Duna for Less

[Red Iron Crown]

Economics are coming, so I've been trying to start taking the cost of my craft into consideration, which I've basically ignored so far. I'm finding it interesting to see how this affects part choices and craft design.

So I propose a challenge: Duna for Less

Goal:

Land a Kerbal on Duna and return safely to the surface of Kerbin for the lowest possible cost.

The Rules:

• Stock parts only, no parts adding mods.
  
• Kerbal Engineer Redux is required, for verification of cost in the VAB. The cost of the part is to be included in your costs.
  
• No cheating via HyperEdit, debug menu, cfg editing, etc.
  
• Control/design mods are acceptable, i.e. MechJeb, Docking Alignment Indicator, Editor Extensions, Kerbal Alarm Clock, Protractor, etc are all acceptable. If you use any of these that require parts, the cost of those parts will be included in your costs.
  
• You can use as many or as few launches as you like, however your score will be based on the total cost of all your craft used for the mission.
  
• Your craft cannot dock or otherwise interact with craft not counted in your mission cost. E.g. no refueling at an existing propellant depot.
  
• No command seats. (I consider them unrealistic for atmospheric landers/interstellar craft)
  
• Your Kerbal must plant a flag somewhere on the surface of Duna.
  
• Your Kerbal must return safely to the surface of Kerbin and be recovered.
  
• There are some irregularities in the pricing of parts, this is part of the challenge.
  
• No bonus for recovered parts/stages. (I know this is a bit unrealistic but makes the bookkeeping simpler)

Submission Guidelines:

Required screenshots of your craft(s):

• Each craft in the VAB, with the KER window showing the cost of all stages.
  
• Safely on the surface of Duna, with a flag planted.
  
• Safely on the surface of Kerbin, before recovery.

Any other screenshots/videos are encouraged but not required.

Scoring:

Your score is the total cost of all your craft used in this mission. Lower scores are better.

Leaderboard:

1. 6,170 Tigik

2. 8,112 Mesklin

3. 9,302 Jasonden

4. 42,757 Mr.Rocket

5.

6.

7.

8.

9.

10.

I will update the leaderboard as time permits. The challenge will continue as long as there is interest.

Edited March 4, 2014 by Red Iron Crown
Updated leaderboard

[Jasonden]

RedIronCrown:

While this seems like a good idea, and someday it will be, minimizing costs doesn't make much sense yet. The cost values attached to items in the game at the moment just make no sense at all. For instance, a basic jet engine costs 950. But a mainsail is 850! And an LV-T45 is more than a Mainsail, too, at 950. Now compare that to, say a TR-18A stack decoupler, which is 975. Or a Place-Anywhere Linear RCS port which is 2500! It's worse than random! I'm sure that Squad will fix this before using costs for Career mode on future releases, because it's clear that they haven't been even trying to balance the 'cost' values yet.

[Red Iron Crown]

There are some irregularities in the pricing of parts, this is part of the challenge.

This is the part that makes it interesting, IMO. There may be parts that are overpowered when cost is a factor, and I think it's useful for us to discover which they are. And I'm finding that I'm analyzing parts by new metrics, like T/$, rather than the usual TWR and Isp. The LV-N, which is almost too good not to use in most missions, is almost too expensive to use in this challenge, at 8700. The 48-7S, though high performance, is expensive for its size. The cubic octagonal strut has an excessive cost, too. My usual "go-to" parts are not really cost effective.

One of the irregularities is that the wiki pricing doesn't seem to be accurate. The Mainsail is 2850 in the game, but only 850 in the wiki. The Linear RCS is "only" 850.

[Jasonden]

Okay, my mistake about the Wiki -- I was using that for info, and not the game itself.

It seems that in the game the fuel tanks are just stupidly more expensive than the engines themselves. Therefore I did some calculations for fuel tank efficiency:

[table=width: 500, class: grid, align: center]

[tr]

[td]Tank Name[/td]

[td]Tank Mass[/td]

[td]Liquid Fuel[/td]

[td]Cost[/td]

[td]$/fuel-ton[/td]

[/tr]

[tr]

[td]Oscar-B[/td]

[td]0.0713t[/td]

[td]5.6[/td]

[td]$280[/td]

[td]$50[/td]

[/tr]

[tr]

[td]Round-8 Toroidal Tank[/td]

[td]0.1266t[/td]

[td]10.1[/td]

[td]$220[/td]

[td]$21.8[/td]

[/tr]

[tr]

[td]FL-T100[/td]

[td]0.5625t[/td]

[td]45[/td]

[td]$110[/td]

[td]$2.44[/td]

[/tr]

[tr]

[td]FL-T200[/td]

[td]1.125t[/td]

[td]90[/td]

[td]$225[/td]

[td]$2.5[/td]

[/tr]

[tr]

[td]FL-T400[/td]

[td]2.25t[/td]

[td]180[/td]

[td]$850[/td]

[td]$4.72[/td]

[/tr]

[tr]

[td]FL-T800[/td]

[td]4.5t[/td]

[td]360[/td]

[td]$1600[/td]

[td]$4.44[/td]

[/tr]

[tr]

[td]X200-8[/td]

[td]4.5t[/td]

[td]360[/td]

[td]$900[/td]

[td]$2.5[/td]

[/tr]

[tr]

[td]X200-16[/td]

[td]9t[/td]

[td]720[/td]

[td]$1800[/td]

[td]$2.5[/td]

[/tr]

[tr]

[td]X200-32[/td]

[td]18t[/td]

[td]1440[/td]

[td]$2600[/td]

[td]$1.80[/td]

[/tr]

[tr]

[td]Jumbo-64 (orange)[/td]

[td]36t[/td]

[td]2880[/td]

[td]$10500[/td]

[td]$3.64[/td]

[/tr]

[/table]

Bottom line: use the double-height X-32's for best fuel/dollar. For smaller sizes, use the FL-T100. Don't use T-400 or T800's or the Big Orange Tank. They don't make any sense.

[Jasonden]

ZOMG a cubic octagonal strut costs $620? WTF!

[Mesklin]

Looks like I will be first ))

There is my craft with cost 8112 k$:

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[Red Iron Crown]

Well done, Mesklin! You've set the bar rather high, the design I've been working on comes in at $40k or so. Guess I need to optimize a bit more...

[Mr.Rocket]

I like this challenge, it's good for preparing for .24

Richcott made it to Duna and back under a good budget today

KER says $42, 757, i did the math myself and got the same

Mission Picks:

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Was not able to beak Mesklin, although i am still happy with the results. I probably could have made it more cost efficient, but i was more concerned about mission completion than cost

(p.s.: that's not mechjeb, that's VOID, it requires no parts)

Edited February 18, 2014 by Mr.Rocket

[Red Iron Crown]

Nice entry, Mr.Rocket. I've added you to the leaderboard.

[Jasonden]

An entry of mine -- all rockets, no jets. $15,520.

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[Streetwind]

You should add a special tier for those who manage to do it without the broken 48-7S

[Kasuha]

Something is telling me that part prices as they are now visible are not prices for buying or manufacturing the part, rather prices of developing the part. Meaning, when you uncover a tech tree node, you don't have all its parts immediately available and must spend money on doing research of each individual part you intend to start using in your spacecrafts. In that context current part prices would even make sense.

[Jasonden]

You should add a special tier for those who manage to do it without the broken 48-7S

I didn't even use enough of them! I could get under $15000 if I swapped out the LV-909 for a 48-7S and went to 3 fuel tanks on that stage from 4. But I dunno if I want to do it all again just for that

If cubic octagonal struts really cost $600, then that would make a CLUSTER of 48-7S's get expensive quick, which might help to balance them out.

[Red Iron Crown]

Nice mission report, Jasonden. Love the two precision landings. I've added you to the leaderboard.

[Red Iron Crown]

You should add a special tier for those who manage to do it without the broken 48-7S

I'm fully expecting the 48-7S to get nerfed in the next update, like the aerospike did back in 0.18. It's simply overpowered, and even in this challenge where its thrust per dollar ratio is poorer than some alternatives it's still hard not to use it.

[Jasonden]

Got it down to $9302, just rockets! Within striking distance of Mesklin's brilliant Jet tour-de-force. Not sure how to whittle it down any further, though . . .

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[Mesklin]

Got it down to $9302, just rockets! Within striking distance of Mesklin's brilliant Jet tour-de-force. Not sure how to whittle it down any further, though . . .

You can easily decrease cost of ship by $1200, if you replace deckouplers by junior docking ports and make actions groups for detach it in flight time. See picture:

But your design is brilliant, set trhrust limit for solid fuel buster for increase working time and decrease acceleration... Very, very good

Edited February 28, 2014 by Mesklin

[Red Iron Crown]

Nicely done, Jasonden. I've updated the leaderboard.

I've been trying to do a jet/rocket combo that only uses the cheaper X200-32 fuel, having a single tank in the whole design, but I can't get it to have enough dV without resorting to an LV-N for the rocket motor, which sends the price out of contention.

[Jasonden]

You can easily decrease cost of ship by $1200, if you replace decouplers by junior docking ports and make actions groups for detach it in flight time.

ZOMG great idea -- I hadn't even looked at the docking port costs. This actually only saves $1000, though, since the separator at the top was only $400. But then if I eliminate the landing gear and one of the solar panels . . . I might be able to make it work (at the cost of operational complexity) for way cheap. Sweet! I will try this over the weekend maybe.

set trhrust limit for solid fuel buster for increase working time and decrease acceleration...

Yeah, just the liquid has a poor TWR at takeoff, so the solids really help. But if you let the solids fly at full power then they drive you faster than terminal velocity. Actually I ran a methodical exploration of which limiter percentage to use. What I did was to run the Ascent Komputron on .craft files with many different thrust limiter percentages to map out the performance curve. I had it calculate the maximum circular orbit that the craft could get to under different SRB thrust limiter percentages:

55% was the optimum.

[jfull]

Looks like I will be first ))

There is my craft with cost 8112 k$:

http://imgur.com/a/Wf7j0

Why do you seem to suddenly have full fuel after landing on Duna? Am I missing something?

Wait, nevermind, it only looked that way because you weren't using fuel pipes and had to move fuel around manually.

Wonderful design by the way

Edited March 1, 2014 by jfull

[Dust]

Why do you seem to suddenly have full fuel after landing on Duna? Am I missing something?

Wait, nevermind, it only looked that way because you weren't using fuel pipes and had to move fuel around manually.

Wonderful design by the way

It's because he decouples from the lander tanks. Fuel goes from 49/225 to 45/45.

[Mesklin]

Why do you seem to suddenly have full fuel after landing on Duna? Am I missing something?

Wait, nevermind, it only looked that way because you weren't using fuel pipes and had to move fuel around manually.

Wonderful design by the way

Exactly, fuel pipes is too costly, without it, more hand work, but more cheap ship

[Tigik]

Special offer!

cheap trip to Duna

it costs only $6170

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[Red Iron Crown]

Nicely done, Tigik, that must be approaching the minimum possible. I've added to you to the leaderboard.