Sisyphus - Industrial Class E Hauling

[SlithyTove]

First post here since this is the first thing that I have built that actually seems worthy of sharing.

It's primary purpose was built to handle a contract to throw a Class E asteroid out of the kerbin solar system. Yikes. Still can't believe I accepted that contract. But it's secondary purpose is that it is re-usable, so with this one ~$500k craft without re-supply I can throw as many class Es into kerbin orbit (or quite a few other places) as needed. Industrial asteroid hauling. The pictures are of it throwing a 2100 ton asteroid out of Sol SOI. It could certainly tackle the 3500+ ton monster E-class asteroids.

I decided to pull rather than push which required that I have engine which can clear the edges of a class E. I pretend to ignore the fact that engine backwash only extends a relatively short distance in Kerbal physics and act like I actually have to clear the asteroid as in real life. So it is long, tall, and has engines set on a slight angle to avoid hitting the asteroid with rocket backwash. This robs a bit of power and efficiency but still not too bad.

Design Features:

Structural spine: All power is transimitted to the claw through connected trusses with high strength. Nothing weak and destructable like in-line reaction wheels. Very tough and very rigid. Mk I and Mk II failed due to Kraken attacks. Mk III has so far has resisted all Krakens.

Dimensions: The final stage is about the tallest thing that can be built in the VAB and still manipulate all the pieces. 57.5 meters tall and fairly wide at 25 meters width.

Low part count: Parts were shaved constantly to keep lag low. Precision flying is needed for craft this large and lag is a killer. Final stage is a modest-for-the-size 271 parts and 153 tons.

Reaction probes: Features four small detachable and re-dockable probes which are basically just double stacks of large reaction wheels and rcs thrusters that can be distributed around the asteroid to improve handling. When docked they help the mothership turn during maneuvers.

Mining: Double drills and ISRUs flow fuel up to the main engines through a set of interconnected small tanks

Verdict: Unladen it flies pretty well, one of the least wobbly craft I have piloted especially considering it's size. When laden it is capable of holding a flight direction with only minor wobble and the ISRUs and drills mostly keep up with fuel consumption. Doing 180 turns while hauling the 2100 ton asteroid are no problem at all. Burn times are long, but it was designed to set on a course and be able to leave it alone while it does its thing. Except there is one problem: there is a bug in Kerbal's fuel model which restricts fuel to one of the four engines if I run the ISRU's at the same time. Needless to say unbalanced engine output is disasterous in a craft this large. So this one is getting mothballed until they fix that bug. But in the meantime the $1.1 million Sisyphus Heavy is currently in flight testing over Kerbin.

[Mad Rocket Scientist]

I love how it looks prepared for launch! Nice work, one day I should try to redirect an asteroid...

[Jon144]

I love how it looks prepared for launch! Nice work, one day I should try to redirect an asteroid...

To hit Kerbin

But yes. Very Industrial. I love it!

[SlithyTove]

I love how it looks prepared for launch! Nice work, one day I should try to redirect an asteroid...

Thanks!

I had only redirected one other asteroid prior which was a 50 ton class C to minmus orbit. It gave me so much trouble that my mind fairly exploded at a contract to throw a class E out of the system.

[Rune]

Hum. Four nukes, right? And you say only one of them could be run with the refinery? I saw a similar thing with mine, it auto-throttled to 35.1kN, matching the refinery with a benign thermal profile (I'm starting to suspect the fixed radiators don't actually radiate anymore than standard parts). So, since I also could hold a course with only cursory input every five mins or so as I read a book, I think I did the same thing that you did... "slightly smaller", and certainly more reusable. As in, I only spent fuel:

Rune. I make about 1m/s per minute... orienting it for burns, though, takes patience (and physical timewarp for >15º turns).

Edited September 15, 2015 by Rune

[SlithyTove]

Hum. Four nukes, right? And you say only one of them could be run with the refinery? I saw a similar thing with mine, it auto-throttled to 35.1kN, matching the refinery with a benign thermal profile

It wasn't really that it could only run one of them. Even with full tanks, if I turned on the ISRU it throttled down one of the four engines. So I would be getting three engines running at full and one at < 50% or so which would unbalance the flight pattern pretty quickly. I tried throttling down the opposite side's engine to compensate, but then a different engine would have trouble.

I'm impressed you could get a class E hauler into a cargo bay! Probably a lot closer to something we would use in real life.

I went multi-engine and big when I started looking at things like ~50 hour burns. With it throttled down due to the bug, maybe even more like 80 hours? Was shooting for something that I could set on course, go to sleep, and wake up to discover I'd earned $2.8 million.

Those radiators definitely seem to suck up more than their fair share of heat when I look at the thermal overlay while the craft was running. I think the big radiators are probably overkill for just about any situation though.

[Darth Lazarus]

"KSC? We have succesfully redirected minmus to a low kerbin orbit... ksc ... do you copy?"

sweet "little" ship you got here

[SlithyTove]

"KSC? We have succesfully redirected minmus to a low kerbin orbit... ksc ... do you copy?"

sweet "little" ship you got here

Hehe, Minmus does seem to be a bit much to handle. Now Gilly on the other hand.... if KSP physics didn't classify it as a planet/moon we could probably come up with something that could drop Gilly directly on the KSC...

[pTrevTrevs]

Mein Gott, it's huge!!!

I've never tried to capture an asteroid before, but this makes me want to try it. I'll probably take the weenie route and wrangle a puny little Class A though.