Return Money

[7499275]

Hey guys, fooling around with... Okay, not fooling around, doing a KSP series with the MKS mod, modular colonization.

It states, that you can make money by returning harvested, and refined resources. Now I understand how this works. Send up an empty cargo ship, fill it, land at Kerbin, retrieve and than you get money.

My problem is, you need to be able to launch a ship with a largo cargo capacity, to Minmus, return it, and make a profit. It seems simple except for the launch vehicle because even though the cargo compartment is empty its still gonna weight a fair amount. I have considered changing the density of the resources but that feels too much like cheating. A SSTO could do it the best (100%) vehicle recovery just minus the fuel. However... It would have a much smaller payload cap and would need to be stable when empty and fully loaded.

Suggestions?

[zekes]

Try this, it's 100% reusable.

Z12 Medium Lifter

Designer: Zekes

Status:

COMPLETED

This launcher is 100% reusable, and comes in two stages. The first stage is 7 SRBs, and decouples right after the gravity turn starts. The second stage takes the ship to a 200km apsis (about 5 minutes lead time) so that you can switch to the falling 1st stage. The parachutes should open automatically. Hit "Recover Vessel" as soon as it touches down, otherwize it might tip over. Then, switch back to the 2nd stage, circularize the burn (or as much as you can with a little fuel leftover). Then, decouple and deorbit the 2nd stage with the remaining fuel, and follow it down to see the parachutes open and recover just like the 1st stage. Max tonnage to orbit is 13-17 tonnes.

Download: https://www./?ou5gc708yyui15l

Cost: $36,304.00

Refund Value (for safe recovery): $16,000 Approx

[7499275]

thank you Zekes, however, I would rather use a craft, I construsct. Just need ideas on how to do it. I'd rather not have to deal with swtiching to boosters to recover them.

[Claw]

Realize that at some point, carrying all that excess SSTO weight will cost you more in excess fuel than what it would have cost to simply throw an SRV or tank away. I haven't done the math to figure that out yet, but there will be a threshold out there where it's cheaper to throw away.

-Claw

[Pecan]

SSTOs are only one way to look at it:

SSTO planes will need a lot of parts and mass to get up so they can bring back the resources (plus all the time messing-around flying them).

SSTO rockets will need a lot of fuel to get up so they can bring back ... some fuel?

The alternative way to think of things is ... refuel with the material you've harvested. Launch transfer/lander stages empty of fuel - huge launch-to-orbit mass reduction, therefore launch-vehicle size & complexity. Refuel with your new resources you haven't had to drop into the gravity well just to launch it again. Keep vehicles in space, instead of using them for a single mission then recovering them.

ETA: Oh yeah, and if you do want to SSTO, a KR-2x1 (or whatever it's called) will lift 10t to orbit and be able to perform a powered landing afterwards. If you want to lift 20 tons use two of them, etc. Who cares what it costs to build' you'll be getting all that back when you recover it.

Edited August 6, 2014 by Pecan

[7499275]

SSTOs are only one way to look at it:

SSTO planes will need a lot of parts and mass to get up so they can bring back the resources (plus all the time messing-around flying them).

SSTO rockets will need a lot of fuel to get up so they can bring back ... some fuel?

The alternative way to think of things is ... refuel with the material you've harvested. Launch transfer/lander stages empty of fuel - huge launch-to-orbit mass reduction, therefore launch-vehicle size & complexity. Refuel with your new resources you haven't had to drop into the gravity well just to launch it again. Keep vehicles in space, instead of using them for a single mission then recovering them.

ETA: Oh yeah, and if you do want to SSTO, a KR-2x1 (or whatever it's called) will lift 10t to orbit and be able to perform a powered landing afterwards. If you want to lift 20 tons use two of them, etc. Who cares what it costs to build' you'll be getting all that back when you recover it.

Problem, I'm not harvesting "fuel". its other resources instead. No Kethane is nearby.

My only problem with a space plane will be having a huge difference in CoM to CoL balance coming back due to a couple tons of cargo that it did not have on launch.

[Pecan]

Yep - so make it a rocket. Much easier to balance a tail-sitter than something that has to fly to a horizontal landing. I have no problem doing SSTO with a 40t payload and returning with 15 (payload after mission complete, fuel expended).

Gah! I'm post-pub and it's late. I'm trying not to give to many hints because you said "however, I would rather use a craft, I construsct.". I realise that might mean I'm just not making sense ^^.

Goodnight all.

[Laie]

Realize that at some point, carrying all that excess SSTO weight will cost you more in excess fuel than what it would have cost to simply throw an SRV or tank away.

That point may be hard to reach. Too lazy to look up precise figures, but IIRC the tank itself is about eight times as expensive as the fuel it holds. Boosters however ... *pfffft*

thank you Zekes, however, I would rather use a craft, I construsct. Just need ideas on how to do it. I'd rather not have to deal with swtiching to boosters to recover them.

Then just pick up the general idea: an SSTO doesn't need to be a plane. Meaningful rocket SSTOs are entirely possible. And I suggest that you're not too strict about recovering everything, either: boosters really are cheap. Just look at how many boosters you can buy at the price of a single orange tank.

However, if your hardware can handle it, you may try jets as a recoverable booster replacement. For a rocket ascent, I strongly recommend basic jets.

[Wanderfound]

http://forum.kerbalspaceprogram.com/threads/88628-Kerbodyne-D7-Heavy-X5-a-heavy-lift-SSTO-spaceplane

All stock parts, ~40 ton to orbit and back for about √5,000 (just an example, I get that you'd like to design your own). The idea that SSTO spaceplanes are restricted to light payloads is a myth.