Asteroid/Near Earth object mining

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  • #3
rootone
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OK I might as well throw this one in.
What is there on asteroids that is so specially valuable that it cannot be found or made on Earth without the extreme risk and cost.?
 
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  • #4
1oldman2
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How 'bout you start the discussion?
You bet. :thumbup:
It seems the most reliable link I posted would be the mit.edu, they seem to have the recovery process figured out and documented in a believable manner. The nss.org site mentions a lot of physics that I am ignorant in so commenting that one myself wouldn't mean much. One thing, none of them really got around to mentioning the actual in situ processing as far as method or equipment. I'm thinking any asteroids identified as rich in REE's will be the first to be snagged.
 
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  • #5
1oldman2
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OK I might as well throw this one in.
What is there on asteroids that is so specially valuable that it cannot be found or made on Earth without the extreme risk and cost.?
Good question some of the links mention very high concentrations of ore compared to earth. I suspect a lot of speculation there but it could make the difference.
 
  • #6
Hoophy
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They say "Solar Electric Propulsion" Are they referring to Ion accelerators? If so would an Ion probe even have a high enough TWR to redirect an asteroid in the first place? From my (very basic nearly nonexistent) understanding of Ion propulsion I was under the assumption that ion drives did not have a very good TWR. Would the probe have to make several complete orbits to accomplish the maneuver? Do you think this feasibility study should have included ion drives because I did not think ion propulsion is quite up to that task yet... Please let me know if I am wrong or if you disagree. :)
 
  • #7
Hoophy
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OK I might as well throw this one in.
What is there on asteroids that is so specially valuable that it cannot be found or made on Earth without the extreme risk and cost.?

I believe that a motive is to harvest water ice from asteroids placed in lunar orbit. Running water through electrolysis they could manufacture LOX/LH2 bipropellant rocket fuel in orbit so that they can more cheaply refuel stuff. Kind of like a gas station in space. I guess it is too expensive to bring up extra fuel using launch stages because so much fuel is used putting the extra fuel in orbit that they think that they may actually save money by making the fuel in space.
http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html
 
  • #9
1oldman2
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They say "Solar Electric Propulsion" Are they referring to Ion accelerators? If so would an Ion probe even have a high enough TWR to redirect an asteroid in the first place? From my (very basic nearly nonexistent) understanding of Ion propulsion I was under the assumption that ion drives did not have a very good TWR. Would the probe have to make several complete orbits to accomplish the maneuver? Do you think this feasibility study should have included ion drives because I did not think ion propulsion is quite up to that task yet... Please let me know if I am wrong or if you disagree. :)
They are are coming up with relatively much more powerful Ion engines, see http://www.nasa.gov/centers/glenn/about/fs21grc.html for info. I'm not sure which propulsion method would be best but I would bet on it being the cheapest one.
 
  • #10
Hoophy
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I believe that a motive is to harvest water ice from asteroids...
Water is pretty great stuff! We need it to drink, it can make oxygen to breath, and rocket fuel too! And some even say a layer of water could be used to shield astronauts from interplanetary radiation during a journey to Mars! :D
 
  • #11
1oldman2
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I believe that a motive is to harvest water ice from asteroids placed in lunar orbit. Running water through electrolysis they could manufacture LOX/LH2 bipropellant rocket fuel in orbit so that they can more cheaply refuel stuff. Kind of like a gas station in space. I guess it is too expensive to bring up extra fuel using launch stages because so much fuel is used putting the extra fuel in orbit that they think that they may actually save money by making the fuel in space.
http://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html
There is no such thing as "extra fuel, barring solar" in space. It's very valuable once it's in orbit, so manufacturing it in space would be a popular project.
 
  • #12
rootone
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Yay for ion engines, they do what it says on the tin.
I wonder if we well ever find a way to get beyond Earth orbit using something better than a controlled explosion though.
I hope so.
 
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  • #13
Hoophy
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Yay for ion engines, they do what it says on the tin.
I wonder if we well ever find a way to get beyond Earth orbit using something better than a controlled explosion though.
I hope so.

Didn't the Dawn already do that?

Edit* I think I was incorrect, although the Dawn does have 3 ion thrusters I believe it actually used traditional rockets to escape from Earth.

"NASA's first purely exploratory mission to use ion propulsion engines. The spacecraft also has twelve 0.9 N hydrazine thrusters for attitude control, which are designed to assist in orbital insertion."
https://en.m.wikipedia.org/wiki/Dawn_(spacecraft)

It is unclear to me whether or not they used the traditional thrusters to escape Earth orbit specifically. If somebody could help, I would appreciate it. We're the traditional thrusters used for propulsion or RCS?

Edit** No apparently the ion drives were used to propel the probe out of Earth orbit. The ion drives each have a thrust of 92 mN but the traditional rockets each have a thrust of 0.9 N. And I missed the part mentioning "attitude control"

http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=2007-043A
 
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  • #14
rootone
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Didn't the Dawn already do that?
No, it was launched by a conventional rocket, the ion engines are used to make precise adjustments now that it is orbiting Ceres.
Dawn also visited Vesta before going to Ceres, and the ion engines were enough to get that job done.
 
  • #15
Hoophy
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No, it was launched by a conventional rocket, the ion engines are used to make precise adjustments now that it is orbiting Ceres.
Dawn also visited Vesta before going to Ceres, and the ion engines were enough to get that job done.

Wait are you sure? Did the launch vessel decouple after the probe was on an escape trajectory?
 
  • #17
Hoophy
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I don't think that contains the information I need, that tells me the Delta 2 propelled the probe out of the atmosphere and decoupled. It does not tell me if the the probe was on an escape trajectory from Earths gravity well, we're you suggesting that you can't wait until the day ion drives can propel probes out of the atmosphere or out of earths gravity well? I thought you meant Earths gravity well. Am I mistaken?
 
  • #18
rootone
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I cannot imagine an ion drive that would be powerful enough to escape the gravity of Earth, (and the atmosphere problem)
Maybe somebody else can though.
 
  • #19
Hoophy
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I THINK: An ion drive could be used to bring a probe from low Earth orbit to interplanetary space given time. All you need is sufficient potential for delta V, as it happens, for their weight ion engines have more potential for delta V than chemical rockets. After many fly-bys and prograde 'burns' at a probes perigee you could escape earths gravity well. I don't think it matters how high your thrusters thrust to weight ratio is in this case because given TIME you could escape from earth by burning low thrust over a longer period of time. Ion thrusters are highly efficient and given TIME they could be used to bring a probe to interplanetary orbit. In any rate I think it is indeed possible to bring a probe using solely ion propulsion from low Earth orbit to interplanetary orbit. It is not so much how fast you can complete a maneuver, but if you have the potential to sufficiently change your velocity enough to escape. Maybe I'm wrong and I just play too much KSP, If I am wrong please let me know why.
Edit: I am not suggesting in this post specifically that this was the case for Dawn.
 
  • #21
Bandersnatch
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The first link talks about the KECK Institute study, but doesn't directly link to it. It's a fun read, and very thorough. Propulsion system analysis is included. Check it out:
http://www.nss.org/settlement/asteroids/Asteroid_Retrieval_Feasibility_Study_2012.pdf

There's also this site that seems relevant to the discussion:
http://www.asterank.com/
From their own description:
Asterank is a scientific and economic database of over 600,000 asteroids.

We've collected, computed, or inferred important data such as asteroid mass and composition from multiple scientific sources. With this information, we estimate the costs and rewards of mining asteroids.

Details on orbits and basic physical parameters are sourced from the Minor Planet Center and NASA JPL. Composition data is based on spectral classification and size. Our calculations incorporate conclusions from multiple scientific publications in addition to cross-referencing known meteorite data.

(...)
Value estimates are based on the mass of a given asteroid and its spectral type. Asteroid spectra is used to infer composition, which, in conjunction with current market prices, determine potential value.

Accessibility estimates are based primarily on delta-v, but it also incorporate orbital characteristics such as perihelion, aphelion, eccentricity, and period. The formula is biased toward low delta-v with orbits that maintain a generally consistent distance from the sun (ie., no objects that swing far into the belt).

Profit and ROI calculations are a combination of accessibility and value. The formula strikes a balance between high value and high distance and energy expenditure. Mining costs are factored in as a flat percentage of potential value.
 
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  • #22
Hoophy
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Rootone it turns out we were talking about two different regions of gravity! We are both right, it was just a misunderstanding! :D
 
  • #23
russ_watters
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What is there on asteroids that is so specially valuable that it cannot be found or made on Earth without the extreme risk and cost.?
Nothing.
 
  • #24
D H
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What is there on asteroids that is so specially valuable that it cannot be found or made on Earth without the extreme risk and cost.?
Nothing.
That's close to the mark, but it's not quite true.

The supposed trillions of dollars to be made by plucking the low hanging solar orbiting fruit are pure science fiction science fantasy for the foreseeable future, where "foreseeable" means within the next 25 to 50 years or so. What might be viable in the near-term future is harvesting volatiles such as water and methane from those asteroids and then finding a way to use those volatiles in space. But that's not worth trillions of dollars.
 
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  • #25
1oldman2
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The first link talks about the KECK Institute study, but doesn't directly link to it. It's a fun read, and very thorough. Propulsion system analysis is included. Check it out:
http://www.nss.org/settlement/asteroids/Asteroid_Retrieval_Feasibility_Study_2012.pdf

KISS is an impressive collaboration of resources, that is an interesting "read"

This will be interesting to watch in the future as far as the projections go, thanks for the links.
 
  • #29
1oldman2
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There must be a position at NASA whose job description consists solely of coming up with new acronyms for their projects.
I wouldn't be surprised if there isn't a dept. dedicated to that pursuit. :wink:
 
  • #30
Chronos
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Ion rockets use extreme exhaust velocity of tiny mass particles [like ions] to achieve thrust. A conventional rocket utilizes low exhaust velocity, high mass particles [like gas molecules] to achieve thrust. Thrust remains mass times acceleration in both cases. An ion rocket is useful in the vacuum of space because a relatively small propulsion mass goes a long way. They are not so good in earths atmosphere because the engine would have to burn so hot to deveop sufficient thrust to overcome frictional losses it would be incinerated. For a brief discussion, see http://www.qrg.northwestern.edu/projects/vss/docs/propulsion/1-could-this-work-on-earth.html
 
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  • #31
glappkaeft
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Ion rockets use extreme exhaust velocity of tiny mass particles [like ions] to achieve thrust. A conventional rocket utilizes low exhaust velocity, high mass particles [like gas molecules] to achieve thrust.

Actually you have the masses of the exhaust gasses the wrong way around. Ion engines usually use rather heavy Xenon ions (atomic weight 131). Thermal rockets however get the highest exhaust velocity by having light molecules in the exhaust. Common exhaust gases are water, CO, CO2, HF, excess H2 and similar.

For any interested parties a recommend IGNITION! An Informal History of. Liquid Rocket Propellants by John D. Clark (available at http://library.sciencemadness.org/library/books/ignition.pdf )
 
  • #32
Chronos
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Actually you have the masses of the exhaust gasses the wrong way around. Ion engines usually use rather heavy Xenon ions (atomic weight 131). Thermal rockets however get the highest exhaust velocity by having light molecules in the exhaust. Common exhaust gases are water, CO, CO2, HF, excess H2 and similar.

For any interested parties a recommend IGNITION! An Informal History of. Liquid Rocket Propellants by John D. Clark (available at http://library.sciencemadness.org/library/books/ignition.pdf )
From the link I posted:
"...Ion rocket:
Force = little tiny mass x BIG ACCELERATION
Normal rocket:
Force = HUGE MASS x less acceleration..."
 
  • #33
glappkaeft
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Yes, that is correct, it about mass flow not the mass of the exhaust particles. The stuff from your previous post I quoted is not (in bold below).

Ion rockets use extreme exhaust velocity of tiny mass particles [like ions] to achieve thrust. A conventional rocket utilizes low exhaust velocity, high mass particles [like gas molecules] to achieve thrust.
 
  • #34
Chronos
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Agreed. Thrust is proportionate to the aggregate mass discharged, not the mass of individual particles discharged.Thrust of a chemical rocket is limited by propellent mass payload, whereas thrust of an ion rocket is limited by the energy payload available to discharge ions.
 
  • #35
1oldman2
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Being curious about the actual processing of the raw materials once the asteroid has been returned to Earth or lunar orbit, (I can imagine there will be considerable hand wringing over asteroids purposely brought into near earth orbit), I did some searching and came up with a few links, should be good discussion material here.
First off there seems to be a lot of "Start up" interest in the field of Astro-mining. Deep Space Industries is partnering with Ames research of NASA affiliation, Their site https://deepspaceindustries.com/mining/ contains a lot of info on the companies plans and technology.

I found this one to be particularly interesting as it discusses aspects of Astro-mining I hadn't considered. http://www.permanent.com/asteroid-mining.html
This would likely fall in the R&D department. (Once again leaning heavily towards Mechanical Engineering)
http://info.heylpatterson.com/blog/heyl-patterson-develops-equipment-for-asteroid-mining
And then I thought I'd throw in another video (Which links to many other videos concerning the subject)

Also the video Greg has posted is an excellent take on this up and coming industry, highly recommended viewing.
I wouldn't be surprised to find E. Musk getting involved before long. :wink:
 
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