Guess what ESA is planning to do with space junk.

[PB666]

http://www.bbc.com/news/science-environment-43418047

This is too incredible to be true. How much more risky could this be.

Why couldn't you have little space-bots deploy that tie rope around the rogue satellite, much safer, much less risk of a object disintegrating event.

 

[DerekL1963]

Setting aside the fact that the harpoon is simpler than the non-existent space bots, such bots don't exist.  The harpoon is also at least a couple of decimal places cheaper than the complex and non existent bots.  (Yes, complex - maneuvering in 3d remotely, dragging a rope around, etc... etc... not gonna be cheap or simple.  Don't even try to claim otherwise.)

[kerbiloid]

(So, they downloaded KAS mod.)

The scavenger grapples the junk with the hook, they get connected with a tether.

A minute later...

Spoiler

 

 

[p1t1o]

Any solution that deals with objects on a one-for-one basis is doomed to be ridiculously expensive.

Though I do like the Moby-Dick level of engineering here. There arnt that many discussions where "Shoot a spear at it" is a legitimate response.

 

Has anyone considered adhesive-based capture systems? Using something like this kind of riot-suppression foam?

You wouldnt "hose down" the target, you'd just kind of expand a bubble of sticky foam and bump into the target. And if it set hard, it could still retain objects that didnt adhere too well. Plus no risk of shrapnel, and less risk of just shooting the target off onto a random trajectory.

[PB666]

33 minutes ago, DerekL1963 said:

Setting aside the fact that the harpoon is simpler than the non-existent space bots, such bots don't exist.  The harpoon is also at least a couple of decimal places cheaper than the complex and non existent bots.  (Yes, complex - maneuvering in 3d remotely, dragging a rope around, etc... etc... not gonna be cheap or simple.  Don't even try to claim otherwise.)

Uh huh, and of course if it hits the wrong part of the craft, you then have 10 or 100 pieces of space junk instead of 1 piece to deal with. There are other ways do deal with the problem.

Space bots are mearly a matter of propulsion system (ION drive on electrical teather) and a guidance system. Its not a fusion reactor in space. If space X can land from a trajectory going the opposite direction, bots in space can tether.

In fact some sort of vacuum pliable adhesive would also do the trick.

2 minutes ago, p1t1o said:

Any solution that deals with objects on a one-for-one basis is doomed to be ridiculously expensive.

Though I do like the Moby-Dick level of engineering here. There arnt that many discussions where "Shoot a spear at it" is a legitimate response.

 

Has anyone considered adhesive-based capture systems? Using something like this kind of riot-suppression foam?

You wouldnt "hose down" the target, you'd just kind of expand a bubble of sticky foam and bump into the target. And if it set hard, it could still retain objects that didnt adhere too well. Plus no risk of shrapnel, and less risk of just shooting the target off onto a random trajectory.

With ION drive based systems you would mearly need a 5 directional (one drive and four steering, about 6 kg, about the same mass in fuel) and ideally tap into the satellites power system. This could place the craft where part of the orbit is below 130 km, it will decay on its own quite rapidly. You could have 10 or so of these things in a single cube sat that searches out all rouge satellites that have similar orbits. Not that expensive. All you would need is an ION drive based 'tip' on the device, a glue that is eject in the moment before collision at some ridiculously low velocity and release the tip to wander off with the satellite.

Whatever is going to be done needs to be done soon, the number of satellites is rising exponentially and trend is economics based, going to get more productive once SpaceX is launching their own PLs for commercial apps. Lots and lots of satellites running around in LEO.

 

[p1t1o]

Lets be honest. None of these things are going to work because there are too many objects, and thats not even counting things like debris or shrapnel.

The only way to solve it properly is if we all agree to not use space at all for a few years, then we nuke the feaces out of the whole zone. Just literally go to town. Keep going until the statistical probability that there is anything significant left in orbit asymptotes to zero.

Then we can go back to space....but carefully this time.

*****

But seriously, here's an idea.

We start launching large tanks of something like nitrogen in retrograde orbits and we just release it as gas.

Done often enough it will raise drag in large regions for object in prograde orbits, slowly deorbiting them over time.

This would also deorbit fragments and shrapnel, paint chips and the like.

Still-active satellites could be re-boosted, I'd wager there are a lot fewer active satellites than there are junk objects, especially if you count debris/shrapnel etc.

Im just spitballin' I havnt thought this all the way through, obviously.

[PB666]

8 minutes ago, p1t1o said:

Lets be honest. None of these things are going to work because there are too many objects, and thats not even counting things like debris or shrapnel.

The only way to solve it properly is if we all agree to not use space at all for a few years, then we nuke the feaces out of the whole zone. Just literally go to town. Keep going until the statistical probability that there is anything significant left in orbit asymptotes to zero.

Then we can go back to space....but carefully this time.

*****

But seriously, here's an idea.

We start launching large tanks of something like nitrogen in retrograde orbits and we just release it as gas.

Done often enough it will raise drag in large regions for object in prograde orbits, slowly deorbiting them over time.

This would also deorbit fragments and shrapnel, paint chips and the like.

Still-active satellites could be re-boosted, I'd wager there are a lot fewer active satellites than there are junk objects, especially if you count debris/shrapnel etc.

Im just spitballin' I havnt thought this all the way through, obviously.

I have a solution for small pieces. its a bit like a crab trap. with a flexible opening. Again all these systems are ION electric based. By some other means you locate the small debris. Approach the debris such that the debris falls into the open with just enough force to push through, it is then trapped in a carbon fiber mesh, then move to the next piece once the bag is full the ion drive places the entire thing in an unstable orbit, releases at opogee and climbs out of the unstable orbit pops open another trap and then captures the bag from its back side (the bag would have three hooks which could be grappled. Repeat process. Once the bag has a ton of mass its released.

So in response to DerekL, there are many non-invasive systems that could be deployed. the Harpoon based system is, in comparison, a very bad idea.

[sevenperforce]

If you have reaction wheels and a reusable tether, you can use rotational deorbiting to boost your antidebris sat.

[kerbiloid]

A duct tape.
 

Spoiler

Warning!
Violent or disgusting content.
This image can psychically hurt you.

Spoiler

 

 

[PB666]

1 hour ago, sevenperforce said:

If you have reaction wheels and a reusable tether, you can use rotational deorbiting to boost your antidebris sat.

That's true another solution. If you harpoon it the harpooner goes down with the harpooned.

[KSK]

I love this idea.

"Out-gassing satellite at 3km and closing, Flight."

"Arrrr - there she blows! Avast there ye scurvy hunk 'o space junk!"

White vests and tricorn hats become the new mandatory dress code for all flight controllers overseeing Operation Poke-it-with-a-Pointy-Thing.

[DerekL1963]

2 hours ago, PB666 said:

Uh huh, and of course if it hits the wrong part of the craft, you then have 10 or 100 pieces of space junk instead of 1 piece to deal with.

Uh huh, and if the space bots fail then we have additional pieces of junk to deal with too.  And if the space bots wrap their tethers around the wrong part of the craft, they too can generate additional debris.
 

2 hours ago, PB666 said:

Space bots are mearly a matter of propulsion system (ION drive on electrical teather) and a guidance system.

Well, setting aside the fact that ion drives (despite your obsession with them) lack the thrust to perform the mission (not able to perform fine rendezvous maneuvers on their own) and that tethers are unproved technology...  You've left out the communications systems they'll need.  And the power management system.  And the RCS needed for fine maneuvers near the target.  And the sensors needed.  And the computer systems needed to control the whole thing.  And....  I'll just stop right there and say that you've not only grossly misrepresented the systems required, you've equally ignored all the devils in all the details.

2 hours ago, PB666 said:

If space X can land from a trajectory going the opposite direction, bots in space can tether.

Well, no.  Not only are these completely different problems - SpaceX required a modest amount of additional systems (all based on existing proven technology) added to a proven system.  You require a completely new vehicle with a number of speculative technologies.

2 hours ago, p1t1o said:

We start launching large tanks of something like nitrogen in retrograde orbits and we just release it as gas.

Done often enough it will raise drag in large regions for object in prograde orbits, slowly deorbiting them over time.

 A tank of liquid nitrogen the size of a small continent would just about increase the density of gases at the relevant altitude by roughly one part in millions...  for a couple of years I'd guess.

So, no, not really a practical solution.

[p1t1o]

48 minutes ago, DerekL1963 said:

 A tank of liquid nitrogen the size of a small continent would just about increase the density of gases at the relevant altitude by roughly one part in millions...  for a couple of years I'd guess.

So, no, not really a practical solution.

 

What? You only need to boost a mere 38 trillion tons of nitrogen to fill space out to GSO with 1e-7atm of nitrogen.

"Impractical"...Pshaw!

[PB666]

1 hour ago, DerekL1963 said:

Uh huh, and if the space bots fail then we have additional pieces of junk to deal with too.  And if the space bots wrap their tethers around the wrong part of the craft, they too can generate additional debris.

 Easily solved problem, have the practice on the low hanging fruit, since the bots are small if they target junk in low orbit first, if they develop problems their debris quickly decays into earths atmosphere, well below the danger zone.

BTW without chemical fuels where is all the inertia for hurling into higher orbit going come from.

1 hour ago, DerekL1963 said:

Well, setting aside the fact that ion drives (despite your obsession with them) lack the thrust to perform the mission (not able to perform fine rendezvous maneuvers on their own) and that tethers are unproved technology...  You've left out the communications systems they'll need.  And the power management system.  And the RCS needed for fine maneuvers near the target.  And the sensors needed.  And the computer systems needed to control the whole thing.  And....  I'll just stop right there and say that you've not only grossly misrepresented the systems required, you've equally ignored all the devils in all the details.

Living in the stone age still?

You do realize that ION driven steering factor thrusters are already on the market.
https://www.accion-systems.com/tile
http://www.busek.com/index_htm_files/70000700 BHT-200 Data Sheet Rev-.pdf
http://www.busek.com/technologies__ion.htm
https://gizmodo.com/5935973/penny-sized-ion-thrusters-could-steer-the-satellites-of-the-future
Communications is an old problem. There are robots than can manage all by themselves to do tasks, so this is just a matter of learning algorythm in space.
Any decent computer can set them up to rendezvous. Might take a while but they have all the time they need.

All this stuff is pretty self contained, unlike what would happen if you carelessly harpoon a satellite.

Quote

Well, no.  Not only are these completely different problems - SpaceX required a modest amount of additional systems (all based on existing proven technology) added to a proven system.  You require a completely new vehicle with a number of speculative technologies.

Once again you exaggerate to the extreme and you are pulling emotional arguments. There is nothing about the guidance system that cannot be modeled. The only under-performance problem is the lack of sufficiently light solar panels and sufficiently efficient small ION drives with 1500 to 3000 ISP.

 

[DerekL1963]

7 minutes ago, PB666 said:

You do realize that ION driven steering factor thrusters are already on the market.

Yup I realize that.  And I also realize they aren't suited for the application you're proposing.

8 minutes ago, PB666 said:

Communications is an old problem. There are robots than can manage all by themselves to do tasks, so this is just a matter of learning algorythm in space.

I didn't say communications wasn't an old problem.  I said that you'd left them and practically every other system the 'bot would require off the list.  And you seriously overestimate the current state of the art in autonomous robots.  And you very seriously underestimate the weight and costs.

[PB666]

1 minute ago, DerekL1963 said:

Yup I realize that.  And I also realize they aren't suited for the application you're proposing.

I didn't say communications wasn't an old problem.  I said that you'd left them and practically every other system the 'bot would require off the list.  And you seriously overestimate the current state of the art in autonomous robots.  And you very seriously underestimate the weight and costs.

And so, any new process is going to draft developed technologies for new application. ESA already tried harpoons with the Philo lander, and guess what, they FAILED!

I didn't specify either how to put clothes in a washing machine to wash them or how to chop carrots for a beef stew. One assumes that if a agency is dumb enough to try to harpoon satellite with velocities sufficient to penetrate quarter inch aluminum plate that they are at least smart enough to devise a communication system for a rocket. Course again given their progress on the Orion service module that is a valid question.

[Green Baron]

No need to get personal ...

Tethers have been thought of before. I don't remember by whom. But i think the basic idea is that it makes little sense to shoot something up to bring something else of similar size down. Also the big hunks can easier be taken care of than all the small little bullets buzzing around.

I first thought the harpoon is an April joke but then realized that the idea isn't new either. It reminds me (as somebody who has studied archaeology) of a spear thrower, the cruise missile of the late ice age :-)

Ion drives are nice for interplanetary travel where they burn for days, weeks or months, i doubt you can use them to alter an orbit quickly near a gravity well like earth's (this isn't KSP, ya know :-)), which would be a prerequisite for something trying to rendezvous something else in LEO.

We'll see. As satellites grow in number and shrink in size the harpoon will probably end up at the side of the atl atl/spear thrower/propulseur/Speerschleuder in a museum. Enter the fly swat. With a hole to give 'em a chance :-)

Edited March 15, 2018 by Green Baron

[Canopus]

26 minutes ago, PB666 said:

One assumes that if a agency is dumb enough to try to harpoon satellite with velocities sufficient to penetrate quarter inch aluminum plate that they are at least smart enough to devise a communication system for a rocket.

Maybe these guys know what they are doing? Maybe they actually weighed the options and determined this one to be the most feasable? I mean they don‘t work there for no reason. 

[kerbiloid]

They need a mirror.

[PB666]

8 minutes ago, Green Baron said:

No need to get personal ...

Tethers have been thought of before. I don't remember by whom. But i think the basic idea is that it makes little sense to shoot something up to bring something else of similar size down. Also the big hunks can easier be taken care of than all the small little bullets buzzing around.

I first thought the harpoon is an April joke but then realized that the idea isn't new either. It reminds me (as somebody who has studied archaeology) of a spear thrower, the cruise missile of the late ice age :-)

Ion drives are nice for interplanetary travel where they burn for days, weeks or months, i doubt you can use them to alter an orbit quickly near a gravity well like earth's (this isn't KSP, ya know :-)), which would be a prerequisite for something trying to rendezvous something else in LEO.

We'll see. As satellites grow in number and shrink in size the harpoon will probably end up at the side of the atl atl/spear thrower/propulseur/Speerschleuder in a museum. Enter the fly swat. With a hole to give 'em a chance :-)

One could have some other propulsion system. ION drives are decent for moving light things (on the order of 20 kg) their weakness is for heavy things.

As discussed before What is the power supply. Solar. If you increase the mass of something you increase the volume, that increases with the cube of average radius, panels increase with the square therefore an object with panels with roughly the same surface area as the object itself, the power increases with the square. As you decrease size your power density goes up which means the ability to accelerate goes up, because of a lower structural basis the weight per unit panel can go down. This can be a small as a film on the surface of the wide rectangular cube sat. 

Objects travel in orbits, if you are planning a hohmann transfer you need lots of power, however hohmanns are not the only way to get to the target. Because ION drive can spiral, the potential and kinetic energy differences they have with objects already in orbit (with comparable angular positions) is small relative to objects approaching from hohmann transfers. Is simply a matter of approaching, slowing down a few meters per second.

How to capture. Most satellites have solar panels, the system could deposit  a probe with a very fine spider silk thread, it could basically make a trip around the devices panel and return to the parent ship, magnetically attaching. We are talking about speeds in the 10s of millimeter per second range. The ship returns and the parent device slowly reels the two craft closer together. After this the parent device determines the retrograde direction and using a combination of steering instruments slowly decelerates the craft at apogee so that its perigee is low enough to decay. Once complete the parent releases the thread and powers itself back into a stable orbit.

For objects in GTO, it is something like 11 m/s to gain a graveyard orbit, but ION driven craft could actually push the craft into heliocentric orbit with 10s of meters per second of dV using the moon to aid in its exit. Once in an escape orbit it tosses.

ION drives will be the future of space garbage clean-up for one very simple reason, you don't want to put trash in space to haul trash from space on a  1:1 ratio, they have to be capable of completing multiple garbage disposal missons.

Hydrolox cannot do this, hydrogen burns off. Metholox, oxygen eventually burns off, everything else is too low of ISP to accomplish multiple missions.

[DerekL1963]

24 minutes ago, Green Baron said:

But i think the basic idea is that it makes little sense to shoot something up to bring something else of similar size down.

Since nobody has specified the size of the bird the ESA is planning to send up...  That seems a bit of a stretch to assume.

But frankly, given the nature of the mission and the environment...  I suspect no solution is going to be small or cheap. 

[Toonu]

What about pushing the debris by laser?

[KSK]

9 minutes ago, Canopus said:

Maybe these guys know what they are doing? Maybe they actually weighed the options and determined this one to be the most feasable? I mean they don‘t work there for no reason. 

Well, according to the article, they're testing the harpoons (of different sizes depending what they're intended to snag) against aluminium/composite panels which are apparently representative of satellite construction materials. So yeah, sounds like it. The harpoons are powered by compressed air, cut through the test panels with ease and are intended to be used from about 25m. They also have deployable barbs to stop them punching right through their target.

So it sounds as though they have thought about this (amazingly enough). In particular punching a hole into their target but not out of it, so containing any debris inside. 

21 minutes ago, PB666 said:

How to capture. Most satellites have solar panels, the system could deposit  a probe with a very fine spider silk thread, it could basically make a trip around the devices panel and return to the parent ship, magnetically attaching. We are talking about speeds in the 10s of millimeter per second range. The ship returns and the parent device slowly reels the two craft closer together. After this the parent device determines the retrograde direction and using a combination of steering instruments slowly decelerates the craft at apogee so that its perigee is low enough to decay. Once complete the parent releases the thread and powers itself back into a stable orbit

I appreciate that's just an example but wrangling a satellite using a relatively large, fragile and unwieldy component such as a solar panel doesn't sound like a great idea, especially if the satellite is tumbling.

Also - a personal request. Ion drives are quiet, gentle devices. ION drives sound so shouty, don't you think? Especially as ion isn't an acronym.

[sevenperforce]

13 minutes ago, Toonu said:

What about pushing the debris by laser?

You run into some problems with power management and heat rejection. If the laser is powerful enough to ablate the surface and therefore produce thrust, then it's powerful enough to rupture something and blow it up.

[Green Baron]

33 minutes ago, PB666 said:

ION drives are decent for moving light things (on the order of 20 kg) their weakness is for heavy things.

Or medium things (mass of a ton) like Dawn or New Horizons over a loooong time. Anything that is based on reaction, like harpoon, tether, etc. needs some mass. Imagine ESA shoots the harpoon, the harpoon stays where it is and the empty tube flies in the other direction. Kerbal style :-) Ion drives of the day don't have enough oomph to adjust orbit of a deorbit satellite in LEO. In less than months or even years of time, and then the problem might be gone anyway, or has changed orbit due to interaction, or just because ...

33 minutes ago, DerekL1963 said:

Since nobody has specified the size of the bird the ESA is planning to send up...  That seems a bit of a stretch to assume.

Sorry for being unclear, i mean, shooting something with a certain reaction mass up to bring something else down is probably a little impractical, at least as long as launch costs really count, so yeah, not cheap. I mean this is all a very premature discussion about details nobody really knows of. The tether thing needs a mass at the other end, the more the quicker it works. Just in principle, no nitpicking about the number of molecules please *propellerhatkerbal*

Be it as it may, good night everybody :-)

15 minutes ago, Toonu said:

What about pushing the debris by laser?

Throw a laser ? *duckandcover*

I think there is a proposal ....

Edited March 15, 2018 by Green Baron