Ideas on how to move Class E asteroid to Pol

[fireblade274]

:huh:I need ideas on how to move a Class E asteroid to Pol lol. I've never asked for help in how to design my own ship, but im making an exception for this:huh:

I decided to use what ive been using for C and D ones, which is mainly a Mk3 5000u rocket fuel tank, 4x Mk1 400u rocket fuel tanks with 4 LV-A engines, ore hopper, and drill. I attached it to the "not yet mined" Class E and with only 300 delta V, I decided to add a second "booster" section with the Mk3 10,000u rocket fuel tank and 2 LV-A engines, and I got 980 delta v. I needed at least 2800dv to get to Jool, and even more then that to orbit around Pol (Jool moon with highest orbit). Note that I would have gotten more DV if i got to the point where I would de-couple my 10000u empty fuel tank. I saved and decided to try it out anyways to see how everything preformed. (note I am using a Engineer as the craft operator, so this should increase my ore yield right?)

Here is a picture of what I tried to use:

https://www.dropbox.com/s/sn52xdu8kt7xl75/2015-08-14_00004.jpg?dl=0 that was it swaying to the left

One second later its back to center https://www.dropbox.com/s/sib4y8m83y1qwn8/2015-08-14_00005.jpg?dl=0

The craft is in line with the asteroid's center of mass

I got half way through my Delta V until i new this would need major changes. My craft would sway quite a bit, increasing even more as the 10,000 rear fuel tank emptied. I used a total of 4 large SAS units to help, but they didnt help that well. Maybe place more of them at the end of my craft? 3 were in the middle of the final craft (see pictures) and one at the end of the 10000u fuel tank.

I feel like I need to move the weight closer to the asteroid, yet increase the total weight of the craft. The best way I can think of to do this is with multiple launches and making it in stages, probably more then the 2 I used previously.. I would also have to make sure what ever I assemble wont be too big and encompassing, as you all know we cant place struts once in space (though that would be awesome if engineers could do that)

This is to get it to Pol, but originally before I even saw the mission, I'd been wanting to take a Class E and attach it to my space station orbiting Jool. The way this went in my head, I could then have a large supply of fuel there without having to launch many expensive re-fueling missions; this is seeming less and less possible after realizing how much effort it is to control and move these objects, but if there is anyway to move the thing there--with enough ore left inside it to keep my space station happy--im very down to try.

I'm having a lot of trouble visualizing it all.. Anyone have their 2 cents?

[FancyMouse]

I've towed a 4000t class E from an Kerbin escape trajectory to a (highly eccentric) orbit, using 64 Ions without mining it at all, but I only spent about 200m/s dV for this purpose. My experience is:

Reaction wheel does nothing. You need to constantly adjust claw pivot, and use engine thrust to gain torque. It's going to be tedious, and if you feel lucky you can try 5x warp to stop rotation - if krakens happen to be away from you.

Mining is a must for all practical and sane purposes. However given this big dV requirement, I don't really know how much you really need from your ship and how much asteroid you can expect at the destination. I would guess only a fraction about 1/4 or so, but that's a wild guess.

But going back - expensive refueling mission? You probably need to rethink about the design there. Usually with a drilling base, fuel tanker (to move around fuel), and orbital station, it's self sufficient in terms of fuel - after the infra is set up, you don't launch something new to refuel. Ships dock to orbital station to refuel, and tanker transports the fuel produced from drilling base when necessary.

[cantab]

What I've done for my asteroid redirections is to dot a few "control sections" around the asteroids. These each have a claw and some reaction wheels and/or RCS/vernors. Then for my main drive section, which is a pusher, I want relatively little control - engine gimbals locked and light on the reaction wheels. The idea is that the control sections turns the asteroid and the turning asteroid turns the engines with it. The final element is to use an engine cluster and individually adjust the thrust limiters to fly straight. You can either check the "thrust torque" value in KER, or watch which way the asteroid veers and reduce thrust on the "outside" of the curve.

I'll add the caveat that the biggest thing I shifted was a 500 ton class-D.

[fireblade274]

FancyMouse-- WOW 4000 tons is a monstrosity.. The one I attempted was about 1500 tons Thanks for your input, maybe I should try using Ions with lots of gas? and a single LV-A that is being constantly fed by drilling on the asteroid, so I don't need a large fuel tank?

You also bring up a good point, instead of moving the asteroid, make a station out of the asteroid to be a base and bring fuel to other places. That seems less of an engineering mountain and a good way to go (though id still like to know what it will take to move the E to Jool with a good amount of it left, just because lol)

Can you tell me a good fuel tanker design fundamental you use? I'm thinking ill just use what I normally would; a 10000u tank with a few asparagus stages, and 2 LV-A motors to reduce fuel consumption as apposed to using 3 or 4? I don't mind long burn times; my longest one was 45 min, moving a station to Jool from Kerbin. Or do you think using a bunch of Ions would work?

The idea is that the control sections turns the asteroid and the turning asteroid turns the engines with it.

Cantab-- Control sections is genius! But they have to be connected to your main pushing section, right? I'm visualizing them as separate "ships" dotted at all 4 sides, and top & bottom, but then its like you cant control their actions while controlling your main pusher section.. Making a connected "ring" around it sounds very complicated.. Do you have a picture? And you should take on a Class E yooooooooooo and let me know how you do lol

Does anyone have experience to share in regards to using the least amount of fuel possible when transporting fuel efficiently? Im thinking Ions over LV-A's but is it possible to make that viable?

Edited August 15, 2015 by fireblade274

[FancyMouse]

This contains what I tried, and no, unless you want to torture yourself like what I did, Ion is a bad idea. Go drill.

And my tanker is along this line, although it may not fit your requirement because this is even capable of lifting off itself from Mun when you don't need that.

[fireblade274]

dam you weren't kidding! 2 days?! Yea Ions bad idea..

[cantab]

Cantab-- Control sections is genius! But they have to be connected to your main pushing section, right? I'm visualizing them as separate "ships" dotted at all 4 sides, and top & bottom, but then its like you cant control their actions while controlling your main pusher section.. Making a connected "ring" around it sounds very complicated.. Do you have a picture? And you should take on a Class E yooooooooooo and let me know how you do lol

The claw acts like a docking port, so once everything is set up it all acts as one ship.

https://flic.kr/p/nVTQZ7 that's my old tug with a class D. I had a mere 100 m/s of delta-V but it was enough to arrange an aerocapture into Kerbin orbit.

[Mastikator]

Dres has Asteroids around it. It might be useful to go there, use ISRU to refill on a smaller Asteroid then do a hoffman transfer to Jool from Dres.

I don't know if Dres is guaranteed to have class E asteroids though. I haven't tried this, it's just a thought

[Sharpy]

I'm fairly sure my Claymore could do it. It took a very reasonable time bringing a Class E from a very bad orbit - highly inclined, almost retrograde, into LKO. If you pick one of Dresteroids, bringing it to Pol shouldn't be all that hard. Just refuel at one of local asteroids before the trip

[Kuansenhama]

Mine most of the ore and dump it. If the asteroid is 90% ore that will take you from 4,000 tons to 400. Maybe don't dump all the ore, leave enough to make into fuel for the DV you need to get there.

I might also recommend Kerbal Joint Reinforcer if you're moving anything bigger than say C-class asteroids. Some say this mod is kind of cheaty, but if you want to move big asteroids without your ship flexing and wobbling and flying off course, it's a must. It also gradually introduces physics forces if you find your ship is getting jolted by the asteroid every time you come out of warp; this will fix that.

[Sharpy]

Don't dump the ore. Burn it along the way That way you don't need to struggle with Nukes and can use something with more kick.

[Mastikator]

I'm fairly sure my Claymore could do it. It took a very reasonable time bringing a Class E from a very bad orbit - highly inclined, almost retrograde, into LKO. If you pick one of Dresteroids, bringing it to Pol shouldn't be all that hard. Just refuel at one of local asteroids before the trip

https://dl.dropboxusercontent.com/u/3152580/sshots/screenshot31.png

What dark sorcery did you use to put that monster into space?!

[Sharpy]

Just finished the KerbalX upload so that you could try for yourself A meager √663,131 from which roughly half goes boom during launch. (though if you have StageRecovery or something, I guess you could adapt most of them to be recoverable.)

[fireblade274]

Sharpy that is one fantastic ship, I can tell that very well could have been a massive headache constructing that behemoth

[Geschosskopf]

The easiest way to move an asteroid to the Jool system would be to start with an asteroid already approximately in Jool's orbit. I suspect such things exist but I'm not sure. I'm sending a SENTINEL out to orbit between Jool and Dres to look for exactly such things, plus KBOs and comets.

[Sharpy]

Sharpy that is one fantastic ship, I can tell that very well could have been a massive headache constructing that behemoth

Actually, it wasn't all that hard once I had the concept in my head. MK3 parts for durability and joint strength, highest ISp engines with reasonable thrust, enough of a distance between the engines and the asteroid not to burn it and enough distance between the engines and the hull not to burn it when they swivel. Then ISRUs on the free, open surfaces, gigantors out of the way of the engines, some fuel tanks, cupola (All engineering crafts get a cupola), and all the rest of the goodies necessary. Funny that to attach cupola I had to sink the "blade" in VAB floor and to attach the drills I had to move the cupola through VAB roof.

For launch stage I went with the asparagus setup, which while costly, is very efficient. Since all my nose cones were shock cones (least drag) jet boosters were too tempting not to include. The initial TWR was very low (and that means wasteful) so I added some SRBs for initial kick, to give the rest some time to burn some fuel and let the jets acquire some thrust - once the SRBs burn out the TWR of the rest is quite reasonable.

The actually tricky part was developing all the "operation procedures", from launch that wouldn't burn away all the gigantors or rip the drills off, through turning the asteroid without breaking the joints, to switching the ISRUs off for duration of the burn to achieve full thrust. The "Procedures" part on the KerbalX entry was the hardest work.

[Belphegor]

... as you all know we cant place struts once in space (though that would be awesome if engineers could do that)

before 1.0 i've used KAS mod (kerbal attachment system) to secure oversized wobbly loads to the transfer stage in space. i'm not sure if the mod is updated or still functional but it may be worth checking it out. it allows you to bring spare parts on your ship (like struts, rcs ports, ...) and manually attach/remove them during EVA

[cantab]

KAS is still up to date. It's now been "split" into two mods, KIS (Kerbal Inventory System) handles moving parts around and attaching/removing them from ships, while KAS proper has parts like struts and winches for use with KIS.