5 ms·

Australians lead efforts to move space junk with lasers

33 points by srikar 12y ago

juedcuIcZi 12y ago
why don't somebody build a net and a parachute to pull it down with high velocity ?
- DanBC 12y ago
  Space debris is in orbit, which means it's travelling fast. Space debris travels at 7 km/s. That would destroy any net you put up. Space debris that isn't travelling that fast just falls out of orbit. http://orbitaldebris.jsc.nasa.gov/faqs.html#7 http://orbitaldebris.jsc.nasa.gov/faqs.html#7
- richmarr 12y ago
  Assuming I haven't misunderstood... the cost of launching 200,000+ nets into orbit would be high (in my opinion, maybe someone has a sneaky solution). Assuming you could get each net (including guidance and propellant) down to about 1kg (not sure how realistic that is), and you can launch them into orbit for $4000/kg, then that'd be an expenditure of $800+ million not including R&D, manufacture, salaries, etc. It'd also mean increasing the number of objects in orbit for while.
  - deleted 12y ago
    [deleted]
- maxerickson 12y ago
  One of the pie in sky ideas that gets floated is a large aerogel object that can slow down/trap the particles without creating a bunch of new ones. It would be put in an orbit that crosses orbits with a lot of debris.
  - deleted 12y ago
    [deleted]
- nine_k 12y ago
  What could work might be a purpose-built spacecraft with a low-power but efficient engine (e.g. ion drive). This spacecraft would align velocities, then touch and bind every piece of space debris along its orbit. Eventually it would snowball enough to just let smaller pieces of debris hit it and stick. After it has become too heavy to maneuver, or when the propellant is depleted, the spacecraft would go down and burn in the atmosphere. The problem is the way to properly bind the pieces of debris.
  - chiph 12y ago
    Sort of an orbital Katamari Damacy.
  - JoeAltmaier 12y ago
    Sounds a bit like rain formation: nucleation and aggregation. But space is big, and the spacecraft is not attracting anything (too small for gravity to matter). Not sure even a big snowball is going to collect much debris. A solar sail perhaps? Cross-section has to be key.
YungLean 12y ago
And nothing was heard from this ever again.
- aaron695 12y ago
  For those who don't get it see - http://content.time.com/time/specials/packages/article/0,28804,1934259_1934610_1934634,00.html http://content.time.com/time/specials/packages/article/0,288...
  - jessaustin 12y ago
    Maybe they could try badass projects of a slightly smaller scale? Keep going with the badass projects though!
  - discardorama 12y ago
    Their website would seem to indicate that they're still in business: http://www.enviromission.com.au/EVM/content/home.html http://www.enviromission.com.au/EVM/content/home.html But I couldn't find any information about the solar tower they were building.
tribaal 12y ago
Could somebody explain to me (non-physicist) what the principles at play are? Is it "simply" that they fire a strong laser at the front of the object to slow it down, so that orbital mechanics do the rest and make it burn up? Do lasers really allow you to "push" things?
- thegp 12y ago
  not a physicist, but an electrical engineer. At least 2 principles that I know allow a laser to push things: 1) photons do have impulse, given by its energy divides by the speed of light. This causes Radiation pressure (see https://en.wikipedia.org/wiki/Radiation_pressure https://en.wikipedia.org/wiki/Radiation_pressure ) 2) if a laser vaporises part of a structure, the resultant gas will push against the structure, delivering momentum
  - FreeFull 12y ago
    Both principles have an impact, and in this case, I think the second one is the one that causes most of the impulse.
simonmales 12y ago
Australian sharks with frickin laser beams
authatheist 12y ago
Feel like playing with laz0rz and shit? How about using your own money to arrange for that? Don't wanna? Well, good thing you can just use shitloads of money that's been forcefully taken from people!
- noonespecial 12y ago
  I'd totally and completely voluntarily pay extra taxes if I knew it was going to be spent blasting junk out of orbit with giant lasers. Hell, I'd buy tickets just to watch.
  - authatheist 12y ago
    I'm sure the people playing with lasers appreciate the sentiment, but what about the vast majority of people that, given the choice, would not finance the endeavour? If one of your friends doesn't want to pitch in to support the laser games, would you want him thrown in jail for refusing to go along with the plan, or do you accept that he's got the right to use his hard-earned dollars as he sees fit? Now apply that same reasoning to all government spending.
imurray 12y ago
Wikipedia tells me that lasers have been considered before to fight off the https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
panzagl 12y ago
Nice press release- this is all old news. If you know where something is well enough to hit it with a laser, you're probably better off leaving it where it is and tracking it.

33 points by srikar 12y ago

juedcuIcZi 12y ago

why don't somebody build a net and a parachute to pull it down with high velocity ?

DanBC 12y ago
Space debris is in orbit, which means it's travelling fast. Space debris travels at 7 km/s. That would destroy any net you put up. Space debris that isn't travelling that fast just falls out of orbit. http://orbitaldebris.jsc.nasa.gov/faqs.html#7 http://orbitaldebris.jsc.nasa.gov/faqs.html#7
richmarr 12y ago
Assuming I haven't misunderstood... the cost of launching 200,000+ nets into orbit would be high (in my opinion, maybe someone has a sneaky solution). Assuming you could get each net (including guidance and propellant) down to about 1kg (not sure how realistic that is), and you can launch them into orbit for $4000/kg, then that'd be an expenditure of $800+ million not including R&D, manufacture, salaries, etc. It'd also mean increasing the number of objects in orbit for while.
- deleted 12y ago
  [deleted]
maxerickson 12y ago
One of the pie in sky ideas that gets floated is a large aerogel object that can slow down/trap the particles without creating a bunch of new ones. It would be put in an orbit that crosses orbits with a lot of debris.
- deleted 12y ago
  [deleted]
nine_k 12y ago
What could work might be a purpose-built spacecraft with a low-power but efficient engine (e.g. ion drive). This spacecraft would align velocities, then touch and bind every piece of space debris along its orbit. Eventually it would snowball enough to just let smaller pieces of debris hit it and stick. After it has become too heavy to maneuver, or when the propellant is depleted, the spacecraft would go down and burn in the atmosphere. The problem is the way to properly bind the pieces of debris.
- chiph 12y ago
  Sort of an orbital Katamari Damacy.
- JoeAltmaier 12y ago
  Sounds a bit like rain formation: nucleation and aggregation. But space is big, and the spacecraft is not attracting anything (too small for gravity to matter). Not sure even a big snowball is going to collect much debris. A solar sail perhaps? Cross-section has to be key.

YungLean 12y ago

And nothing was heard from this ever again.

aaron695 12y ago
For those who don't get it see - http://content.time.com/time/specials/packages/article/0,28804,1934259_1934610_1934634,00.html http://content.time.com/time/specials/packages/article/0,288...
- jessaustin 12y ago
  Maybe they could try badass projects of a slightly smaller scale? Keep going with the badass projects though!
- discardorama 12y ago
  Their website would seem to indicate that they're still in business: http://www.enviromission.com.au/EVM/content/home.html http://www.enviromission.com.au/EVM/content/home.html But I couldn't find any information about the solar tower they were building.

tribaal 12y ago

Could somebody explain to me (non-physicist) what the principles at play are? Is it "simply" that they fire a strong laser at the front of the object to slow it down, so that orbital mechanics do the rest and make it burn up? Do lasers really allow you to "push" things?

thegp 12y ago
not a physicist, but an electrical engineer. At least 2 principles that I know allow a laser to push things: 1) photons do have impulse, given by its energy divides by the speed of light. This causes Radiation pressure (see https://en.wikipedia.org/wiki/Radiation_pressure https://en.wikipedia.org/wiki/Radiation_pressure ) 2) if a laser vaporises part of a structure, the resultant gas will push against the structure, delivering momentum
- FreeFull 12y ago
  Both principles have an impact, and in this case, I think the second one is the one that causes most of the impulse.

simonmales 12y ago

Australian sharks with frickin laser beams

authatheist 12y ago

Feel like playing with laz0rz and shit? How about using your own money to arrange for that? Don't wanna? Well, good thing you can just use shitloads of money that's been forcefully taken from people!

noonespecial 12y ago
I'd totally and completely voluntarily pay extra taxes if I knew it was going to be spent blasting junk out of orbit with giant lasers. Hell, I'd buy tickets just to watch.
- authatheist 12y ago
  I'm sure the people playing with lasers appreciate the sentiment, but what about the vast majority of people that, given the choice, would not finance the endeavour? If one of your friends doesn't want to pitch in to support the laser games, would you want him thrown in jail for refusing to go along with the plan, or do you accept that he's got the right to use his hard-earned dollars as he sees fit? Now apply that same reasoning to all government spending.

imurray 12y ago

Wikipedia tells me that lasers have been considered before to fight off the https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome

panzagl 12y ago

Nice press release- this is all old news. If you know where something is well enough to hit it with a laser, you're probably better off leaving it where it is and tracking it.