Asteroids: Impacts vs. Captures

[Guest]

Now as of the time I am posting this. ARM has not came out...

But when there is an asteroid that is going to impact Kerbin.

What would you do? Impact the asteroid and make It blow up? or... Push the asteroid out of orbit.

Well... I know It is possible top impact It... Danny did It.

So... Would you be like a boss and do a very awesome (But risky...) Impact... You'd problably use a Probe. (Unless you hate kerbals)

Or... Would you latch on to the Asteroid throw It out of orbit.

There are advantages and disadvantages to them.

Impacts are quicker and you can retry them easily.

Captures are time consuming and take time to retry It.

Impacts are extremely risky and normally screw up.

Captures are almost certain to work once you are next to It.

[Tex]

I'd probably try for captures first, but I'll honestly be lucky to even see one not in map view

[_jack]

Personally I wan to make a base on a C class that orbits a fair distance from Kerbin.

[TranquilTempest]

Land it and recover it.

[Aragosnat]

I'll do both. Impact and capture. Eve needs a few new craters. =^.^= As well as it seems like a nice way to send a craft down into its thick atmosphere. =^.^=

[merendel]

While I'll cut my teeth on smaller roids I fully intend to capture a big one, a D or an E and make it the core of a station. It drives me crazy haveing a perfectly aligned station only to have it wobble off axis every time you dock something. Now I can either solve this by puting 50 or so full orange tanks as my stations central core to keep the rotation down or I can build around a single 2000 ton spacerock. The spacerock means fewer needed parts so I'm all for it even if geting it into the right orbits going to be a chore.

I'll do both. Impact and capture. Eve needs a few new craters. =^.^= As well as it seems like a nice way to send a craft down into its thick atmosphere. =^.^=

lol epic heatshield ftw I actualy wonder how deadly reentry will handle asteroids.

[zarakon]

Crash it into the Mun

Or Kerbin

whichever

[Vostok]

I plan on docking wheels to an A class asteroid, then landing it near KSC and driving it to the space center and having it as a pet.

I'm thinking of making a collection, starting small and then seeing if it's possible to land an E class with wheels.

[DisarmingBaton5]

I'm going for a more realistic approach with capture. I might do an impact mission at some point, though, just for fun.

[RocketPilot573]

I'm gonna land it.

[Tanner Rawlings]

id recreate the nasa mission and capture it then put it in munar orbit for safety then send crews out to meet it

[Deathsoul097]

Eh, it won't do any damage anyway, at least, no more than the kerbals do. I say just rendezvous and pull a pretty aerobraking (Or gravity assist) manoeuvre.

[soranno]

capture one, and then bowl it into another one

or failing that, make up some kind of asteroid to asteroid adapter, and see how many I can chain together in a great big asteroid conga

[LaydeeDem]

Make a base on a huge asteroid and then bring it home to Kerbin.

EDIT: By Kerbin I mean its surface.

[Madrias]

Capture and fly to Kerbin... With a spaceplane. And I'll try to land it with the asteroid attached... Should be fun.

[Guest]

I'll deorbit it over the Mun and see if I can land safely with just the asteroid as a "cushion". Let's see just how hard these rocks are...

[Rakaydos]

Lithobreak against a class E to save fuel.

[a-rod48]

I would say kerbin needs rings.

[timsfitz]

I would say kerbin needs rings.

My thoughts exactly. Huygens rings. Will need a lot of them though.

[cantab]

lol epic heatshield ftw I actualy wonder how deadly reentry will handle asteroids.

Probably the same as anything else. It would make sense for larger ones to have more heat tolerance, though it might be something you don't notice anyway if even the small ones aren't going to be destroyed.

I'll probably attempt to impact one, precisely because that's very hard to do.

[homeslicerae]

I'll deorbit it over the Mun and see if I can land safely with just the asteroid as a "cushion". Let's see just how hard these rocks are...

In Scott Manley's 2 hour ARM video stream I recall having him crash an asteroid into Kerbin with no prior slowdown or parachutes and both the rock and the crew survived. I would say they are pretty durable.

[Streetwind]

To actually get back to the question posed in the OP:

If an asteroid is on a collision course with Kerbin, you'll likely have to move it into a capture orbit. Altering its course enough to miss Kerbin by using an impactor will be nearly impossible.

The reason for this is: all asteroids we've seen so far are "near-kerbin objects" in the truest sense of the word. They have solar orbits nearly identical to that of Kerbin, and as such, the velocity difference to Kerbin is almost negligible. This counts double for an asteroid on a collision course: those match Kerbin's orbit more than any other kind.

In other words, when most asteroids enter Kerbin's SoI, they're not objects screaming through at insane speed; much rather, they're objects that come in with little relative velocity and then fall into the gravity well in a (hopefully) hyperbolic orbit around Kerbin. The larger the relative velocity difference, the further away from Kerbin it will swing by. But if it comes in very slowly, or in an angle where the velocity vector points towards Kerbin, then you get a collision course. Not because the asteroid happens to pass through and Kerbin is in the way, but because it actively falls towards Kerbin on an orbit so extremely elliptic that the periapsis is below the surface.

If you frontally impact an asteroid on this kind of trajectory, it will simply be slowed down. Which means: the periapsis will drop even further, and you just made the situation worse. You would have to impact it from behind to accelerate it, which costs a huge amount of dV in addition to the costs of the rendezvous itself; and then there's the fact that pure prograde acceleration isn't very effective in altering a highly elliptic trajectory. No, you want an impulse in the direction of the light blue maneuver node markers, an impulse from the side. And aiming an impactor to hit from the side is prohibitively difficult. Remember: you're trying to collide two objects of maybe 10 meters in length - both of which are traveling at several huindred, maybe over a thousand meters per second on trajectories orthogonal to each other. Even a computer would struggle to get it right. Look how Danny had to retry several times (plus who knows how often off-camera) to force a collision even with roughly similar vectors.

No, it's far, far easier and reliable to attach a booster to the asteroid and perform a burn to push its periapsis above Kerbin's atmosphere in order to prevent a collision. And then, if you have dV left, the vessel can perform another burn at periapsis to try and capture the asteroid. (Conveniently it will already be aligned retrograde at that point without having to redock with the asteroid, so long as it didn't start spinning.)

[Highlad]

Honestly, I think it will be relatively easy to smash an asteroid into kerbin if you know what you are doing. Capturing an asteroid on the other hand, now thats a challenge. Im aiming to put a few round the Mun.

[DarthRaptor]

I want to capture an E class asteroid and use it as a station core, maybe even dock a few smaller asteriods to it. I haven't decided on the orbit, maybe I'll do a geostationary orbit.

[whaaw]

I put 10 pins ( rockets with landing legs) on the mun. Then capture a class e asteroid put in very low mun orbit and then try to bowl all pins away;)

Not forget to listen "i come in like a wreckingball" when i do this

Edited March 28, 2014 by whaaw