an asteroid ship?

[Brainlord Mesomorph]

Given this:

http://www.nasa.gov/feature/reconstituting-asteroids-into-mechanical-automata

and my current contract to capture a class D asteroid,

Anyone think I can turn it into a ship? and mine fuel my way across the solar system?

Edited April 14, 2016 by Brainlord Mesomorph

[Jhawk1099]

Well if you were using a nuke power plant then you would have the Delta-v to go anywhere but the big problem would be getting your center of thrust directly behind the center of thrust of the asteroid 

[steuben]

A better design would be setting it up as a puller design rather than a pusher. With the claw on free pivot the centre of mass takes care of itself.

[Kerbart]

3 minutes ago, steuben said:

A better design would be setting it up as a puller design rather than a pusher. With the claw on free pivot the centre of mass takes care of itself.

With the engines a good distance away from the surface of the asteroid, unless you want to blow it up (been there, done that).

[Jarin]

I assume it would also matter what the ore richness of the asteroid is, and what it comes out to in fuel/weight ratio.

[Brainlord Mesomorph]

It seems to me that If I use a Claw, clamp down, and then free the pivot and "lift" up on it  (pulling) with RCS thust, shouldn't it just find a line opposite the CoM?? (then lock)

Edited April 14, 2016 by Brainlord Mesomorph

[Jarin]

14 minutes ago, Brainlord Mesomorph said:

It seems to me that If I use a Claw, clamp down, and then free the pivot and "lift" up on it  (pulling) with RCS thust, shouldn't it just find a line opposite the CoM?? (then lock)

Seems like it'd certainly be worth a try.

[Pecan]

16 minutes ago, Brainlord Mesomorph said:

It seems to me that If I use a Claw, clamp down, and then free the pivot and "lift" up on it  (pulling) with RCS thust, shouldn't it just find a line opposite the CoM?? (then lock)

In theory, yes, but you still face the 'wobbly rocket' proplem with pushing.  Using a pull arrangement means the asteroid/payload will always fall into line behind you neatly.

[LordKael]

I feel like the best way to do this would be to launch a series of modular chunks of rocket up, so that you can use RCS to simply move the thrusters, ISRU/drills, and fuel tanks around to adjust the CoM vs CoT relationship.

[OutlawFarmer]

2 hours ago, LordKael said:

I feel like the best way to do this would be to launch a series of modular chunks of rocket up, so that you can use RCS to simply move the thrusters, ISRU/drills, and fuel tanks around to adjust the CoM vs CoT relationship.

I feel like this would be super tedious, making a long puller would seem ideal.

 

My only asteroid related craft is a pusher and I tried it on the class E I think, honestly.. didn't end very well, I was able to claw it in the right spot to push in the direction I wanted but after a little burn (using about 25 nukes) my craft started to bend one way so I cut power and she whipped back around the other way, it all went downhill from there, any attempt I tried to rest the motion just made it worse...

At the point where my engines were 90 degree to the asteroid I just said to hell with this and blasted full power, saw some fireworks and returned to the KSC.

Luck jeb took a day off and I used a probe

[LordKael]

2 hours ago, OutlawFarmer said:

I feel like this would be super tedious, making a long puller would seem ideal.

 

My only asteroid related craft is a pusher and I tried it on the class E I think, honestly.. didn't end very well, I was able to claw it in the right spot to push in the direction I wanted but after a little burn (using about 25 nukes) my craft started to bend one way so I cut power and she whipped back around the other way, it all went downhill from there, any attempt I tried to rest the motion just made it worse...

At the point where my engines were 90 degree to the asteroid I just said to hell with this and blasted full power, saw some fireworks and returned to the KSC.

Luck jeb took a day off and I used a probe

You know, I agree that it would be super tedious, but if they all rendezvoused with the asteroid as a single craft, then split up and enveloped the asteroid, then it's much more doable. 

Also, your anecdote seems to prove why a long craft is the wrong design for the job...

[OutlawFarmer]

3 minutes ago, LordKael said:

You know, I agree that it would be super tedious, but if they all rendezvoused with the asteroid as a single craft, then split up and enveloped the asteroid, then it's much more doable. 

Also, your anecdote seems to prove why a long craft is the wrong design for the job...

Oh I didn't realize you ment every component will attach separately, that could be interesting

And I believe my craft will work if made into a puller rather then a pusher

Ill test it when I get home next week, maybe even a video

[FyunchClick]

5 hours ago, Pecan said:

In theory, yes, but you still face the 'wobbly rocket' proplem with pushing.  Using a pull arrangement means the asteroid/payload will always fall into line behind you neatly.

In my experience with an E class with 16 LV-Ns in pull configuration there still tends to be an awful lot of instability involved as the whole thing is rather heavy and any stabilization using either reaction wheels or vernors sets it thing oscillating, with very little you can do in the way of dampening it. Without locking the claw it was even worse as there's even less dampening.

I ended up making a lot more passes to wrangle in a circular LKO than I originally planned, to act as a stepping stone to fuel my interplanetary missions.

[LordKael]

2 hours ago, OutlawFarmer said:

Oh I didn't realize you ment every component will attach separately, that could be interesting

And I believe my craft will work if made into a puller rather then a pusher

 

1 hour ago, FyunchClick said:

In my experience with an E class with 16 LV-Ns in pull configuration there still tends to be an awful lot of instability involved as the whole thing is rather heavy and any stabilization using either reaction wheels or vernors sets it thing oscillating, with very little you can do in the way of dampening it. Without locking the claw it was even worse as there's even less dampening.

 

There's some interesting physics as to why pushers will almost always work better than pullers, which somebody who has a firmer grasp of them can explain. 

If we were to think of this problem as a free body diagram, then it actually becomes very simple. Take the CoM of the asteroid, and attach the drive section so that it provides a force straight through the CoM. Then, to allow the drive section to do a useful amount of work, attach an ISRU unit and several drills somewhere that the CoM won't be moved.

Ideally, you will want the CoT going straight through not only the CoM, but also the approximate center of volume (CoV) so that when you aerobrake at the target body, the asteroid doesn't flip around nearly as much. Now, this suggests putting the entire assembly on in a single taller vessel, so that everything is protected by the asteroid's mass and bulk during reentry, but that is, in fact, the wrong way to do this. The best (in my opinion) way to wrangle an asteroid is to attach a series of very short modules to the surface all on one side of the asteroid, such that you can align the CoT, CoM, and CoV, which will translate roughly to having the CoL/CoD in that same line during an aerobraking maneuver.

Having all of the components in a single rocket will increase the likelihood of the rocket flexing under the thrust, even when using the relatively low thrust of a NERVA cluster. My solution prevents that as much as possible. One can even have a drive section made up of only a Klaw, probe core, and the engines, as the asteroid will cross-feed between tanks clawed to any other part of it, which allows for some truly low profile Asteroid Wrangling modules.

TL;DR: build a bunch of shorter modules and attach them closer together, because taller rockets get all wobbly, which runs the risk of an escalating procession, and a lack of controllability to the massive space rock.

[cantab]

I did an asteroid ship long before mining was a (stock) thing.

https://flic.kr/p/nTmzTU

I grant it's not the biggest rock, but a pusher seemed to work fine for me. Two key aspects I feel make it work. An engine cluster means I only need to align the drive section more-or-less, and can fine tune by setting thrust limiters. And steering is handled by the separate "control sections", they act to turn the asteroid which in turn turns the drive section with it. This avoids the problem with a single pusher ship where trying to turning left bends the claw such that the thrust actually acts to turn right.

[Xyphos]

Get out those square girders... lots of them. build 3 or more arcing girder arms with claws on both ends.
what you want to do, is build a nerva-powered rocket with mining equipment that can meet up with the asteroid,
have that rocket grapple on to the asteroid, after adjusting for the center of mass,
then deploy and attach your girder arms probes to the asteroid using the claws.
then jiggle the whole thing using RCS to make the other end's claws attach to the central rocket.
these "claw-arms" act as struts to reduce the wobble you'd normally get without them.
now you can push or pull your rock, depending on how you setup the engines.
just note that the longer your arms are, the more joints and wobble you'll get.
try to reduce the part count as much as possible per arm,
but the more arms you deploy, the less it will wobble.

Edited April 15, 2016 by Xyphos

[samstarman5]

I definitely recommend the short story "Misfit" by Robert Heinlein. It gives some ideas about what might be required to turn an asteroid into a controllable craft.  I wouldn't mind if Squad took up the challenge of wireless linking of modules in order to use them as one unit. It would actually make moving asteroids a lot easier, not to mention give new opportunities to do other crazy kerbal stuff.

[Speeding Mullet]

If Patcan is sitting in the command chair during a 3.2 km/s re-entry does that make the asteroid a ship? 

Seriously though I read the Mars trilogy last year by Kim Stanley Robinson (WHAT a series) and asteroid "ships" did feature but obviously as hollowed out objects.  Would be amazing to be able to do the same in KSP and so great to see it, but I'm forever going to remain hopeful on that one I think.

SM

[Zoidos]

You can even turn an asteroid into a spaceplane and land it. Just ask @5thHorseman

 

[l0k0]

This is my E class asteroid ship.

I managed to put it in a 120km equatorial orbit with many many aerobrake manouvers, a lucky close encounter with the mun and a lot of fuel mined from the rock for changing the plane. Despite of it, there's 2,500t left.

So now it's an orbital fuel station... long travels will require lighter ships. And I also can see it from KSC!!!

 

Edited April 16, 2016 by l0k0
cannot embed imgur gallery - ok made it

[RocketBlam]

Fifth Horseman turned one into an airplane once, and this was before you could get fuel from them!

[Renegrade]

Er, this "puller" business sounds a lot like the pendulum rocket fallacy... unless some wonky aspect of Unity/PhysX or KSP physics is making that actually work (which is entirely possible heh).  I've never used a puller myself, I always managed to get by with pushers.

On 2016-04-15 at 1:07 AM, samstarman5 said:

I definitely recommend the short story "Misfit" by Robert Heinlein. It gives some ideas about what might be required to turn an asteroid into a controllable craft.  I wouldn't mind if Squad took up the challenge of wireless linking of modules in order to use them as one unit. It would actually make moving asteroids a lot easier, not to mention give new opportunities to do other crazy kerbal stuff.

I haven't read the story, but if you're talking about festooning an asteroid with controllable, useful parts, you can already do this in stock.  Keep in mind that the asteroid is in fact a craft like anything else - a single part, big, ugly craft.  Therefore, you can attach anything you want to it via claws and control it.

My pusher craft have little modules that detach that are basically a probe core, panels, batteries, RCS thrusters and a claw.  I re-attach these all over the asteroid with the claws, and then I have solar input and RCS thrust from everywhere.  Other uses could be made too - an almost-balanced aster-ship could be balanced more finely with some sort of ballast attachment, for example, or crew modules could be added, ISRU modules, etcetc.

[Choctofliatrio2.0]

That'd be an interesting idea! If I ever captured an asteroid, I'd try it (I really should start practicing redirecting asteroids)

[Curveball Anders]

It's a classic SciFi dream to use a comet or an asteroid as a ship/base/station.

KSP allows it, I'll get around to it once I'm done with Mars/Duna (so 2020 or so).

[AbacusWizard]

Star Fleet Battles includes a species of roaming aliens called the Jindarians who make ALL of their ships out of hollowed asteroids, with warp drives installed in the aft craters and railguns in the fore craters. I used tiny volcanic pebbles (intended for landscaping) for the miniatures.