Author Topic: $500,000 Pricetag for Mars Trip  (Read 58290 times)

Offline QuantumG

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Re: $500,000 Pricetag for Mars Trip
« Reply #40 on: 11/28/2012 01:37 am »
Musk keeps mentioning public-private partnerships to settle Mars.  I wonder if his $500,000 figure assumes that development costs are paid by government customers so that the passenger is only having to pay manufacturing and operation costs.  How much would a 747 cost if Boeing had developed it for 'free'?

Based on other information he's said I doubt it. He talks about $500,000 being the price at which someone could sell everything they have and move (ala the english colonists). Those wouldn't be government passengers.

Yes, mrmandias was talking about the development cost of such a system that would enable that.
Human spaceflight is basically just LARPing now.

Offline A_M_Swallow

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Re: $500,000 Pricetag for Mars Trip
« Reply #41 on: 11/28/2012 03:35 am »
>
A colony able to produce its own food, water, clothing, transport, energy, furniture and buildings is going to be very sophisticated.  I suspect that level of self reliance will not be available until towards the end.

ISRU doesn't just mean using what's thrre, but finding multiple uses for what you bring with you. Look to the past, as in our ancestors handcrafts.

Water: subsurface & recyclng
Food: grow your own, see greenhouse
Clothing: growing your own food & other plants are a great source of cellulose fibers. See spinning wheel & looms. Worked for great-granny.
Furniture: thicker plant stems are easily made into wicker. Wicker makes very durable furniture.
Buildings: look to the opal miners of Australia who dig their shelters underground as they mine. Lots of other ways to do it as well.



Look at the number of people in Australia.

Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #42 on: 11/28/2012 06:05 am »
If we assume that the average stay on Mars is 10 years (some will stay permanently, others only a couple of years), then using 150 person transfer habs in low energy trajectories about 1000 are needed. If it takes 20 years to build up, then the production rate is 50/year or 1/week. This is about twice that of the 747-8. Although a high rate for large aerospace structures it is nowhere near car production levels.

If using high energy (say 2 weeks one way on average) only about 40 transfer habs are needed. I know of no current technology which could give such high speed trajectories and even if such a technology is developed the cost of the energy for the trip would be high.

Offline Robotbeat

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Re: $500,000 Pricetag for Mars Trip
« Reply #43 on: 11/28/2012 04:57 pm »
If we assume that the average stay on Mars is 10 years (some will stay permanently, others only a couple of years), then using 150 person transfer habs in low energy trajectories about 1000 are needed. If it takes 20 years to build up, then the production rate is 50/year or 1/week. This is about twice that of the 747-8. Although a high rate for large aerospace structures it is nowhere near car production levels.

If using high energy (say 2 weeks one way on average) only about 40 transfer habs are needed. I know of no current technology which could give such high speed trajectories and even if such a technology is developed the cost of the energy for the trip would be high.
One per week is a lot. But what if instead of 150 people per transfer hab, it's more like 4 or 5? And what if the build-up is much faster, like ten years? That's 60 per week, much closer to car production numbers.

This whole plan is crazy, we must not lose sight of that. But is it possible to make an RV-sized pressure vessel with simple RCS (perhaps cold/warm gas), simple ECLSS (not recycling, just scrubbing CO2 from a reusable scurbber and adding O2 from a liquid oxygen tank, possibly recycling water or using electrolysis to get oxygen from water for simpler storage), some body-mounted solar panels, docking port, etc? Can it be done on that sort of scale, equivalent almost to luxury car production runs? For maybe $5-10 million or less a piece?

It doesn't seem /physically/ impossible, and conceivably if done with enough automation and with the development/engineering costs spread over thousands of these units, maybe it could be done economically, if the demand were there.

Remember, all a transfer vehicle has to do is keep the passengers alive from when they leave Earth orbit until arrival at Mars orbit. Delta-v for trans-Mars-insertion and for Mars orbit insertion can be done by reusable rocket stages (used for multiple transfer vehicles for each synod) on each end of the trip. Landing would be handled by a reusable lander of some sort, but landing can occur over a broader time scale, once everyone has arrived safely at Mars orbit.
« Last Edit: 11/28/2012 05:18 pm by Robotbeat »
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Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #44 on: 11/28/2012 06:00 pm »
If we assume that the average stay on Mars is 10 years (some will stay permanently, others only a couple of years), then using 150 person transfer habs in low energy trajectories about 1000 are needed. If it takes 20 years to build up, then the production rate is 50/year or 1/week. This is about twice that of the 747-8. Although a high rate for large aerospace structures it is nowhere near car production levels.

If using high energy (say 2 weeks one way on average) only about 40 transfer habs are needed. I know of no current technology which could give such high speed trajectories and even if such a technology is developed the cost of the energy for the trip would be high.
One per week is a lot. But what if instead of 150 people per transfer hab, it's more like 4 or 5? And what if the build-up is much faster, like ten years?

I'm assuming a professional crew of 8 will be needed and that no more than 20 passengers per crew are practical.

Major systems will include, power, heat removal, air replenishment and distribution, water recycling and distribution, lighting, comms, data networks, secondary propulsion, exercise and entertainment, safety, emergency response, airlocks, docking ports and many others. Then there are the more domestic side (cooking, cleaning, washing, etc.).

In general I think it likely that larger sizes will be more efficient.  Production rates for a 150 person hab would be large enough that there will be few extra gains from going to 30x the rate for 5 person habs.

I agree that reusable rocket stages that do not travel with the hab might be a possible way forward. An alternative might be some form of beamed power for propulsion with power stations at Earth and Mars.

Offline Elmar Moelzer

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Re: $500,000 Pricetag for Mars Trip
« Reply #45 on: 11/28/2012 06:07 pm »
I think that the key to making this work is reducing the transfer times. If transfer times are a month or less, you dont have to bring as many consumables with you on that passenger flight. Things needed for the stay on mars can then be sent ahead of time with a slower and cheaper cargo transport and can focus on production of things on mars instead of consumables for the trip.

Offline Robotbeat

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Re: $500,000 Pricetag for Mars Trip
« Reply #46 on: 11/28/2012 06:12 pm »
If we assume that the average stay on Mars is 10 years (some will stay permanently, others only a couple of years), then using 150 person transfer habs in low energy trajectories about 1000 are needed. If it takes 20 years to build up, then the production rate is 50/year or 1/week. This is about twice that of the 747-8. Although a high rate for large aerospace structures it is nowhere near car production levels.

If using high energy (say 2 weeks one way on average) only about 40 transfer habs are needed. I know of no current technology which could give such high speed trajectories and even if such a technology is developed the cost of the energy for the trip would be high.
One per week is a lot. But what if instead of 150 people per transfer hab, it's more like 4 or 5? And what if the build-up is much faster, like ten years?

I'm assuming a professional crew of 8 will be needed and that no more than 20 passengers per crew are practical.

Major systems will include, power, heat removal, air replenishment and distribution, water recycling and distribution, lighting, comms, data networks, secondary propulsion, exercise and entertainment, safety, emergency response, airlocks, docking ports and many others. Then there are the more domestic side (cooking, cleaning, washing, etc.).

In general I think it likely that larger sizes will be more efficient.  Production rates for a 150 person hab would be large enough that there will be few extra gains from going to 30x the rate for 5 person habs.

I agree that reusable rocket stages that do not travel with the hab might be a possible way forward. An alternative might be some form of beamed power for propulsion with power stations at Earth and Mars.
Beamed propulsion makes no sense. Just go with solar. Seriously, people who advocate beamed power for use when solar power is available constantly (unlike the Earth's surface) are severely under-estimating how good solar power is.

You may indeed be right WRT economy of scale. I was assuming no paid personnel, and just eating pre-prepared rations for the duration.

60 craft per week would, after a decade, would be as high of a total production as just about any aircraft and much greater than any pressurized aircraft.

But I'm thinking of what sort of production rate you'd want with extreme automation and economies of scale. Cars are a lot cheaper than airplanes, partially because cars are produced with high levels of automation (and because the margins are higher in cars), and have been for most of the century:
« Last Edit: 11/28/2012 06:20 pm by Robotbeat »
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Offline go4mars

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Re: $500,000 Pricetag for Mars Trip
« Reply #47 on: 11/29/2012 01:57 am »
what if instead of 150 people per transfer hab...And what if the build-up is much faster, like ten years? That's 60 per week, much closer to car production numbers.  ...possible to make an RV-sized pressure vessel with simple RCS (perhaps cold/warm gas), simple ECLSS (not recycling, just scrubbing CO2 from a reusable scurbber and adding O2 from a liquid oxygen tank, possibly recycling water or using electrolysis to get oxygen from water for simpler storage), some body-mounted solar panels, docking port, etc? Can it be done on that sort of scale, equivalent almost to luxury car production runs? For maybe $5-10 million or less a piece?

It doesn't seem /physically/ impossible, and conceivably if done with enough automation and with the development/engineering costs spread over thousands of these units, maybe it could be done economically, if the demand were there.

Exactly.  Though I expect the pressure vessels to be bigger than any RV's I've ever seen. 

In the future, the CEO of SpaceX might go talk to the CEO of Tesla (I know), and say "I notice you have expertise with mass-producing tens of thousands of relatively complex aluminum vehicles per year.  Care to collaborate on a project of joint benefit?  It would be a little different, but I believe it will be good value for your shareholders."  To which the CEO of Tesla, while leaning in close to the SpaceX CEO (to dislodge some popcorn from his teeth) might reply, "I trust the look in your eyes, and believe in your market projections.  Let's collaborate." 
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Offline joek

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Re: $500,000 Pricetag for Mars Trip
« Reply #48 on: 11/29/2012 02:55 am »
But this is such far-fetched talk our ability to guess the future is really limited.

We're probably in "advanced topic" land here.

Agree.  Maybe better to consider what a (sustainable over X years, Y years into the future) Mars colonization effort might look like, and the ground rules & assumptions, or the technology advances required to achieve a price point if $Z/person/Mars-yr.

Notably missing from many such discussions are potential advancements in bio-sciences which could have a significant impact on the compexion of such an endeavor including, but not limited to, significant increase in working life expectancy, human hibernation, "synthetic meat", etc.

In short, way too many variables and contributing factors which are extremely difficult or near-impossible to predict or extrapolate with much confidence--and of which "rocket science" is only one part.

Offline go4mars

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Re: $500,000 Pricetag for Mars Trip
« Reply #49 on: 11/29/2012 03:16 am »
Agree.  Maybe better to consider what a (sustainable over X years, Y years into the future) Mars colonization effort might look like, and the ground rules & assumptions, or the technology advances required to achieve a price point if $Z/person/Mars-yr.
The funny thing about a colony on Mars:  There are no half-steps imo.  To make it big enough to be successful, you need to do it on a huge scale.  Otherwise you're talking about unbearably expensive per person prices.  The only way to possibly realize the thread title's claim, is to go big.  Giant reusable BFR's that are mass produced and use the cheapest fuel(s) possible. 

Though I might be missing what you are getting at.  Feel free to elaborate on your post with some specifics or claims.  Then there's something more concrete to discuss.   
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Offline joek

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Re: $500,000 Pricetag for Mars Trip
« Reply #50 on: 11/29/2012 03:45 am »
Agree.  Maybe better to consider what a (sustainable over X years, Y years into the future) Mars colonization effort might look like, and the ground rules & assumptions, or the technology advances required to achieve a price point if $Z/person/Mars-yr.
The funny thing about a colony on Mars:  There are no half-steps imo.  To make it big enough to be successful, you need to do it on a huge scale.  Otherwise you're talking about unbearably expensive per person prices.  The only way to possibly realize the thread title's claim, is to go big.  Giant reusable BFR's that are mass produced and use the cheapest fuel(s) possible. 

Though I might be missing what you are getting at.  Feel free to elaborate on your post with some specifics or claims.  Then there's something more concrete to discuss.   

At the risk of wandering into what probably belongs in advanced topics, consider...
- What if your working life expectancy was 100+ years?
- What if you could ship people between Earth and Mars for little more than the price of cargo?
- What if sustaining human presence on Mars (above bare sustenance levels) was nil?
How would those answers change the equation?  Moreover, are the answers likely to found in advances in bigger-cheaper-rockets-transports-whatever, or in other disciplines?

Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #51 on: 11/29/2012 05:43 am »
Beamed propulsion makes no sense. Just go with solar. Seriously, people who advocate beamed power for use when solar power is available constantly (unlike the Earth's surface) are severely under-estimating how good solar power is.

For high energy trajectories (2 weeks transit) the power required is in the GW. The several km2 needed for solar becomes unwieldy at those power levels (imagine several manoeuvering [British spelling] around a spaceport). Beamed power is a possibility for solving that.

Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #52 on: 11/29/2012 06:07 am »
Mars is likely to be high wage, high cost of living.

High wage because of the high skill levels needed and the fact that low added value activities are better done on Earth.

High cost of living use to the cost of imports and the low population level leading to inefficiency in manufacturing, distribution, services, etc.

If say the average wage was $400,000/year and cost of living $200,000/year then the $500,000 cost of the trip is minor.

A point of reference is recruitment of high-flyers. It is not unusual for them to be given golden hellos of the order of $500,000. Neither is it unusual for rent to be paid on luxury flats (appartments) in London to be paid when recruiting from overseas, luxury flats can go for $50,000 / week although $5000 - $10000 / week is more usual.

Offline Dave G

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Re: $500,000 Pricetag for Mars Trip
« Reply #53 on: 11/29/2012 09:25 am »
Quote from Musk:

[How many people on a flight?] "In the beginning you'd go with a smaller number of people and you'd have a higher proportion of cargo and emergency equipment and that kind of thing. Once you really got rolling, you'd increase the number of people on the flight because you'd have supplies there. So you wouldn't need to worry about carrying with you all the supplies for the journey there, the stay on the surface and coming back. So initially you start off with maybe a handful of people, less than 10, just trying to give orders of magnitude here, but then you'd go to 100 or more in steady state, down the road."

I believe the $500,000 price tag corresponds to that "down the road" number of passengers. 

To be clear, Musk wants to get people on Mars within 10-20 years, but that's nowhere near the $500K ticket price. 

Musk also mentioned there would be a lot of investment required to build a Mars base large enough to support normal passengers at $500K each.  I believe this would require many years to come to fruition.

So we're talking probably 25 to 50 years from now before this $500K price has a chance of becoming real.
« Last Edit: 11/29/2012 02:12 pm by Dave G »

Offline Robotbeat

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Re: $500,000 Pricetag for Mars Trip
« Reply #54 on: 11/29/2012 06:23 pm »
Beamed propulsion makes no sense. Just go with solar. Seriously, people who advocate beamed power for use when solar power is available constantly (unlike the Earth's surface) are severely under-estimating how good solar power is.

For high energy trajectories (2 weeks transit) the power required is in the GW. The several km2 needed for solar becomes unwieldy at those power levels (imagine several manoeuvering [British spelling] around a spaceport). Beamed power is a possibility for solving that.
You're talking as if power is independent of mass. You can also use a much smaller array if you have a much smaller mass. Also, the mass of the solar array itself is important, and can be driven quite small. 1kW/kg is possible... even beyond, 5kW/kg, if you use a solar power sail. At 5kW/kg, 1GW takes 200mT. Sure, it may take a couple km^2, but that is not a show-stopper in space, where there is ample room for large structures.

But have you even CONSIDERED the size of antenna or optics needed to transmit power efficiently from Earth to Mars? Calculate it and let us know, starting with microwaves. Even just from GSO to the surface is quite a feat. Going from Earth orbit to Mars would be ridiculous. A large solar power sail looks pretty appealing compared to that.

Also, remember that that is just a small portion of the mass needed... you also need the thrusters themselves, which are very heavy as well. Supposing a miracle happens and you could get them to 10kW/kg, including power conversion... That'd be 100mT for 1GW. Suppose you also have 100mT of cargo, 4mT of tanks. That'd give you 400mT dry mass for 1GW, giving you a dry mass specific power of ~2.5kW/kg.

But suppose instead you had only 10mT of cargo? That'd mean "only" 100MW is needed, for a much smaller solar array. Giving power requirements without mass is meaningless.
« Last Edit: 11/29/2012 06:46 pm by Robotbeat »
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Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #55 on: 11/29/2012 06:52 pm »
But suppose instead you had only 10mT of cargo? That'd mean "only" 100MW is needed, for a much smaller solar array. Giving power requirements without mass is meaningless.

10 tonnes for 150 people? No way!

I assumed a slightly smaller volume and reduced supplies when I came up with the several GW estimate.

Put it another way the 39 days to Mars using VISIMR was widely rejected when Ad Astra mooted the idea, because of the insanely optimistic specific power. Reducing down from 39 days to 14 days takes ~(39/14)^2 (=7.76) as great a specific power.

Offline Robotbeat

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Re: $500,000 Pricetag for Mars Trip
« Reply #56 on: 11/29/2012 07:24 pm »
But suppose instead you had only 10mT of cargo? That'd mean "only" 100MW is needed, for a much smaller solar array. Giving power requirements without mass is meaningless.

10 tonnes for 150 people? No way!

I assumed a slightly smaller volume and reduced supplies when I came up with the several GW estimate.

Put it another way the 39 days to Mars using VISIMR was widely rejected when Ad Astra mooted the idea, because of the insanely optimistic specific power. Reducing down from 39 days to 14 days takes ~(39/14)^2 (=7.76) as great a specific power.
That's about right.

But that's a very high number for beamed power propulsion as well! And higher than any fission (or fusion) process other than maybe ol' bang-bang (which isn't exactly flawless, either).

Solar power may actually be high enough performance for it (you can make solar cells as thin as a solar sail), but the rest of the components aren't, and they become really important. There are ways around this, but usually they are inefficient.
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Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #57 on: 11/29/2012 08:13 pm »
That's about right.

But that's a very high number for beamed power propulsion as well!

True, but if you look back at what I originally wrote:

Quote
I agree that reusable rocket stages that do not travel with the hab might be a possible way forward. An alternative might be some form of beamed power for propulsion with power stations at Earth and Mars.

Quote
For high energy trajectories (2 weeks transit) the power required is in the GW. The several km2 needed for solar becomes unwieldy at those power levels (imagine several manoeuvering [British spelling] around a spaceport). Beamed power is a possibility for solving that.

you can see I was never advocating beamed power in the first place. For a system that is several decades in the future things that cannot be ruled out, are at least possible. I agree that beamed power is probably not the solution that is going to be picked. But there are many possibilities, e.g. neutral particle beam propulsion - a beam of neutral particles at almost the speed of light is fired at the spacecraft, it ionizes them and then uses magnetic fields to deflect them producing a very high Isp drive. The technology to do that is formidable! There are dozens of variants of beamed power propulsion and probably many that have not been thought of yet.


Offline DLR

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Re: $500,000 Pricetag for Mars Trip
« Reply #58 on: 11/29/2012 08:31 pm »
As suggested before, I think the $500,000 per passenger price could be achieved with high-performance light sails acclerated and decelerated by orbital lasers. These "lightcraft" could make the trip in a matter of days / weeks regardless of launch windows.

The laser stations would have to be huge though, in the multi-GW range at least. The advantage is that these lasers could be used at all times. Chemical or solar electric rockets would be much slower and launch window constrained and thus not suitable for a reusable transportation system, which requires a high number of trips to recoup capital costs.
« Last Edit: 11/29/2012 08:40 pm by DLR »

Offline MikeAtkinson

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Re: $500,000 Pricetag for Mars Trip
« Reply #59 on: 11/29/2012 08:47 pm »
I've one last thing to say on this topic. Even if you had extremely high energy trajectories (2 weeks one way) only about 10 trips per year would be possible, over a 20 year lifespan of the hab it can only be reused 200 times.

This is miniscule compared to the reuse we expect out of cars, trains and planes. If bonds are issued at a rate of 7% then about 0.7% of the purchase cost needs to be used to pay back the interest on the bond and another 0.5% is needed to pay back the capital. On top of that are running costs (fuel, maintenance, crew, etc.) and profit.

If the capital costs of the hab were 10% of the total ticket price, that gives a cost/person for the hab of 15,000 / 0.012 = $1.25M. This does not seem impossible, but is in m opinion extremely difficult to reach, as in this high energy short trip time scenario there will be few habs produced so the benefits of mass production will not kick in.

We've discussed the likelihood of these high energy transfers. It seems that they will require massive improvements in technology.

[edit: high energy trajectories by definition have high energy demands, the cost of energy is likely to be the dominant factor.

Only 10 or so habs would be required, at a production rate of one every other year, hab capital cost is likely to be dominated by development and engineering team sustainment costs.]

----

I've also discussed 2 year transfers. The low number of reuses (10 in twenty years) and large size due to their transit times mean that the capital costs are likely prohibitive, using the above assumptions about 25% of the capital cost needs to be paid each trip, so the cost per capita is only 15,000 / 0.25 = $60,000

It seems to me impossible to produce a hab so cheaply. The comparison is not so much with a car, but a trailer home (passengers are going to be living in it for 6 months or more), with all the additional systems needed for space on top.

[edit: perhaps 16,000 people would transfer every window, even with 150 person habs, this is many a day. It is inefficient to have such bursts in demand, and this is bound to add to costs.

Beamed power would be overwhelmed, beamed power is not likely to be efficient for slow trajectories anyway]

----

What is left are medium energy trajectories, perhaps 3-6 months round trip. So in 20 years about 60 trips may be made. About 3.5% is needed to pay of capital, so that comes out to 15,000 / 0.035 = $430,000/person.

In my opinion these medium energy trajectories are most likely what Elon has in mind. The technology is still difficult, but not impossible, perhaps what VISIMR can realistically be expected to produce after several iterations. Costs of in-space hardware would need to come down by 3 orders of magnitude (when manufactured in lots of 100s).

« Last Edit: 11/29/2012 09:06 pm by MikeAtkinson »

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