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B Asteroid/Near Earth object mining

  1. Jun 1, 2016 #1

    1oldman2

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    Gold Member

  2. jcsd
  3. Jun 1, 2016 #2

    berkeman

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    Staff: Mentor

  4. Jun 1, 2016 #3
    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.?
     
  5. Jun 1, 2016 #4

    1oldman2

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    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.
     
  6. Jun 1, 2016 #5

    1oldman2

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    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.
     
  7. Jun 1, 2016 #6
    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. :)
     
  8. Jun 1, 2016 #7
    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. Jun 1, 2016 #8
  10. Jun 1, 2016 #9

    1oldman2

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    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.
     
  11. Jun 1, 2016 #10
    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
     
  12. Jun 1, 2016 #11

    1oldman2

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    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.
     
  13. Jun 1, 2016 #12
    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.
     
  14. Jun 1, 2016 #13
    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
     
    Last edited: Jun 1, 2016
  15. Jun 1, 2016 #14
    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.
     
  16. Jun 1, 2016 #15
    Wait are you sure? Did the launch vessel decouple after the probe was on an escape trajectory?
     
  17. Jun 1, 2016 #16
  18. Jun 1, 2016 #17
    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?
     
  19. Jun 1, 2016 #18
    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.
     
  20. Jun 1, 2016 #19
    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. Jun 2, 2016 #20
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