Economy of design

[boolybooly]

IMHO orbit is both AP and PE over 70,000m.

Flying the flight profiles in the 'supplied spacecraft' challenge does help make the lift more efficient.

But if you want a limo ride and guaranteed safe landing of with Pod, Parachute, Decoupler, ASAS then I think 5 tanks is the minimum.

[sal_vager]

Well I can get to a stable 70k orbit with:

Chute

Capsule

Stack Decoupler

Fuel tank x3

Light engine

With fuel left to de-orbit, and that\'s with my crappy flying, I read someone did it with 2 tanks and no chute or decoupler, but that\'s beyond me.

Edit:

The 2 tanks to orbit was done by foamyesque in this thread, his post: http://kerbalspaceprogram.com/forum/index.php?topic=555.msg101237#msg101237

He didn\'t say if he got down safe, I\'m thinking the answer is 'No'

[foamyesque]

That\'s correct, I didn\'t, but earlier in this thread, PakledHostage managed it.

[foamyesque]

Finally got around to uploading a video of one of my launches, for those curious about how to do it.

[PakledHostage]

Playing around with the Tsiolkovsky rocket equation, it occurred to me that I could get a stock 1-1/2 LFT rocket into orbit that could also return safely to the surface. I borrowed Kosmo-not\'s idea of using a large LFE in the first stage and a small LFE in the second stage, but placed the large LFT on the upper stage.

Interestingly, the delta-V for this stack with a parachute (4875 m/s), is actually greater than the Delta-V for the Pod-2LFT-LFE, without parachute stack (4537 m/s), even though it has 1/2 tank less fuel! This means it is easier and takes less fuel to send our heros on a survivable mission than an almost certainly suicidal one...

Here are my screenshots:

Splashed down after 1-1/2 trips around Kerbin

[sal_vager]

Very nice PakledHostage, is this because you have a much shorter high power burn letting you lose the weight early, then you have a much more efficient long burn to orbit?

I have had some success saving weight before by burning off the LV-T30 with the LV-909, saving the weight of the decoupler, maybe that trick could work here letting you ditch the LV-T30 even earlier and have both tanks on the upper stage?

[PakledHostage]

Is this because you have a much shorter high power burn letting you lose the weight early, then you have a much more efficient long burn to orbit?

To be honest, I\'m not sure... I would guess that it is because the first stage quickly boosts us to something close to the optimal climb speed that was worked out by Clossette, et al. It does this by about 1000 m altitude at which point it is possible to reduce throttle to about 2/3 and climb at something close to the optimal ascent profile until the fuel runs out. Following staging, the LV-909 then maintains something close to the optimal climb speed profile (albeit a bit on the slow side) the rest of the way to orbit.

I have had some success saving weight before by burning off the LV-T30 with the LV-909, saving the weight of the decoupler, maybe that trick could work here letting you ditch the LV-T30 even earlier and have both tanks on the upper stage?

It is an interesting idea. I guess you\'d run a fuel line down to the LV-T30? I have to admit that I\'ve never actually used fuel lines in any of my designs. My Kerbals are luddites. Maybe you could improve on this design with your own tweaks?

[PakledHostage]

I'm probably one of the last of the "regulars" to try out v0.16 but I finally got to it this evening. And I figured that since so much has changed with the stock components, I would start by just trying to get to orbit. I didn't want to launch just any rocket though. I wanted to reach orbit on a fuel budget. I did some calculations and figured I could do it on 4 tanks with a two stage rocket, but it turned out that I was overly conservative in my assumptions. On my second mission, I replaced a full LFT in the first stage with a small LFT. Those 3-1/2 tanks were enough to get me into orbit and back to a landing on the KSP compound. I am sure someone can do better but I'll post my mission highlights anyway...

These are my screenshots:

Landed after 4 trips around Kerbin

Edit: Fixed a broken link to an image

Edited August 8, 2012 by PakledHostage

[Atimed]

What is the most economical design to achieve orbit? Even though money is unlimited at this stage in the game.

Hope I'm not late..

Well here's a simple orbiter, just on the way back don't forget to turn on the parachute like i did..

P.s. its fuel bug proof i was always at 100% or at 0% thrust..

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.....Ascend........Gravity Turn....Orbit Height....Curricular Orbit.....Landing.....

[ATTACH=CONFIG]30904[/ATTACH] [ATTACH=CONFIG]30905[/ATTACH] [ATTACH=CONFIG]30906[/ATTACH] [ATTACH=CONFIG]30907[/ATTACH] [ATTACH=CONFIG]30908[/ATTACH]

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Keep up the good work.. Edited August 8, 2012 by Atimed

[arbiter26]

My absolute cheapest design:

600 - Capsule

225 - FL-T200 Fuel Tank

750 - LV-909 Engine

450 - RT-10 Booster

450 - RT-10 Booster

450 - RT-10 Booster

Total: 2925

Get as much out of each booster as you can, but make sure you use the next stage to overheat before it finishes. You'll have to burn at max to reach orbit, so the fuel bug is irrelevant. Landing is difficult, but not impossible without a parachute.

[Markus Reese]

Best I had was:

MK16 Parachute

MK16 Pod

FL-T200 Fuel Tank

LV-909 Liquid Fuel Engine

----------------

TR-18A Stack Decoupler

FL-T400 Fuel Tank

FL-T400 Fuel Tank

LV-T49 Liquid Fuel Engine

That setup can get up to, capture orbit and land. I simply cannot get a landing one any cheaper.

[Nao]

Welp i managed 3610m/s at 86 km (with 85km Pe) - its more than enough for Kerbin escape velocity

cost: 2400

RT10 upside down: 450

command pod: 600

RT10: 450

RT10: 450

RT10: 450

Decopuling was done by engaging next engine just as previous was running out of fuel overheating it and "decopuling" it with a bang (fun note: engine with something attached to the bottom doesn't actually add thrust).

With one booster less it's not possible to achieve orbit .

I don't really consider it a valid way to create cheap rockets but it's fun. I also seriously consider this newly discovered decoupling technique for my real rockets now. XD

[gyroscope]

Best one I had into orbit was

*Chute

*Pod

*Decoupler

*T-250 fuel tank

*T-250 fuel tank

*T-250 fuel tank

*T-30 rocket engine

[Rickenbacker]

In 0.16 I just got an 83km stable orbit, with half a tank of fuel left (more than enough to deorbit) with the following:

Parachute

Pod

Decoupler

LFT x 3

LFE

Probably helped by the fuel bug, though, as I used less than 2/3 throttle through the lower atmosphere.

[Rickenbacker]

Aha! Tried a simpler, cheaper design, not dependent on the fuel bug. I'm sure many others have tried it before me, but it works like a charm, gets into a 90-100km orbit with half a tank of fuel left.

Parachute

Pod

Decoupler

LFT

LFE

SRB

SRB

SRB

Just light the next SRB off a few seconds before the previous one burns out. It'll overhead and blow up, which works for staging . Once the SRBs burn out, it's a simple matter of a few short full throttle burns with the LFE to get into orbit and circularize.

[RedDwarfIV]

Isn't there a design that can make a Munar return because it's so damn tiny?

[Avatar98]

parachute

---

pod

---

decoupler

---

T-400 Fuel tank - 4 radial decouplers - 4 T-400 fuel tanks ( one on each of the decouplers)

---

A fuel line from each of the radial tanks, straight to the engine

---

LV-T30 engine, under the central fuel tank.

The radial tanks are dropped as soon as they are empty.

[DEADBEEF]

If we're allowed MechJeb then this is pretty simple....

It cuts it a little fine on the fuel (25L left), but that's the entire thing....

* MechJeb pod edition ball -

* 400L fuel tank - 850

* Aerospike engine - 850

Total - 4700

Although light, the MechJeb pod ball is ridiculously expensive though, so it's actually cheaper to go with a living pilot and get extra fuel for the additional weight...

* Single capsule - 600

* 400L fuel tank - 850

* Aerospike engine - 850

* 2X radial decouplers - 400

* 2x fuel hoses - 500

* 2x 200L fuel tanks - 450

Total - 3650

In orbit...

I added a radial mount MechJeb (+550) just to see if could actually get into orbit and MechJeb got it up there first time with ease.

It took me around 10 attempts to get it into a nicely circular 75km orbit though as it's really tight on fuel (5L left for a 75km orbit when I did it manually, vs 30L for MechJeb).

[maro]

pod 600,-

chute 422,-

decoupler 975,-

3x2x FTL400 5100,-

3 x LVT45 2850.-

2xTT38K Rad-decoupler 2550,-

2 x FTX2 fuelduct 500,-

12.997,- (80x328km orbit + deorbit + 50l left(could be more))

For the time beeing liquid paralell staging and feeding fuel inwards trough the stages is the most economical way i have found.

Works with 2-4-6-8 boosters and so on.

Example - inner core with 6 boosters

you stage

- inner core

- boosters 1&2

- boosters 3&4

- boosters 5&6

- engines start inner + 1 to 6 all paralell

fuel ducts are running from 5->3->1->inner and 6->4->2->inner

when you launch all engines running using fuel only from boosters 5+6

you drop 5+6 and all other stages are still full of fuel and you have not break in acceleration because engines running trough during separation.

there is also no dead weight of unused engines to carry (except of an upper stage)