Using Multiple vessels for missions

[Grover]

I was curious about the benefits of using two seperate vessels for missions to the Mun and Minmus (where the science grinding will be going on), focusing mainly on the "cost" of the solutions. I know money isnt yet a factor in our space programs (i guess the kerbal government gave us all a blank cheque), but when money does become an issue, getting our science done cheaply may be a serious consideration

so i designed two solutions, the first being my usual munar science lander/return craft, with all the science apparatus on board and enough fuel to take me from Munar insertion (where the final launcher stage leaves me, similar to the Apollo missions) to return, including everything i would need, mainly power, and the total cost racked up to just shy of 26k

then i designed a second solution, using one command module for the munar insertion and trans-Kerbin ejection, and a seperate lander, with the science apparatus on, capable of simply landing and returning to the CSM after completing the science. in stock KSP, there is a fatal flaw in this design, whereby the CSM command pod cannot store all the science data to be returned, so by using a couple EVA Data Storage Pods, created by Talisar and available here i could transfer the science from the lander to the CSM pod to be hauled home.

this solution, though using far less fuel overall, required an RCS system for docking procedures, and two docking ports, all costing moolah, ending up with a total cost of just over 35k

the big difference is partly down to the extortionate price of the mk1 lander can, which costs 2600 (compared to the mk1 pod which costs 600), so we can safely assume that teh cost would be 2k less when money becomes an issue and the can is appropriatley priced, but that still leaves a 7000 [insert Kerbal currency here] difference in cost, in FAVOUR of the simpler, less efficient solution.

so, my question is, is there a benefit to using multiple vessels for a mission in this way, other than using less fuel overall, (though your dv is not necessarily increased because you have the mass of two pods, two engines, RCS system etc added on) in place of using one simple craft built efficiently enough to perform the same mission?

for those wondering, the .craft files are here. you will need Kerbal engineer redux and the data storage containers installed, otherwise all is stock

Thanks peeps

[Dispatcher]

I'm not sure how it really boils down in KSP, but from the standpoint of overall dV use in real crewed space programs, it usually saves dV when one has the separate components of surface to orbit flight, orbit to orbit, and then orbit to surface; especially when those steps can be reversed for a 2 way mission. Of course on a 2 way trip the final 2 components may be combined (the capsule jettisoning for a parachute landing, for example).

To clarify: the launcher for everything (or SSTO to dock with orbiting interplanetary ship), the interplanetary ship and the destination lander.

In the past, my interplanetary missions have been of the "launch that behemoth into orbit" variety. The interplanetary portion is mainly a dock-able set of fuel tanks and engines. My lander is also the command module when attached to the interplanetary ship. Once I get serious about Career mode and Science, I can see that your questions will be interesting in relation to my approaches to interplanetary travel. I find Kerbal Engineer to be very useful (and MechJeb too) for such mission design.

[Godot]

There is one example of which I can think of already now:

As soon as Biomes on Duna (and other planets/moons) are unlocked, it makes sense to split a mission into 2 stages:

1. Remote-Launch an orbiting station to Duna ... this station consists of a science lab and as much fuel as you can get into Duna-Orbit (also, if using TAC, a lot of supplies for Kerbonauts) and of course one or more docking modules

2. Launch a manned mission to Duna ... with an interplanetary spaceship and a docked lander and all types of science modules that you have available fitted onto the lander.

Upon arrival your spaceship + lander docks to the Duna station (which you launched in mission 1), your lander crew goes into the lander can and then the laner is used to explore all Biomes, docking to the station after each single mission, transferring the science to the spaceship and resetting its science modules and refilling its tanks with the stations facilities.

Finally, after the Biomes have been explored, the spaceship returns to Kerbin, with all science and its Kerbal crew.

Much more efficient (and cheaper) than using a single mission for each Biome on the planet.

(in small scale this already can be used now, for Mun and Minmus)

[Grover]

There is one example of which I can think of already now:

As soon as Biomes on Duna (and other planets/moons) are unlocked, it makes sense to split a mission into 2 stages:

1. Remote-Launch an orbiting station to Duna ... this station consists of a science lab and as much fuel as you can get into Duna-Orbit (also, if using TAC, a lot of supplies for Kerbonauts) and of course one or more docking modules

2. Launch a manned mission to Duna ... with an interplanetary spaceship and a docked lander and all types of science modules that you have available fitted onto the lander.

Upon arrival your spaceship + lander docks to the Duna station (which you launched in mission 1), your lander crew goes into the lander can and then the laner is used to explore all Biomes, docking to the station after each single mission, transferring the science to the spaceship and resetting its science modules and refilling its tanks with the stations facilities.

Finally, after the Biomes have been explored, the spaceship returns to Kerbin, with all science and its Kerbal crew.

Much more efficient (and cheaper) than using a single mission for each Biome on the planet.

(in small scale this already can be used now, for Mun and Minmus)

hm, so i guess its not cost effective for a single mission, but when planning a longer science campaign (multiple missions) it is far beneficial to use it in conjunction with the lab in a polar orbit (so it can reach every biome), allowing for more than one missions gain in science to be earned with only one flight to and from (plus perhaps a few refuelling missions, but when youre not carrying a heavy pod, you can carry a LOT of fuel, which doesnt need to return either because it can perform lithobraking at the destination planet/moon to clean itself up

i guess me design might see some use after all

[Sirrobert]

For the Mun I don't care so much about it, but when I design landers for other planets, I always go for a seperate lander/command module.

This to make sure the lander doesn't have to carry the fuel needed to return back up from the surface

[Markus Reese]

For Mun and Minmus, I found that the single vessel works more than decent enough. The fuel to intercept and dock back up is about equal to what it would take to perform an atmospheric braking orbit for kerbin. On top of that, if you have side engines, they work well to have a wide based and stable lander. Really the main part between the Appollo missions and KSP is this fuel usage and support equipment. The orbiter had longer term survival, alot more fuel just to make a landing, plus all the electronics necessary.