SpaceX Dragon spacecraft for low cost trips to the Moon.

[DarkenedOne]

When it comes to the LH2 rocket it is a very reliable and very well proven system. It has been used on every Saturn V launch,

Well except for the first stage, which was RP-1/LOX

every Shuttle launch,

Well, except for the two SRB's that are required to get it off the ground...

And your point is? Some how I fail to understand how the fact that these rockets used more than one fuel helps your argument any, especially since they were not hyperbolic.

On the other hand I am not sure, but I do not believe that hyperbolics

:lol: :lol:

You can launch anything with hyperbolics... even interstellar spacecraft :lol: :lol: :lol:

Can and should are two very different concepts. Sure launching a rocket on hyperbolics is possible, but is it wise or economic? What has been left out of this conversation is the nature of hyperbolics themselves. Hyperbolic fuels are deadly poisonous in the few parts per million. Its poisonous nature has two effects. One is makes it more expensive than other fuels to produce, transport, and store. Two it make using large amounts of it as a fuel within the atmosphere a very bad idea.

 

[rcsplinters]

Guys, I'm really having trouble following what's going on in this thread. Help me out.

Hyperbolic Fuels? is that a mispelling for hypergolic fuels such as described here: http://www.osti.gov/bridge/servlets/purl/767866-RgDT1x/webviewable/767866.pdf? If not, provide a link please, I never heard of them. Hypergolic fuels would take you where ever you have to go. Sort'a poison and they go bang in the presence of an oxidizer (which is why they use them in orbit, highly dependable). Hyperbolic? You got me.

Next, no shuttle was ever destroyed with the root cause of LH2 as a fuel. We lost one due to a management screw up for not taking warnings seriously about O ring performance as a function of temperature and another as a result of failing to take ice shedding seriously with a side mount vehicle. I guess you could blame super-cooled fuels for that, but it was really a management issue there as well.

And what about Dragon as a low cost conveyance to the moon? That's not in its design requirements. The thing, if it is ever produced in a human rated form, is a taxi cab to LEO. Its not shielded properly for radiation. its not designed for weeks long sustaining of human life. About the only thing you can say about it is the heat shield is theoretically able to withstand a 25K mph re-entry though I'd expect They'd want to revisit those numbers if someone actually tried to do that.

What's up with the suggestion that ignoring individual component failures is either wise or even a common engineering practice. From an engineering perspective, you do that, you die, it dies or someone dies after enough time passes.

I'm missing the point, I guess. The next craft with people that goes around the moon will use LOX/LH2 or kero with solid boosters, heavily shielded, proper human factor considerations, hypergolic manuvering jets and yes, some team of engineers will have considered every reasonable and most unreasonable failure mechanisms and assigned a failure probability to it. Dragon just doesn't lay down with all those requirements, it wasn't designed to be and I've never heard SpaceX claim that it did. Why would SpaceX even dream of operating that craft outside its limits? I'm no fan of Musk or SpaceX, but they aren't stupid. They'll fly their bird within the flight profile it was designed for.

 

[jimoutofthebox]

hypergolic is the the correct spelling. I started this string of posts with the correct spelling but it seemed to have wandered off.

The point I have been trying to make is that we will need a company like SpaceX to build the next manned spacecraft and I used what I believe is a flawed designed for the Altair lunar lander as my example of how NASA has lost its way. The point I made is that the assent stage should use pressure fed hypergolic fuel due to its inherent reliability. Its quite clear that we will need LH2 rockets to do most of the mission but using it for the lunar assent stage is clearly far less safe.

I do believe that the Dragon spacecraft could be modified to do a lunar mission requiring days not weeks, but I also made the point that limitation is not the Dragon but the means to reach the Delta V required to perform the mission.

 

[rcsplinters]

Ah. Well, that clears up that matter. I thought the thread was about using the Dragon to run a couple of laps around the moon. A lander in that case would be a bit extraneous. I'm also not sure why the nation or a pseudo-private enterprise would want to shell out money to modify an orbital taxi when we'll have a much more capable capsule, formerly known as Orion. I'm also not sure why we'd need to run a couple of laps around the moon except to shake out a system with much greater goals in mind. After reading the HEFT presentation, it surely seems that NASA doesn't feel the need repeat Apollo 8 with a craft design for that specific purpose. The capsule formerly known as Orion will be the US mission vehicle.

While we are on the subject of landers, I think the LM used an exotic fuel and oxidizer. Is that a necessity? I doubt it, though it might be a simple solution. As far as the ascent stage requiring any special reliability more than the descent stage or any other critical component, why would that be? Dead is dead. The act of stranding a live astronaunt on the moon is not much different than smashing one into the moon. The difference is largely emotional. Frankly, I'd rather the ascent engine fail to ignite, I might have a second chance that way. As the astronaunt, if I just felt the need to die quick after being stranded, I need only open the door or take a pill. My point to this morbid rationalization is merely that what works for descent is likely good enough for ascent.

As far as the position that only a company like SpaceX can build a lander, well that's kinda silly. I need only point and the Mars landers, rovers and Huygens probe to suggest that NASA is clearly up to the task. I won't bring up the fact that the only human carrying foreign body lander, the LM itself, was a NASA project. A company like SpaceX might be able to do that, but then let's have them actually put a human in orbit first. Perhaps, that's jumping the gun. Let's see them actually deliver cargo to the ISS first or even have a test flight where they can precisely control their booster and payload.

Regarding Altair, I don't think it ever went through a design review. Hence the "design" was never finalized and would likely have been subject to any number of changes. Rather pointless to suggest a design that was never finalized is somehow flawed in expected implementation.

I'd strongly recommend reading that HEFT slide deck. Its pretty good at digging at the logistics of operations BEO. We'll need space specific vehicles in the form of crew modules, a/d modules, propulsion modules and tactical modules. When NASA gets round to designing and building those, we'll learn that the capsule and boosters were small potatoes.

 

[exoscientist]

Guys, I'm really having trouble following what's going on in this thread. Help me out.
...
And what about Dragon as a low cost conveyance to the moon? That's not in its design requirements. The thing, if it is ever produced in a human rated form, is a taxi cab to LEO. Its not shielded properly for radiation. its not designed for weeks long sustaining of human life. About the only thing you can say about it is the heat shield is theoretically able to withstand a 25K mph re-entry though I'd expect They'd want to revisit those numbers if someone actually tried to do that.
What's up with the suggestion that ignoring individual component failures is either wise or even a common engineering practice. From an engineering perspective, you do that, you die, it dies or someone dies after enough time passes.
I'm missing the point, I guess. The next craft with people that goes around the moon will use LOX/LH2 or kero with solid boosters, heavily shielded, proper human factor considerations, hypergolic manuvering jets and yes, some team of engineers will have considered every reasonable and most unreasonable failure mechanisms and assigned a failure probability to it. Dragon just doesn't lay down with all those requirements, it wasn't designed to be and I've never heard SpaceX claim that it did. Why would SpaceX even dream of operating that craft outside its limits? I'm no fan of Musk or SpaceX, but they aren't stupid. They'll fly their bird within the flight profile it was designed for.

In regards to its feasibility SpaceX intended to use the Dragon capsule for manned circumlunar flights and to, likely, use an unmanned version for cargo transport to the Moon:

Musk: $80 million to go to the Moon.
By Rob Coppinger
on July 7, 2008 10:38 AM
http://www.flightglobal.com/blogs/hyper ... the-m.html

DATE:02/10/08
SOURCE:Flight International
SpaceX offers NASA $80 million lunar cargo lander service
By Rob Coppinger
http://www.flightglobal.com/articles/20 ... rvice.html

In that first article the reporter raised some objections to the SpaceX plan. In regards to one of them, about the heat shield, SpaceX had already designed it to be able to handle return from lunar missions:

Second Falcon 9 rocket begins arriving at the Cape.
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: July 16, 2010
The ablator, called PICA-X for short, was tested inside an arc jet laboratory at NASA's Ames Research Center at Moffett Field, Calif.
"It's actually the most powerful stuff known to man. Dragon is capable of re-entering from a lunar velocity, or even a Mars velocity with the heat shield that it has," Musk said.
http://spaceflightnow.com/falcon9/002/100716firststage/

For the manned circumlunar version, from Elon's description it clearly would use the Dragon capsule. For the unmanned lunar cargo version he did not say specifically the Dragon would be used but it seems likely since the Dragon has a cargo version so rather than developing a whole new capsule and considering the low cost they claimed to offer this lunar cargo lander that they would use the Dragon for this purpose as well.

Bob Clark

 

[jimoutofthebox]

While we are on the subject of landers, I think the LM used an exotic fuel and oxidizer. Is that a necessity? I doubt it, though it might be a simple solution. As far as the ascent stage requiring any special reliability more than the descent stage or any other critical component, why would that be? Dead is dead. The act of stranding a live astronaunt on the moon is not much different than smashing one into the moon. The difference is largely emotional. Frankly, I'd rather the ascent engine fail to ignite, I might have a second chance that way. As the astronaunt, if I just felt the need to die quick after being stranded, I need only open the door or take a pill. My point to this morbid rationalization is merely that what works for descent is likely good enough for ascent.

The reason I would use hypergolic for the assent stage is due to the risk at each stage of the trip. For example I would use LH2 engines for the desent due to the higher ISP. The crew could abort, drop the landing stage, and return to orbit at almost any stage of the landing since the hypergolic engine has a fast response time. The ascent stage needs to use the most reliable engine possible which is a pressure fed hypergolic engine. I'm not too worried about either type of engine lighting on the moon for the ascent. My concern would have some moving part in the LH2 engine such as bearings or impeller failing with no backup. The hypergolic engine has no moving parts once it's lit so the chance of a failure during ascent is slim. In addition if the crew stays on the moon for a week or more they don't have to worry about the fuel in the ascent stage boiling off as it would for a LH2/LOX engine.

Concerning using Dragon as a lander. I don't see how this will work. Every spare gram would have to cut off to make it light enough to land and return to orbit. Might as well design a lander from scratch to be as light as possible.

As far as delivering cargo to the moon why not add some landing legs to a Centaur and strap a couple of cargo pods to it. This would be alot cheaper than using the dragon to deliver cargo.

 

[rcsplinters]

Exo, Even if dragon is designed for circum-lunar missions (which I suspect that would work only for very short durations), why would they do such a thing? Where's the revenue stream for that? Without a lander, you are talking about laps and the only purpose for that would be to shake out equipment for much longer missions. Somewhere I seem to recall Musk countermanding some of his staff dreamers which contemplate such things and making it quite clear their focus is on LEO markets. He's got a market for cargo which is under contract and has an outside chance for one for HSF. Its several decades TOO early to talk about a lunar revenue stream. I think folks miss that change in paradigm. No profit, no return on investment, no mission.

Jim, The question over hypergolics versus LH2 for a landar is simply an engineering question to me. They'll pick whatever meets requirements and will optimize the system, not merely optimize the fuel selection. Its not necessarily a best of breed design process. Oddly enough, I could see this question being related to fuel depots. If the propellent loss issue is resolved, it would probably raise the likelyhood of using cryo fuels. I doubt the next lander is going to sit around for a few days. We could be talking weeks or months. Boil off would be a bad thing, hence the linkage with depots. Maybe solids. Maybe exotics. Maybe cryos. Its an engineering question based on mission parameters. Since we don't know parameters, we can't really answer the question. Still fun to muse about it, I suppose.

 

[exoscientist]

Exo, Even if dragon is designed for circum-lunar missions (which I suspect that would work only for very short durations), why would they do such a thing? Where's the revenue stream for that? Without a lander, you are talking about laps and the only purpose for that would be to shake out equipment for much longer missions. Somewhere I seem to recall Musk countermanding some of his staff dreamers which contemplate such things and making it quite clear their focus is on LEO markets. He's got a market for cargo which is under contract and has an outside chance for one for HSF. Its several decades TOO early to talk about a lunar revenue stream. I think folks miss that change in paradigm. No profit, no return on investment, no mission.

One market would be for tourism for the circumlunar missions. Remember individuals and nations have paid 10's of millions just to go to orbit:

Space Tourism.
"John Denver considered a flight to Mir for $10 million, according to "John Denver harbored dream to fly in space", Florida Today Space Online, 15 Oct 1997; this price is about what France paid to send a person to Mir, according to "Russian Yuri's and French woman return to Earth", Florida Today Space Online, 2 Sep 1996. Germany paid $60 million, according to "Russia-German space team blasts off for Mir station", Florida Today Space Online, 10 Feb 1997. My guess would be that the difference between the figures for France and Germany reflect differences in which costs are counted, but I have no information on that.
"Dennis Tito is paying $20 million for 7-10 days on Mir, according to " U.S. businessman plans stay aboard Mir", Florida Today Space Online, 17 Jun 2000. Best Tito article I've seen is "Earth's First Self-Financed Astronaut", SpaceRef, Keith Cowing, 10 Dec 2000."
http://www.panix.com/~kingdon/space/tourism.html

It is certainly expected that for circumlunar missions it would be for more. However, another key market for this would be deliveries to L2, the lunar Lagrange point for, for example, propellant depots.
As I argued actually I think low cost lunar lander missions are doable. There would be an even a higher market for that.

Bob Clark

 

[exoscientist]

Here's one company that plans on tourist circumlunar flights for $100 million per person:

Will Tourists Beat the Government Back to the Moon?
For $100 million, a U.S. company promises you the vacation of a lifetime: a week in lunar orbit.
By Joshua Tompkins Posted 11.01.2005 at 3:00 am
http://www.popsci.com/node/10302

The article mentions some modifications to the Soyuz capsule. The main one for the Soyuz is strengthening the heat shield to handle the higher heating on lunar return. But as I mentioned the Dragon already has this stronger heat shield.


Bob Clark

 

[rcsplinters]

Exo, not to evade your question, but I've editorialized on those sorts of demands for service before. I'm very skeptical. Let me summarize why. First, all those testimonies are annecdotal. Second, the investment community simply doesn't buy into it. Third, you can't support an industry on the few customers worldwide that afford that sort of cash layout for a thrill ride. Also, as it regards SpaceX, I've done a bit more research on them lately and what I find is interesting. If you get past the slide decks and media hype, I get the distinct impression they are consumed with their cargo commitments. HSF is toward the back burner until they get ramped up on the cargo stuff and get several flights on the falcon and dragon. While some of their fans seem ready to hire Captain Kirk and fly to Vulcan on a Dragon, it seems SpaceX is quite a bit more measured in their expectations.

I say all that to say this. I don't buy into the concept that there is a burgeoning market for circumlunar joy rides nor LEO frolics for that matter. I could be wrong, but the investment community doesn't seem to think so.

 

[jimoutofthebox]

I have to agree with rcsplinters. I think there are ways to make a buck on the lunar surface like creating memorials on the moon that last a million years. Something like that could be easily manufactured on the moon and it would appeal the egos of the baby boomers. I'm sure with some thought even better ideas can be generated. But first you have to get there and the market for $200 million joy rides is real limited.

 

[EarthlingX]

In case you managed to miss this :

www.bbc.co.uk : Manned flyby of Moon considered

posted in SB&T From Around The World Updates.

 

[exoscientist]

In case you managed to miss this :
http://www.bbc.co.uk : Manned flyby of Moon considered
posted in SB&T From Around The World Updates.

Thanks for that. Hadn't seen it. Interesting they focused on assembly in orbit. This in some form would be required for attaching the crew capsule, propulsion system,and fuel load supplied in orbit in my plan.
I also agree with the idea of using reliable man-rated launchers such as the Soyuz to get the crew to orbit. But using low cost unmanned launchers for getting the propellant and vehicle components to orbit.


Bob Clark

 

[DarkenedOne]

Exo, not to evade your question, but I've editorialized on those sorts of demands for service before. I'm very skeptical. Let me summarize why. First, all those testimonies are annecdotal. Second, the investment community simply doesn't buy into it. Third, you can't support an industry on the few customers worldwide that afford that sort of cash layout for a thrill ride. Also, as it regards SpaceX, I've done a bit more research on them lately and what I find is interesting. If you get past the slide decks and media hype, I get the distinct impression they are consumed with their cargo commitments. HSF is toward the back burner until they get ramped up on the cargo stuff and get several flights on the falcon and dragon. While some of their fans seem ready to hire Captain Kirk and fly to Vulcan on a Dragon, it seems SpaceX is quite a bit more measured in their expectations.

I say all that to say this. I don't buy into the concept that there is a burgeoning market for circumlunar joy rides nor LEO frolics for that matter. I could be wrong, but the investment community doesn't seem to think so.

First of all Elon Musk, Bigelow, and a few others are spending hundreds of millions of their own money on it, so it is clear that there is definitely investor support. Now these guys are what are called angle investors. If you are talking about venture capitalists than your right that are not investing that much. Of course their reluctance is understandable as they typically have a lower risk tolerance than angel investors. However at the same time you do have major aerospace corps like Boeing pushing the idea.

Thirdly the idea is to not to do just a few billionaire tourists, but to bring the costs down to allow more and more people to go.

Lastly as far as SpaceX goes they are definitely pursuing HSF as every single design decision made on their rocket was made so that human-rating would be simple. As far as their cargo commitments are concerned their Dragon vehicle is same capsule that they take people in, so getting the cargo right will build confidence in the system's ability to safely and reliably perform.

 

[rcsplinters]

Dark, you know full well, I have no objections to commercial flight. I've stated that dozens of times. I strongly object to wasting public money which should be going to exploration or BEO programs. If the business model was as strong as you say, that public charity would not be needed. Bottom line is that the market not strong enough to attract investment capital and you admit to knowing that. There is a very small customer base. There is limited revenue stream. There is no business model. The American public is hedging Buffy's ability to take a joy ride in several years, not to mention buffering Musk's own wallet in case things go bad. You are entitled to your opinion, but there is more than one side to this coin. If we are to have commercial HSF, then it should exist privately. We don't need another future bailout opportunity and there is a very good probability that is just what this will become. We have enough of those today.

And yes, SpaceX has its hands very full with its cargo commitments (which by the way, I'm extremely happy to see). I'd suggest reading outside of the SpaceX web site.

Sorry, for getting off topic. Just wanted it clear that I have nothing against commercial flight, my gripe is the funding.

 

[exoscientist]

Apollo took 3 days to go from Earth orbit to lunar orbit. The Apollo capsule had a 6 cubic meter habitable volume for a 3 man crew. The Dragon spacecraft has a 10 cubic meter habitable volume. So this would be doable in regards to the volume for the Dragon for say a 3 to 5 man crew.
Still for non-astronauts ideally the one-way trip time should be shorter than this. At 11 km/s escape velocity a straight to the Moon flight would take less than 10 hours. Are there trajectories from Earth orbit to lunar orbit that would take comparable amounts of delta-V as that now used but result in travel times of less than a day?

Bob Clark

 

[EarthlingX]

Perhaps this can be of use :

Marco's Space Mission Calculator

 

[exoscientist]

Perhaps this can be of use :

Marco's Space Mission Calculator

Thanks for that link. But I'm fairly sure that is just using the Hohmann orbital transfer to get a minimal delta-V requirement to go from one orbital altitude to another. This does not give you a minimal travel time.


Bob Clark

 

[DarkenedOne]

Dark, you know full well, I have no objections to commercial flight. I've stated that dozens of times. I strongly object to wasting public money which should be going to exploration or BEO programs. If the business model was as strong as you say, that public charity would not be needed. Bottom line is that the market not strong enough to attract investment capital and you admit to knowing that. There is a very small customer base. There is limited revenue stream. There is no business model. The American public is hedging Buffy's ability to take a joy ride in several years, not to mention buffering Musk's own wallet in case things go bad. You are entitled to your opinion, but there is more than one side to this coin. If we are to have commercial HSF, then it should exist privately. We don't need another future bailout opportunity and there is a very good probability that is just what this will become. We have enough of those today.

And yes, SpaceX has its hands very full with its cargo commitments (which by the way, I'm extremely happy to see). I'd suggest reading outside of the SpaceX web site.

Sorry, for getting off topic. Just wanted it clear that I have nothing against commercial flight, my gripe is the funding.

Lets ditch the retoric, and adopt an objective metric for judging the value of both ideas. Lets use the old cost benefit analysis shall we.

First lets analyze Constellation. Of course the costs are well known. Almost a hundred billion spend on rockets and spacecraft. Then of course there is the significant risk of failure or the program getting CANCELLED. If it fails the money would have been spent for nothing, and if it does succeed the benefits are that you put a few government astronauts on the moon. To collect dust and perform scientific experiments that many argue a robot can do at a hundredth of the cost.

Second lets analyze commerical spacefight. Here the costs are also well known. About 3 billion dollars have been appropriated for supporting commercial spaceflight. As far as the risks goes there is the risk that they will fail in which case the money will be wasted. Of course there is also the probably that they will succeed in which case it is like the government will be repaid many times over and humanity will actually benefit from human spaceflight.

Seems pretty clear according the any objective anaylist that supporting commercial human spaceflight is far more deserving of federal money than Constellation style programs.

Secondly as far as your statement that "if the business model was as strong as you say, that public charity would not be needed" is utterly and completely false. The government has a long history of supporting transportation industries. Private corporations really are not in the position to support long term development. The government supported the railroads and helped fund the intercontinental railroad. The government funded the current interstate highway system. The government has subsidized ship building numerous times. The government helped start commercial aviation with commercial mail delivery contracts kind of in the same way the COTS is supporting the launch industry.

So really what you are arguing against is the support that every other transportation service has received due to its strategic importance. Is space not strategically important? Is it not worth it that we invest in our long term capabilities.

 

[exoscientist]

An even lower cost possibility for the capsule and lander might be one proposed by the University of Maryland aerospace engineering department:

Phoenix: A Low-Cost Commercial Approach to the Crew Exploration Vehicle.
http://www.nianet.org/rascal/forum2006/ ... _paper.pdf

As with the Orion CEV, this Phoenix spacecraft was intended to be used in conjunction with a separate lander for lunar missions. However, by using it both for the trip from LEO and as the lander you get great savings in cost.
On page 3 of the report is given a breakdown of the weights of the various subsystems. By removing the propulsion system as I suggested for the Dragon for this purpose, the mass with crew would be about half that of the Dragon, at about 2,000 kg.
Then assuming again 10 to 1 mass ratios for two Centaur style stages for propulsion, we would need about half the propellant load as for the Dragon, about 20,000 kg, which could be lofted by a single launch of the current largest launchers.
Then the cost of lofting this propellant load to LEO would be about $100 million. And if a new heavy lift launcher could get a $2,400 per kg launch price, it would only be in the range of $50 million.
This would increase even further the market for such low cost lunar missions.

Especially innovative about this design is the "parashield" thermal
protection. Not only is this lightweight but another advantage is that
it has a higher protective area so that you can use a larger volume
cylindrical structure rather than the usual conical structure for the
capsule.
From the report "Phoenix: A Low-Cost Commercial Approach to
the Crew Exploration":
"Figure 5.9-1: Phoenix ParaShield in stowed and deployed
configurations."

Bob Clark

 

[exoscientist]

An even lower cost possibility for the capsule and lander might be one proposed by the University of Maryland aerospace engineering department:

Phoenix: A Low-Cost Commercial Approach to the Crew Exploration Vehicle.
http://www.nianet.org/rascal/forum2006/ ... _paper.pdf

As with the Orion CEV, this Phoenix spacecraft was intended to be used in conjunction with a separate lander for lunar missions. However, by using it both for the trip from LEO and as the lander you get great savings in cost.
On page 3 of the report is given a breakdown of the weights of the various subsystems. By removing the propulsion system as I suggested for the Dragon for this purpose, the mass with crew would be about half that of the Dragon, at about 2,000 kg.
Then assuming again 10 to 1 mass ratios for two Centaur style stages for propulsion, we would need about half the propellant load as for the Dragon, about 20,000 kg, which could be lofted by a single launch of the current largest launchers.
Then the cost of lofting this propellant load to LEO would be about $100 million. And if a new heavy lift launcher could get a $2,400 per kg launch price, it would only be in the range of $50 million.
This would increase even further the market for such low cost lunar missions.

The price for these commercial lunar flights could be cut dramatically if instead of hauling the fuel from the Earth, it could be obtained from the Moon. This would require automated systems to produce propellant from the materials on the Moon.
Then as a precursor to show this is feasible it would be necessary to do a smaller unmanned lunar lander mission that demonstrates ISRU propellant production. We will want to do a reusable, round trip mission to also show the feasibility of the manned missions. However, as a low cost first step we'll only do an expendable one-way lander that drops off an electrolysis station to produce hydrogen/oxygen from the water found by LCROSS to be near surface in the polar regions.
To keep costs low we'll use the Russian Dnepr rocket:

Dnepr specifications.
http://www.spaceandtech.com/spacedata/e ... pecs.shtml

According to this page, the price is $10-$13 million for up to 4,500 kg to LEO. So we'll need to keep the total mass for the lander and the propulsion system under 4,500 kg.
One possibility for the propulsion might be the solid motor "Star" series, but multiply staged. Find the specifications for the Star 48 version here:

Star 48 - Specifications.
http://www.spaceandtech.com/spacedata/m ... pecs.shtml

They have a good mass ratio at around 18 or 19 to 1. And a moderate Isp, from 286 s to 292 s. However, it should be noted that the low dry mass indicated, which results in the high mass ratio, is coming from the fact this is only considering the nozzle and casing. Reaction control thrusters and the avionics assemblies are not included in this dry mass.
A more accurate accounting for the dry mass for this upper stage might be here:

PAM-S.
"Solid propellant rocket stage. Loaded/empty mass 2,182/220 kg. Thrust 66.60 kN. Vacuum specific impulse 288 seconds.
Cost $ : 4.060 million."
http://www.astronautix.com/stages/pams.htm

Note this page, with the higher dry mass, indicates this upper stage with the Star 48 engine does also use reaction control thrusters. The extra mass was about 100 kg added onto the 111 kg Star 48 bare mass. I'll reserve 100 kg for the RCS and avionics within the mass of the payload, and use the bare masses for the Star engines in the delta-V calculations. The final, smallest stage will have slightly more powerful RCS than needed and for the lower stages I'll rely on spin-stabilization and the upper stage RCS for stability while the lower stage motors are firing.
Let's calculate how much payload we could deliver to the Moon's surface. This page gives the delta-V requirements in the Earth-Moon system:

Delta-v budget.
Earth–Moon space.
http://en.wikipedia.org/wiki/Delta-v_bu ... Moon_space

To get to the lunar surface from LEO would require a delta-V of 5.93 km/s. The stages used will be the Star 48B:

STAR 48B - Short Nozzle PAM STS.
"Effective Isp (vacuum): 286.0 sec
Motor Loaded Mass: 4705.4 lb, 2134.3 kg
Motor Burnout Mass: 245.4 lb, 111.3 kg"
http://www.spaceandtech.com/spacedata/m ... pecs.shtml ,

the Star 37FM:

STAR 37FM.
"Effective Isp (vacuum): 289.8 sec
Motor Loaded Mass: 2530.8 lb, 1148.0 kg
Motor Burnout Mass: 162.5 lb, 73.7 kg"
http://www.spaceandtech.com/spacedata/m ... pecs.shtml ,

and the Star 30:

Star 30.
"Gross mass: 492 kg (1,084 lb).
Unfuelled mass: 28 kg (61 lb).
Diameter: 0.76 m (2.50 ft).
Specific impulse: 293 s."
http://www.astronautix.com/engines/star30.htm

Estimate the payload to the Moon as 400 kg. The delta-V needed for Trans Lunar Injection will be in the range of 3.05 to 3.25 km/s:

Trans Lunar Injection.
History.
http://en.wikipedia.org/wiki/Trans_Luna ... on#History

The delta-V you could get from the Star 48 first stage would be: 286*9.8ln((2134.3+1148+492+400)/(111.3+1148+492+400)) = 1,857 m/s.
The delta-V you get from the Star 37FM second stage will be: 289.9*9.8ln((1,148+492+400)/(73.7+492+400)) = 2,125 m/s. The two lower stages give you a total of 3,982 m/s, sufficient for TLI.
You need now 5,930 - 3,982 = 1,948 m/s additional delta-V to complete the landing. The delta-V you get from the Star 30 will be: 293*9.8ln((492+400)/(28+400)) = 2,109 m/s, sufficient for the landing.
The total gross mass of the 3 stages plus payload will be 2,134.3+1,148+492+400 = 4,174.3 kg, within the lift capacity of the Dnepr 1. The cost of the Dnepr 1 might be $13 million. The costs of the upper stages? The Astronautix page on the PAM-S powered by the Star 48 motor gives the price as $4.06 million. The Star 37 is smaller by half, and the Star 30 is smaller by an additional factor of one-half. Then we might estimate their prices as $2 million and $1 million respectively, for a total cost of these upper stages of $7 million. Then the total launch cost might be $20 million.
We would have to add onto that the cost of the avionics and the cost of the lander.


Bob Clark

 

[markododa]

Its not practical to land the capsule on the moon, i think that if a lunar landing with the dragon spacecraft takes place it would include a highly modified dragon (less crew space, more radiation shielding, heat shield, avionics etc ...), and instead of a trunk an service module(with an hypergolic pressure fed engine for safety, lets say something like kestrel) that will do the lunar orbit insertion braking and earth departure boosting. The second part of the mission would conclude of an lander (SpaceX's or armadillo's developed desent stage) with an accent stage/crew module that will be delivered out of dragons pressure vessel, avionics & propolsion. You could also make the lander a cargo ship, and evolve that into an moon base, with 2 launches of an heavy launch vehicle, one for the lander and after the lander a dragon delivered spacecraft (that docks with the lander in lunar orbit), then you send a cargo lander on the moon and start making a moon base .

 

[exoscientist]

The delta-V you could get from the Star 48 first stage would be: 286*9.8ln((2134.3+1148+492+400)/(111.3+1148+492+400)) = 1,857 m/s.
The delta-V you get from the Star 37FM second stage will be: 289.9*9.8ln((1,148+492+400)/(73.7+492+400)) = 2,125 m/s. The two lower stages give you a total of 3,982 m/s, sufficient for TLI.
You need now 5,930 - 3,982 = 1,948 m/s additional delta-V to complete the landing. The delta-V you get from the Star 30 will be: 293*9.8ln((492+400)/(28+400)) = 2,109 m/s, sufficient for the landing.
The total gross mass of the 3 stages plus payload will be 2,134.3+1,148+492+400 = 4,174.3 kg, within the lift capacity of the Dnepr 1. The cost of the Dnepr 1 might be $13 million. The costs of the upper stages? The Astronautix page on the PAM-S powered by the Star 48 motor gives the price as $4.06 million. The Star 37 is smaller by half, and the Star 30 is smaller by an additional factor of one-half. Then we might estimate their prices as $2 million and $1 million respectively, for a total cost of these upper stages of $7 million. Then the total launch cost might be $20 million.
We would have to add onto that the cost of the avionics and the cost of the lander.

As a point of comparison about the feasibility of using solid motor upper stages for the purpose, the Dnepr has been studied to be used to launch a 500 kg payload to GEO by using two Star solid motor upper stages and lunar gravity assist:

Dnepr (R-36M2).
"The Dnepr launch vehicle does not have the capability to deploy
payloads directiy into GTO. However, Kosmotras has studied a technique
to deliver small spacecraft to GEO using the gravity of the Moon to
provide the plane change and perigee raising. In this scenario, the
spacecraft is attached to Star 48A and Star 27 solid motors, supplied
separately by ATK Thiokol. The Star48A would send the spacecraft to
the Moon, where a gravity slingshot maneuver would lower the transfer
orbit inclination from 50.5 deg to 0 deg, and raise the orbit perigee
to geostationary altitude. When the spacecraft reaches perigee of the
new transfer orbit, the Star 27 motor would fire to circularize the
orbit at GEO. Using this method, a 500 kg (1100 lbm) spacecraft could
be delivered to GEO."
http://www.b14643.de/Spacerockets_1/Eas ... /Frame.htm


Bob Clark

 

[exoscientist]

This page has this link to a video of a panel discussion at the Space
Manufacturing Conference 14 held in October this year:

WEDNESDAY, NOVEMBER 10, 2010
The Moon, Mars, or Asteroids: The Future of Extraterrestrial
Resources.
http://newpapyrusmagazine.blogspot.com/ ... -next.html

About 12 minutes in, one of the panel members made an interesting
comparison between what is considered to be a profitable mine on Earth
and what the LCROSS data suggests is available near surface in some
shadowed craters on the Moon. He said a mine on Earth might be
profitable if you can make in the range of $150 per ton of material
excavated. But judging from the LCROSS data, the minerals available in
shadowed craters might value in the range of $1,000,000 per ton of
excavated material.
This might be sufficient justification for some mining companies to
pay for a low cost exploratory lander mission. For instance the Dnepr
rocket can lift 550 kg to TLI at a cost of $10 to $13 million. This
might be sufficient mass for a lander with a descent rocket with just
simple instruments such as a APXS and infrared spectrometers and radio
transmission capability.


Bob Clark

 

[exoscientist]

This page has this link to a video of a panel discussion at the Space
Manufacturing Conference 14 held in October this year:

WEDNESDAY, NOVEMBER 10, 2010
The Moon, Mars, or Asteroids: The Future of Extraterrestrial
Resources.
http://newpapyrusmagazine.blogspot.com/ ... -next.html

About 12 minutes in, one of the panel members made an interesting
comparison between what is considered to be a profitable mine on Earth
and what the LCROSS data suggests is available near surface in some
shadowed craters on the Moon. He said a mine on Earth might be
profitable if you can make in the range of $150 per ton of material
excavated. But judging from the LCROSS data, the minerals available in
shadowed craters might value in the range of $1,000,000 per ton of
excavated material.
This might be sufficient justification for some mining companies to
pay for a low cost exploratory lander mission. For instance the Dnepr
rocket can lift 550 kg to TLI at a cost of $10 to $13 million. This
might be sufficient mass for a lander with a descent rocket with just
simple instruments such as a APXS and infrared spectrometers and radio
transmission capability.

As a point of comparison there is a company planning to do deep sea mining starting in 2013 at a depth of 1,600 meters:

October 08, 2010
Nautilus Minerals the first commercial ocean floor gold and copper mining company.
http://nextbigfuture.com/2010/10/nautil ... rcial.html

They estimate the costs would be $70 per tonne of excavated material but with the minerals valued at $1,000 per tonne. (Compare this to the estimated $1,000,000 per tonne on the Moon from the LCROSS data.)
They would also use remote operated vehicles on the sea floor for the mining. The delay time in their case would only be fractions of a second though rather than the 3 seconds required from the Moon.
Then we need an estimate for the costs of remote operation of mining vehicles on the Moon as there is for the sea floor.


Bob Clark