Asteroids.

[Cloakedwand72]

What TWR is required for each asteroid to redirect it to orbit Kerbin or the mun? Also which ones can I mine ore from & what class asteroid has good quantities?

[steuben]

TWR is arbitrary. How long to you want to wait during your burn? It is delta-V you're after. You're looking at roughly 1500 to 2500 m/s depending on where the rock is. Less with some fancy fly-bys of the Mün and other bodies.

You should be able to mine from all of them. Class E has the largest amount of ore, but is also the heaviest/largest. But, an ore rich C may have more useable ore than an ore poor E.

[Xd the great]

11 hours ago, Cloakedwand72 said:

What TWR is required for each asteroid to redirect it to orbit Kerbin or the mun? Also which ones can I mine ore from & what class asteroid has good quantities?

DeltaV is more important, but anything above 0.3 is very good already. Just don't use a single ion engine to direct a Class E asteroid.

Edited November 2, 2019 by Xd the great

[Linkageless]

A higher TWR on a vessel attached by klaw to an asteroid is undesirable, especially pushing.  It's hard to precisely line up on an asteroid and that misalignment puts strain on your stack, and may cause the combination to drift off target or worse oscillate terribly.  The Kraken awaits those that push asteroids too hard with inadequate setups.  Adding some reaction wheel/RCS pods, with their own klaws, distributed around the asteroid may help stabilise things and allow higher thrust.  If you do start to oscillate, back off on the throttle (which is effectively lowering your TWR).

Some have had more luck towing asteroids rather than pushing, but its not something I've tried in a while.  The main considerations for that would be:

1. the length of the plume from your engines in vacuum (if it's thrusting against the asteroid, that will decrease the effective thrust you get) and

2. the strength of the boom and klaw holding your ship to the asteroid.  (I understand the long mk3 parts are perfect for this)

I'd say it's probably a lot less bother to go after class B & C than the largest ones if you need to alter their course a lot.  Class D and E tend to need much planning and patience in the absence of experience.

[paul23]

Uh as far as I know 1 isn't the case with vanilla ksp.

[Laie]

22 hours ago, Cloakedwand72 said:

What TWR is required for each asteroid to redirect it to orbit Kerbin or the mun? Also which ones can I mine ore from & what class asteroid has good quantities?

From the questions you ask, you will be in for a surprise or two.

https://wiki.kerbalspaceprogram.com/wiki/Asteroid lists the size classes and their respective masses. All asteroids can be mined, the ore concentration is usually well above 60% to begin with (I don't think I've ever found one under 80%). Mining is fast, a single drill will suffice. Unlike planets and moons, asteroids can be depleted: they will lose mass as you extract the ore, and concentration changes accordingly.

The worst problem in capturing a large asteroid is controlling it, that is, make your asteroid-and-tug point in the right direction for the next burn, and keep it pointed that way during the burn. You may find that you cannot apply as much thrust as you brought.

[Linkageless]

8 hours ago, paul23 said:

Uh as far as I know 1 isn't the case with vanilla ksp.

I recall finding lack of thrust due to the plume being blocked experimentally quite some time ago, but can't certify that this is still the case in 1.8.1 (although I would expect so).  It's always possible I dreamt this so won't mind being proven wrong.

[paul23]

On 11/2/2019 at 9:01 PM, Linkageless said:

I recall finding lack of thrust due to the plume being blocked experimentally quite some time ago, but can't certify that this is still the case in 1.8.1 (although I would expect so).  It's always possible I dreamt this so won't mind being proven wrong.

I think there's a fixed "distance" it checks, independent of the plume.. And it's quite close, like 5ish meters. (1 thumb solid booster distance seems to make this check not find anything).

[Laie]

Iirc it varies by engine. Try it with a stack of Ox-Stat panels in the exhaust: Those overheat and blow up quickly, until you get to one that doesnt even get warm. That is the distance where the plume no longer interacts with the vessel.

[Linkageless]

On 11/5/2019 at 9:55 PM, paul23 said:

I think there's a fixed "distance" it checks, independent of the plume..

Yes, this is what I remember, the actual distance is independent of the plume displayed, but except as @Laie says, varies by engine.  I don't know if this is exhaustDamageDistanceOffset or another attribute, but RCS thrusters don't seem to be constrained in this way.

I've knocked up a mining/towing vehicle in career as I had a contract sitting around anyway, will do some experimentation and report back when I get chance.