I Catching Space Debris: Chameleon-Inspired Capture System

[CdE62021]

TL;DR Summary

Inspired by nature

Can chameleon inspired capture system function to deorbit or even recover orbital debris? What are the physics challenge?

 

[phinds]

Can chameleon inspired capture system function to deorbit or even recover orbital debris? What are the physics challenge?

What is a "chameleon inspired capture system"

 

[CdE62021]

Hey thanks for the fast response phinds, check the following around 6minute mark:

 

[Baluncore]

For the chameleon, the prey is a static target. Space junk has high velocity and is on a well defined orbit. If the junk hits you it will destroy you, which will simply increase the amount of junk.

If you are in the exact same orbit you will never catch the target. You must pass the junk in orbit on a similar path to reduce the differential velocity. You can add the kinetic energy of the junk you catch to that of your craft in order to change your orbital trajectory to reach the next junk item.

Once you have a collection of junk, you must bind it all together into a bundle that can be tracked.
It takes energy to knock the bundle out of orbit to reenter Earth's atmosphere. Maybe the scrap is better used to feed a solar furnace,to build useful things at a space station.

 

[CdE62021]

Is there modeling software to test this? Totally agree on the whole reduce, recycle reuse and why I propose a chameleon inpired design to capture.

Is the chameleon and static prey target scenerio relative in space?, for example, if both are placed in space both are traveling at same speed, the tongue will have to shoot fast though.

 

[Drakkith]

Can chameleon inspired capture system function to deorbit or even recover orbital debris?

Unlikely. Objects in orbits which do not coincide with each other are typically moving at very high speeds relative to each other, and any capture system that just 'catches' the debris is very likely to sustain damage and possibly be blown apart from the impact.

I suppose you could bring the device into a similar orbit as the debris, but that's costly in terms of fuel.

 

[alan123hk]

I believe that It is possible that the artificial chameleon capture system is more agile and accurate than that of the real chameleon, because the rapidly retractable tip of tongue of the chameleon should have no eyes, but for the the artificial chameleon capture system, humans can install a micro camera on the tip of tongue, and after installing the micro camera, the retractable tongue can even be able to bypass obstacles.

 

[Filip Larsen]

Try search for "space junk harpoon".

 

[256bits]

I believe that It is possible that the artificial chameleon capture system is more agile and accurate than that of the real chameleon, because the rapidly retractable tip of tongue of the chameleon should have no eyes, but for the the artificial chameleon capture system, humans can install a micro camera on the tip of tongue, and after installing the micro camera, the retractable tongue can even be able to bypass obstacles.

Hand-eye/tongue co-ordination is quite accurate in the animal kingdom.

 

[phinds]

Hey thanks for the fast response phinds, check the following around 6minute mark:

Ah. Well, that doesn't tell me anything about chameleons that I didn't already know, it just leaves me wondering why in the world you think that would be a good idea for space debris.

I see that the reasons for my wonderment have already been given by others.

 

[sophiecentaur]

I wouldn't normally go for a 'zappem' solution, which is what is often suggested misguidedly for rogue asteroids but the majority of space debris is not that huge and the smaller stuff could be dealt with ballistically with small projectiles. That could reduce the orbital energy of the junk items and cause them to fall to where the atmosphere would produce braking. Using a high power laser (low momentum) would only be of use if it reduced an object to dust / vapour or it would just result in more, smaller bits. Very good where suitable.
But finding the debris is not an easy task; there is still a large distance between them or no satellites could survive for long. Nasa tells us that each significant items occupies a 'box', of representative size 4 x 50 x 50 km. For the 'fishing boat' to intercept them could involve a lot of fuel so the debris would need to be dealt with remotely and by following a planned course, intercepting and dealing with a sequence of several to make it efficient.

 

[Baluncore]

For the 'fishing boat' to intercept them could involve a lot of fuel so the debris would need to be dealt with remotely and by following a planned course, intercepting and dealing with a sequence of several to make it efficient.

Correct.
The hunter must not only reach the next target, but must get there at the correct time. That must be done using a transition orbit to convert the previous target's orbit into the next target's orbit. Two fuel burns for each transition. This is actually a more dynamic form of the traveling salesman problem. The aim must be to save fuel, and still get the job done in a reasonable time.

The collection task becomes one of filling garbage bags with many small items, bags that can then be tracked and processed, or de-orbitted. I expect that a master control vehicle, with the garbage bag, would have a number of drones to go collect nearby fragments. The advantage of the tethered tongue is that solar energy could be used instead of chemical energy to gather the junk. But how much would the tongue weigh? Could this be more like "fly fishing" with a basket trap on a few kilometres of Kevlar line. The speed of sound in the line will be critical to equipment survival at capture.

 

[Filip Larsen]

Could this be more like "fly fishing" with a basket trap on a few kilometres of Kevlar line.

Tethered satellites have special dynamics and interactions that allow some fancy stuff (like doing in-orbit low-impulse maneuvering, sky-hook dynamics) at the price of being rather tricky to keep under (mechanical/electrical) control and of having fairly narrow attitude control flexibility (that is, a typical satellite is likely to have primary mission pointing requirements that lie outside the limits a tether would impose when deployed).

If you by "fly fishing" imagine a hunter satellite with a tethered capture basket is reeled in and out and the hunter-basket system is "spun up" to match the targets speed, that sounds plausible but also sounds like something that would require a great deal of precision in both hunter-target measurements and hunter-basket control to have a realistic chance of actual capture. The "capture cross section" of a skyhook-like system seems very narrow compared to the traditional rendezvous-like capture where the target just "sails into" a non-rotating basket over some time. Highly dynamic captures also increase the risk of uncontrolled impact and break-up of the hunter, effectively just adding to the space junk problem.

My personal candidate for space junk removal at low Earth orbit is a larger satellite with orbit maneuvering capability and a storage of many small deployable canisters, with each canister able to spin up and unfold into a self-stabilising thin disc (like 10 meter diameter, perhaps with canisters of different sizes) after deployment. If such a disc is then placed into an orbit slightly ahead of a one or more co-orbiting pieces of junk differential drag should eventually make the disc capture the junk and slowly deorbit. Should the disc miss it will simply deorbit anyway and not add to the problem. Should the disc be hit by a high-speed (unplanned) piece of junk then it seem feasible to construct the disc material and structure such that the junk punches clean through a small hole leaving the rest of the disc intact.