SpaceX Dragon spacecraft for low cost trips to the Moon.

RGClark · 2012-01-31 15:29:37

SpaceX has said two Falcon Heavy launches would be required to carry a manned Dragon to a lunar landing. However, the 53 metric ton payload capacity of a single Falcon Heavy would be sufficient to carry the 30 mT (Earth departure stage + lunar lander system) described below. This would require 20 mT and 10 mT gross mass Centaur-style upper stages. This page gives the cost of a ca. 20 mT Centaur upper stage as $30 million:

Centaur IIA.
http://www.astronautix.com/craft/cenuriia.htm

A 10 mT Centaur-style stage would be somewhat less than this, so the total for both less than $60 million.

The 53 mT to LEO capacity of the Falcon Heavy would also allow large lunar cargo transport using two of the 20 mT gross mass Centaurs that already exist either using the Dragon to carry the cargo or by carrying somewhat more cargo just within a lightweight container.

An important cargo delivery to the Moon would be in-situ resource utilization (ISRU) equipment, specifically for producing propellant from the water discovered to lie within the shadowed craters near the lunar poles. Elon Musk has said a key goal of his is to mount a manned Mars mission within 1 to 2 decades. Such a mission could be mounted more cheaply if the large amount of propellant required did not have to be lofted from the Earth's deep gravity well but could be taken from the Moon.

Another important cargo delivery would be to carry a rover that could do a sample return mission from the near polar locations. Lunar orbiter observations suggest there may be valuable minerals concentrated in such locations:

SCIENCE -- October 21, 2010 at 2:05 PM EDT
Moon Blast Reveals Lunar Surface Rich With Compounds.
BY: JENNY MARDER
"There is water on the moon ... along with a long list of other compounds,
including, mercury, gold and silver. That's according to a more detailed
analysis of the chilled lunar soil near the moon's South Pole, released as six papers by a large team of scientists in the journal, Science Thursday."
http://www.pbs.org/newshour/rundown/201 … water.html

If these tentative detections could be confirmed then that could possibly form a commercial market for flights to the Moon.

In this vein note there is even stronger evidence for large amounts of valuable minerals on asteroids. Observations suggest that even a small size asteroid could contain trillions of dollars (that's trillions with a 't') worth of valuable minerals:

Riches in the Sky: The Promise of Asteroid Mining.
Mark Whittington, Nov 15, 2005
http://voices.yahoo.com/riches-sky-prom … -8776.html

It is quite important to note then that since the delta-V requirements to some near Earth asteroids is less than that to the Moon, that the sample return version of the lunar lander could also be used to return samples from the near Earth asteroids. If these asteroidal detections could be definitively confirmed by a sample return mission then that would provide further justification for private investment in lunar propellant production installations.

SpaceX expects to launch the first Falcon Heavy in 2013. Because the required Centaur stages already exist it is possible that a lunar lander could be formed from such mated together stages within this time frame at least for a unmanned cargo version.

It is important though that such a lander be privately financed. Because the required stages already exist I estimate a lander could be formed from them for less than a $100 million development cost. This is based on the fact that SpaceX was able to develop the Falcon 9 launcher for about $300 million development cost. And this required development of both the engines and the stages for a 300 mT gross mass and 30 mT dry mass launcher. But for this lunar lander, the engines and stages already exist for a total 40 mT gross mass and 4 mT dry mass system.

If the system were to be government financed then based on the fact that SpaceX was able to develop the Falcon 9 for 1/10th the development cost of usual NASA financed systems, the cost of the lander would suddenly balloon to a billion dollar development.

Note that while the evidence for valuable minerals in the lunar shadowed craters is not yet particularly strong, the evidence for such minerals in the asteroids is. So there is a strong financial incentive for forming such a lunar lander as it could also be used for the asteroidal lander.
But asteroidal mineral retrieval flights could be launched much more cheaply if the propellant could be obtained from the Moon. Then there is a strong financial incentive to produce ISRU installations on the Moon which would require lunar return missions from the shadowed crater regions to assess the best means of harvesting this lunar water for propellant. If such return missions also confirm the presence of valuable minerals in the shadowed craters then that would be like icing on the cake for justification of private investment in such missions.

Bob Clark

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The Orion spacecraft and Altair lunar lander intended for a manned Moon mission are large craft that would require a heavy lift launcher for the trip. However the Dragon capsule is a smaller capsule that would allow lunar missions with currently existing launchers.
The idea for this use would be for it to act as a reusable shuttle only between LEO and the lunar surface. This page gives the dry mass of the Dragon capsule of 3,180 kg:

SpaceX reveals first Dragon engineering unit.
DATE:16/03/07
By Rob Coppinger
http://www.flightglobal.com/articles/20 … -unit.html

The wet mass with propellant would be higher than this but for use only as a shuttle between LEO and the Moon, the engines and propellant would be taken up by the attached propulsion system. With crew and supplies call the capsule mass 4,000 kg.
On this listing of space vehicles you can find that the later versions of the Centaur upper stage have a mass ratio of about 10 to 1:

http://www.friends-partners.org/partner … pndexc.htm

The Isp's given for the RL-10A engines used on these stages are around 450 s, but an updated version with a longer, extensible nozzle has an Isp of 465.5 s:

RL10B-2.
http://www.pw.utc.com/products/pwr/asse … l10b-2.pdf

This page gives the delta-V's needed for trips within the Earth-Moon system:

Delta-V budget.
Earth–Moon space.
FluxBB bbcode 2ef1b28
http://en.wikipedia.org/wiki/Delta-v_bu … Moon_space

The architecture will be to use a larger Centaur upper stage to serve as the propulsion system to take the vehicle from LEO to low lunar orbit. This larger stage will not descend to the surface, but will remain in orbit. A smaller Centaur stage will serve as the descent stage and will also serve as the liftoff stage that will take the spacecraft not just back to lunar orbit, but all the way to back to LEO. The larger Centaur stage will return to LEO under its own propulsion, to make the system fully reusable. Both stages will use aerobraking to reduce the delta-V required to return to LEO.
For the larger Centaur, take the gross mass of the stage alone as 30,000 kg, and its dry mass as 1/10th of that at 3,000 kg. For the smaller Centaur stage take the gross mass as 10,000 kg and the dry mass as 1,000 kg. The "Delta-V budget" page gives the delta-V from LEO to low lunar orbit as 4,040 m/s. In calculating the delta-V provided by the larger Centaur stage we'll retain 1,000 kg propellant at the end of the burn for the return trip of this stage to LEO: 465.5*9.8ln((30,000 + 10,000 + 4,000)/(3,000 +10,000 + 4,000 + 1,000)) = 4,077 m/s, sufficient to reach low lunar orbit. For this stage alone to return to LEO, 1,310 m/s delta-V is required. The 1,000 kg retained propellant provides 465.5*9.8ln((3,000 + 1,000)/3,000) = 1,312 m/s, sufficient for the return.
The delta-V to go from low lunar orbit to the Moon's surface is 1,870 m/s. And to go from the Moon's surface back to LEO is 2,740 m/s, for a total of 4,610 m/s. The delta-V provided by this smaller Centaur stage is 465.5*9.8ln((10,000 + 4,000)/(1,000 + 4,000)) = 4,697 m/s, sufficient for lunar landing and the return to LEO.
The RL-10 engine was proven to be reusable for multiple uses with quick turnaround time on the DC-X. The total propellant load of 40,000 kg could be lofted by two 20,000+ kg payload capacity launchers, such as the Atlas V, Delta IV Heavy, Ariane 5, and Proton.
The price for these launchers is in the range of $100-140 million according to the specifications on this page:

Expendable Launch Vehicles.
http://www.spaceandtech.com/spacedata/elvs/elvs.shtml

So two would be in the range of $200-$280 million. The Dragon spacecraft and Centaur stages being reusable for 10+ uses would mean their cost per flight should be significantly less than this. This would bring the cost into the range affordable to be purchased by most national governments.
Still, it would be nice to reduce that $200 million cost just to bring the propellant to orbit. One possibility might be the heavy lift launchers being planned by NASA. One of the main problems in deciding on a design for the launchers is that there would be so few launches the per launch cost would be too high. However, launching of the propellant to orbit for lunar missions would provide a market that could allow multiple launches per year thus reducing the per launch cost of the heavy lift launchers. For instance, the Direct HLV team claims their launcher would cost $240 million per launch if they could make 12 launches per year:

JULY 23, 2009
Interview with Ross Tierney of Direct Launch by Sander Olson.
http://nextbigfuture.com/2009/07/interv … irect.html

This launcher would have a 70,000 kg payload capacity. However, if you removed the payload fairing and interstage and just kept the propellant to be launched to orbit in the ET itself and considering the fact that the shuttle system was able to launch 100,000+ kg to orbit with the shuttle and payload, it's possible the propellant that could be launched to orbit could be in the range of 100,000 kg. Then the cost per kg to orbit would be $2,400 per kg, or about a $100 million cost for the propellant to orbit.
Reduction of the per launch cost for the heavy lift launchers would then allow affordable launches of the larger spacecraft and landers for lunar missions.

Bob Clark

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Last edited by RGClark (2012-02-07 03:42:23)

louis · 2012-02-01 10:09:03

All good stuff! Things seem to be coming together nicely, much along lines I have argued for - Space X in the lead, using orbital assembly and with the possibility of lunar propellant.

I think the post does actually underestimate just how much revenue could be generated from regolith sales, tourism, taking love messages and loved ones' ashes the moon- to name a few ideas. Plus there is clearly scope for considerable sponsorship and sale of TV rights I would say - maybe $200-300millon at least.

The great thing is that Musk will of course all the time have his eye on the real prize: Mars!

Terraformer · 2012-02-01 11:03:15

What sort of mission could we launch if we used ISRU fuel? Land the Hab and fuel production at the poles using one launch - that's about 12 tonnes to Luna, more if we can use higher Isp, lower thrust drives, so we'll be able to land maybe 10 tonnes. If we do it all in a single stage, we'll be able to reuse the tank for propellent. Send a Dragon with additional tanks for fuel and just land it, not leaving anything in orbit. When it's time to leave, fuel up and perform a direct reentry.

RGClark · 2012-02-01 20:23:04

Edit:

RGClark wrote:

SpaceX has said two Falcon Heavy launches would be required to carry a manned Dragon to a lunar landing. However, the 53 metric ton payload capacity of a single Falcon Heavy would be sufficient to carry the 30 mT (Earth departure stage + lunar lander system) described below. This would require 20 mT and 10 mT gross mass Centaur-style upper stages.

That should say 40 mT gross mass for the (Earth departure stage + lunar lander) system that was originally described with 30 mT and 10 mT Centaur-style stages.

Bob Clark

RGClark · 2012-02-02 04:07:26

RGClark wrote:

It is important though that such a lander be privately financed. Because the required stages already exist I estimate a lander could be formed from them for less than a $100 million development cost. This is based on the fact that SpaceX was able to develop the Falcon 9 launcher for about $300 million development cost. And this required development of both the engines and the stages for a 300 mT gross mass and 30 mT dry mass launcher. But for this lunar lander, the engines and stages already exist for a total 40 mT gross mass and 4 mT dry mass system.
If the system were to be government financed then based on the fact that SpaceX was able to develop the Falcon 9 for 1/10th the development cost of usual NASA financed systems, the cost of the lander would suddenly balloon to a billion dollar development.

Nice article here:

SpaceX Might Be Able To Teach NASA A Lesson.
May 23, 2011
By Frank Morring, Jr.
Washington

“I think one would want to understand in some detail . . . why would it be between four and 10 times more expensive for NASA to do this, especially at a time when one of the issues facing NASA is how to develop the heavy-lift launch vehicle within the budget profile that the committee has given it,” Chyba says.
He cites an analysis contained in NASA’s report to Congress on the market for commercial crew and cargo services to LEO that found it would cost NASA between $1.7 billion and $4 billion to do the same Falcon-9 development that cost SpaceX $390 million. In its analysis, which contained no estimates for the future cost of commercial transportation services to the International Space Station (ISS) beyond those already under contract, NASA says it had “verified” those SpaceX cost figures.
For comparison, agency experts used the NASA-Air Force Cost Model—“a parametric cost-estimating tool with a historical database of over 130 NASA and Air Force spaceflight hardware projects”—to generate estimates of what it would cost the civil space agency to match the SpaceX accomplishment. Using the “traditional NASA approach,” the agency analysts found the cost would be $4 billion. That would drop to $1.7 billion with different assumptions representative of “a more commercial development approach,” NASA says.

http://www.aviationweek.com/aw/generic/ … 324881.xml

Bob Clark

RGClark · 2012-02-02 04:24:26

Terraformer wrote:

What sort of mission could we launch if we used ISRU fuel? Land the Hab and fuel production at the poles using one launch - that's about 12 tonnes to Luna, more if we can use higher Isp, lower thrust drives, so we'll be able to land maybe 10 tonnes. If we do it all in a single stage, we'll be able to reuse the tank for propellent. Send a Dragon with additional tanks for fuel and just land it, not leaving anything in orbit. When it's time to leave, fuel up and perform a direct reentry.

My post was for a two-way mission so had to carry the propellant for the return trip as well. But I found this post on the Nasaspaceflight.com board that gives estimates of the delivered cargo for one-way missions by hydrogen fueled, hypergolic fueled, and a mixed propulsion system:

Re: ISS-based cryogenic third stages as expendable Earth-Moon tugs
« Reply #10 on: 06/14/2011 12:01 AM »
http://forum.nasaspaceflight.com/index. … #msg756590

For hydrogen fueled, the estimated lunar cargo delivery was about 1/6th the mass of the LEO payload capability. So for 53 mT to LEO, it would be about 9 mT.

Bob Clark

GW Johnson · 2012-02-02 15:38:03

Myself, I would not count on ISRU from the first landing anywhere. Chances are it won't work the way you want, because what resources are actually at the site are not quite what you expected (and assumed in your design).

First trip (moon, Mars, just about anywhere), you bring the propellant with you to go home. You try some ISRU experiments while you're there. Maybe they work, maybe they don't. But the data and experience you gain will make the second trip's ISRU far more likely to work. Maybe even enough to count on, if the first experiments turn out fairly well.

It's all about suspenders-and-belt, and learning-as-you-go. That's how you get the crew home safe. Killing a crew can get your program killed. NASA has 3 dead crews so far, and look what has happened to them.

GW

louis · 2012-02-02 18:49:39

GW Johnson wrote:

Myself, I would not count on ISRU from the first landing anywhere. Chances are it won't work the way you want, because what resources are actually at the site are not quite what you expected (and assumed in your design).
First trip (moon, Mars, just about anywhere), you bring the propellant with you to go home. You try some ISRU experiments while you're there. Maybe they work, maybe they don't. But the data and experience you gain will make the second trip's ISRU far more likely to work. Maybe even enough to count on, if the first experiments turn out fairly well.
It's all about suspenders-and-belt, and learning-as-you-go. That's how you get the crew home safe. Killing a crew can get your program killed. NASA has 3 dead crews so far, and look what has happened to them.
GW

I would agree GW that you wouldn't want to place reliance on it. You definitely need a failsafe plan. Personally I would favour sending fuel/propellant to the surface in robot pre-landers to ensure the first mission personnel can get off the planet. But, equally, I would like to try for propellant production because it seems one of the easier processes and could be accomplished robotically as well.

Rune · 2012-02-02 20:22:46

Hummm. You know the centaur is so flimsy that it needs self-pressurization to withstand it's own weight at sea level, right? And you propose to land it on the moon with no provision for a landing gear... or deep throttling. Though NASA is working on the last part and modifying a RL-10 to throttle form 104% to 8%, building a lander with a structural fraction of 10% is not really an easy task to accomplish, much less so if it has to deal with boiloff issues (you are landing it in an illuminated area for a significant amount of time after a lenghty, illuminated flight, right?) and have integrated on it the equipment to be refueled and berthed in some depot. Oh, and the astronauts have to get to the surface from the top of the stage. A stage that has to support a dragon while partially empty under lunar gravity. It's not much, but it's something, and it all adds up to "it's not going to have nearly the same structural fraction than a usual Centaur, if built the same way". Too many bells and whistles added on top.

So I doubt all this can be done with a straight-off-the-factory stretched/shortened good old Centaur. Even with a 21st century ACES stage. You push the margins a bit too close everywhere and don't leave room for eventual complications, and there are always some of those.

Rune. Other than that, great architectural concept, and I mean that.

SpaceNut · 2012-02-02 21:05:49

Even Nasa is saying that it do the moon cheaper now than the 108 billion now cancelled Constellation that Bush had planned for 2020...
To the Moon? its not that loony

Surprise Surprise A former NASA adviser says he and others at the space agency drew up an approach that could put astronauts on the moon for $40 billion, as a “Plan B” for future exploration.

RGClark · 2012-02-03 03:29:41

Rune wrote:

Hummm. You know the centaur is so flimsy that it needs self-pressurization to withstand it's own weight at sea level, right? And you propose to land it on the moon with no provision for a landing gear... or deep throttling. Though NASA is working on the last part and modifying a RL-10 to throttle form 104% to 8%, building a lander with a structural fraction of 10% is not really an easy task to accomplish, much less so if it has to deal with boiloff issues (you are landing it in an illuminated area for a significant amount of time after a lenghty, illuminated flight, right?) and have integrated on it the equipment to be refueled and berthed in some depot. Oh, and the astronauts have to get to the surface from the top of the stage. A stage that has to support a dragon while partially empty under lunar gravity. It's not much, but it's something, and it all adds up to "it's not going to have nearly the same structural fraction than a usual Centaur, if built the same way". Too many bells and whistles added on top.
So I doubt all this can be done with a straight-off-the-factory stretched/shortened good old Centaur. Even with a 21st century ACES stage. You push the margins a bit too close everywhere and don't leave room for eventual complications, and there are always some of those.
Rune. Other than that, great architectural concept, and I mean that.

The Centaurs have not been used for manned missions but they were considered for the Gemini missions when low cost alternatives to the Apollo lunar architecture were being considered. The Centaurs have been very successfully used for satellite launches for decades. Also this "balloon tank" type lightweight structure was used to launch men into space with the original Atlas rocket in the 60's.
Resting on the Moon for a lightweight structure is actually easier than on Earth of course. And on the Moon the propellant tanks will not be empty since they'll contain the propellant for the return trip and pressurants.
But in any case the most important fact is they don't have to be Centaurs. Two Centaur stages of total gross mass 40 mT would be able to carry a Dragon to the Moon and back. But you have so much leeway with the 53 mT LEO payload capacity of the FH that you could use currently existing LH upper stages with worse mass ratios that don't use "balloon tanks" for the purpose. Take a look at the list of LH2/LOX stages here:

http://www.astronautix.com/props/loxlh2.htm

Scroll down to the "Associated stages" section. You'll see several russian, european, and chinese stages can be used in combination to transport the Dragon to the Moon and back while fitting within the 53 mT LEO capability of the FH.

Bob Clark

louis · 2012-02-03 07:27:04

Why can't we be more flexible? Why can't we land a Bigelow expandable hab robotically on the surface and just have a small lander to go from lunar or Mars orbit to the surface, more like the Apollo. The personnel then transfer from the small lander to the larger surface hab.

RGClark · 2012-02-03 10:20:20

louis wrote:

Why can't we be more flexible? Why can't we land a Bigelow expandable hab robotically on the surface and just have a small lander to go from lunar or Mars orbit to the surface, more like the Apollo. The personnel then transfer from the small lander to the larger surface hab.

The Dragon is the smallest capsule we have now for carrying a crew. Quite likely one could be made for half its size though. For instance I believe the LEM ascent stage only weighed about 2,000 kg.
I mentioned this NasaSpaceFlight.com post that gave NASA estimates for the cargo mass you could send on a one-way expendable lander to the Moon:

Re: ISS-based cryogenic third stages as expendable Earth-Moon tugs
« Reply #10 on: 06/14/2011 12:01 AM »
http://forum.nasaspaceflight.com/index. … #msg756590

For hydrogen only propulsion, the cargo mass delivered to the Moon was about 1/6th the LEO payload capability of the launcher. So for the Falcon Heavy it would be about 9 mT. However, 9 mT would not be enough for the BA 330 module Bigelow is planning at about 20 mT. It would be just barely enough for the Sundancer module if Bigelow chooses to restart that:

Sundancer.
http://en.wikipedia.org/wiki/Sundancer

Bob Clark

Last edited by RGClark (2012-02-03 10:22:08)

Terraformer · 2012-02-03 17:40:17

Hmmm. How many launches would we need to set up a small base at the Lunar poles to do prospecting? We're looking at, probably, a Sundancer module (which I expect will be developed) for the habitat, a Dragon capsule for transit both ways, a hefty solar power source and chemical factory for ISPP experiments, as well as a digger and other extraction equipment. Could we do it for under a billion dollars? Possibly. If each F9H can get 9 tonnes to the surface, then we need one for the Hab, one for the power supply and chemical factory (it shouldn't be more than this) and one for the digger and other such equipment (make them swappable?). Add in another F9H launch and a F9 regular for the Dragon and it's kickstage, which should allow us to leave enough fuel inside for the return journey (only ~2.5km/s; we'd need an Isp of 370 to perform this with a mass ratio of 2, so perhaps 5 tonnes of fuel for the return journey).

Total launch costs come to under half a billion; depending on how off the shelf everything is, we might be able to pull it off for under a billion total. Remember that this leaves in place a habitat and ISPP facility, which means that for simple missions to it without using depot's would require a Falcon 9 regular and heavy, so potentially a quarter of a billion for additional missions? If you add in a LEO depot and keep a crew transport vehicle in space, with an absurd (~8.5km/s...) mass ratio, you just need to launch your crew. Obviously, a LEO depot needs to be done in conjunction with an EML1 depot. Expanding it with these gets to the infrastructure I proposed earlier, so we can actually start to develop the place...

RGClark · 2012-02-04 16:23:06

Terraformer wrote:

Hmmm. How many launches would we need to set up a small base at the Lunar poles to do prospecting? We're looking at, probably, a Sundancer module (which I expect will be developed) for the habitat, a Dragon capsule for transit both ways, a hefty solar power source and chemical factory for ISPP experiments, as well as a digger and other extraction equipment. Could we do it for under a billion dollars? Possibly. If each F9H can get 9 tonnes to the surface, then we need one for the Hab, one for the power supply and chemical factory (it shouldn't be more than this) and one for the digger and other such equipment (make them swappable?). Add in another F9H launch and a F9 regular for the Dragon and it's kickstage, which should allow us to leave enough fuel inside for the return journey (only ~2.5km/s; we'd need an Isp of 370 to perform this with a mass ratio of 2, so perhaps 5 tonnes of fuel for the return journey).
Total launch costs come to under half a billion; depending on how off the shelf everything is, we might be able to pull it off for under a billion total. Remember that this leaves in place a habitat and ISPP facility, which means that for simple missions to it without using depot's would require a Falcon 9 regular and heavy, so potentially a quarter of a billion for additional missions? If you add in a LEO depot and keep a crew transport vehicle in space, with an absurd (~8.5km/s...) mass ratio, you just need to launch your crew. Obviously, a LEO depot needs to be done in conjunction with an EML1 depot. Expanding it with these gets to the infrastructure I proposed earlier, so we can actually start to develop the place...

Thanks for that. I definitely think your low cost estimates are in the ballpark of what's doable. I think you get how frustrating it is to hear it might take $100 billion dollars and another 20 years to get back to the Moon. When you look at the technical capability we already have available and take into account the fact that government financed programs inflate costs by as much as a factor of 10, you realize a Moon landing program can be accomplished at a fraction of that both in time and cost.

Bob Clark

louis · 2012-02-04 16:54:34

RGClark wrote:

Terraformer wrote:
Hmmm. How many launches would we need to set up a small base at the Lunar poles to do prospecting? We're looking at, probably, a Sundancer module (which I expect will be developed) for the habitat, a Dragon capsule for transit both ways, a hefty solar power source and chemical factory for ISPP experiments, as well as a digger and other extraction equipment. Could we do it for under a billion dollars? Possibly. If each F9H can get 9 tonnes to the surface, then we need one for the Hab, one for the power supply and chemical factory (it shouldn't be more than this) and one for the digger and other such equipment (make them swappable?). Add in another F9H launch and a F9 regular for the Dragon and it's kickstage, which should allow us to leave enough fuel inside for the return journey (only ~2.5km/s; we'd need an Isp of 370 to perform this with a mass ratio of 2, so perhaps 5 tonnes of fuel for the return journey).
Total launch costs come to under half a billion; depending on how off the shelf everything is, we might be able to pull it off for under a billion total. Remember that this leaves in place a habitat and ISPP facility, which means that for simple missions to it without using depot's would require a Falcon 9 regular and heavy, so potentially a quarter of a billion for additional missions? If you add in a LEO depot and keep a crew transport vehicle in space, with an absurd (~8.5km/s...) mass ratio, you just need to launch your crew. Obviously, a LEO depot needs to be done in conjunction with an EML1 depot. Expanding it with these gets to the infrastructure I proposed earlier, so we can actually start to develop the place...
Thanks for that. I definitely think your low cost estimates are in the ballpark of what's doable. I think you get how frustrating it is to hear it might take $100 billion dollars and another 20 years to get back to the Moon. When you look at the technical capability we already have available and take into account the fact that government financed programs inflate costs by as much as a factor of 10, you realize a Moon landing program can be accomplished at a fraction of that both in time and cost.

Bob Clark

Yes, and people still quote the Apollo figures adjusted for inflation! - absurd!!

Plus we have to factor in revenue. At the very least you would get $500 million from commercial sponsorship, taking mementoes to the Moon, maybe the first (inflatable) art sculpture, sale of regolith, and TV rights. In fact you could probably cover a whole billion - I am being conservative here I think.

Terraformer · 2012-02-05 11:03:37

Erm... we could maybe defray some of the costs of getting there by selling TV rights, but you're not going to make a profit. If this is done in the context of a Lunar Development Corporation - which IMO is the only context which is sustainable - then you can count sponsorship out (the sponsorship *is* from the LDC). Perhaps we could charge governments a few hundred million to have a government Astronaut come along for the ride (leaving maybe 5 seats for the employee astronauts), but you're still talking at least $500 million. Would it be a worthwhile investment? Given that it would leave infrastructure on the surface which can be built upon - fuel production mainly, since that will be the first thing we're experimenting with - I'd say it would be quite likely. From there it's the addition of an EML1 depot to reduce costs even further to keep the base running, and from there we can bootstrap even further into a full infrastructure.

Terraformer · 2012-02-06 07:26:57

Maybe we could modify the Dragon cargo trunk to contain fuel tanks, linked in to the (super)Draco thrusters, and land the Dragon that way? Granted, it's going to be more cramped than Apollo for the crew on the journey, but they only have to endure it for a few days each way. Transfer the fuel in orbit and use a kickstage for the TLI, so you only need a delta-V of about 2.5km/s for the Dragon. Preland the fuel on the surface and refuel when you're ready to go home.

So, we'll end up needing maybe 4 F9H launches and 1 F9 launch, to get a digger/drilling rig, power supply, ISPP equipment, habitat, and crew to the Lunar surface, in the process leaving us with plenty of fuel tanks for the products of the ISPP experiments. Say we go for a 6 month intensive prospecting mission, after which they will transfer fuel to their Dragon and return to Terra. If the ISPP has been successful, later missions will be able to carry a greater payload, to be used for building up the base, with each mission requiring a Falcon Heavy and Regular launch. Later, an inspace transport craft could be launched, which would require less refueling - so even more payload could be launched. With the addition of an EML1 depot, all the payload launched to orbit could be taken to Luna.

How much will the Dragon + F9 setup cost?

GW Johnson · 2012-02-06 10:49:46

Terraformer:

I, too, looked at adding extra fuel to the Dragon in the unpressurized module, for a different reason. Go look at the 7-25-11 posting over at http://exrocketman.blogspot.com, and scroll down to figure 11. It summarizes what I got after a bit of reverse-engineering the data Spacex had posted on their website back then.

I was calculating 0.9 km/sec max delta vee for the basic Dragon with 1290 kg propellants, with another 1.4 km/sec possible from propellant tanks at 10% inert in the unpressurized cargo space. That's about 2.3 km/sec total, but, some of that must be used for attitude control.

There's one other thing to consider. Dragon cannot land with the unpressurized module. You have to stage it off.

GW

Terraformer · 2012-02-06 11:08:00

Ah, it won't work then, since I was suggesting using the fuel for landing.

ARD · 2012-02-06 15:56:06

How about we start out with a Dragon on an Early Lunar Access-type system? That system would have relied on using Titan IV or Ariane 5 with the STS to put 8.5 metric tons of payload on the lunar surface at a time. Three of those 8.5 ton payloads would have been used to two crewmembers on the lunar surface for a three week period. Could we substitute Dragon for the Apollo CM, put a Centaur on top of the Falcon Heavy, and put a landing stage on top of that? How much payload can Falcon Heavy and that hypothetical hydrogen-oxygen landing stage (assume specific impulse of 450 seconds) put at the lunar North Pole?

JoshNH4H · 2012-02-06 16:24:38

Hey ARD, welcome to Newmars!

Falcon Heavy has a payload of 53 tonnes to LEO. The delta V from LEO to the Moon is about 6.3 km/s, with a bit (~400 m/s) of margin to account for the fact that you're not going to the lunar equator and for a bit extra for attitude control while landing. With an Isp of 450 s, this would be a mass ratio of 4.36 (Are you familiar with the rocket equation?). That is a payload of 12,700 kg to the Moon. However, some of this will be taken up with fuel tanks and the like. Assuming a centaur-like ratio of fuel mass to dry mass, which is about 10:1, 4000 kg of this will be used up with rocket structure. Therefore, the payload to the lunar surface would be 8,700 kg.

Terraformer · 2012-02-06 16:36:42

So, we're looking at ~9 tonnes to the surface? Hmmm. If we used high performance LOX/LH2 engines, would we be able to reuse the LH2 tanks for storing Methane? As far as I'm aware, LH2 engines have been used successfully with Methane, so we could pre-position the return propellant on the surface and use the same landing stage as we used for the Dragon, or possibly even just have the Dragon stage running on LOX/Methane to start with.

Hmmm, I'm thinking we could get a Lunar base for under a billion dollars...

ARD · 2012-02-06 17:03:08

JoshNH4H wrote:

Hey ARD, welcome to Newmars!
Falcon Heavy has a payload of 53 tonnes to LEO. The delta V from LEO to the Moon is about 6.3 km/s, with a bit (~400 m/s) of margin to account for the fact that you're not going to the lunar equator and for a bit extra for attitude control while landing. With an Isp of 450 s, this would be a mass ratio of 4.36 (Are you familiar with the rocket equation?). That is a payload of 12,700 kg to the Moon. However, some of this will be taken up with fuel tanks and the like. Assuming a centaur-like ratio of fuel mass to dry mass, which is about 10:1, 4000 kg of this will be used up with rocket structure. Therefore, the payload to the lunar surface would be 8,700 kg.

Thank you for the welcome.

I am familiar with the rocket equation, but I was unsure about how much delta-v would be necessary for a lunar polar mission as opposed to an equatorial one.

So, 8.7 metric tons. Enough for Sundancer, or for a Dragon to serve as the logistics vehicle for each manned mission. Of course, we'll want a somewhat cheaper and smaller unmanned logistics vehicle to do most of that work, but in the Early Lunar Access-derivative I suggest, we could possibly reduce the total number of lunar landings per expedition to just one per launch, so we have the following architecture:

Falcon Heavy 1: Deploy Sundancer

Falcon Heavy 2: Deploy first equipment lander--rovers, scientific equipment, a bigger set of solar panels, stuff to outfit Sundancer with, the like. Pre-position methane/oxygen propellant for return trip.

Falcon Heavy 3: Deploy first crew (original ELA called for two, but I think we can do three) for 3-week expedition. They set up the Sundancer and do a geological survey. Refuel their lander with CH4/LOX (we'll need a hydrogen/oxygen engine that can reliably burn methane).

Falcon Heavy 4: Start landing basic ISRU equipment--stuff to cut the ice out of the craters. Given what we currently know of the Moon, water ice is far from the only thing we'll find--methane, methanol, and probably ammonia are up there too.

This is just the rudiments of a plan, I fear, but I'd like to know how plausible this is. But if at least the first few landings can be done for an Elon Musk-size fortune, and this thing can get some sort of government contract ($200 million per US Astronaut or Russian Cosmonaut on board), then this could just work out.

And, of course, if SpaceX gets that fully-reusable-Falcon-9 up by the end of the decade, it might even become a viable business!

JoshNH4H · 2012-02-06 18:12:30

Sounds basically feasible, though real development work would have to be done before it would be possible to comment on whether the engineering would actually work out. The one thing that I'm not comfortable with is where you're going to get the oxygen from. It's probably not frozen in the craters, and electrolyzing your way to it would be difficult. I suppose you could use a TiO2 catalyst to photodissociate water in open sunlight, but that will only be about 6% efficient and possibly mass-intensive.

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