Space lasers

Removing Orbital Debris with Lasers. How's that for a great research paper title?

Most of you are probably aware of the existence of space trash—that collection of disused satellites, lost tools, spent rocket boosters, and various other flotsam that is starting to become a physical hazard to the objects we actually want circling the globe in Low Earth Orbit. Currently, we get around the problem (mostly) by attaching bumpers to spacecraft and to the ISS. But there are lots of different ideas for how we could deal with the problem of space junk in a more proactive way.

The team of private and government scientists who wrote this paper want to aim lasers at space junk. But not like you're thinking. Instead of blowing up our trash in a life-size game of Asteroid (something that would really only succeed in creating a lot more, smaller pieces of space junk) the team wants to use laser pulses to alter the momentum of large pieces of junk, slowing those pieces enough that they fall out of orbit and back to Earth.

Such a system could be used to precisely time the reentry of dead satellites and other junk, ensuring that when chunks of metal fall out of the sky they won't be falling on any densely populated regions. That's one of the major benefits to this proposal.

The major detriment: Politics. How do you build a laser big enough to knock space junk out of orbit without convincing half the world that what you've really built is a giant death ray? That's something the authors hope to avoid through international cooperation.

Via We Are All In the Gutter

Image: Goddard Celebrates International Observe the Moon Night with Laser Show, a Creative Commons Attribution (2.0) image from gsfc's photostream


  1. Oh man, that’s cool!  But wouldn’t it be both?  A space junk de-orbiter AND a massive death ray?  Why play down that angle when it’s a sure fire way to get more funding?

    Also get some private funding by marketing it as a laser logo engraver for moon based advertisements.  Moonvertisements, if you will.

  2. “How do you build a laser big enough to knock space junk out of orbit without convincing half the world that what you’ve really built is a giant death ray?”

    Fuck ’em.  What are they going to do?  We’ve got a giant death ray!

  3. “There. You see, Lord Vader? She can be reasonable. Continue with the operation. You may fire when ready.”

  4. I for one think that a ring around the old Earth would look mighty pretty. Put more debris up there – now!

  5. In 50 years or so ,  won’t  we have a moon base or orbiting shipyard, and  wish there was a scrapyard nearby?

    Also  what happens when  you  shoot  a cloud?

  6. In the 80s there was some hubbub around the fact that the Soviets had built some kind of space thing near a large hydroelectric facility near Dushanbe.  Some people thought it was an anti-satellite laser weapon.  The Soviets said it was a tracking facility for space junk.  If Americans were to build such a facility today, would it spook other space-going nations?

  7. But wouldn’t breaking it up into smaller pieces  be beneficial as these smaller pieces would be more likely to burn up on re-entry?

    1. The smaller the pieces are the harder its is to track them. Two fairly recent incidents involving satellites have increased the amount of pieces in orbit immensely. One of them was the Chinese military shooting one of their satellites with a missile. This single event created
      “2,300 pieces  of trackable debris (approximately golf ball size or larger), over 35,000 pieces 1 cm (0.4 in) or larger, and 1 million pieces 1 mm (0.04 in) or larger. “
      That’s a lot to keep track of and have your satellites try to dodge if they are in the path of one of those. And as you can see from these numbers, even more that you cannot track. And this debris will be in orbit for decades.

      At the speeds necessary to keep an object in low earth orbit all but the most massive chunks of spacecraft burn up once they re-enter the atmosphere. So that’s really not an argument for making more pieces out of the ones already in orbit.

      The quote is from:

  8. Thank you for the edumacation, Mr. Vader. I knew there had to be a perfectly good reason but had never read anything on it. Still, it seems even from that link that if objects are in a low orbit that is about to decay, perhaps it could be beneficial to attempt to destroy them. For instance, the recent satellite that everyone was so worried about since it was coming down anyway.

    1. The dangers from reentering birds is so stunningly low, periodic media attention aside, that whether you prefer them to enter in a unitary fashion or a cloud of itty bits is essentially aesthetic- except for the old Soviet oceanic surveillance satellites with nuclear reactors, which one would most definitely prefer to come down in one piece. (Don’t worry- all the remaining ones have been disposed of by going up, not down. They aren’t due to reenter for 50,000 years.) The planet is 70% ocean, and the remainder is overwhelmingly farms, forests, ice, and desert, and the offending object in question is usually the size of a small car, and by the end, is traveling at a speed more akin to falling than bullets.  Defunct satellites are exclusively a danger to other satellites, and in that case, we prefer them large and intact, instead of chipping off other bits and making self-replicating swarms of hypersonic hail.

      Also, it’s rather easy to disable a satellite with a laser (indeed, there is cause to believe that the US and the Russians have done so, at least temporarily, before, including a laser blinding of a shuttle,) but blowing one to pieces would likely depend on rupturing something that had explosive desires all its own- or hitting it with something, like, say, an uprated SM-3 missile. The US claims that our most recent satellite shootdown was about eliminating the risks from residual hydrazine or reducing fall damage were sillye at best- it was a weapons demonstration, pure and simple. Damn good one, I should add.

  9. Space Debris is our friend. Soon as some nasty alien type decides to try and invade us, BAM! Half a satellite in the ear! Now if we combine that with ground based death rays, so much the better!

  10.  won’t the laser heat up one side of the space junk and cause it to evaporate,  evaporating stuff on the earth-facing side will jet out a little and add an outward push to the satellite.  So instead of one big piece of space junk you’ve been tracking in the same orbit for years you’ve got a bunch of smaller space junk that’s harder to track and has been pushed into different orbits. How the hell is this useful?

    But ground laser that can destroy stuff in orbit? Massively cool. It’s just like Master of Orion.

    1. You have the mechanism right, but not the effect. The ablation effect on the Earth-facing side of the particle produces an impulse on the order of sub-millimeters per second- not nearly enough to blast it into pieces. What said outward thrust does is change the eccentricity of the orbit,  and thus lowers the perigee or lowest point- and if said perigee drops below 200km, then even the lowest drag object will reenter in a couple days.  It’s not so much about shooting things down with lasers as it is about herding them- every time one of the thousands of bits of trackable space junk peeks over the horizon, you squirt a little laser at it, and then at the next, and you forget about it until it comes over the horizon again, and the all the while the average time to reentry goes down, and thus the statistical likelihood it will either get blasted into chunks too small to track anymore, or that it will run into something you care about. If you can ensure that some upper stage fragments reenters in six months instead of fifteen years, you’ve made progress.

  11. “How do you build a laser big enough to knock space junk out of orbit without convincing half the world that what you’ve really built is a giant death ray?”

    Well, first off, be sure not to build it inside a dormant volcano. That’s one. And don’t surround it with an army of Ninja Women in Hot Pants with double entendre names. And don’t shave your head, and no twirly eagg-shaped chairs. And no cats! Absolutely positively no goddamn cats!

  12. “Politics. How do you build a laser big enough to knock space junk out of orbit without convincing half the world that what you’ve really built is a giant death ray? That’s something the authors hope to avoid through international cooperation.”

    Something like CERN, but laser based would offer lots of opportunity for research, but would have practical uses.   Next, figure out how to get people to pay for it in a global recession.

Comments are closed.