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Landing an asteroid on collision course


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I've got a contract where I must (gently) land a class C asteroid on Kerbin.

By some incredible luck, I've got a C asteroid on a collision course (it's gonna crash on kerbin!) 5 days away from Kerbin SOI...

At first I thought this was good since I don't even have to waste fuel on orbit, I just have to strap a couple of dozen of parachute on a rocket, make contact and (assuming it does not splash down in the sea) that's it!

But now that I think about it... the orbital speed of the asteroid is going to be TREMENDOUS and I will have to MATCH that speed if I ever want to make contact.

I would basically need to get into a collision course with kerbin too BUT at just the right time (and speed and altitude) so I would be able to reach my target. That sound almost impossible...

Is that even possible? Did anyone try (and succeed) on that?

Edited by wibou
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Yes

(+ 7 chars)

Slightly more helpfully - it isn't easy but it's just a bigger orbital-rendezvous. Landing an asteroid is more of a pain that just getting one into a stable orbit but still very doable.

Whether it's worth doing for you at the moment is a matter of confidence and how much time you want to put into it. Look at the deadline for the contract - it may well be years in the future and, without actually going to expense/inconvenience of cancelling it, you may well be able to ignore it for a long time to come and until you've done a lot more other missions ;-)

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It's not that bad... Asteroids that are on a collision course typically have lower relative speeds with they enter Kerbin's SOI. Basically, lower speed -> more effected by gravity -> pulled closer to Kerbin.

However, if you want to land it gently, yeah, you're gonna need some serious dV.

Try to intercept it as far out as possible and nudge it into a good aerobraking trajectory. That'll probably be your lowest dV solution.

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However, if you want to land it gently, yeah, you're gonna need some serious dV.

Try to intercept it as far out as possible and nudge it into a good aerobraking trajectory. That'll probably be your lowest dV solution.

What I was planning to do was to pack about one hundred parachutes on a special claw and hope it is strong enough to hold the entire asteroid mass while the 'chutes do their trick. I already made the claw + 126 chutes design actually... What you are telling me is that it won't work and I should try to rocket-land that monster?

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Be aware that if the asteroid is on a direct collision course and you are using FAR, you may not be able to land it 'gently'. Should be fine with stock soupy aerodynamics though, especially with drogues (otherwise that 500m sudden deployment will probably rip all your chutes off due to the asteroid's sheer inertia). Remember that you have a few days before impact, giving you plenty of time to plan your intercept.

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What I was planning to do was to pack about one hundred parachutes on a special claw and hope it is strong enough to hold the entire asteroid mass while the 'chutes do their trick. I already made the claw + 126 chutes design actually... What you are telling me is that it won't work and I should try to rocket-land that monster?
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Under stock Aerodynamics, you won't even need parachutes.

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If you want it to touch down gently, and not rip off the claw. Use multiple claws each with their own chutes.

I launch a large rocket. That has several probe cores with monopropellant and multiple parachutes. Once I intercept the asteroid, I attach one at a time. have them set to deploy their parachutes and just let it crash.

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'>Claw has a tutorial for making an asteroidal rendezvous outside of Kerbin's SOI. If you've got the tech, you can catch the tater. Class Cs range from a little over 40 tonnes up to about 165 tonnes; 90 tonnes is a good planning average. Claw's probe design is good for Class A and Class B, so your craft will need a little bit more oomph. The good news is that it won't take a good deal of delta-V to put it into low Kerbin orbit. Once it is in orbit you've got time to do some planning; send up whatever packages you like to the tater to help bring it down - nothing more complicated there than normal rendezvous and docking. You'll know what kind of mass you're dealing with at that point, so the '>parachute calculator can give you an idea of exactly how many chutes you'll need for the final de-orbit.
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If you want it to touch down gently, and not rip off the claw. Use multiple claws each with their own chutes.

I launch a large rocket. That has several probe cores with monopropellant and multiple parachutes. Once I intercept the asteroid, I attach one at a time. have them set to deploy their parachutes and just let it crash.

This is the way forward I think. You'd need enough dV to intercept the asteroid, and a swarm of radially- attached probe core-girder-claw-parachute 'harpoons' that would all grab hold of the asteroid. With just one claw you'd most likely tear something off when the chutes open

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.. and a swarm of radially- attached probe core-girder-claw-parachute 'harpoons' that would all grab hold of the asteroid. With just one claw you'd most likely tear something off when the chutes open

Allright, I will change my ship to use that idea.

I didn't had much time to play but I'm definitely going to try that landing this week-end.

Thanks guys, I will keep you informed of the success/failure of "Operation Mammoth-Feather" :)

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So I did it! Operation Mammoth Feather was a resounding success!

It wasn't easy, toying with asteroid is _VERY_ buggy (hence, dangerous).

I experimented all sort of weird bugs, from being accelerated to near lightspeed to becoming perfectly still while the universe keep on moving. I had to restart KSP several times.

The notoriously buggy manoeuver nodes around asteroid were also quite a pain. Especially since 90% of the rendezvous it was giving me were AFTER the asteroid would have crashed on Kerbin (geee that's very helpful, thanks).

I had to perform SEVERAL "simulation" (AKA "F5-F9") but in the end I made it :)

Here is a photo album of the whole operation.

Sorry to wake up an old thread like this... It's not just because I am damn proud of it, I ALSO felt it could help others to do the same ;)

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Ps: Jeb INSISTED on coming, I couldn't help it.

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It always feels slightly wrong when planning this sort of rendezvous, since you have to establish yourself on a Kerbin-impact trajectory as well. Jeb apparently had no fear though, completed another risky mission, and Kerbkind is saved from almost certain doom. Great work! :D

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