I want a big roid

[Tortoise]

I want a large D, but it's too hard for me to get one. Getting there is hard enough, but getting it back to kerbin would be even harder. Can you guys give me tips on how to capture one?

[Lanrutcon]

Keep searching asteroids until you find a class D asteroid that will enter in the Kerbin's SOI.

Then make a nice rocket, use 1 or 2 LV-Ns to bring that big rock to a stable orbit around Kerbin.

If you know how to rendezvous with a ship, you know how to rendezvous with an asteroid. Make sure you burn at the periapsis with a couple of mins of "delay" because LV-N is not famous because of its power.

Another important thing is the point of application, you can always adjust, the klaw let's you "rotate" after you grab it.

If you want to land that beast, make another rocket with tons of parachutes, this time will be easier because the asteroid is already orbiting Kerbin.

[Tortoise]

Well Ik how to rendezvous and stuff, but what are the delta-v recommendations and stuff?

[robopilot99]

A lot. If you can catch in interplanetary space and set up a aerrobreaking manuver or even a desirable encounter the amount will drop significantly. Ultimately its hard to know how much it will take due to the random nature of astroids.

[JTMilne]

I got an E-Class into Kerbin orbit on my first attempt at getting an asteroid haha.

I used the nuclear engine and managed to change the asteroid's trajectory while still very far away so it did'nt use too much fuel, aerobraked a few times around Kerbin, then went to Apoapsis and perfected my orbit. It was intense!

[LethalDose]

I got an E-Class into Kerbin orbit on my first attempt at getting an asteroid haha.

I used the nuclear engine and managed to change the asteroid's trajectory while still very far away so it did'nt use too much fuel, aerobraked a few times around Kerbin, then went to Apoapsis and perfected my orbit. It was intense!

i really think this is the trick: catching the asteroid ASAP. I prefer hitting them inside of Kerbin's SOI, but others apparently have good luck outside the SOI too. the earlier you intercept, the less dv it will take to capture the 'roid. You really have to be smart with your burns too: combine maneuvers, wait until youre very high to make inclination changes, etc.

[Red Iron Crown]

I want a large D

Must...resist...crude...joke.

Seriously, though, I find it useful to send a probe to intercept an asteroid before sending the capture ship, it will give you the asteroid's mass so you can do proper dV and TWR calculations.

Other than that, the further away you can intercept it, the less fuel will be required to change its course to something more desirable. Aerobraking bigger asteroids is definitely recommended.

[Stickyhammy]

I tried to capture an E by making a main rocket ship to move it and 6 small probes with rcs that clawed into other sides of the asteroid to help with turning. My advice, don't do what I tried. The only thing that happens is the probes go crazy if you hit time accelerate, whip back and forth, and ultimately explode into lots of small parts. I only got 4 probes in before the asteroid had a fit and started tumbling. What a mess.

In general it seems to be easy to get to an asteroid outside kerbins SOI if you burn properly. On a 70 day timer until it hits the soi you should be able to hit it at around 40 days left. Then you can putter around with your Kerbal poking at the rock with a stick for 40 days. By the time it enters the SOI of Kerbin your Kerbal will have made a scientific discovery. The asteroid is in fact not made of cheese after all.

Also be sure to save often before starting a burn. If a 3500 ton E class starts to tumble you might as well untrack it and let it despawn. Your not going to get it back under control even if every Kerbal on Kerbin gets out and pushes.

[Nothing But Rubus]

if you want an easy catch. find an big asteroid composed of something soft. it shouldn't be hard

[cantab]

Rendezvous with it in solar orbit. It'll take you more delta-V to get there, but you can then make a small correction to set your periapsis for aerocapture. For bigger asteroids it's the way to go. Provided the asteroid is due to enter Kerbin's SOI, you can get to it simply enough by leaving in the direction it's predicted to enter. There's a fuller tutorial on this on the forums.

Here's my standard asteroid tug, using the same approach Stickyhammy mentioned of having little control sections to dot around the asteroid. I've fortunately not hit the bug he described, but be aware it is a risk. I suggest pointing a backup tool at your save folder so you can roll back if need be.

All set up by cantab314, on Flickr

That's a 500 ton asteroid and I only had about 100 m/s of delta-V once I'd grabbed it, but 100 m/s will be plenty since I'm aerocapturing.

[Tortoise]

Thanks, I got have big D now.

[iFlyAllTheTime]

I want a large D

Must...resist...crude...joke.

The first thing I did with the ARM patch, captured two class D asteroids in a stable orbit around Kerbin.

My current plan: attach two claws to either end of a girder segment and capture those two asteroids on either end.

Hopefully they'll bounce off in unison when I try to land them, as one did when I brought it down on its own.

Back to the topic, as has been already mentioned, the farther away you capture the roid the less dV you need. I've done a few intercepts now and on all of them, I've managed to capture the roid at least 10-15 days before they enter Kerbin SOI. I then burn, so as to get the Kerbin SOI around 60KM, and fine tune it to about 36-40KM once in the SOI. After the atmosphere has done its job in capturing it in an elliptical orbit, I raise the Pe at the Ap.

ONE FINAL NOTE: When you attach yourself to the asteroid, your vessel has to deal with the additional mass. Be prepared for a drastic decrease in your ship dV figure (mechjeb and/or kerbal engineer read out) when attached to the roid.

Edited July 3, 2014 by iFlyAllTheTime
Forgot to mention a detail.

[Oafman]

I tried to capture an E by making a main rocket ship to move it and 6 small probes with rcs that clawed into other sides of the asteroid to help with turning. My advice, don't do what I tried. The only thing that happens is the probes go crazy if you hit time accelerate, whip back and forth, and ultimately explode into lots of small parts. I only got 4 probes in before the asteroid had a fit and started tumbling. What a mess.

Yup, same here. It seems to be an easy way to summon the kraken.

I added 12 RCS pods to my roid. It does turn more quickly, though hardly on a sixpence. But if I even think about time warping anything within 10km, explosions happen.

All those parts have also not helped my FPS at all. So this wasn't really a success. The only consolation is that the ship which delivered the RCS drones looks cool....