Indian Robot Will Capture Space Debris

CowboyRobot writes "India is set to launch the 'Space Robot', which, controlled from Earth, will capture damaged satellites and space debris. This seems a less ambitious, and more immediately practical venture than the current Mars missions."

Comments

Heh.

[ivan256]

It's nice to think of this as practical from the perspective of cleaning up space debris, but the real point of this is almost certainly for India to show that they have the ability to take out sattelites they don't like, much like the early Soviet and American sub-orbital flights and sattelite launches were demonstrations that we could drop explosive devices on each other from halfway around the world. Don't assume that something this complex and costly is being done out of the kindness of the Indian government's heard, or for the good of humanity when there's an obvious military benefit; especially considering their current cold war with Pakistan, and the technological escilation in China.

Excellent application of ion engines

[G4from128k]

Ion engines would be well suited to this application. Their high specific impulse means they could have the fuel reserves needed to change orbits multiple times to catch debris. Solar power, instead of a nuclear power source, could provide the electricity to run the engine.

Hmmm... figuring out the optimal set of manuveurs to catch a set of debris objects that are all in different orbits would be very tricky. I guess that would have to be called the Traveling Spaceman Problem.

Re:Excellent application of ion engines

[Unknown Kadath]

Hmmm... figuring out the optimal set of manuveurs to catch a set of debris objects that are all in different orbits would be very tricky.

I'm picturing it towing a huge red horsehoe magnet on a string, with all kinds of dead satellites stuck to it.

Really, while it's nice in concept to talk about cleaning up Earth orbit, the real danger is from the bits we can't even find, never mind capture, like paint chips. Sure, they only mass a few grams, but get a few grams travelling at a few km/s in one direction, and a spacecraft travelling a few km/s in the other, then do the math to find out the total kinetic energy of the system. (Hint: KE = 0.5 * m * v^2) Fortunately, space is big, but we're still doing our best to clutter it up, especially in LEO.

What we need is a satellite with a really big version of one of those pool skimmer thingies.

-Carolyn

Re:Excellent application of ion engines

[zwanglos]

This doesn't really seem like a good application for ion engines. They are designed more for long distance deep space travel as they build speed very slowly.

This device will probably have more conventional thruster units that allow for high thrust and greater manueverability - especially if trying to catch objects that are no longer in orbit.

Here is a comparison of space engine capabilities: Engine Comparisons.

Re:Excellent application of ion engines

[RobertB-DC]

This device will probably have more conventional thruster units that allow for high thrust and greater manueverability - especially if trying to catch objects that are no longer in orbit.

Well, technically, if it's up there, it's "in orbit" around the Earth's center of gravity. It just may be the case that at some point in the object's orbit, the distance to the center of the earth is less than the earth's radius!

The problem with the low-power ion engine would be conservation of momentum, I'd think (though I'm not any sort of expert). If the craft is moving "forward", and the object it encounters is at the same altitude but moving "backward", capturing the object will cause some sort of change in the momentum of both objects.

The small object will abruptly begin moving in the opposite direction (unless it punches a hole in yer scoop!), but its kinetic energy (???) will slow down the big object. Just like the atmosphere, thin as it is, exerts a drag on objects in orbit that's proportional to the number of atoms hitting the object (which is proportional to the object's surface area).

That's when orbital mechanics kicks in. The slower you go, the smaller your orbit. Each "hit" sends the catcher closer to a fiery end, kind of like a celestial Slashdot effect.

Also, how will the satellite "catch" its targets?You can't just step on the accelerator to catch up to something, because increasing your orbital velocity increases your altitude. To go "up", you have to accelerate forward, to go "down", you have to accelerate backward, and I still don't fully understand what happens when you accelerate in some direction outside your orbital path!

All this is facinating, but boy, does it make my head spin...

Re:Indian robot?

[theMerovingian]

Maybe they could bring the Hubble back for a 10th the cost.......?

Even if they only got a 10th of it for us, we could put it in the Smithsonian.

Re:Orbital Debris: Plot of Planet-es Anime/Manga

[Bonker]

I was going to bring up Planetes. One of the very few "hard" sci-fi stories I've ever thought was really excellent.

Main characters are astronauts who collect space debris of various kind for a corporation who does space cargo and passenger flights.

An entire episode of the anime is devoted to medical issues arising from extended periods in space. One of the minor characters describes herself as a 'Lunarian'. She's a 12-year old girl who's over five feet tall and has very brittle bones and other medical problems. Accordingly, she lives in a hospital and is in medical testing and treatement almost constantly.

Good stuff. Check it out if you can.

This could be a great fiscal venture

[E1v!$]

If the robot could capture the debris, and put it all in some kind of framework, a 'junk warehouse' if you will.. It could be a fantastic way to aquire raw material in orbit without having to pay much of the shipping cost.

Another robot...

[geoswan]

Maybe it is worth comparing the design of this robot to the Indian one. It was discussed in this slashdot thread entitled Inspection Microsat Tested In Orbit.