4 ms·

I think the much more likely method would be a laser that heats one side of an object, causing a net propulsive effect leading to eventual deorbit. https://en.

I think the much more likely method would be a laser that heats one side of an object, causing a net propulsive effect leading to eventual deorbit. https://en.wikipedia.org/wiki/Laser_broom https://en.wikipedia.org/wiki/Laser_broom

jcims 6y ago
Directed energy approaches are the only thing that will scale IMHO. The heating approach is one way, but I believe something that could use the kinetic energy of ablative laser pulses would work for smaller objects. To get the correct retrograde velocity, however, I believe you would need an orbital platform and some ridiculous laser technology (which, when combined, tend to create political drag) I also wonder about sending focused packets of ionized gas to collide with an object and reduce its kinetic energy. If you were operating in an opposite orbit you'd have a ~35km/sec closing velocity. Then spit out small targeted puffs of krypton/xenon at 50km/s, it wouldn't take a lot to knock real energy off of the target. (Stubby pencil work says 80 femtojoules per molecule or roughly 30 micrograms of gas to reduce the velocity of a 20g bolt by 1000m/s. I think.)
- phreeza 6y ago
  I assume you are proposing to launch these packets from some other sattelite? Then by conservation of momentum, you will be boosting your own orbit by the same amount you are diminishing the target, right? Not sure this would be a very sustainable model.
  - jcims 6y ago
    Yes it would require equal/opposite correction and lots of mass on board to send.
- sand500 6y ago
  How would you prevent the puff of gas from diffusing into nothing? Where did you get ~35km/sec? ISS orbital speed is 7.66 km/s and it only gets slower the higher you go up. I was thinking something similar but instead launching equivalent mass of water in the exact same orbit in the opposite direction. Right before the collision, release the water. The water would spread enough that the entire spacecraft would basically slam into a wall. The net momentum post collision should be 0. Most spacecraft debris would fall straight down to earth.
  - jcims 6y ago
    Quick caveat, I'm extremely shallow in my knowledge of any of this: >How would you prevent the puff of gas from diffusing into nothing? My thinking about this is that at low concentrations the gas would maintain a largely ballistic trajectory and not be subject to typical diffusion properties. Would require a purpose-built accelerator to condition for 'beam' coherency. Not sure how well that scales. > Where did you get ~35km/sec? ISS orbital speed is 7.66 km/s and it only gets slower the higher you go up. Major brain-o. Ultimately I think we're on the same page of 'kinetic deorbit', just a function of what is actually feasible.
- adverbly 6y ago
  The gas idea is interesting, and gave me another idea. Assuming that you could track an object, I wonder how much much you could slow down/redirect debris using air resistance. The idea would be to fill a balloon with air, and then release the air at exactly the right moment just as the debris is passing. The air shoots out into the vacuum right into the path of the oncoming debris. If you got the timing and positioning just right, you could probably both slow down and redirect the debris earthward. These things could use their pressurized air for maneuvering themselves, and given that they just use air itself, you could probably devise an efficient means of refueling them via some kind of weather balloon thing where you'd refill at high atmosphere without having to go all the way back to earth. I have no idea what I'm talking about really, but its a sort of interesting concept...
  - jcims 6y ago
    >I have no idea what I'm talking about really, but its a sort of interesting concept... Me neither, fortunately we don't have the burden of actually having to solve this problem xD. The big bubble o' gas idea is honestly where I started and I think there's real merit to the idea...it's relatively harmless to operational satellites yet operates rather indiscriminately on debris and isn't as finicky as the directed energy options. Basically a fly trap for space.

jcims 6y ago

Directed energy approaches are the only thing that will scale IMHO. The heating approach is one way, but I believe something that could use the kinetic energy of ablative laser pulses would work for smaller objects. To get the correct retrograde velocity, however, I believe you would need an orbital platform and some ridiculous laser technology (which, when combined, tend to create political drag) I also wonder about sending focused packets of ionized gas to collide with an object and reduce its kinetic energy. If you were operating in an opposite orbit you'd have a ~35km/sec closing velocity. Then spit out small targeted puffs of krypton/xenon at 50km/s, it wouldn't take a lot to knock real energy off of the target. (Stubby pencil work says 80 femtojoules per molecule or roughly 30 micrograms of gas to reduce the velocity of a 20g bolt by 1000m/s. I think.)

phreeza 6y ago
I assume you are proposing to launch these packets from some other sattelite? Then by conservation of momentum, you will be boosting your own orbit by the same amount you are diminishing the target, right? Not sure this would be a very sustainable model.
- jcims 6y ago
  Yes it would require equal/opposite correction and lots of mass on board to send.
sand500 6y ago
How would you prevent the puff of gas from diffusing into nothing? Where did you get ~35km/sec? ISS orbital speed is 7.66 km/s and it only gets slower the higher you go up. I was thinking something similar but instead launching equivalent mass of water in the exact same orbit in the opposite direction. Right before the collision, release the water. The water would spread enough that the entire spacecraft would basically slam into a wall. The net momentum post collision should be 0. Most spacecraft debris would fall straight down to earth.
- jcims 6y ago
  Quick caveat, I'm extremely shallow in my knowledge of any of this: >How would you prevent the puff of gas from diffusing into nothing? My thinking about this is that at low concentrations the gas would maintain a largely ballistic trajectory and not be subject to typical diffusion properties. Would require a purpose-built accelerator to condition for 'beam' coherency. Not sure how well that scales. > Where did you get ~35km/sec? ISS orbital speed is 7.66 km/s and it only gets slower the higher you go up. Major brain-o. Ultimately I think we're on the same page of 'kinetic deorbit', just a function of what is actually feasible.
adverbly 6y ago
The gas idea is interesting, and gave me another idea. Assuming that you could track an object, I wonder how much much you could slow down/redirect debris using air resistance. The idea would be to fill a balloon with air, and then release the air at exactly the right moment just as the debris is passing. The air shoots out into the vacuum right into the path of the oncoming debris. If you got the timing and positioning just right, you could probably both slow down and redirect the debris earthward. These things could use their pressurized air for maneuvering themselves, and given that they just use air itself, you could probably devise an efficient means of refueling them via some kind of weather balloon thing where you'd refill at high atmosphere without having to go all the way back to earth. I have no idea what I'm talking about really, but its a sort of interesting concept...
- jcims 6y ago
  >I have no idea what I'm talking about really, but its a sort of interesting concept... Me neither, fortunately we don't have the burden of actually having to solve this problem xD. The big bubble o' gas idea is honestly where I started and I think there's real merit to the idea...it's relatively harmless to operational satellites yet operates rather indiscriminately on debris and isn't as finicky as the directed energy options. Basically a fly trap for space.