Dust for space junk

Discussion in 'Fred's House of Pancakes' started by bwilson4web, Nov 24, 2021.

  1. ChapmanF

    ChapmanF Senior Member

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    As I understand it, it is fair to describe what trees do with carbon as 'sequestering' it, whether said trees are on our payroll or are operating on a freelance basis.

    Accordingly, if somebody comments on the combustion of ~ 10^10 square meters of trees by saying something like "gee, it's unfortunate to see the rapid unscheduled desequestration of that much carbon", that could turn out to be more of a general fairly-accurate (if understated) comment, without necessarily the further significance being attached to it here.
     
  2. tochatihu

    tochatihu Senior Member

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    There seem to be some LDEF results in free for view 'space':

    LDEF Intercostal Data and Plots

    ldef1.gif
    it started in orbit 257 nautical miles, after 5.7 years that decayed to 175 nautical miles and it was brought back. For that orbital band, in the late 1980s, statistics can be derived. The brave might develop a way to extrapolate to larger crater sizes. In any case, there is much more orbiting debris now. Debris at other altitudes has not been as carefully assessed at any time.

    The growing fleet of orbiting objects has some amount of impact damage. Most of that will never be seen at close range by human eyes (or sensors) and so remains unknowable. I can't take any comfort from that ignorance.

    If there are paywalled publications please give their DOI here. Access is not always difficult :)

    Someone also might list satellite collisions that have happened. Year, altitude, size of participants - things like that.

    ==
    Is seems to have been implied earlier here, that because Kessler Syndrome has not happened, it can not happen. Do not attach yourselves too tightly to such notions.

    ==
    It has tickled my fancy, so I may ask around in the remote sensing community to see it anyone wants to assess the burn of reforestation projects. Anywhere, not just in a country that has done so much reforestation in such a half-assed way.
     
    fuzzy1 likes this.
  3. bisco

    bisco cookie crumbler

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    i like planting trees. and i also like cutting them down (n)
     
  4. tochatihu

    tochatihu Senior Member

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  5. bisco

    bisco cookie crumbler

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  6. tochatihu

    tochatihu Senior Member

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    Saws large enough for redwoods were developed after photography, so there are many photos like this for your Ent album.
     
  7. bisco

    bisco cookie crumbler

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    they need a uge stump grinder
     
  8. tochatihu

    tochatihu Senior Member

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    Fair enough to wonder about condition of such stumps ~130 years later. I suppose that many are on private 'timber enterprise' land, with limited options for (legal) entry. Plenty of time for most types of dead wood to succumb to fungi, but redwood is more resistant than most.
     
  9. bisco

    bisco cookie crumbler

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    you could make a lot of paddy o' furniture from a stump like that
     
  10. fuzzy1

    fuzzy1 Senior Member

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    And probably felled before chainsaws.

    Were any chainsaws ever big enough?
     
  11. Rmay635703

    Rmay635703 Senior Member

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    Orbital mine sweeper
     
  12. fuzzy1

    fuzzy1 Senior Member

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    Open copy here, it seems to be the same as the paywalled version. It is a photocopy of a dead tree version, doing no justice to the photos.
     
  13. tochatihu

    tochatihu Senior Member

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    Wow, even core.ac.uk does not like my isp
     
  14. bisco

    bisco cookie crumbler

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    can you blame them?
     
  15. tochatihu

    tochatihu Senior Member

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    I don't take it personally, I assume that web hacking or similar malfeasance is done by similar isp numbers. A blanket ban. It is perhaps interesting to note that the great firewall operates in both directions.
     
  16. fuzzy1

    fuzzy1 Senior Member

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    Your NASA link above appears more detailed. But if you want to try for this too, here are some hooks:

    LDEF experiment M0003 meteoroid and debris survey - NASA/ADS

    LDEF experiment M0003 meteoroid and debris survey
    Abstract
    A survey of the meteoroid and space debris impacts on LDEF experiment M0003 was performed. The purpose was to document impact phenomenology and to obtain impact crater data for comparison to current debris and micrometeoroid models. The survey consists of photomicrographs of significant impacts in a variety of material types, accurate measurements of impact crater coordinates and dimensions for selected experiment surfaces and data basing of the crater data for reduction, manipulation, and comparison models. Large area surfaces which were studied include the experiment power and data system sunshields, environment exposure control canister sunshields, and the M0003 signal conditioning unit covers. Crater diameters down to 25 microns were measured and catalogued. Both leading and trailing edge surfaces were studied and compared. The results shows the different response of materials to hypervelocity impacts. Comparison of the data to curves derived from the Kessler debris model and the Cour-Palais micrometeoroid model indicates a marked tendency for overprediction of small impacts and underprediction of large impacts with there being better agreement for the medium sized impacts. Representative impact data is presented.


    Publication:
    In NASA. Langley Research Center, Second LDEF Post-Retrieval Symposium Abstracts p 34 (SEE N92-27218 18-99)
    Pub Date:
    June 1992
    Bibcode:
    1992ldef.symp...34M
    Keywords:
    • Hypervelocity Impact;
    • Long Duration Exposure Facility;
    • Meteorite Collisions;
    • Micrometeoroids;
    • Space Debris;
    • Craters;
    • Leading Edges;
    • Photomicrographs;
    • Signal Processing;
    • Trailing Edges;
    • Astrophysics

    upload_2021-11-28_18-44-13.png
     
    #36 fuzzy1, Nov 28, 2021
    Last edited: Nov 29, 2021
  17. kenmce

    kenmce High Voltage Member

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    What you need is a flying water canon. You would squirt out a small cloud of water or ice at the highest velocity you can generate and let them collide. A short time in raw sunlight and it would soon go to harmless vapor.
     
  18. fuzzy1

    fuzzy1 Senior Member

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    I don't believe it would be liquid water for more than a moment, before it flashes into a mixture of vapor and ice particles.

    But even if it could be kept or used while still liquid, when impacting the target at orbital head-on or T-bone speeds, the impactor's solid vs liquid state is completely irrelevant. The per-molecule kinetic energy is much greater than the energy of the bonds that determine material phase. Particle size, mass, and density are what matter. A liquid water droplet would leave the same crater as a solid particle of the same size and mass. A standard raindrop, much larger and heavier than any of the particles that cased the craters and penetration pictured earlier in this thread, would pierce metal armor the same as a (low density) bullet.

    To get the more common soft liquid impacts that we are accustomed to (from some material that doesn't boil or evaporate as fast as water), the target would have to run down the liquid with a comparatively low speed differential. The liquid cloud would need to be traveling in nearly the same direction, just somewhat slower.
     
    #38 fuzzy1, Nov 30, 2021
    Last edited: Nov 30, 2021
  19. Rmay635703

    Rmay635703 Senior Member

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    Sublimation rates are very high in a perfect vacuum

    The “ice” would need to be extremely cold to last long enough to hit anything,

    Liquid water doesn’t exist in space certainly not long enough to matter anyway
     
  20. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    I was thinking that a space borne water cannon would have to have an exceptionally short barrel….;)
     
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