Mun Cheapskate Challenge

[Jasonden]

The object of this challenge is to develop the cheapest possible system to deliver a Kerbal to the Mun, plant a flag, and then to return him safely to Kerbin. This is particularly useful in the sense that minimizing costs leads to maximized profits. In hard mode at 10% funds, planting a flag contract gives only something like $7000. So ideally you should be able to do it for cheaper than that!

By cheapest system, it doesn't need to be initially cheap -- it's net costs that matter. So if you recover stages then those costs do not count against you. You may use spaceplanes, rockets, ions, anything you want. There will be two categories -- stock and modded. Stock will count as stock parts that affect performance -- so MechJeb is okay. Modded parts and use of Parts recovery mods will be put in the other category.

No cheats, infiniglides, etc. Please post pictures of your craft at key points, and a calculation of your net cost. Also include the tech level of your craft -- I will include separate categories for cheap missions at varying technology levels.

Good luck, and let me know if you have questions!

[table="width: 500", class: grid]

[tr]

[td]Tech Level[/td]

[td]1[/td]

[td]2[/td]

[td]3[/td]

[td]4[/td]

[td]5[/td]

[td]6[/td]

[td]7[/td]

[td]8[/td]

[/tr]

[tr]

[td]Stock[/td]

[td][/td]

[td][/td]

[td] Mesklin $3672

bhauth $5943[/td]

[td][/td]

[td][/td]

[td]Tsevion $4372[/td]

[td]Tsevion $424

Jasonden $1433

Coam $6367 [/td]

[td][/td]

[/tr]

[tr]

[td]Modded[/td]

[td][/td]

[td][/td]

[td][/td]

[td][/td]

[td][/td]

[td][/td]

[td][/td]

[td][/td]

[/tr]

[/table]

And here's my entry to get things started -- $1433 net; just the cost of fuel, as all stages recovered for 100% return on the landing strip. Tech level is 7 due to the Probodobodyne HECS modules on stages 1 and 2 -- I think that I could get it down to 5 maybe by replacing the HECS with some Stayputniks and ASAS controls.

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Edited January 25, 2015 by Jasonden

[Agifem]

I'm afraid, above level 4-5, you'll only find SSTO spaceplanes. Their only cost is fuel, and they can land on the KSC more easily than rockets recovery stages. I doubt even ion gliders can compete.

At lower difficulty levels, it can be interesting to see what is the best design, and yours looks really cheap.

Edited January 14, 2015 by Agifem

[Tsevion]

I did this a few months ago... Gross cost: 5201, it's tech level 6 (decouplers oddly enough are the top tech needed). The returning pod is worth 1659 totally empty. No idea on the actual recovery value I would've gotten as the actual mission was run in a Creative save. So net cost is somewhere between 3542 and 5201, depending on recovery percentage.

It's pretty hard to beat me on gross cost though

[Jasonden]

http://youtu.be/BPvZc4AbYxo

I did this a few months ago... Gross cost: 5201, it's tech level 6 (decouplers oddly enough are the top tech needed). The returning pod is worth 1659 totally empty. No idea on the actual recovery value I would've gotten as the actual mission was run in a Creative save. So net cost is somewhere between 3542 and 5201, depending on recovery percentage.

It's pretty hard to beat me on gross cost though

I'm happy to give you at least half credit on your recovery value, as usually it's possible to hit the proper half of Kerbin. That puts you at $4372. Yeah, what I found was similar to you, it seems, in that SRBs are super-cheap for their top-line costs, but actually in terms of fuel alone liquid fuel/oxidizer is cheaper. Hence if you're recovering a stage you're better off with liquid fuel, but if you're disposing of it go solid.

- - - Updated - - -

I'm afraid, above level 4-5, you'll only find SSTO spaceplanes.

Oh I fully expect this! I'm a rockets guy so I always have jet people blow me away with their smaller designs

[bhauth]

Here's a tech level 3 entry. √7655, with a bit over 2700 m/s ∆V remaining in LKO. Without the landing legs it's √7255, and I'd also made one with manual solid booster staging that's slightly cheaper than that.

picture

craft file

[Jasonden]

Here's a tech level 3 entry. √7655, with a bit over 2700 m/s ∆V remaining in LKO. Without the landing legs it's √7255, and I'd also made one with manual solid booster staging that's slightly cheaper than that.

Looks good in principle -- can we see it in flight? Clearly getting the order of the solids right is going to be tricky; the rules do state that you need to show pictures of your craft at key points. I look forward to seeing it! I'm perfectly okay with manual staging, too, if that gets you cheaper You'll also likely gain some money back when you recover your vessel after being at the Mun, so that should help your bottom line.

[bhauth]

Looks good in principle -- can we see it in flight? Clearly getting the order of the solids right is going to be tricky; the rules do state that you need to show pictures of your craft at key points.

That's not the version with manual staging. It's just tweaked solid boosters and hitting spacebar twice.

I'll probably get around to getting screenshots of a Mun trip with it at some point.

[bhauth]

OK then, here's my tech 3 entry.

http://imgur.com/a/QpPTm

This wasn't in career mode so recovered parts aren't counted, and I didn't go to the trouble of landing at KSC, but going by the assembly cost of what was returned:

7330 - 3573 = 3757 net cost

[ttnarg]

Landing at KSC from a Mun trajectory is not easy I don't think its fair to can claim 100%. I think the lowest you can get is 10%? If Jasonden accepts this then it would be OK to claim the 10% giving you the score of 7330 - 3573 *0.10 = 6973

[ManlyPotatoe]

I will attempt this tomorrow. i need to dream about how i will achieve low prices.

[Coam]

First of all, I have to credit Tsevion for the idea of fitting a detachable fuel tank to the top of the craft and transferring fuel out of it. Before I tried that, this craft didn't seem to work very well. This design is already beaten for the tech-level (7, I believe. The most advanced part is the C7 adaptor.) but I thought I'd show it anyway as it's about as good as I can do.

Part Cost:11170

Parts Returned:4803

Net Cost:6367

This gallery doesn't cover the entire flight yet as I only started taking pictures when I realized it might actually work.

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1x SRB-KD25K

2x TR-18A Stack Decoupler

1X LV-T45 Liquid Fuel Engine

3X C7 Brand Adaptor - 2.5m to 1.25m

3x LT-1 Landing Struts

1x LV-909 Liquid Fuel Engine

1x Mk 1 Command Pod

1x OX-STAT Photovolaric Panel

1x RV-105 RCS Thruster Block

1x MechJeb (AR202 Case)

1x Mk2-R Radially Mounted Parachute

1x TR-2V Stack Decoupler

1x FL-T400 Fuel Tank

Flight profile:

SRB to ~8000m

2xC7 Adaptor fuel burned by LV-T45 to ~48,000m (possibly inaccurate, will update when I do a second flight)

1x FL-T400 fuel transferred to C-7 Adaptor and burned by LV-909 most of the remainder of the way to orbit, then jettisoned.

1xC7 Adaptor fuel burned by LV-909 for transfer to Mun, Mun landing, Mun liftoff, Orbit, escape to Kerbin influence, and retroburn back to Kerbin. There's a lot of delta-v in that top stage!

As a purely theoretical level 4 entry (Currently flight testing)

C7 Adaptors are swapped with FL-T800s, and the TR-2V Decoupler is swapped with another TR-18A. This should give a craft with identical performance (although harder to land without tipping.), leaving the most advanced parts as the OX-STAT Photovolaric Panels + The SRB. Initially I thought this cost the same, but in reality the final costs for this design are:

13,303 funds for the ship

5,703 returned to kerbin

=7600 total, over the 7000 ideal. (the FL-T800 is twice as expensive as the C7 Adaptor)

Edited January 17, 2015 by Coam
Updated Costs

[Mesklin]

Tier 3 craft, full recoverably, easy to fly, fuel cost is 3672

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[bhauth]

Mesklin: Are you using a recovery mod there? You seem to be going back in time when you switch craft.

[Jasonden]

OK then, here's my tech 3 entry.

http://imgur.com/a/QpPTm

This wasn't in career mode so recovered parts aren't counted, and I didn't go to the trouble of landing at KSC, but going by the assembly cost of what was returned:

7330 - 3573 = 3757 net cost

I'll give you half-credit for the returned ship, without direct evidence for the return value. That puts you at $7730-3573/2=$5943. Have to say, I love the explosive decoupling -- that is really hard to get right. Nice job!!!

- - - Updated - - -

First of all, I have to credit Tsevion for the idea of fitting a detachable fuel tank to the top of the craft and transferring fuel out of it. Before I tried that, this craft didn't seem to work very well. This design is already beaten for the tech-level (7, I believe. The most advanced part is the C7 adaptor.) but I thought I'd show it anyway as it's about as good as I can do.

Sweet -- I love the look of the Mk-1 pod atop the C7 adaptor. Looks very streamlined, like a real lander might look!

- - - Updated - - -

Tier 3 craft, full recoverably, easy to fly, fuel cost is 3672

http://imgur.com/a/7LQW6

Dude -- masterful as always. I totally *LOVE* your Kerballed second stage; great way to get around no probe cores in Level 2!

What was the cost of your parts -- you should get 98% return on them since you landed at KSC but not 100%. . .

[Astrofox]

May I use Stage recovery as a means to recover parts?

[Mesklin]

Mesklin: Are you using a recovery mod there? You seem to be going back in time when you switch craft.

Nope, not any mods like stage recovery. All actions I did simultaneously, looks like mission time stopped for debris, when debris are out of action area in 2.5km around active craft. First stage do not has any probes and, technically, it is debris. Chutes on first stage were tuned for more high atmospheric pressure for deploy then default value and were activated before decoupling first stage

[Jasonden]

May I use Stage recovery as a means to recover parts?

Yes! But that will put you over into the 'modded' category for scoring. I am interested to see how this would improve the costs, though!

[Tsevion]

I went and did a different challenge to make the lightest Mun SSTO possible... and it turns out it's a big winner for this challenge as well.

Tech level 7.

Cost: 18,377

Recovered: 17,953

Net Cost: 424

Stock other than Kerbal Engineer.

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[Jasonden]

I went and did a different challenge to make the lightest Mun SSTO possible... and it turns out it's a big winner for this challenge as well.

Nice! I knew that I'd get beat out by a jet mission Amazingly small, too, dude -- great job!

[Kelderek]

@Tsevion: where is your rocket engine? Is it placed inside of your jet engine? It's hard to see in your images, the exhaust makes it look like it's in the center somehow, but that's where your jet engine is located.

Cool, simple design, I like it.

[SkyRender]

I've begun prototyping for a cheap Mun-capable spaceplane/rocket hybrid that will work in FAR.

Here's a small preview of what's in development. It still needs some tweaks (such as a reaction wheel for the lander stage, and a little tiny bit more fuel for said lander as well), but it should be able to allow a single Kerbal to get to the Mun and back on 225/245 LFO, approximately. It may even be possible to get this design to work in stock; we'll see.

[Tsevion]

@Tsevion: where is your rocket engine? Is it placed inside of your jet engine? It's hard to see in your images, the exhaust makes it look like it's in the center somehow, but that's where your jet engine is located.

Yeah, my attachment order is rocket then jet, then I used the offset tool to move the jet up to matching positions.

[numerobis]

You could probably even halve the cost by landing the jet separately (on a drone core), so you don't have to bring it to Mun and back.

[SkyRender]

This was one of the craziest missions I have ever run.

The Minimun Lander took off for orbit late at night, bearing its payload of Jebediah Kerman and his tiny Mun lander capsule.

Once in orbit, Jeb boarded his mini-lander (and I turned off TAC because he would die horribly on this crazy mission if I didn't).

The trip out to the Mun was uneventful.

I made a few test-landings before deciding on this site, which was pretty high up and took the least amount of fuel to pull off.

My return was where the mission genuinely got nuts. Jeb had to use his (genuinely limited!) supply of EVA propellant to push his little lander into alignment with the target craft, and I had to perform the single most insane aerobraking I have ever done. Look at that margin!

Even with all of my careful planning and antics, it was up to Jeb upon intercept with the mother craft, EVA over, take control of it, and perform final docking with it since the lander was bone-dry at this point.

Landing... took a long time. A very long time. Pinpoiinting KSC was difficult, and actually landing right at it was effectively impossible thanks to FAR misbehaving so badly. So I settled for "close enough".

The results screen compared with the original cost tell the tale: overall the trip cost 724 funds. If I'd managed to land it perfectly at KSC's runway somehow, the total mission cost would have been only 273 funds.