Forgot your password?

typodupeerror
This discussion has been archived. No new comments can be posted.

NASA's Top 10 Space Junk Missions

Comments Filter:
  • by teebob21 (947095) on Thursday July 29 2010, @11:09AM (#33069414) Journal

    For the sake of discussion, let's assume this report showed a problem orders of magnitude worse, and we were on the verge of Kessler syndrome conditions. What technologies exist today to combat the problem? (Yes, I know, no government today would unilaterally scrub space without a quid pro quo...)

    If there are 19,000 trackable chunks of debris, how many untrackable (and just as deadly) small particles are there? I know that particle densities are minute. If we launched an array of satellites with Aerogel paneling, is it reasonable to expect a significant improvement in "air" quality up there?

    What about that heat-ray device recently pulled our of Afghanistan? Can we launch one of those to spray microwaves tangentially to the Earth's surface? Would the heat applied to a paint-chip sized debris particle be enough to change the orbit? It doesn't take too much delta-v to alter the eccentricity of a paint fleck enough to burn up in orbit, does it?

    (Less coffee, more sleep next time, methinks)

  • by starglider29a (719559) on Thursday July 29 2010, @11:36AM (#33069796)
    In no order:
    • It takes the same delta-v to de-orbit any two masses in the same orbit. Paint chip or Star Destroyer. Thrust requirements follow Newton, not Roddenberry.
    • Whatever energy you have to apply to an object must be applied to the object. It's 100km away at 7km per second. Good luck.
    • The delta-v to get close enough to where you can apply delta-v (bump a paint chip) adds up. If you could hit it with a beam from 100km away, that would be great, but delivering delta-v at 100km is problematic.
    • Almost nothing is magnetic, so forget that. We don't have a tractor beam, and Yarkovsky Effect is insignificant on these tiny pieces. A maser/laser doesn't deliver momentum very well. Heat does nothing.
    • Blobs of Aerogel in a counter-directional/retrograde orbit could sweep up the small stuff, but the volume that needs to be swept is like mopping a basketball court with a cotton swab.

    Solve the "how do you apply force at a distance" issue and yer halfway there.

  • brooms, plural (Score:3, Interesting)

    by starglider29a (719559) on Thursday July 29 2010, @11:45AM (#33069932)
    To accomplish this, you would need a vast array of laser brooms. The percentage of objects which travel through your cone of opportunity are a minuscule proportion. You can't cover 180 degrees (the part you can see) of the sky because the distance to the target at the horizon is several hundred km through thermal layers.

    The inverse of that minuscule proportion is the number of brooms you'd need.

    Forget the energy needed and environmental impact of blasting a terawatt (ok, then... how big?) laser into space. You hit a Vulcan in the eye with that an they will be pissed!
  • Spacewar Pollution (Score:3, Interesting)

    by Doc Ruby (173196) on Thursday July 29 2010, @12:00PM (#33070240) Homepage Journal

    Military "tests" ("warnings") that destroy orbiting satellites leave junk in orbit that makes future space exploitation more dangerous, costly, and even impossible (vulnerable equipment). It's like the hidden costs of manufacturing (and war) at the surface, which are left as problems for someone else. We humans should quickly force people, governments and corporations which produce debris to either clean it up, or to pay for someone else who cleans it up. We don't want to box in our growing space development just as it's getting started with the pollution from the first few generations.

  • by rickb928 (945187) on Thursday July 29 2010, @12:07PM (#33070356) Homepage Journal

    "It would be like searching the beach in Fiji, looking for a particular 1957 nickel."

    By that analogy, how do fishermen around Fiji actually catch fish? Chase one around with a net until they get the advantage? No, they cast the net, catch what is there, and throw back the rest.

    Who sent a satellite to capture comet dust? Oh yeah, us. "Stardust'. Aerogel as a capture mechanism for comet material.

    Why not try sending some aerogel into LEO and use a similar method? Send it through debris fields, verify useful capture, and then throw it into Earth to either burn up or land somewhere 'safe'. Pick it up and throw it in a landfill, or send it off to be autopsied.

    I know there are challenges - a maneuverable spacecraft, fuel, coordinating the orbits, where to land the debris, who gets it back. But this seems obvious to me. Aerogel is uniquely suited to this.

    Alternatively, there are other ways to catch debris if you don;t much care what shape it is in when you catch it. A few layers of metal and some intervening goo, for instance. But aerogel is so light that it's cheaper to send up, it captured comet debris adequately, so it would probably be great to catch a lot of small stuff. Larger items may need a bigger or better 'net'.

    It's about the money, and what to do with the more interesting pieces of junk. Russia may want their satellite stuff back.

    And of course, if we do this, we just encourage China to keep on testing space weapons. Is this good?

  • by slick7 (1703596) on Thursday July 29 2010, @12:34PM (#33070864)

    Maybe some international body could charge a property tax on birds up there and use it to fund regular garbage collections, a bit like local councils down on earth.

    Why? The insurance recovery fee would do more than make up the difference. A $100 million satellite that goes bad because of a $1500 circuit board can be re-activated if somebody could get to the satellite either physically or by remote tele-presence.
    The ISS can be setup as a base of operations, but a commercial space station would be better.

  • by starglider29a (719559) on Thursday July 29 2010, @01:17PM (#33071814)
    Parent is a degreed Aerospace engineer. You are correct about the delta-V. Google "specific impulse" and realize why it takes a 365 foot rocket to lift a volkswagen. That is... why the propellant to payload ratio is so freaking high! (Technical term)

    Regarding the radiometer: The answer is 'yes, but...' You would have to hit the object with enough "photon momentum" to change the velocity, literally, delta the v. The losses of distance, surface area reduce your killer beam to a few photons pretty fast. And it's SURE not worth the cost.

    Magnitudes are your enemy here. If you shot a .308 rifle out the "back" of the ISS (retrograde to velocity), the bullet probably wouldn't de-orbit. That's a lot of delta-v! If you shot it straight down (down the radius vector), it would loop around you and come back DOWN at you 1 orbit later and at the same velocity it left!
  • by Martin Blank (154261) on Thursday July 29 2010, @01:55PM (#33072638) Journal

    Setting up a net isn't that easy. Aside from the 19,000 "large" items (those over about 10cm), there are tens of millions of smaller items like washers and paint flecks. Let's say there are 50 million such objects between altitudes of 150 miles and 300 miles. That space totals up to 11.7 billion cubic miles for an average about 235 cubic miles per piece of debris. There are, of course, higher densities in some spots, but not enough to make something like this economical.

    Additionally, aerogel is some fragile stuff. I know it is, because I have some at home. It came from a polite request to purchase some small, random piece from an aerogel manufacturer about ten years ago, and the person who replied was kind enough to simply put a piece of shop scrap in a plastic box and send it to me (complete with MSDS). Within ten minutes of opening it and despite what I thought was careful handling, I had broken the piece in two, and in the intervening years, it has broken further into about six major pieces and a dozen minor bits. It may be good for capturing micrometeors, but it would shatter if it were hit by a bolt, adding to the debris problem.

    As for who gets back the space debris and whatever else is deorbited, the answer should be "nobody." Send it to break up over the Pacific. If a country wants something back badly enough, they can design the important parts to survive re-entry and bring it back on their own, or provide funding for a dedicated retrieval mission.

  • by Demolition (713476) on Thursday July 29 2010, @04:23PM (#33075354)
    Does anybody remember "Salvage 1" [imdb.com] starring Andy Griffith? The premise involved a junkyard owner who builds a rocket so that he can salvage abandoned moon landing equipment (e.g. lunar landers, rovers, cameras, etc.) to sell for profit upon returning to Earth.

    It ran for 1.5 seasons back in 1979-80. It was one of the many things that sparked my interest in space exploration when I was a kid.

After all, it is only the mediocre who are always at their best. -- Jean Giraudoux

Working...