Active measures are more difficult. IIRC ESA have a low level study using a tank of gas on a satellite that "puffs" a cloud in front of debris, essentially a brick wall at these altitudes and densities, creating a sort of mini reentry.
Can you remember where you saw this? I've seen similar suggestions from ESA (although the one I found was using the gas to propel a net), and Boeing. If you've got any references that would be awesome.
I've been workshopping a somewhat similar concept with some engineers that I know, but the economics of my idea will sink or swim based on the precision of the known path of the targeted bit of debris (i.e. if you imagine a cylindrical shaped volume in space through which the targeted piece debris is likely to pass, what's the radius of that cylinder?).The graph I'm really hoping to see is (for a given orbital altitude):X-axis: size of the debrisY-axis: standard error of path of debris (in m).
Active measures are more difficult. IIRC ESA have a low level study using a tank of gas on a satellite that "puffs" a cloud in front of debris, essentially a brick wall at these altitudes and densities, creating a sort of mini reentry. I think any effective solution to the massive numbers of small fragments must act over a volume of space.
Do you have a reference on active measures being harder? I don't exactly dispute it but Im not sure in what sense you mean it. In some senses it is trivially true.
Im attracted to the idea of point defence because the difficulty is largely in vision and control, things that could advance very quickly through things such as computing power and programming. Otherwise you are dealing with difficulties based on physical properties such as the sheer volume of cislunar space, perhaps better performing materials, more efficient propulsion and so on.
Also there is the motivation that it defends your most critical targets immediately. Otherwise you are just talking about statistically managing the problem, eg a really exceptional solution might reduce the risk by a factor of 10 in a decade. This could also justify the system being funded for reasons of pure self interest rather than the long term greater good.. not typically something corporations and nations put a high dollar value on.
This is a general thread now?
A non-technological (partial) solution to the problem: slap a tonnage-based tax on new satellites which are not equipped with an effective deorbiting system. This would provide a strong economic incentive for satellite makers and/or operators to ensure their satellites can be safely deorbited at the end of their lifetimes.
Large debris seems to be the easier of the two problems to deal with. So let's dwell on the small debris issue for a moment.Supposing BFR/ITS becomes operational and we are able to place a 747-sized laser system in orbit.How effectively could such a system vaporize 5cm and smaller sized debris? Would 5 minutes of laser burn time be sufficient to eliminate one small piece of debris? If so, the system could vaporize 105,000 pieces of small debris per annum. If its lifetime is 10 years that's about 1 million pieces of debris removed for each laser deployed in space.Is this a potentially feasible solution?
I think if there was an economic incentive for space debris removal, one of the proposed technical solutions like the one mentioned above, or something nobody has yet thought of, could definitely be made to work.The question is how you get this economic incentive.
Who'd collect this tonnage tax? How hard would it be to launch from another jurisdiction?