Good asteroid moving engines/good effeciency+power solutions for heavy movers?

[XOIIO]

Hey all, I was wondering what you guys think/use for heavy asteroid moving ships, what sorts of engines and configurations, and other engine setups for moving heavy loads, I just had an idea, I usually use the poodle for asteroids, but this will give more thrust and burn for a fair bit longer than the poodle, maybe this would be a good solution, though I don't know how well it works, haven't even put it in orbit yet let alone try to move a class e asteroid.

It also stacks nicely which is a bonus.

[Random Tank]

Apparently the stock KR-2L is supposed to be a roid puller, but I think its TWR and ISP are too high, so I changed it; it's still good for your application I suppose. Out of the 3 390 vac ISP engines, the Aerospike has the highest TWR, so it could be useful; nukes are pretty good, probably the best, but you will need a few for a D or E.

Configurations? The best way I've found to move a roid is to pull it, not push it; why do you think HGV's pull their loads?

Just make sure your engines are near the front of the ship, away from the roid, so the roid can't block their thrust.

[XOIIO]

Yeah, I've found pushing to be a pain in the arse most times. I made an asteroid lander with four of the large radial mount rockomax engines for a suicide burn to slow it down before I deploy chutes but I think that pulling will be a lot better, I guess I might just have to add an extra probe body so mechjeb can pull off burns properly, unless it handles systems with reverse thrusters well. Guess I'll find out.

[Xacktar]

This is my normal pusher. 8 NERVAs around one of the big tanks, then above that is a Skipper engine setup and four pylons that deploy 'Parachute Darts' that you slap on the asteroid for descent. There are RCS tanks on the pylons as well for fine maneuvering. You get quite a bit of Oomph out of it.

[NecroBones]

Yep, my pullers generally worked better than my pushers. In both cases though, it was useful to put SAS/RCS pods on the other side of the Asteroid. Here was one of my more successful designs:

The parachutes worked out well too:

[XOIIO]

Nice, I was thinking something similar, did you get that asteroid from kerbin;s SOI or interplanetary? I'll have to use more fuel tanks for sure, and yeah, my first asteroid redirector had several pods with grabbers and rCS that mounted on various points, it was a lot easier to move than with just RCS on one side.

[NecroBones]

Nice, I was thinking something similar, did you get that asteroid from kerbin;s SOI or interplanetary? I'll have to use more fuel tanks for sure, and yeah, my first asteroid redirector had several pods with grabbers and rCS that mounted on various points, it was a lot easier to move than with just RCS on one side.

I usually grab them inside Kerbin's SOI, but closer to the edge of the SOI than to Kerbin itself.

[Pecan]

T30s are my preferred 'thrust' engines when nukes are just too underpowered. Aerospikes for launch unless the ARM parts are required.

Mass-optimal engine type vs delta-V, payload, and min TWR - cross-reference how much mass you want to push vs the deltaV you need and read-off the best engine.

[Victus]

I'm ashamed to admit I've yet to get the courage to get an asteroid yet..

[XOIIO]

I'm going to capture one of each and line them up as a display somewhere in the space center, difficult bit will be rigging something up that can move them on the ground, I'm thinking the huge rover wheels and lots of fuel tanks to weigh them down, as well as some engines to help pull.

Also, did you just change the color of the lights, or what is that orange glow? It's funky

[merendel]

I like that puller design. I'll have to try pulling the roids instead of pushing them. That was also clearly better planed than my first capture. I went after a D class on my first try to avert the impending impact but I only had a pair of nukes on it. Changeing the orbit way out of the SOI was easy but capturing that bad boy took forever and I eventualy just sent up another flying fuel tank with a KR-2L to help circularize the thing.

[XOIIO]

Here's my take on it, I'll add other parachute pods most likely, not sure what size this will work well for.

It's made so that you jettison the engines and tanks once you hit your re-entry path, so that it has less weight when you deploy the chutes.

[XOIIO]

Amazingly the launcher I made actually works! The third picture is the stage that it uses to get to the asteroid, then it detaches that and pulls. I just need a wee bit more fuel so that I can get into a 200km orbit.

[XOIIO]

I managed to get it to the roid, had to use infinite RCS because the damn claw went through the asteroidinstead of grabbing it. I'm also going to use the splitters so that I connectwith 3 claws, it's way too wobbly now. I also need to get more torque for it to use.

Aisde from that it works great, had around half fuel when I got to the asteroid, still 18 minutes of burn time on the LV-N's.

Annoyingly I can't place a maneuver node on the trajectory for some reason, even rebooting the game didn't fix it so I have to wait ages for mechjeb to do it, and it's overshooting with the RCS since it's moving so much mass.

Edited May 24, 2014 by XOIIO

[SSSPutnik]

Nukes or ions are ideal if you have time.

Ions may hit troubles when solar panels are shaded?

[ArcFurnace]

A few warnings about using multicouplers for multiple claw points (I tried the same thing)- (1) with multiple claws, when you get them all attached you'll be perpendicular to the asteroid surface, which is not necessarily oriented through the center of mass, and you won't be able to rotate around the joint to fix it like you can with a single claw, and (2) when I tried using a multicoupler-claw attachment point it seemed to be a spectacular Kraken lure. Pretty much guaranteed the bug where you start bending when you go into timewarp, until you bend too far and the ship bursts into an expanding cloud of debris.

If we start talking non-stock, the plasma engines from KSPI are great for shifting hefty chunks of rock. You'd think the DT Vista engines would be awesome, but I tried that, and there's a few ... problems ...

Oops.

A variety of tips from my experience moving heavy asteroids (class E):

• Use a single claw, puller-style
  
• Set up the node you want to use, get yourself pointing in that direction, then line up with the asteroid's center of mass and dock (if you were already clawed to the asteroid, it may be worth undocking and redocking rather than trying to rotate a stupid-huge asteroid and then get it stopped again) - this one's not always necessary but can be helpful
  
• Strong RCS and plenty of monopropellant to fuel it will help keep your ship pointed in the right direction
  
• Unlock the claw's pivot while thrusting so it's like you're dangling the heavy asteroid off a rope, so it will always swing back into line - make sure you have enough RCS to keep yourself pointed in the right direction before trying this, though, or it'll still swing you around
  
• MechJeb makes long-duration burns oh so much easier to deal with, if you're into that kind of thing
  

Edited May 24, 2014 by ArcFurnace

[XOIIO]

Well, once my single claw one started moving a bunch, it turned into a kraken every time, I have a setup with 3 on a strutt frame right now, I'll see how that goes.

Also turns out the large SAS module provides torque just like the inline reaction wheel so I slapped two of those on.

as tempting as some mods are I am sticking with stock so that I don't have to wait around whenever an update is released to use my stuff.

I didn't bother aligning the puller last time and it worked excellently, it's a class C asteroid, I'll just target the center of mass before I latch on and it should be good enough. I'm not doing super precise stuff, just getting it decently close to the space center.

Edited May 24, 2014 by XOIIO

[ArcFurnace]

Ah, class C, yeah, that's probably a lot more forgiving, especially if you're not trying to be super precise. Interestingly, even within a class (I focused on class E asteroids for my collection) there's very substantial mass variance. The very first Class E the game threw at me (on a collision course with Kerbin, no less- sure gave that career save's tech progression a kick in the pants when I rushed to get to technology powerful enough to stop it) was ~800 tons, which seemed big at the time, but the biggest was ~3200 tons or so, and most were rather more than 800; that first one was actually unusually small.

Those are all Class E's. The one named Apophis was the one I mentioned earlier as the first one I caught off a collision course (one of the others was also spawned on a collision course ... makes me wonder if there's a reason the Kerbals are so space-program obsessed). I should really get around to renaming the rest of those and getting more-accurate mass values one of these days. Circular equatorial orbits at intervals of 1000km, because I had plasma engines and felt like making it a challenge.

Edited May 24, 2014 by ArcFurnace

[XOIIO]

O.O the get to 3200 tons?

Crap, setting up a collection in a tidy line might be harder than I thought, I was going to try and rid up a big heavy truck to pull them with rocket assist.

Nice in orbit collection though, I want to network a bnch together in a large cluster using claws and beams, and make something like the magog world ship form Andromeda XD

[cantab]

I've heard rumours of 5000-tonners, but it seems like anything much above 3000 tons is rare.

My design for wrangling a C class used four little SAS/RCS units with their own claws, distributed around the asteroid. Made it handle nicely, though I don't know how well it would scale up. The drive section's a pusher and a bit underpowered with a single LV-N, I'm going to swap it out for a cluster of six when the rock flies by Kerbin on its way to Duna.

[merendel]

If we start talking non-stock, the plasma engines from KSPI are great for shifting hefty chunks of rock. You'd think the DT Vista engines would be awesome, but I tried that, and there's a few ... problems ...

Talking non stock another nice option to have is either Kerbal Attachment System or quantum struts. QS in particular you can very easily lock on very tightly as soon as the claw grabs on. Set the struts on an action group and you can engage/disengage at will if you need to free the pivot and adjust slightly. Kas also alows you to add struts in flight but you actualy need to fly a kerbal out there to place them. Once you get it properly struted that joint is rock solid and you dont have any wobble when trying to turn a roid.

[XOIIO]

Working well, one connected, set it to free pivot and connected the other, they look broken but are not. Unfortunately this thing is spinning around a fail bit when you apply thrust, I am a little off the center of mass, I guess since it's a fairly light asteroid it has a lot more effect.

I can't do anything accurate with it right now.