100t Payload on a Budget?

[spinomonkey]

I'm attempting to push a 100t payload into Kerbin orbit, about 5 million meters out. In particular what I'm attempting is this: I want to take a Kerbodyne S3 144000 filled with fuel and use it to refuel my orbiting Space Station. But- because this is career mode I'm on a budget. The best I've done is about 1 Orange Fuel tank for $300,000. I'm starting to wonder if numerous small runs are better then one large run.

Orbiting Space Station: Currently has two fuel tanks mounted on the bottom- but there's room for 4 if I ever can find a cheap(ish) method to send fuel. Until recently it hasn't been a huge deal. With each module I added to the station, the extra fuel was filling the tanks. But now that construction is finished, I need a solution.

Thanks-

Edited December 28, 2014 by spinomonkey
Answered Question

[silks]

The cheapest way to get payload to orbit tends to be via SSTO spaceplanes. It requires more time to design one and also to fly into orbit but could reduce the cost of one orange tank to a mere few thousand currencies(or however much fuel is burned). Check The Spacecraft Exchange sub-forum for some SSTO design ideas.

[GoSlash27]

spinomonkey,

If you have everything unlocked, the cheap way to go about it is a turbojet SSTO lifter.

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/Lifter-Ception

This one can lift over 20 tonnes of payload into LKO for the cost of $1,000. Since it's fully recoverable, you won't lose any funds operating it (unless, of course, you crash it).

If you want a copy of the craft file, just let me know.

Best,

-Slashy

[Pecan]

Something like ? 740.925t, 52 parts, cost 320,866.

Not as efficient as a jet launch like Slashy's (spaceplanes aren't worth it at this mass) but it's a SSTO, so reusable, and a whole lot simpler.

[Anquietas314]

Something like http://i.imgur.com/iCBdSA0l.png? 740.925t, 52 parts, cost 320,866.

Not as efficient as a jet launch like Slashy's (spaceplanes aren't worth it at this mass) but it's a SSTO, so reusable, and a whole lot simpler.

Why not? You can use the new Mk3 parts to lift things on this scale. Granted it's a lot of work, but in terms of (money spent - money recovered) it will probably be cheaper than a giant rocket like that.

[spinomonkey]

I haven't found a solid solution just yet- but I appreciate the feedback. Thanks guys!

[Pecan]

Why not? You can use the new Mk3 parts to lift things on this scale. Granted it's a lot of work, but in terms of (money spent - money recovered) it will probably be cheaper than a giant rocket like that.

1) Spaceplanes aren't worth it for a 100t+ payload because you need so many wings and things the extra mass doesn't pay for itself even if you get the 2% extra recovery for landing on the runway (I'm assumng people practice enough to land SSTOs 'at KSC' for 98% anyway).

2) A tail-sitter jet (vertical takeoff/vertical landing) "like Slashy's" has all the efficiency advantages of jets without the mass and awful part-count of a HTOL. I didn't say the rocket was cheaper - I offered it as 'easy'; and although it uses a LOT more fuel than a jet-launch it ain't exactly expensive either, since it's a recoverable SSTO. Still, you build me a <52 part spaceplane that lifts 100t to orbit and we'll start talking.

3) Now ... Mk3 parts? What are they for? Ohhhh, I seeee - you think somehow it makes it cheaper/easier/simpler if you ALSO carry a cargo bay to put the payload IN!

Good luck with that then.

I look forward to your cheap 100t+ payload spaceplane designs.

Still with me. Stock. < 350k initial cost, anything extra better be paid for by your 2% extra recovery. <= 52 parts or explain how easy to build it is. Simple, fast, flight to orbit - because rockets do.

Altogether now ... Hodo, Wanderfound and (no doubt) a few other spaceplane specialists might be able to.

... Everything aside, I'm not saying that rocket is a great design. I'd never launch 100t at a time anyway. If I were designing an economical launch-vehicle for that though I'd first ask how many missions it's expected to perform (how many can I spread the build-cost over) and then what the per-launch fuel costs and recovery-losses were. I have yet to see any spaceplanes beat an equivalent tail-sitter under several 10s of missions, because their (potential) extra 2% recovery doesn't cover their build-cost due to added complexity.

(It gets as complicated as the discussions about whether the US Space Shuttle was 'economical' or not and comes down to 'depends what you mean'. If you want to use spaceplanes then do so. For me, it isn't worth it to the extent I'd often rather use a very simple, easy, fuel-hungry rocket for a few hundred extra funds per launch than even a very-efficient tail-sitter).

[Anquietas314]

1) Spaceplanes aren't worth it for a 100t+ payload because you need so many wings and things the extra mass doesn't pay for itself even if you get the 2% extra recovery for landing on the runway (I'm assumng people practice enough to land SSTOs 'at KSC' for 98% anyway).

The 2% extra recovery isn't the only factor here: rockets consume much more fuel than spaceplanes. If it's a huge rocket like that one, that can start to become significant. The fuel in an orange tank costs just shy of 3k funds. You have 16 orange tanks on that rocket; obviously at least one of those is payload (I'll assume 3 - it's difficult to tell from the screenshot). That leaves 13 to launch, which costs ~38k in fuel. Never mind the rocket and 2% loss from landing at KSC but not the launchpad/runway, assuming you managed to do that.

2) A tail-sitter jet (vertical takeoff/vertical landing) "like Slashy's" has all the efficiency advantages of jets without the mass and awful part-count of a HTOL. I didn't say the rocket was cheaper - I offered it as 'easy'; and although it uses a LOT more fuel than a jet-launch it ain't exactly expensive either, since it's a recoverable SSTO. Still, you build me a <52 part spaceplane that lifts 100t to orbit and we'll start talking.

Okay, why the 52 part restriction? Obviously planes require wings, intakes, engines, etc. That means high part count in stock, although I imagine with pWings and pParts (does it have intakes?) you could get that way down. Secondly, jet-powered tailsitters are a real pain in the backside to land unless you use parachutes - and if you do, you'll need an engineer to repack them in case you miss your landing site.

Edited December 29, 2014 by armagheddonsgw

[GoSlash27]

1) Spaceplanes aren't worth it for a 100t+ payload because you need so many wings and things the extra mass doesn't pay for itself even if you get the 2% extra recovery for landing on the runway (I'm assumng people practice enough to land SSTOs 'at KSC' for 98% anyway).

2) A tail-sitter jet (vertical takeoff/vertical landing) "like Slashy's" has all the efficiency advantages of jets without the mass and awful part-count of a HTOL. I didn't say the rocket was cheaper - I offered it as 'easy'; and although it uses a LOT more fuel than a jet-launch it ain't exactly expensive either, since it's a recoverable SSTO. Still, you build me a <52 part spaceplane that lifts 100t to orbit and we'll start talking.

3) Now ... Mk3 parts? What are they for? Ohhhh, I seeee - you think somehow it makes it cheaper/easier/simpler if you ALSO carry a cargo bay to put the payload IN!

Good luck with that then.

I look forward to your cheap 100t+ payload spaceplane designs.

Still with me. Stock. < 350k initial cost, anything extra better be paid for by your 2% extra recovery. <= 52 parts or explain how easy to build it is. Simple, fast, flight to orbit - because rockets do.

Altogether now ... Hodo, Wanderfound and (no doubt) a few other spaceplane specialists might be able to.

... Everything aside, I'm not saying that rocket is a great design. I'd never launch 100t at a time anyway. If I were designing an economical launch-vehicle for that though I'd first ask how many missions it's expected to perform (how many can I spread the build-cost over) and then what the per-launch fuel costs and recovery-losses were. I have yet to see any spaceplanes beat an equivalent tail-sitter under several 10s of missions, because their (potential) extra 2% recovery doesn't cover their build-cost due to added complexity.

(It gets as complicated as the discussions about whether the US Space Shuttle was 'economical' or not and comes down to 'depends what you mean'. If you want to use spaceplanes then do so. For me, it isn't worth it to the extent I'd often rather use a very simple, easy, fuel-hungry rocket for a few hundred extra funds per launch than even a very-efficient tail-sitter).

All of this.

If I'm just doing a one-off launch, I'm not going to bother building an expensive reusable launch system for it. Makes more sense to slap together a cheap, disposable rocket.

A vertical mass lifter like what I've shown here is really best for chucking outsized and massive structures that don't conveniently fit in a spaceplane. This would be stuff like chunks of space stations/ ships/ etc.

A spaceplane is generally preferable for moving supplies and Kerbals to/from orbit. It doesn't operate quite as cheaply as a vertical mass lifter, but it gives you a lot more safety options if something goes wrong during the launch, whereas with a vertical mass lifter the payload would be doomed. Plus it lands on the runway.

Needless to say, my Kerbals are forbidden to ride anything into orbit other than spaceplanes.

Best,

-Slashy

Edited December 29, 2014 by GoSlash27

[Pecan]

The 2% extra recovery isn't the only factor here: rockets consume much more fuel than spaceplanes. If it's a huge rocket like that one, that can start to become significant. The fuel in an orange tank costs just shy of 3k funds. You have 16 orange tanks on that rocket; obviously at least one of those is payload (I'll assume 3 - it's difficult to tell from the screenshot). That leaves 13 to launch, which costs ~38k in fuel. Never mind the rocket and 2% loss from landing at KSC but not the launchpad/runway, assuming you managed to do that.

Okay, why the 52 part restriction? Obviously planes require wings, intakes, engines, etc. That means high part count in stock, although I imagine with pWings and pParts (does it have intakes?) you could get that way down. Secondly, jet-powered tailsitters are a real pain in the backside to land unless you use parachutes - and if you do, you'll need an engineer to repack them in case you miss your landing site.

Does the fuel really cost that much? - ah well, I'll give you that then. It's never been significant in my games. (All those fuel tanks are fuel - the NRAP on top is the 100t payload) With 2% loss that thing would cost 15k per launch as well.

That gives you a 63k per-launch premium for your spaceplane (630 funds/tonne) or, expecting 10 launches, a budget of 950,000 funds to build the thing in the first place. Should be do-able, although my machine probably couldn't run a flight if I wanted to do anything else during 2015 ^^.

52-parts solely because simplicity is one of the virtues of that rocket (probably its only one). Jet-tailsitters, like any well-designed SSTO, come down almost empty of fuel - therefore they mass much less than at launch and whatever rocket engine(s) you use for circularisation should be ample to power-land if drogue-assisted. Why would I want an engineer when the thing's unmanned? I'm recovering the vehicle, why would I repack chutes 'in the field'? In the unlikely event I miss KSC I'd just take the extra few % recovery-loss.

Remember, I only said "spaceplanes aren't worth it". There are many factors apart from price that affect 'worth'. The OP asked for a "cheap(ish)" solution and I offered one which I think is the part-, simplicity- and time-optimal while still being reasonably cheap. Slashy had already given the cheapest solution, which is a tail-sitter.

Between cost-optimal tail-sitter jet SSTO and almost-everything-else-optimal rocket SSTO, where is your proposed spaceplane SSTO?

[Anquietas314]

Between cost-optimal tail-sitter jet SSTO and almost-everything-else-optimal rocket SSTO, where is your proposed spaceplane SSTO?

Right now, I don't have a tier 3 R&D in my career save; I'm not about to spend an hour or two in sandbox designing a plane that may or may not be viable to settle an internet argument, but if you want to we can follow this up in a few days time (I'm nearly at 6 million funds! nearly! ). In any case, OP wanted a refueler rather than a generic payload lifter. No cargo bay required, plus you can easily do it in a few launches if you can't quite get a spaceplane to lift 100 tonnes of fuel in one shot (and it'll probably still cost less). I probably will be using Mk3 parts (mental note to install pWing first) to launch/assemble a usable space station though; should be fun

[Pecan]

No worries mate, do it if you think it's worth it. Separate, smaller, launches sounds like a much better idea to me too; how often is anyone going to need that much fuel in one go anyway!

If you do do it I really don't think the Mk3s will be the way to go and you ought to keep it stock so the rest of us can compare. No doubt your findings will be interesting, the most I've built a spaceplane to deliver is 40t (generic/dockable) at a time.

[Anquietas314]

If you do do it I really don't think the Mk3s will be the way to go and you ought to keep it stock so the rest of us can compare. No doubt your findings will be interesting, the most I've built a spaceplane to deliver is 40t (generic/dockable) at a time.

pWings would only be to keep the part count down - my computer's 9 years old dude, she can't take the strain of a 400 part behemoth that's mostly wings and intakes

[Pecan]

...- my computer's 9 years old dude, she can't take the strain of a 400 part behemoth that's mostly wings and intakes

Same here (*grin* see 'spaceplanes aren't worth it' in my earlier post; there are many things apart from cost to consider)

@spinomonkey - sorry if we've hijacked your thread a bit but this is 'worth' your consideration - do you really want to stick that much fuel in orbit?

[vladd148]

1) Spaceplanes aren't worth it for a 100t+ payload because you need so many wings and things the extra mass doesn't pay for itself even if you get the 2% extra recovery for landing on the runway (I'm assumng people practice enough to land SSTOs 'at KSC' for 98% anyway).

2) A tail-sitter jet (vertical takeoff/vertical landing) "like Slashy's" has all the efficiency advantages of jets without the mass and awful part-count of a HTOL. I didn't say the rocket was cheaper - I offered it as 'easy'; and although it uses a LOT more fuel than a jet-launch it ain't exactly expensive either, since it's a recoverable SSTO. Still, you build me a <52 part spaceplane that lifts 100t to orbit and we'll start talking.

3) Now ... Mk3 parts? What are they for? Ohhhh, I seeee - you think somehow it makes it cheaper/easier/simpler if you ALSO carry a cargo bay to put the payload IN!

Good luck with that then.

I look forward to your cheap 100t+ payload spaceplane designs.

Still with me. Stock. < 350k initial cost, anything extra better be paid for by your 2% extra recovery. <= 52 parts or explain how easy to build it is. Simple, fast, flight to orbit - because rockets do.

Altogether now ... Hodo, Wanderfound and (no doubt) a few other spaceplane specialists might be able to.

... Everything aside, I'm not saying that rocket is a great design. I'd never launch 100t at a time anyway. If I were designing an economical launch-vehicle for that though I'd first ask how many missions it's expected to perform (how many can I spread the build-cost over) and then what the per-launch fuel costs and recovery-losses were. I have yet to see any spaceplanes beat an equivalent tail-sitter under several 10s of missions, because their (potential) extra 2% recovery doesn't cover their build-cost due to added complexity.

(It gets as complicated as the discussions about whether the US Space Shuttle was 'economical' or not and comes down to 'depends what you mean'. If you want to use spaceplanes then do so. For me, it isn't worth it to the extent I'd often rather use a very simple, easy, fuel-hungry rocket for a few hundred extra funds per launch than even a very-efficient tail-sitter).

I've actually really gotten immersed into the spaceplane aspect and have been more or less obsessed for the past few weeks with designing an HL cargo plane, able to achieve a HKO, with minimal parts and operating costs able to lift 2 orange tanks each launch. Mind you I also use B9 parts and FAR so your miles may vary.

I don't have updated pictures of my latest model, but I have managed to get it down to 220k initial cost, 140t vehicle mass and 89 parts. Each launch and recovery (landing on KSC runway) costs me approximately 1000.

[Anquietas314]

I've actually really gotten immersed into the spaceplane aspect and have been more or less obsessed for the past few weeks with designing an HL cargo plane, able to achieve a HKO, with minimal parts and operating costs able to lift 2 orange tanks each launch. Mind you I also use B9 parts and FAR so your miles may vary.

I don't have updated pictures of my latest model, but I have managed to get it down to 220k initial cost, 140t vehicle mass and 89 parts. Each launch and recovery (landing on KSC runway) costs me approximately 1000.

1000 funds for fuel? Is that all?! I'm impressed - I'd expect it to be closer to 5k

[vladd148]

1000 funds for fuel? Is that all?! I'm impressed - I'd expect it to be closer to 5k

I will double check and post pictures of my next launch/recovery. Been meaning to haul some more fuel in space anyways. The only fuel that's actually being used during flight is stored in the SABRE engine pre-coolers.

[Pecan]

...I don't have updated pictures of my latest model, but I have managed to get it down to 220k initial cost, 140t vehicle mass and 89 parts. Each launch and recovery (landing on KSC runway) costs me approximately 1000.

Very nice :-)

[spinomonkey]

So an update: I've been playing with optimizing a rocket for an orange tank delivery. Seeings as the destination never changes I've been optimizing the staging to use solid states when possible to cut down on the costs. At the moment I've transfering about half an orange tank for about $150k, though I'd really like to do a full tank without going over $250k. I'll be playing with the mk3 parts tonight. I haven't used the cargo bays before, so that'll be interesting.

[Pecan]

..At the moment I've transfering about half an orange tank for about $150k...

I have no idea how '$' translates to KSP but if that's 150k funds per launch it's much too expensive!

LV-40-P, Chapter 7 of my tutorial (link in signature) is an unoptimised, disposable rocket designed for a 40t (orange-tube + accessories) payload that 'only' costs 104k.

[vladd148]

So an update: I've been playing with optimizing a rocket for an orange tank delivery. Seeings as the destination never changes I've been optimizing the staging to use solid states when possible to cut down on the costs. At the moment I've transfering about half an orange tank for about $150k, though I'd really like to do a full tank without going over $250k. I'll be playing with the mk3 parts tonight. I haven't used the cargo bays before, so that'll be interesting.

I don't know whether or not you play with mods, but I would honestly recommend using StageRecovery (now for 0.9). It is a great mod which allows you to put parachutes on your stages and recover them!

http://forum.kerbalspaceprogram.com/threads/86677-0-90-StageRecovery-Recover-Funds-from-Dropped-Stages-v1-5-3-%2812-22-14%29

[Laie]

This might be of interest: http://ksp.schnobs.de/tanker/T-80.html

A jet-powered tailsitter lifting one large Kerbodyne tank of fuel. The tank is part of the vessel, but it shouldn't be all that difficult to make it detachable.

$369k at launch, $357k recovered, $12k spent. Settling for 98% recovery would cost another 7000 funds.

208 parts and 15 Minutes (game-time) to orbit. Purists claim it's totally overpowered; for Pecan, 15min would probably be way too slow, without even considering part count and lag. Btw, it's tailored to what my box can still handle (a not too recent i5).

I've also written a kOS script that takes it to orbit so I don't have to babysit it myself, but that thing handles well under manual controls. With all those intakes at the rear the vessel will want to turn into the wind at high speeds; the many reaction wheels are necessary or you won't be able to snap out of it. For whatever reason, they work better than any amount of rudders and control surfaces.