The large objects in space that are being proposed for collection by Dr Gugliemo are actually the smallest risk in regards to a collision. They are easy to track and are thus well cataloged in various databases of space debris and can then be avoided by operational satellites when a conjunction is predicted. The dangerous items are the very small ones, those of 10 cm or less, which are difficult to track and catalog and thus pose a higher risk of collision because no one knows where they are at any point in time. When collisions occur with small particles, the high relative velocities mean they can still cause serious damage to a satellite, a space station or an astronaut. (KE = 1/2 mv^2)
So if as proposed a harpoon is used on a large, inert object in space, it stands at worst to shatter the entire object, leading to a debris field of small, untraceable bits that are now in different orbits from the original mass. Or at best the lance penetrates the mass with hopefully only a few flecks and particles being released on impact. But are these small potential debris pieces being flung about not a problem also? The same applies to a net, which could break off small portions of an irregular structure during capture, leading again to a debris field of small particle. For example, the net could snap an antenna or a solar panel off a cubesat that is being secured.
In both these cases, these solutions can cause problems that are much worse than the cure. In that sense, I would think that the UK Space Agency, as the regulator in this matter, would be most unlikely to authorize a mission that can cause small, dangerous debris in an attempt to remove large, harmless items. International best practices are for countries to avoid the release of space debris and this is specifically the risk that the Surrey mission could cause. It's noteworthy that from a legal sense, the UK would be responsible for any damage that could be caused by the small debris emitted by this recovery mission. If those small bits eventually destroy a large satellite, the bill will be presented to the UK for this multi-million pound satellite. (May wish to look at the web site of the UN Office of Outer Space Affairs, particularly in regard to the conventions on registration of space objects and on liability.)
On a separate point, there is the technical challenge that the Surrey platform has to lock orbit with the debris it wants to capture. While the debris that is easiest to reach is in low orbit , what is the point of capture as it will eventually reenter the atmosphere as the orbit decays? Going after pieces in higher orbit would be more useful but will take more delta V to reach and then takes even more delta V to reduce the debris' altitude for it to eventually de-orbit. That means more fuel and thus more cost.
Even if that were to be funded, the Surrey platform will then need to make significant orbital maneuvers that will require yet more fuel so as to go after another debris object in yet another orbit. And let's not forget that the Surrey module also needs to be de-orbited as well once its mission is complete, so that it doesn't add to the already large collection of space junk. Again, the higher it 's altitude, the more fuel it will need to de-orbit, again at more cost.
So how is this viable? Did I misunderstand?
BTW Naked Scientist, have you considered a follow-on piece after looking into the UN work in this areas being done by the Committe on the Peaceful Use of Outer Space (COPUOS)? That could be interesting.
Nets and Harpoons
The large objects in space that are being proposed for collection by Dr Gugliemo are actually the smallest risk in regards to a collision. They are easy to track and are thus well cataloged in various databases of space debris and can then be avoided by operational satellites when a conjunction is predicted. The dangerous items are the very small ones, those of 10 cm or less, which are difficult to track and catalog and thus pose a higher risk of collision because no one knows where they are at any point in time. When collisions occur with small particles, the high relative velocities mean they can still cause serious damage to a satellite, a space station or an astronaut. (KE = 1/2 mv^2)
So if as proposed a harpoon is used on a large, inert object in space, it stands at worst to shatter the entire object, leading to a debris field of small, untraceable bits that are now in different orbits from the original mass. Or at best the lance penetrates the mass with hopefully only a few flecks and particles being released on impact. But are these small potential debris pieces being flung about not a problem also? The same applies to a net, which could break off small portions of an irregular structure during capture, leading again to a debris field of small particle. For example, the net could snap an antenna or a solar panel off a cubesat that is being secured.
In both these cases, these solutions can cause problems that are much worse than the cure. In that sense, I would think that the UK Space Agency, as the regulator in this matter, would be most unlikely to authorize a mission that can cause small, dangerous debris in an attempt to remove large, harmless items. International best practices are for countries to avoid the release of space debris and this is specifically the risk that the Surrey mission could cause. It's noteworthy that from a legal sense, the UK would be responsible for any damage that could be caused by the small debris emitted by this recovery mission. If those small bits eventually destroy a large satellite, the bill will be presented to the UK for this multi-million pound satellite. (May wish to look at the web site of the UN Office of Outer Space Affairs, particularly in regard to the conventions on registration of space objects and on liability.)
On a separate point, there is the technical challenge that the Surrey platform has to lock orbit with the debris it wants to capture. While the debris that is easiest to reach is in low orbit , what is the point of capture as it will eventually reenter the atmosphere as the orbit decays? Going after pieces in higher orbit would be more useful but will take more delta V to reach and then takes even more delta V to reduce the debris' altitude for it to eventually de-orbit. That means more fuel and thus more cost.
Even if that were to be funded, the Surrey platform will then need to make significant orbital maneuvers that will require yet more fuel so as to go after another debris object in yet another orbit. And let's not forget that the Surrey module also needs to be de-orbited as well once its mission is complete, so that it doesn't add to the already large collection of space junk. Again, the higher it 's altitude, the more fuel it will need to de-orbit, again at more cost.
So how is this viable? Did I misunderstand?
BTW Naked Scientist, have you considered a follow-on piece after looking into the UN work in this areas being done by the Committe on the Peaceful Use of Outer Space (COPUOS)? That could be interesting.