Mad Grad Student · 2005-08-03 17:31:09

If/when we finally get around to colonizing Mars, this cost estimate is a great example of why it will not be done this way. $200 million billion is well beyond what is economically feasible for every government on Earth combined, even if amoritized over a century. Moreover, I seriously doubt that this plan would be viable from a logistical standpoint either. I'm usually one of the last people to say that a plan is impossible, but I'm pretty confident that sending 10 million colonists to Mars over the course of a century is quite undoable with anything even resembling today's technology. Think about what this would require; more than 200,000 people would need to be sent each launch window. Fewer than 500 astronauts and cosmonauts have been beyond Earth's atmosphere over the last 44 years, and none of them have ventured beyond cislunar space. Sending 200 times this number to an alien planet every single year for a century will not be physically possible for quite some time.

Humanity's first colony on another planet will have to be a much different, more austure venture. How many people are really needed for a permanent, self-sustaining colony? It's likely the same number as the lower limit of people needed for a healthy gene pool, perhaps 100-1,000 colonists. The most that any individual government or consortium of governments will be willing to spend is probably $5 billion a year for about 20 years, so $100 billion becomes our price cap. There's no way on Earth the UN will launch a program such as this; a Mars colony will have to be a mostly one-nation effort. Assuming that travel to the red planet can become relatively routine, it may be possilbe to start a colony on such a basis.

The trick here is to make the colony as self-sufficient as possible as soon as possible. While everything imported from Earth will have an exorbitant price tag and shipping fee, all items produced in situ are practically free, at least, those back on Earth don't have to pay for them. Thus, the best way to save money is to minimize the number of launches required to make the colony completely self-sufficient. Once the colony is independent, no further support launches will be neccessary. According to The Case for Mars, a heavy-lift SDV with an NTR upper stage could potentially launch 24 colonists one-way to the red planet, assuming no technological breakthroughs (scramjets, cyclers, etc.). In other words, ten flights minimum will be required for crew transport. Assuming two such missions can be launched each window of opportunity, it would take roughly ten years to transport the colonists to their destination.

Here's my proposal for a bare-minimum Mars colonization program. Over ten years, ten heavy-lift NTR cargo shipments are made to a site determined by previous manned scouting missions near a ready supply of water and perhaps geothermal energy. The cargo flights would include items such as greenhouses, chemical processing equipment, drilling equipment, a nuclear reactor, and inflatable habitation modules. The following ten flights are devoted to sending the first colonists, who will assemble the base and scramble to expand it as much as possible with local resources. In order to create living space without imported resources, underground tunnels could be built, or perhaps caves could be uitilized. Eventually, greenhouses and new hab modules could be created with plastics produced locally.

Granted, this is at the absolute lower limit of possible colony arcitectures, but it is also entirely possible without any technological breakthroughs. Unfortunately, I don't think that we can ask much more out of the initial colony, at least if we want to see it happen within the next century. I doubt that space exploration will ever recieve much more funding than it is currently in real dollars, so it is unrealistic to expect countries to spend trillions of dollars on an effort that will bring them very few practical benefits. As fun as fantastical sci-fi-like colonies are to imagine, humanity's first self-sufficient outpost outside of Earth will probably have much more humble origins.

GCNRevenger · 2005-08-03 20:02:23

I think that a REAL colony will always need nontrivial amounts of payload sent from the home planet, and an easy/inexpensive way to move modest payloads and persons from Earth to Mars (and maybe a few people back) with a shorter trip time then six months every two years. Putting people on a heavy lifter is out of the question, Bob is out of line for suggesting that in the first place.

Two and a half key technologies will just have to be developed, and thats all there is to it:

-A really, truely, no-kidding 100% reuseable spaceplane with medium lift capability (20-25MT)

-A really, truely, no-kidding reuseable Mars RLV, probobly much like DC-X with similar capability

-Gasseous core fission or high specific power fusion reactors

We have really, really got to have launch from Earth that is cheaper, more modular, more reliable, and more timely than an HLLV. Even an HLLV isn't cheap enough by any stretch of the imagination for colonization, and since we aren't going to be cramming 20-25 people into capsules, then it has to be (or a derivitive of it) safe enough for manned flight. Modularity and timely launch are also very important, that we need shipping-container style transport and we need it more often then "every now and then" with an HLLV.

We also can't be botherd to drag all the fuel and lander hardware needed to go from Mars orbit down to the surface on every trip. Not happening. A Mars-based RLV designed to ferry down Proton-sized shipping containers or a dozen crew at a time is an absolute must, and it will have to be 100% fueled by Martian fuel, probobly LOX/Methane.

And we need a better way to get there other then a huge throw-away rocket stage powerd by whimpy modern-day engines. They are good enough to send explorers, and good enough to maintain a science outpost, but not good enough for colonization. Something with much more power per pound is a must, and since modern nuclear energy sources are already pushing the melting point of practical solids, then we need to talk about gas-core or other higher-energy nuclear sources. Either as a thermal engine in a GCNR, a vapor-core reactor feeding a VASIMR, or Crazy Bob's saltwater rocket. Orion (and flavors of) or fusion are probobly not going to be available.

Getting there faster, going there more often, and doing it with a smaller amount of rocket fuel is non-negotiable. I personally like GCNR best obviously, but NSWR would be good too... VASIMR seems like an awfully complicated/heavy/unreliable gizmo. Anyway I see three types of vehicles in mind: the passenger liner, heavy cargo hauler, and fast cargo hauler. The former would be tailored for a crew of 25 and propulsively brake into Mars orbit, the heavy that would stick to low-energy orbits to maximize payload, and the fast hauler for specialty/time-sensitive goods. Cargo vehicles would either brake into orbit too, or drop an aerobrake "bus" into Mars orbit and continue back to Earth via Mars slingshot ("free return") for the next load.

When they do get there, Martian-made plastic for living quarters will be a high priority. Make greenhouses or use it as a "foundation" and make it double-walled, injecting a rigid insulating foam and then bulldozing regolith over it. Serious payload will still have to be imported from Earth for some time, colonists will be doing well to manufacture most of their food, housing, and furnishings... And the crew ferry will be needed to take people who want to leave back to Earth, such as people who changed their minds, grown children, or guest workers/scientists.

srmeaney · 2005-08-03 22:37:35

Cost savings #1 - don't send so many colonists - send about 300K young colonists, give them strong incentives to have big families (such as per-capita land grants), and you'll have your 10M colonists after a century

The idea is to send ten million, that way they can build a population of one billion on Mars (the absolute limit in population support).

If/when we finally get around to colonizing Mars, this cost estimate is a great example of why it will not be done this way. $200 million billion is well beyond what is economically feasible for every government on Earth combined, even if amoritized over a century. Moreover, I seriously doubt that this plan would be viable from a logistical standpoint either. I'm usually one of the last people to say that a plan is impossible, but I'm pretty confident that sending 10 million colonists to Mars over the course of a century is quite undoable with anything even resembling today's technology. Think about what this would require; more than 200,000 people would need to be sent each launch window. Fewer than 500 astronauts and cosmonauts have been beyond Earth's atmosphere over the last 44 years, and none of them have ventured beyond cislunar space. Sending 200 times this number to an alien planet every single year for a century will not be physically possible for quite some time.

This is why the nation of Space will contract out its own colonization. America is only worth a million dollars per citizen (the cost in infrastructure support). Mars has the Capacity of a Billion and is but a small territorial expanse in something that will be every asteroid, moon, planet and space station. All its citizens will be well educated equal contributors to a civilization and economy..

Despite the Corporate warlords of the new space empire who are currently running about pushing "mine if I land on it" philosophies, Space and everything beyond Earth Will have a single Government and its people will live by the rule of laws that must be to the benifit of every citizen.

No earth Nation or its citizens, have any buisness beyond fifty thousand feet unless they are being contracted to colonize it on Behalf of a Space Government.

RobS · 2005-08-04 02:08:01

I'm not sure where the initial cost of 50 billion per design reference mission came from. I've usually seen figures for each mission in the 3 to 5 billion range.

Colonization is at least phase three. Phase one will involve small exploration missions, either going to different parts of the planet or to a "Martian McMurdo." The latter looks more and more likely to me because of safety concerns (which can only grow over time). Phase two will involve establishment of a permanent base somewhere, initially with perhaps a dozen people, growing to several dozen over a decade or two (depending on money). Phase three probably won't start out being called "colonization" because that term may frighten away governmental budget planners.

Phase two may involve an improvement in the transportation technology of phase one: a reusable Mars shuttle and interplanetary transit vehicle. Phase three certainly will require a cheap, reusable shuttle to lift people and cargo to low earth orbit.

I'm not sure I agree with GCN that phase three will require gas core or fusion or even solid-core fission technology. The question in my mind is relative cost. A gas-core nuclear engine will probably have a unit cost of over a billion dollars and may not be very reusable. If it is being used to push fifty people to Mars, that's a cost of 20 million dollars each. Water from the moon or Phobos may provide cheaper propellant than that. A six-month voyage to Mars will require about two tonnes of propellant for every tonne moved from low earth orbit to low Mars orbit (assuming aerobraking at the Mars end--and by the time we get to colonization that technology should be quite reliable--and a separate system to transport cargo to the surface). Assuming fifty people can be moved to Mars in a one hundred fifty tonne interplanetary transit vehicle, that's three hundred tonnes of water for propellant; it shouldn't cost a billion dollars to obtain that from the moon or Phobos by that time. So it may very well be that the cheapest transportation system for passengers between Mars and Earth may rely on ordinary chemical rockets.

Colonization costs will be a function of two primary variables; the number of tonnes that have to be moved to Mars per colonist and the cost of transportation per tonne. Mars Direct assumes that the first four people will be transported to Mars with about fifty tonnes of stuff (hab, reactor, consumables, ERV, etc.) or about 12 tonnes per person. This may be low, but with a reusable Mars shuttle and the use of Martian water, I think we can easily imagine that even in phase two (small permanent base) the mass per resident could be reduced to five tonnes for initial arrival and perhaps two tonnes of supplies and consumables every two years.

As for transportation costs to the Martian surface, they will initially run about fifty million dollars per tonne (the latest estimate for launch costs for the shuttle-derived system I have seen are $4000 per pound to low earth orbit; that's about 9 million per tonne; but only about a fifth of the total mass launched to low earth orbit will end up on the Martian surface). With the use of lunar water that price will gradually come down, and a reusable Mars shuttle will almost double the percentage of the mass that can be cargo. If a reusable shuttle can take things to low earth orbit for $500 per pound, transportation to the Martian surface drops to about $6,000 per pound or thirteen million per tonne (still assuming one sixth of the total mass is cargo). If we assume five tonnes per new staff position on Mars and two tonnes every two years to maintain the position, that's sixty million dollars to establish the position and twenty-six million dollars every two years to maintain it, excluding the costs to get the staff person there. A one hundred person base would cost $6 billion to establish and $2.6 billion every two years to maintain. That would exclude ground support and the billions in research that would continue to improve the surface vehicles, greenhouses, pressure suits, etc.

This shows that significant Martian exploration would be reasonably inexpensive IF there is a reusable shuttle to get stuff to low earth orbit.

Now let us make a few other assumptions about colonization, to at least help us think about the problem:

1. For every ten-fold increase in the Martian population, imported mass per resident halves. This assumes that a 1,000 person facility, compared to a 100 person facility, can raise its own food; make its own toilet paper and tampons; that a 10,000 person base can manufacture some of the simper parts for pressure suits and vehicles; that a 100,000 person facility can make consumer goods, most of the pressure suit, most of the ground vehicles; that a 1 million person facility can build the fuselage and tanks for their own shuttles and just import engines from earth, etc. Something like that, anyway. I suspect ten million people on Mars will still be importing Barbie dolls, fine French wines, rare antiques, etc. If we make this assumption, then:

100-person: 5 tonnes initially and 2 tonnes every 2 years per person
1000-person: 2.5 tonnes and 1 tonne per 2 years per person
10,000 person: 1 tonne initially and 0.5 tonnes per two years per person

Further, let us assume that each ten-fold increase in population sees a five-fold decrease in import costs per tonne because of improved technology; thus:

100-person: $13 million per tonne
1,000-person: $2.5 million per tonne
10,000-person: $0.5 million per tonne

Combining these together, we see a 100 person base costs (5 x 100 x 13 million) = $6.5 billion to set up per additional 100 residents; the 1000 person base costs (2.5 x 1000 x 2.5 million) = $6.5 billion to set up per additional 1000 residents; similarly the 10,000 person base will cost about $6.5 billion per additional 10,000 residents as well! Of course, going from 100 to 1000 means 900 people have to be added, and this model assumes the price is still 13 million per tonne and 5 million tonnes, so we're talking about $60 billion to build up your surface facility to 1,000 people, $60 billion more to build it up to 10,000, etc.

I haven't figured in the cost of moving that additional person yet. But let us assume the cost is the same as the initial cargo; in other words, at the 100-person level, $65 million per person; at the 1,000-person level, $6.5 million per person; at the 10,000 person level, $0.5 million per person. With this assumption we double the cost of expanding the facility from $60 billion to $120 billion for each ten-fold expansion. Furthermore, let assume that we have to spend an equal amount of terrestrial support and research to improve your Martian surface technology and transportatin technology. One could see the Earth spending $240 billion every 30 years on Mars colonization; that's $8.5 billion per year. If that is true, we could imagine an expansion of this sort:

2030: 10 people on Mars
2060: 100
2090: 1000
2120: 10,000

I don't know whether this is a feasible model. I can imagine we could lower transportation of cargo to Mars to $1 million per tonne if we can get it to low earth orbit cheaply, use solar sailing vehicles or something cheap to get to Mars, and use a reusable shuttle to land it. And $half a million per tonne might be feasible if a space elevator ever materializes. I find a further five fold reduction to $100,000 per tonne unlikely, but who knows?

If we assume that Martian colonization at the 100,000 person level involves the movement of 1 tonne of set-up cargo per additional resident and say 100 kilograms of consumables per person every two years at $1 million per tonne, that means a colony of 100,000 on Mars would cost $100 billion to establish--feasible over ten years time--and $10 billion per year to maintain. If, at the million person level, the per-new-resident import were 100 kilograms and the per year import dropped to ten kilograms per person, assuming 1 million per tonne, the colony would still cost $100 billion to set up and $10 billion per year to maintain. At that scale of an operation, a terrestrial mission control center would be unnecessary--it could be moved to Mars--and the Martians themselves would be doing the research and develoment to improve their technology, so those costs would no longer be needed as separate line items. Ten billion per year might be a reasonable expenditure in the mid twenty-second century.

At some point--probably when per person maintenance drops below half a million per person per year, or $100,000 per person per year--somewhere in that range--the Martian population will be able to cover much or even all of its costs through exports. At that point, Mars would have a tendency to become an independent nation or nations.

Of course, we can't predict the economics or the technological breakthroughs, but some simple sliding scales at least helps us estimate things.

-- RobS

Austin Stanley · 2005-08-04 03:13:21

Wow, what a masterfull analysis RobS, I'm impressed. I would also point out that when transportation reaches around the $2.5 million per ton mark transportation costs have probably droped to the point to which public and private corporations can afford to make serious investments in Mars, and if it ever reaches the $.5 million per ton private individuals financing their own way to Mars becomes a possibility, especialy with the increased prosperity we can expect to have by this time. This may mean that we could expect the growth from 100-1,000-10,000 to happen at a much more rapid rate than the inital establishment. Although the physics of space travel may put an upper limit on the number of people/cargo that can be transfered per year, regardless of the finances.

And I partialy agree with your assesment on GCNR and their use. I am unsure as to how reusable such a engine would be (they certianly are going to require some uranium refuling), however there is no reason that if the engine is signfigantly reusable that it couldn't use H2 produced on the Moon/Mars/Phobos. The bigger issue to me the issue of travel time/vrs payload cost. Taking a faster/more energy intensive path is going to require signifigantly more fuel. In addition faster transits mean a faster approach on Mars which will make aerobraking more difficult or impossible, which would mean you would need to take fuel to slow down again as well. All this extra fuel may end up massing considerably more than the extra food/LSS/consumables you would have to take. Higher ISP engines are of course almost always worth it, but faster trip times may not be.

For cargo I still think the choice is clear, solar sails all the way. In the beginning (pase 2 in your post) throw away solar sails could have a big advantage. Once orbital tugs are avaliable on Earth/Mars the could also be reusable (giving us a handy way to bring cargo back from Mars), and if the could be manufacture on the moon the advantage would be massive. This could dramaticly drop cargo cost much earlier in a colony's development.

As for getting down to $100,000 per tonne a long enough space elevator MIGHT do this. If the cable is long enough you can just wait for the right time and just let the thing hurl the parsel at Mars. But at this point further reductions in cost are likely less important as the cargo itself is probably worth considerably more than $100,000 per ton. Since it is probably high-tech manufactured goods/highly refined minerals as by this point the cheaper commodities are probably manufactured on Earth.

Dook · 2005-08-04 03:46:54

Somehow the posts always exclude accidents as if we have everything figured out and nothing ever goes wrong. What about those colonists who change their mind and want to be sent home? Engines not firing. Dome leaks. Crop failures. Mysterious oxides in the regolith. Power outages. CO2 toxicity.

And I still haven’t read anything convincing as to why we should do this?

GCNRevenger · 2005-08-04 06:51:42

As usual, getting there is half the fun...

I think for your average colonist, that a 6-7mo flight is too much to ask of them, and its right at the borderline of what we can expect from trained/fit excercise-ahulic astronauts. Since a reuseable ferry will be one piece and too small to spin on any of its axies, artifical gravity is out. That goes for the return trip too.

Being able to launch more often than bianually is also vital, that really is too long to at least have the capability. To be able to open the launch window wider (say, anually) or cut trip time down to 3-4mo demands such a large delta-V that the fuel bill becomes too large with chemical engines. High-Isp and high-thrust engines are non-negotiable. There will obviously be a need for high-speed payload at least on occasion, for that reactor spare part, medical goods, or agricultural animals or something too.

And as was pointed out, a fast transit will probobly be going too fast for a practical aerobrake shield, but thats okay if you have a high enough Isp. It really does make all the difference. I think that a reasonably reuseable GCNR/NSWR engine is possible, the thing will be cooled by copious quantities of liquid hydrogen after all, but it will take some doing. Experimental ceramics at Sandia have reached like 5,000K, or perhaps some sort of liquid coating insoluble with LH2 could be used to coat the engine walls like the Orion pusher-plate.

I think that radar and various spectral data reasonably proves that there are no lakes of water ice on the Moon from which to make cheap rocket fuel, and so what is there isn't going to be abundant enough to fuel "fast" ships, and just making LOX from oxide rocks in 100MT quantities will be so energy-intensive that it won't be practical either... then there is the problem of getting it off the Moon and to the ship. Lunar fuel to Earth orbit is dubiously economical with current rockets, it surely won't be at all with a true RLV. Lunar fuel is out.

As far as Phobos/Deimos, as I have sparred with Robert on several occasions, I think that Zero-G mining is never going to be practical. Digging up space rocks with no gravity and somehow getting the water out of them for cracking is too much trouble, and it is much easier to lift it from Earth and develop a high-performance engine, which we will need anyway. We don't even need fueling depots really, just have the spaceplane dock and deliver its fuel directly to the cycler, which will be equipped with a cryogen condenser.

Solar sails are soooo SLOW... they are too slow in my opinion to be worthwhile. What could you ship with them? Bulk cargoes right? Stuff that doesn't mind being cooked by radiation or handle the cold for long periods? This is precisely the type of stuff that we HAVE to learn to make on Mars! There aren't going to be any grain ships, or ships full of base metal ingots, or Ammonia tankers or whatnot because all this stuff will be made locally. They are definatly not worth the trouble, if they would work at all. Manufacturing them on the Moon, given their low gross mass, is a silly idea too. Why would you bother building a sail factory there?

As a side note, the payload fraction figures you cite Rob, are those including aerobrake/lander masses? I know that landing fuel is a signifigant fraction of MD/DRM launch mass, which will instead be provided by local Martian RLVs and fuels. Might improve the situation a little.

Dook: The colony ships being reuseable will be able to carry people back to Earth too, and modern engines like SSME have reached 99.9% reliability, with next-generation engines (like COBRA) aiming for >99.99%. Our rockets are pretty good now-a-days, the technology has not stood still since Apollo you know.

There will always be risks inherint to life on the Red Planet, but most of them will have been discoverd by earlier crews sent to explore the planet and prepare the way for the first colonies. It is desireable to spread humanity to other worlds for a variety of reasons - diversity of culture, insurance against extinction, inspiration to the next generation, nessesity the mother of invention, etc - and Mars is the very best world besides ours. Why not?

TwinBeam · 2005-08-04 14:45:40

Motivations for a distant colony (space or otherwise):
- Exploration: 10-100 person base, despite major hardships

- Profit: Thousands of people, despite major inconveniences

- Better Life: Millions of people, but only if life really is better than back home

"Hardship" is mainly modulated by the ease of getting to the colony. Mars is barely onto the high end of the difficulty scale today, making even an exploration base questionable. A good RLV, or development of some useful in-space infrastructure (e.g. affordable O2 from the moon) might bring it down to "reasonably hard".

I suspect a Mars base of more than a dozen people will be indefinitely on hold pending development of a 'magic' enabling technology (nanotech, spaceship scale fusion power, anti-matter fuel, real-AI-robots, etc).

RobS · 2005-08-04 15:27:20

A few comments.

Zero Gravity and Long Flight Times: I don't agree that artificial gravity is out of the question in the colonization phase when spacecraft can be partially assembled off Earth. Or maybe even earlier: the "Mars 24" system I created two years ago proposed flying two interplanetary transit vehicles, each able to accommodate three or four people, docked together nose to nose and spun at 4 rpm. That would generate Martian gravity at the lowermost level, 15 meters from the axis. The two ITVs would provide lifeboat backup to each other.

When you get to the colonization phase, I envision this: a large flat plate or flying saucer shaped vehicle thirty two meters in diameter. Inside the hard, stationary shell is a rotating structure thirty meters in diameter. If the plate has an average thickness of ten meters, the interior would contain about 7,000 cubic meters; at 90 cubic meters per person it would accommodate 80 people. The bottom of the plate would have a thermal protection system for aerobraking. The vehicle would be connected to a second vehicle of similar size via an inflatable zero-gee gymnasium so either ship could provide backup for the other.

I suspect a ship of this sort would be quite comfortable for six month trips; definitely much more comfortable than six-month clipper ship voyages from New York to San Francisco via the Cape of Good Hope that the gold rush folks endured in 1849 (along with weeks of seasickness, terrifying storms, scurvy, and a mortality rate of a few percent). The two ships would have a zero-gee vollyball tournament, one would organize an orchestra and the other a theater company, and everyone would be in training almost constantly. If the vehicles were Mars based, the trainers would be Mars veterans taking a year or so off from home to visit Earth on a quick shore leave and orient the tenderfeet on their way back.

Even larger vehicles would be even more efficient in terms of tonnes of structure and life support per person, and the number of cubic meters per person could be reduced (because of staggered use of common areas). I don't see why something like this won't work in the colonization phase; we're not talking about terribly difficult technology. Furthermore, these very large vehicles would have sufficient mass to be relatively safe in solar storms.

Lunar water: No lakes of ice, no question about it, but the GUESS right now is for disseminated ice, 1 to 2% by mass in the regolith. There is a paper about this at the Colorado School of Mines website that I have cited before; it says the ice is barely economically exploitable at the 1% level.

Phobos water: If there is a colony on Mars, there will be an incentive to exploit the chondrite. We aren't talking about spending billions to travel vast distances to harvest metals; we're talking about traveling to middle-Mars orbit from a surface base using existing shuttle technology. This would allow a series of brief technology experiments during scientific expeditions to the moons. The best way to extract the water is by drilling and using heat in the drill shaft to produce low pressure water vapor, which will travel up the shaft because of differential pressure (the shaft will have to be lined to reduce leakage and freezing).

Crashes, pressure leaks, and other disasters: These all fall in the "shit happens" category. One can predict they will occur, though we can't predict the frequency. They are a barrier to settlement if they occur very often. In another half century we should be able to land people and cargo on Mars with a 99% certainty of safe arrival. Once on the surface, safety results from redundancy; you don't put your entire base in one dome or one structure, but ideally in at least three.

Magic enabling technology: No, not necessary.

-- Rob Stockman

Rxke · 2005-08-04 15:59:50

Hi, Rob,

re: the ice.

been doing some reading on 'the other side' (the luna Artemis etc people)

Somewhere I read (solar wind deposited) hydrogen can be found in the moondust (not the rocks) in an abundance as high as 146ppm, and they made a point of really trying to use it, but you say 1% is already uneconomical...

they say 1 1/2 pint per cubic meter (weird mixing of measureing standards, I know) could be extracted if they stripminde the upper dustlayer, combining that H with Oxy would give 9 pints IIRC of H2O, and that sounded a lot to me...

So my question: a MER sized rover, trundling around, cooking stuff etc... with low human maintenance efforts... wouldn't that be at least fringe-economically viable? let's say it also collects other volatiles...

srmeaney · 2005-08-04 17:20:39

Would a single contract for space travel be better for Space development or would ten contracts covering the R&D to provide free passenger movement between the Earth and the Moon be better for Tourism, Space, private sector...

If a Space Commonwealth offered a thousand billion dollars each to a hundred different industry players to provide a free passenger service to the moon and back for thirty years, would that be worth the money? Would it be sufficient for Humans to make a go of it?

Now if you dont mind, I've got to go encourage Rebok to branch out into Space Suits for the private Market.

GCNRevenger · 2005-08-04 19:01:34

"a MER sized rover, trundling around, cooking stuff etc... with low human maintenance efforts... wouldn't that be at least fringe-economically viable? let's say it also collects other volatiles"

Short answer: no. Its surprising just how little the MER-class rovers could do on their own. The problem is, primarily, that you need lots of energy to heat the soil to extract the gasses, plus pumps to compress them. Power that dinky rovers don't have.

--------------------------------------------------------------

What are you talking about Rob? Such a ship is a bonefied Battlestar Galactica! For all the huge amount of mass needed to put together such a large and hyper-expensive ship - an orchestra? - you could instead spend the same rocket fuel to just get to Mars faster, cutting months off the travel time.

The design you have in mind would never be able to aerobrake, because its mass/area ratio would be far too low or too high due to the disk shape.

A colony ship isn't about being comfortable, its about being efficent. My 25-person colony ship could be built in only a few launches of a contemporary 100MT class HLLV, and with the exception of the GCNR/NSWR engine, would be technologically AND economically feasable, unlike yours.

Don't build BIGGER ships, just build more of them! Let economies of scale help carry us to Mars, and we will be there a whole lot sooner.

"The best way to extract the water is by drilling and using heat in the drill shaft to produce low pressure water vapor, which will travel up the shaft because of differential pressure (the shaft will have to be lined to reduce leakage and freezing). "

Thermal energy you don't have in a drill that you can't reliably handle on the loose rocky surface down a shaft that you can't easily line with anything to slllloooowly eeke out a little bitty bit of water vapor from the rock, which you would then need to condense/crack/liquify. Ain't happening on any practical scale, and thats all there is to it. Asteroid mining would extremely difficult if you had gravity, but essentially impossible and obviously impractical since you don't.

When we have fuel on Mars, just lift it off the ground with the RLV, thats all there is to it... a GCNR engine would probobly be efficent enough to bring 100% of its round-trip Hydrogen from Earth and still be plenty efficent anyway.

RobS · 2005-08-04 20:33:05

GCN: I'm not talking about a transport ship when Mars has a few hundred people, but when it already has thousands. If, every opposition, you want to send a few thousand people to Mars, you want to do it 25 at a time? That's a lot of systems to fail and a very busy time for Mars Space Traffic Control; why not send them 100 at a time, and later 1000 at a time?

Aerobraking: I agree you can't make a ship too "thick" if you want to aerobrake. But ten meters may still be feasible if you are approaching Mars at close to hohmann trajectories and you're aerobraking into an elliptical 24.7 sol "sun synchronous" orbit, and if the ship has an extra-wide aerobrake around it (or a ballute). The delta-v for aerobraking isn't much; maybe 1.5 km/sec. From that orbit you could rendezvous with a shuttle or with an interplanetary transit station (Mars's equivalent of Earth-Moon L1 "gateway"), transfer passengers, and prepare for returning the vehicle to Earth for another load.

As for Phobosian fuel, again I'm talking about farther into the future, and I am frankly not quite as pessimistic as you about operating in zero-g. Yes, I have already heard your lecture on the subject several times. If lunar and Phobosian fuel are available at a reasonable price, they will blow nuclear engines out of the water in terms of transport cost, unless such engines come down in price A LOT. I think cheap nuclear engines are quite unlikely because of the near-paranoia guaranteed to exist about their safety, and colonization of Mars will depend on cheap transport.

Regarding your question about the mass ratios I was using for cargo: yes, they were rough and off the cuff. I didn't do any calculations. But the entire exercise in calculating cargo costs was rough and filled with a lot of estimates anyway.

-- RobS

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