Economy of design

[bongorider]

What is the most economical design to achieve orbit? Even though money is unlimited at this stage in the game, it seems it will become an issue eventually since parts have a pricetag. Has anyone been working on different designs for best economy? At the moment there are no payloads other than the capsule itself, (Maybe use full fuel tanks as payload to make it harder) but it seems like this is a good challenge since it is one of the main problems facing real life space travel.

[DeCi]

Chute

-------

Pod

------

Dcoupler

---------

SAS

---------

2xfuel

--------

engine

--------

dcoupler

---------

tricoupler

----------

2x SAS

----------

9xfuel (3 on each arm)

3x engine (1 on each arm)

-----------

3x small booster.

[bongorider]

Chute 422

-------

Pod 1600

------

Dcoupler 975

---------

SAS 2300

---------

2xfuel (550 +550) 1100

--------

engine 850

--------

dcoupler 975

---------

tricoupler 680

----------

2x SAS (2300*2) 4600

----------

9xfuel (3 on each arm) (550*3) 1650

3x engine (1 on each arm) (850*3) 2550

-----------

3x small booster. (450*3) 1350

I make that as $19052. Is that just your personal best or is that generally accepted as the easiest way?

[Jarod]

Chute

--------

Pod

--------

Decoupler

--------

2 Fuel Tanks

--------

1 Engine

--------

Decoupler

--------

Tricoupler

--------

3 SAS modules

--------

3 Fuel Tanks (1 on each arm)

--------

3 Engines

That's the smallest 2-stage vehicle I have to achieve orbit (and reentry).

[Iskierka]

What's with the excessive SAS modules? These designs need at most 1, between the decoupler and the tricoupler. Sure, it needs a little flying if you use that little, but not much.

I believe the cheapest orbital design though is:

Chute

Pod

Decoupler

2x LFT (liquid fuel tank)

1x LFE (liquid fuel engine)

3x radial decoupler

3x SRB

I may be wrong though. And even though that one works, if being slightly difficult to perform, I prefer designs like Jarod's

[Jarod]

What's with the excessive SAS modules? These designs need at most 1, between the decoupler and the tricoupler. Sure, it needs a little flying if you use that little, but not much.

You're right.

I changed it to 1 SAS module.

Chute

Pod

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

Decoupler

2 Fuel Tanks

1 Engine

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

Decoupler

1 SAS module

Tricoupler

3 Fuel Tanks (1 on each arm)

3 Engines

Achieve orbit, maneuvers and reentry.

I prefer fuel engine for the launch stage because when it's empty, I'm at 10000 m, ignite the second stage and yaw to 45 degrees.

[Ice]

I usually go with

Chute

Pod

SAS module

------

Decoupler

Fuel tank

Engine

------

Decoupler

Tricoupler

6 Fuel Tanks (2 on each arm)

3 Engines

Plus additional things needed (like bombs on radial decouplers or solid engines with chutes), because then its usually a little heavier and thus the double fuel tanks.

[Animal Mother]

Chute

-------

Pod

------

Dcoupler

---------

SAS

---------

2xfuel

--------

engine

--------

dcoupler

---------

tricoupler

----------

2x SAS

----------

9xfuel (3 on each arm)

3x engine (1 on each arm)

-----------

3x small booster.

Basically what I've been using, but I'm sure the boosters clip into the platform, causing it unable to lift unless you manually fire the next stage

[DeCi]

Basically what I've been using, but I'm sure the boosters clip into the platform, causing it unable to lift unless you manually fire the next stage

Or fire the liquids at the same time as the boosters.

[Finrandojin]

parachute

---

pod

---

coupler

---

fuel tank

fuel tank

fuel tank + 3 boosters on radials

sure it's very demanding of the pilot but I can manage it 2 out 3 times now

[Eduardo X]

I've gotten into a low orbit with a module/parachute, decoupler, 3 fuel tanks and a liquid engine. It's cheap and quick.

[mekilljoydammit]

http://kerbalspaceprogram.com/forum/index.php?topic=113.0

Will reliably do a 100km circularish orbit. Getting down is more iffy.

[Elukka]

Parachute

--

Pod

--

Decoupler

--

4 x fuel tank

--

Liquid engine

--

Decoupler (to get around the weird stuck-on-pad bug)

Single stage to orbit with plenty of fuel left to deorbit. If you really wanted to stretch it, 3 fuel tanks is probably doable if you pilot it ideally. I don't think it's possible to get much more minimal than this.

[foamyesque]

It isn't the most economical, but it's damn easy:

SAS modules are for sissies. They give you a huge performance hit.

[Spacew00t]

Parachute

--

Pod

--

Decoupler

--

4 x fuel tank

--

Liquid engine

--

Decoupler (to get around the weird stuck-on-pad bug)

Single stage to orbit with plenty of fuel left to deorbit. If you really wanted to stretch it, 3 fuel tanks is probably doable if you pilot it ideally. I don't think it's possible to get much more minimal than this.

Good job, people really over estimate what they need to achieve orbit. Unless you can get a lot more thrust, adding more fuel has diminishing returns.

It isn't the most economical, but it's damn easy:

SAS modules are for sissies. They give you a huge performance hit.

Agreed, I've never needed SAS modules.

[foamyesque]

Single stage to orbit with plenty of fuel left to deorbit. If you really wanted to stretch it, 3 fuel tanks is probably doable if you pilot it ideally. I don't think it's possible to get much more minimal than this.

After testing:

Parachute, CM, Tank, Tank, Tank, LFE.

SSTO, with enough fuel to deorbit. Parameters pending.

EDIT:

O'course, you can't land it very easily, the parachute doesn't have the oomph. For an unmanned flight you could cut it, too, and get even better performance. I don't know if it's feasible with the addition of a coupler, I suppose that's my next test.

EDIT2:

Orbit is 115km x 42km. Precision flier, I ain't, and I don't have the fuel to circularise. =(

[Elukka]

Mine has a decoupler under the capsule! It doesn't hurt performance too much.

[foamyesque]

Mine has a decoupler under the capsule! It doesn't hurt performance too much.

You also have a fourth fuel tank. I'll try with but the margins are pretty thin here.

[foamyesque]

Okay, with a decoupler module the ship doesn't even take off until I've burned a quarter tank. This, unfortunately, makes getting into orbit more or less impossible. =(

EDIT:

Which makes me wonder how the hell you managed it with four fuel tanks.

EDIT2:

Okay, sticking a decoupler on the bottom and detonating it makes the rocket lift off immediately but turns the stack into a wobbly mess.

What the hell.

EDIT3:

Even using the decoupler bug to launch the thing, the addition of the upper stage decoupler makes a tripletank SSTO launch impossible, as far as I can find. The speed and altitude just aren't there.

EDIT4:

Damnit. 37km up, 2.1km/s... so close. I'd make it if I didn't have either the parachute or decoupler. Anyone know what the most efficient burn path is? I go straight up, full throttle, to around 430m/s, then tip sideways to get the horizontal. I've tried gaming the throttle but I haven't found a method that results in better final energies than full throttle all the way.

[Finrandojin]

Anyone know what the most efficient burn path is? I go straight up, full throttle, to around 430m/s, then tip sideways to get the horizontal. I've tried gaming the throttle but I haven't found a method that results in better final energies than full throttle all the way.

try to time your pitchover so that your ascent rate is 0 when you are at about 50 km, also after reaching about 2000 m/s you can just stop burning for a while and wait for apogee, burns at apogee are more effective at raising your perigee with the least amount of fuel spent.

[Jarod]

Ok I guess the next step is to be able to drop a full fuel tank in orbit (space gas station) and come back.

Didn't succeeded so far with a minimalist design.

[foamyesque]

try to time your pitchover so that your ascent rate is 0 when you are at about 50 km, also after reaching about 2000 m/s you can just stop burning for a while and wait for apogee, burns at apogee are more effective at raising your perigee with the least amount of fuel spent.

I'm having trouble, on the triple tank w/coupler design, getting above 35k, let alone higher. Couplers are irritatingly heavy. =(

[Warringer]

With the medium engine from the Wobbly Parts mod, I was able to make orbit with this:

chute

capsule

----

decoupler

----

SAS

liquid tank

liquid tank

medium liquid engine

And six sold boosters attached to the single stage...

Broken or not?

[DeCi]

With the medium engine from the Wobbly Parts mod, I was able to make orbit with this:

chute

capsule

----

decoupler

----

SAS

liquid tank

liquid tank

medium liquid engine

And six sold boosters attached to the single stage...

Broken or not?

Absolutely not considering the medium engine is designed to lift much bigger stacks.

[HarvesteR]

My personal best to achieve orbit with minimal parts:

Parachute (optional)

Pod

-----

Decoupler

-----

Fuel

Fuel

Fuel

Fuel

Liquid Engine

-----

3x radial decouplers

3x SRBs

So it's a 1.5 stage thing, with only the pod to provide control and stability. But the design is rather stable, and it can achieve low orbit with about 1/3 of the last tank to spare.

Cheers