DARPA wants vampire satellites to harvest parts from dead sats prior to decommissioning

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28 Responses to “DARPA wants vampire satellites to harvest parts from dead sats prior to decommissioning”

  1. This article is wrong. The satellites aren’t being “deorbited”. They have been moved to parking orbits far higher than geostationary ones they were in before decommissioning. The title and intro blurb of this article have the story exactly backwards.

  2. bkad says:

    Darpa is pretty cool, no doubt. And as people sometimes forget, they do a lot more than just what the d in their name would suggest.

    Agree with Chuck; description is not consistent with video.

  3. brerrabbit23 says:

    Wall-E sats! SO COOL!

  4. benjymous says:

    What?  They’ve tired of eating carrion and have decided they like living prey?  Good lord they’re heading straight for the ISS!

  5. Sarge Misfit says:

    One thing I’ve always wondered about … why de-orbit the satellites to fall back to Earth? Why not send them into the Sun? Seems a lot safer, let alone any enviro impact. I’m assuming some last bit of fuel is used to make that final de-orbit burn, so why not use it to redirect to the Ultimate Incinerator? The calculations can’t be that difficult. They’ve managed to land people on the Moon a half a dozen times using computers that were far less powerful than an iPhone.

    • HahTse says:

      It’s not about difficult calculations, it’s about fuel.

      You need a powerful engine and enough fuel to achieve escape velocity and leave earth orbit. Then you’d have to decelerate pretty violently collapse your orbit around the sun.

      It’s incredibly more easy to just decelerate enough that the satellite can burn up upon reentry.

      And many satellites don’t have engines strong enough to do even that.

      • Sarge Misfit says:

        Actually, if it has an engine powerful enough with enough fuel to change the orbit to de-orbit into the planet, then it should be only a matter of using a different vector to move it out. I don’t think its a matter of having a powerful engine or enough fuel. Its only a matter of providing a bit of momentum in the right direction. Let inertia and gravity take it from there. Heck, slingshot it around the Earth if needed. Who cares if the satellite takes years, decades or even centuries to end up falling into the Sun. 

        • HahTse says:

          Sadly, that’s not how it works.

          • Sarge Misfit says:

            *grins* I think it is. But, I’m not knowledgeable enough about orbital mechanics and such. I would really like to see a write up on this at some point, though.

            Whaddaya think, Cory? Got a rocket scientist stashed around here someplace to answer this?

          • Jardine says:

            Got a rocket scientist stashed around here someplace to answer this?

            Not a rocket scientist, but I read a lot of stuff. A satellite in Low-Earth Orbit (LEO) travels at about 7.8 km/s. It takes quite a bit of fuel to get something up to that speed. Escape velocity from Earth is a bit over 11 km/s. So to get a satellite out of Earth’s gravity well, you’d have to make it go about 45-50% faster than it already was. They don’t carry enough fuel for that.

            Slowing a satellite down enough to let it smack into Earth instead is a lot easier. Point the engine in the direction you’re headed, fire your remaining fuel, satellite slows down and eventually hits the atmosphere. That slows it down even more. Hell, if something goes wrong with a satellite in LEO and you run out of fuel, you can just wait. It’ll slow down anyway because the atmosphere expands and contracts enough that LEO satellites scrape it.

          • Sarge Misfit says:

            Thanks, Jardine. To clarify, I’m simply curious about this. It simply seems to be a better choice to send those defunct satellites into the Sun and I’d like to know what it is that prevents this. If those satellites don’t have enough to go faster, but enough to slow down, what about not slowing down as much. Use the Earth’s gravity to get the extra velocity to slingshot out.

          • Peter Erwin says:

            OK, a very crude estimate of how hard it is to send a satellite into the Sun. To simplify (I’ll come back to this point), let’s assume the satellite is in an Earth-sized circular orbit about the Sun, which means an orbital velocity of about 30 km/s. To drop the satellite straight into the Sun, you’d need to cancel this by applying a delta-V of 30 km/s; even if you just want to change the orbit so the satellite grazes the surface of the Sun at perhihelion, that’s still a delta-V of about 27 km/s.

            That, of course, is an underestimate, because in reality you’d need to use extra fuel to break out of Earth’s orbit before you could consider changing the orbit around the Sun. Probably at least another 1-2 km/s of delta-V.

            Is that a lot? Well, consider that (according to the Wikipedia page on graveyard orbits; see ackpht’s post for the link), geosynchronous orbit satellites typically do not have nearly enough fuel for a proper de-orbit into Earth’s atmosphere, which would require about 1.5 km/s of delta-V; shifting the satellite to a graveyard orbit only takes about 10 m/s (0.01 km/s) of delta-V. This already tells you that sending satellites into the Sun takes far more fuel than geostationary satellites have available. Another way to look at it: station-keeping requirements for geostationary orbits are about 50 m/s (0.05 km/s) of delta-V each year. So to dispose of a geostationary satellite by sending it into the Sun would take something like 600 years’ worth of station-keeping fuel.

        • Guest says:

          I think maybe you’ve watched too many Star Trek episodes, and not enough NOVA. :P Good discussion starter though!

    • Guest says:

       In short, they would still need to break earth’s gravity, which means they would need larger engines, and fuel storage.

      DARPA wants to be able to argue for the safety of nuclear-based fuels in space. Nothing more.

  6. arikol says:

    Vampire satellites?
    Does this involve firing Edward Cullen (from those godawful Twilight books) into orbit? Good plan, if you ask me!

  7. Their feldspars says:

    At first, I thought the headline said “DARPA wants vampire satellites to harvest parts from dead cats.”

  8. ackpht says:

    Disused satellites in geosynchronous orbit are not “deorbited” back to Earth, and certainly not sent into the Sun. Doing either would take a lot of delta-v (fuel), which itself is expensive to put in orbit.

    Geosynchronous satellites are placed in a higher orbit to get them out of the way, but just a very slightly higher orbit that requires a very small delta-v: http://en.wikipedia.org/wiki/Graveyard_orbit. If the satellite cannot be moved to a junk orbit (and it happens), it can potentially interfere with active satellites. But all of them are staying in orbit close to the original altitude because leaving them there is the cheapest thing to do.

  9. Sarge Misfit says:

    Actually, I’ve likely read too much Asimov, Clarke and Heinlein *laughs* You know, though, if those vampire-sats (though vulture-sat may be a better term) can change orbits to match up with those defunct satellites, perhaps they could do the work to send the trash into the Ultimate Incinerator :D

  10. ackpht says:

    I doubt that this is being undertaken in an effort to justify the use of nuclear power in space, because if the US military (or NASA) needs that, they just do it.

    The US military sees an ongoing and increasing need for a presence in space, and while they do have a huge budget, it’s still a budget. A vampire-sat system could cut costs by reducing the amount of fresh hardware that has to be lofted to keep a satellite functional. They are also no doubt anticipating scenarios where satellites suffer battle damage and need repair.

    The biggest problem here is that as yet satellites aren’t designed to be dismantled- in orbit or anywhere else. Part of a vampire-sat program would be to develop vampire-friendly protocols for satellite design and construction.

  11. sockdoll says:

    Mechanical cannibals in space?

  12. Dave Jenkins says:

    Beyond the antennae and other valuable equipment, how about the titanium plating and other metals?  Could these be worth something in building out deck plating for expanding the ISS or other stations?

    Personally, I always wondered why they never tried to re-purpose the shuttle’s external tanks.  There were concept drawings that string several tanks together to form a toroid station.

  13. awjt says:

    There must be a way to melt and re-form metals in space with concentrated sunlight.  Everything we need for a moon-station is probably already up in orbit.

  14. Here’s my proposal: Build a space station in LEO.  At that station build a small unmanned craft with  a low thrust high efficiency drive like ion or plasma that can creep up to the parking orbits in a few days. Grab a couple of satellites and creep back down to the station.  Strip out all valuable materials and all toxic materials and put them into a reentry pod. Drop the pods near my secret base. Dispose of toxics and recycle valuables. Dump the rest from orbit into the atmosphere. 

    Once I’ve recycled all the parked satellites,  I then can threaten all the cable TV sats. Put real history on the History Channel, make Discovery almost all science again, put the original “L” back in TLC, or lose your satellites..

  15. Slam1263 says:

    Then what will I use to get to Mars?

  16. Aleknevicus says:

    “I’d like to know what it is that prevents this.”

    The answer has already been given, but you seem reluctant to accept it: fuel. It takes only a little to decay an orbit, but significantly more to send it “to the sun”.

  17. penguinsix says:

    I’ve always thought we should Katamari old satellites.  Build a hunter that has claws on it or something and can pull in other satellites until you have a large enough ball to plummet to Earth and burn up.

  18. Well, now, we need to have some satellites programmed to modify themselves to better avoid the predators, and then the predators can adapt to better hunt their prey, and… well, you’ve all read “Code of the Lifemaker”, haven’t you?

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