The Promise of Outer Space Mining.

[Robert Clark]

Two separate teams announced plans last month to do asteroidal and lunar mining:

 

Google billionaires, James Cameron backing space resource venture.

By Alan Boyle

Today's media alert says the new company "will overlay two critical sectors — space exploration and natural resources — to add trillions of dollars to the global GDP. This innovative start-up will create a new industry and a new definition of 'natural resources.'"

"That sounds like asteroid mining," Christopher Mims writes on MIT Technology Review's "Mims' Bits" blog. "Because what else is there in space that we need here on earth? Certainly not a livable climate or a replacement for our dwindling supplies of oil."

Parabolic Arc's Doug Messier, meanwhile, writes that the venture will be an "extraterrestrial mining company."

Diamandis has said on more than one occasion that he's intrigued by the idea of digging into asteroids, for materials ranging from water (for fuel as well as for astronauts) to precious metals such as platinum. The Verge points to a TED talk in 2005 where Diamandis discusses his dream, while Forbes magazine has brought up the subject with him more than once in the past few months.

http://cosmiclog.msn...esource-venture

 

Renowned scientists join tech visionaries at Moon Express to mine the Moon for planetary resources.

MOUNTAIN VIEW, Calif., April 24, 2012 /PRNewswire/ -- Moon Express, a Google Lunar X PRIZE contender, announced today that some of the world's leading planetary scientists have joined its Science Advisory Board (SAB) to assist the company in its plans to explore and ultimately mine the Moon for precious planetary resources.

http://www.prnewswir...-148632035.html

 

There has been alot of skepticism evinced about the possible profitability of such plans. However, in regards to the justification for these endeavors, several studies have shown many of the important metals for high technology such as platinum at present global growth rates, especially in the emerging economies such as China, will be depleted within decades:

 

Earth's natural wealth: an audit

23 May 2007

NewScientist.com news service

David Cohen

http://www.science.o...t/027ns_005.htm

 

If these reports are true, and there is some uncertainty in the estimates, then such asteroid mining missions, might turn out to be not merely amusing topics of conversation, but actual necessities.

 

In that New Scientist article the author seems to be implying the uncertainties in the estimates of impending scarcity come from how the producers are reporting their stocks and available mine-able ore. That is, they may be underreporting them to artificially keep prices high. But with some of these key minerals predicted to run out within two decades clearly this is something that needs to be determined definitively. Maybe we need to send in UN inspectors into their accounting departments and into their actual mines like we send in inspectors for rogue nuclear states.

 

In any case, here are some peer-reviewed papers that discuss this issue:

 

Metal stocks and sustainability.

R. B. Gordon*,

M. Bertram†,‡, and

T. E. Graedel†,§

PNAS January 31, 2006 vol. 103 no. 5 1209-1214.

Abstract

The relative proportions of metal residing in ore in the lithosphere, in use in products providing services, and in waste deposits measure our progress from exclusive use of virgin ore toward full dependence on sustained use of recycled metal. In the U.S. at present, the copper contents of these three repositories are roughly equivalent, but metal in service continues to increase. Providing today's developed-country level of services for copper worldwide (as well as for zinc and, perhaps, platinum) would appear to require conversion of essentially all of the ore in the lithosphere to stock-in-use plus near-complete recycling of the metals from that point forward.

http://www.pnas.org/content/103/5/1209

 

An impending platinum crisis and its implications for the future of the automobile.

Chi-Jen Yang

Energy Policy.

Volume 37, Issue 5, May 2009, Pages 1805-1808.

Abstract

The global demand for platinum has consistently outgrown supply in the past decade. This trend likely will continue and the imbalance may possibly escalate into a crisis. Platinum plays pivotal roles in both conventional automobile emissions control and the envisioned hydrogen economy. A platinum crisis would have profound implications on energy and environment. On the one hand, inadequate platinum supply will prevent widespread commercialization of hydrogen fuel-cell vehicles. On the other hand, expensive platinum may enhance the competitiveness of hybrid, plug-in hybrid, and battery-powered electric cars. Policymakers should weigh the potential impacts of a platinum crisis in energy policy.

http://www.sciencedi...301421509000457

 

 

And of course also if such scarcity estimates are valid, then this would clearly have a major impact on the question of the profitability of the space mining ventures.

 

On my blog I present some calculations to show such lunar or asteroidal missions can be accomplished at much lower cost than realized:

 

advertising link removed by moderator

 

Bob Clark

Edited May 15, 2012 by Phi for All
advertising link removed

[swansont]

http://exosciesntist.blogspot.com

 

!

Moderator Note

You appear to have a typo; I get a blog not found error. When you correct this, please provide a link to the specific post(s) showing the calculations, so as to not be in violation of rule 2.7

[Robert Clark]

!

Moderator Note

You appear to have a typo; I get a blog not found error. When you correct this, please provide a link to the specific post(s) showing the calculations, so as to not be in violation of rule 2.7

 

Sorry about that. A typo in the web address. I corrected it in the post.

 

Bob Clark

[Phi for All]

Sorry about that. A typo in the web address. I corrected it in the post.

 

Bob Clark

!

Moderator Note

You were asked to link to the specific post(s) in your blog that showed the calculations, not to repeat the link to the home page. Now you are in violation of our rule 2.7, which prohibits non-relevant links that advertise your blog as a whole.

 

Link to blog has been removed altogether. If you can provide a link to the specific calculations you referenced in the OP, you can add it in a subsequent post.

[Robert Clark]

Sorry about that. Three of the four posts in the nascent blog are directly related to the discussion and all can be seen on the same page of the link I provided.

However, the three posts are these:

 

 

TUESDAY, MAY 1, 2012

Low Cost HLV.

http://exoscientist.blogspot.com/2012/05/low-cost-hlv.html

 

 

MONDAY, MAY 7, 2012

Low Cost HLV, page 2: Comparison to the S-IC Stage.

http://exoscientist.blogspot.com/2012/05/low-cost-hlv-page-2.html

 

 

WEDNESDAY, MAY 2, 2012

SpaceX Dragon spacecraft for low cost trips to the Moon.

http://exoscientist.blogspot.com/2012/05/spacex-dragon-spacecraft-for-low-cost.html

 

 

Bob Clark

[Enthalpy]

Hi Bob, that's Marc, nice to see you here!

 

I appreciate your efforts at Ssto, am myself convinced they're feasible, less so that they're better. Anyway, one difficulty I haven't seen you address (or did you?) is the need to throttle the engines at an Ssto. If one single stage ends 20 times lighter than it starts, the initial 1+0.4G end as inacceptable 28G.

 

For instance the Vulcain has no throttle possibility as far as I know. Even starting with 3 engines and shutting 2 off would leave 9G, too much for the passengers and the structure, and this would need a separate roll actuator since Vulcain has none, alas. The RS-68 and RD-0146 would provide roll control (but not the J-2X, damnit).

 

Some kerosene engines offer throttling, the RD-170 down to 37% (or 40% from other sources), but a kerosene stage needs an even higher mass ratio which worsens this difficulty.

 

This gives a clear advantage to the RL-10, which has been demonstrated to operate properly at very small thrust.

 

----------

 

In the SLS design I see six RL-10B to push a second stage weighing 350t, is that it? I feel the resulting 0.2G don't suffice. Existing launchers get >0.8G from a full stage, even a third or fourth one. A very smooth acceleration is good once the craft is already in orbit.

 

----------

 

Nozzle exit diameter costs room and mass. At a typical RL10 or Vinci mission it may bring 300kg more performance but cost 150kg. Going further would negate any gain. That's an excellent reason for high chamber pressure even for upper stages.

 

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On an other forum the guys willing to mine asteroids were looking for ideas from the participants, and apparently they had none by themselves - the suggestions they tested at the internauts were complete nonsense. Until I see convincing figures and designs, I consider this move to be a crook. Take any impossible idea with high promise, ask for suggestions on the Internet, sell this to a billionaire. Just like the propagating wave breeder sold to Bill Gates.

 

Oh, and, is there any platinum on the Moon? Up to now we've found sand, iron, aluminium, plus traces of semi-banal things, but no single ore of anything I'm aware of.

 

Wouldn't you prefer to send space tourists there?

[Robert Clark]

Hi Bob, that's Marc, nice to see you here!

I appreciate your efforts at Ssto, am myself convinced they're feasible, less so that they're better. Anyway, one difficulty I haven't seen you address (or did you?) is the need to throttle the engines at an Ssto. If one single stage ends 20 times lighter than it starts, the initial 1+0.4G end as inacceptable 28G.

For instance the Vulcain has no throttle possibility as far as I know. Even starting with 3 engines and shutting 2 off would leave 9G, too much for the passengers and the structure, and this would need a separate roll actuator since Vulcain has none, alas. The RS-68 and RD-0146 would provide roll control (but not the J-2X, damnit).

Some kerosene engines offer throttling, the RD-170 down to 37% (or 40% from other sources), but a kerosene stage needs an even higher mass ratio which worsens this difficulty.

This gives a clear advantage to the RL-10, which has been demonstrated to operate properly at very small thrust.

----------

In the SLS design I see six RL-10B to push a second stage weighing 350t, is that it? I feel the resulting 0.2G don't suffice. Existing launchers get >0.8G from a full stage, even a third or fourth one. A very smooth acceleration is good once the craft is already in orbit.

----------

Nozzle exit diameter costs room and mass. At a typical RL10 or Vinci mission it may bring 300kg more performance but cost 150kg. Going further would negate any gain. That's an excellent reason for high chamber pressure even for upper stages.

----------

On an other forum the guys willing to mine asteroids were looking for ideas from the participants, and apparently they had none by themselves - the suggestions they tested at the internauts were complete nonsense. Until I see convincing figures and designs, I consider this move to be a crook. Take any impossible idea with high promise, ask for suggestions on the Internet, sell this to a billionaire. Just like the propagating wave breeder sold to Bill Gates.

Oh, and, is there any platinum on the Moon? Up to now we've found sand, iron, aluminium, plus traces of semi-banal things, but no single ore of anything I'm aware of.

Wouldn't you prefer to send space tourists there?

 

Thanks for the response. You raise a good point about the throttling of the Vulcain. I haven't seen anything to suggest it is either. It may be possible to modify it to be, but that's not always possible with rocket engines. One solution is to add on smaller engines to handle the case far along in the trajectory when most of the propellant is burned off. Since this will be after the vertical thrust portion of the flight the extra engines don't have to have much thrust. So you could add one or two RL-10A engines or the HM7B currently used for the upper stage of the Ariane 5 if you want to keep it all European. Since these engines only weigh in the range ca. 160 kg, you would only lose ca. 160 kg or 320 kg from the payload, depending on whether you need one or two of them.

You would need also to give the two extra Vulcain's gimbal capability, but this is relatively lightweight compared to the weight of the engines, ca. 1,800 kg for the Vulcains.

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

For the HLV discussed on my blog, it is using the same upper stage as the DIRECT teams Jupiter launcher. I attached an image of it below. The upper stage thrust is indeed low even for an upper stage. I've seen upper stage thrust levels at about half the upper stage gross + payload weight. For a 100,000 kg payload, this would be half of 300,000 kg, or 150,000 kgf thrust. The J-2 upper stage engine and the Vulcain have about a 73 vacuum thrust to weight ratio. So this would be about 2,000 kg for the engines, only slightly more than the mass of the 6 RL-10B engines. (The Vulcain, if used for this, would have to be made air-startable but that's planned for it already as the upper stage engine in the Ares I derived "Liberty" rocket.)

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

Your statement about large nozzle diameters for higher Isp affecting negatively engine weight is a reason why altitude compensation can be useful even for upper stage engines. This idea is expressed here:

 

Aerospike rockets for increased space launch capability.

by Carl Hartsfield, Richard D. Branam, Joshua Hall, Joseph Simmons

Air & Space Power Journal / Summer, 2011

http://findarticles....5/ai_n57814072/

 

So there should be increased research on altitude compensation both for SSTO's and for multistage rockets.

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

For the asteroid mining question, what was that other forum where it was discussed? I'd like to see the arguments for and against. From the LCROSS mission there were some surprising indications that shadowed craters on the Moon might contain valuable metals:

 

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/n...e-is-water.html

 

This of course is not proven, but relatively low cost lander missions could prove it definitively.

I don't believe tourists only would provide sufficient market to devote the expense of sending large amounts of mass to the Moon. IF there are valuable minerals there then that could be sufficient reason.

BTW, you used the word "crook". Perhaps you meant the English slang word "crock". This means simply that it is a false or foolish idea. "Crook" on the other hand would mean it is intentionally created to defraud people of their money. Because of the highly regarded scientists involved in these ventures I doubt that is the case.

 

 

Bob Clark

Edited May 17, 2012 by Robert Clark

[Robert Clark]

...

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

For the HLV discussed on my blog, it is using the same upper stage as the DIRECT teams Jupiter launcher. I attached an image of it below. The upper stage thrust is indeed low even for an upper stage. I've seen upper stage thrust levels at about half the upper stage gross + payload weight. For a 100,000 kg payload, this would be half of 300,000 kg, or 150,000 kgf thrust. The J-2 upper stage engine and the Vulcain have about a 73 vacuum thrust to weight ratio. So this would be about 2,000 kg for the engines, only slightly more than the mass of the 6 RL-10B engines. (The Vulcain, if used for this, would have to be made air-startable but that's planned for it already as the upper stage engine in the Ares I derived "Liberty" rocket.)

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

...

 

I looked at the specifications for the current Ariane 5 upper stage and found that the thrust to weight ratio of the upper stage weight plus payload is similarly low:

 

Ariane 5 Data Sheet.

http://www.spacelaunchreport.com/ariane5.html#config

 

The ESC-A cryogenic upper stage has a gross mass about 20,000 kg, and the payload is about 20,000 kg, for a total of about 40,000 kg. The HM7B engine used for the upper stage has a thrust of 6,400 kgf. This is less than 1/6th the total weight of the upper stage plus payload.

So the low thrust of the DIRECT HLV's upper stage is not unheard of.

 

 

Bob Clark

[Enthalpy]

Gathering figures (too) quickly about the HM7B, I get 65kN thrust for 15+5t load, or 0.3G. This stage's mission is to attain Gto, so it could ignite some 3km/s before having Leo energy, similar to your configuration.

 

Something special to Ariane is that it doesn't shut off before joining the Equator. The upper stage burns very slowly while it loses altitude initially. This is possible because Kourou is at 3° only and because the lower stages are programmed to give a higher altitude than the perigee.

[Robert Clark]

Gathering figures (too) quickly about the HM7B, I get 65kN thrust for 15+5t load, or 0.3G. This stage's mission is to attain Gto, so it could ignite some 3km/s before having Leo energy, similar to your configuration.

 

Something special to Ariane is that it doesn't shut off before joining the Equator. The upper stage burns very slowly while it loses altitude initially. This is possible because Kourou is at 3° only and because the lower stages are programmed to give a higher altitude than the perigee.

 

Thanks for that info. What forum was the space mining question discussed?

 

 

Bob Clark