Race to the petrolic seas: get to Eve and back fast and cheap.

[Pds314]

Mission

The aim of this mission is pretty simple, on paper anyway. Get a Kerbal to Eve and let them swim in the deliciously purple but probably not very delicious ocean covering much of its surface, then get them back alive, as cheaply as you can and by the earliest possible ingame date 

Start a new sandbox save (I would recommend sandbox at least, but do career if you're a masochist I guess) and get a Kerbal to Eve. They must actually swim in Eve's oceans, so that's probably where you should land them. Then return that Kerbal to the surface of Kerbin alive.

 

Scoring

Score =  ingame time in days^3 * total mission cost / 10^12

LOWER is better.

Thus, if it costs you 1,000,000, and it takes you 500 days, You'd get a score of 125000.. Reducing it to 400 days would be worth a score of 64000. Reducing the cost to 200,000 will improve the score to 12800.

Recovery: the recovery rules are simple. If it's on the surface of Kerbin and in direct line of site of any KSC building, it is considered fully recoverable. Else, it's considered fully non-recoverable.

 

Rules

0. At least one Kerbal must actually swim on Eve. Not just walk. Swim.

1. No aero exploits of any kind. Regular aero optimization is encouraged.

2. No perpetual motion devices / kraken drives.

3. No mods that provide an unfair advantage.

4. No debug cheats.

5. ISRU is allowed, so stripmine Gilly by all means, but this is KSP, not interplanetary oil company simulator 2021. If deemed to be a significant factor, mined or processed resources will not be included in your recoveries. Additionally, ISRU will be prohibited on Kerbin's surface in order to prevent abuse, as will pre-loading the craft with ore.

6. No stranding or killing Kerbals. All Kerbals must reach home for the mission to be considered a success.

7. Kerbals don't need to be in pods. If they get back legitimately, I don't care what, if anything, they are riding on.

8. Pre-1.12 missions shouldn't exploit things that were since fixed like ladders making Kerbals massless. If your mission would not be possible in 1.12 it will be rejected.

 

Strategy

The first day is on the tail end of a launch window so you should probably start your journey to Eve pretty quick and whatever you do in terms of orbital construction or refueling better be worth it. It will almost definitely be worth recovering your launch vehicle though so you should probably build it to be recoverable in stock KSP.

However, those who do launch early will find the options for getting back much less inviting. So either delaying the return launch or using quite enormous amounts of Delta-V will be likely necessary. However, Kerbals are pretty light and you can get a lot of Delta V when that's all you need to get back to Kerbin.

Keep in mind if you plan on using ISRU that you don't really have unlimited time within the Evean system, so you want to mine and convert quickly. Also keep in mind that you can't make Xenon from ore.

It turns out that recovering heavy nuclear stages from crazy hyperbolic trajectories is kinda hard, but not recovering them is kinda expensive. Who would've guessed? Don't get so committed to optimizing time that you forget completely about cost. Cutting time may be worth more, but it is vastly easier to cut cost than to cut time.

Oh, and remember, it's ingame time from the beginning of the world, not mission time. Launching late won't help you.

Edited August 24, 2021 by Pds314

[OHara]

With mission cost a multiplicative factor, and ISRU allowed, it is tempting to design a electric-prop-assisted spaceplane, decouple from an ISRU and drills at the runway, leave the IRSU making fuel while taking the swimming trip to Eve, and then recouple and refill upon return, much as one would refuel a rental car.  But, probably that fuel would be deemed a significant factor and not counted.  

I think KSP 1.12.x has corrected the recovery-cost calculator with respect to robotic parts and their optional motors.  So the in-game recovery calculator might work for this challenge.

[camacju]

I've got a few questions:

-Are DLC props allowed? I'd like to use them for the initial ascent of my Eve lander.

-Are we allowed to mine on the runway? If so, then recovered cost is only limited to whatever the disposable stages of the Eve lander cost. The biggest loss there will be Vector engines but total cost would probably be about 50000. (Or I might try to make an Eve SSTO??) Time won't be an issue because of recovery - I'd spam enough ore converters to mine the fuel within a day, and pack a level 5 engineer for that mining bonus.

-Does the timer stop when the kerbal reaches Kerbin, or when the last piece of hardware reaches Kerbin? If it's the first, then I'd throw my Eve transfer stage onto a crazy orbit and wait the couple decades necessary to get the right gravity assists to slow down again, while the kerbal only takes a year or so to come back home.

[Pds314]

On 8/20/2021 at 3:28 PM, camacju said:

I've got a few questions:

-Are DLC props allowed? I'd like to use them for the initial ascent of my Eve lander.

-Are we allowed to mine on the runway? If so, then recovered cost is only limited to whatever the disposable stages of the Eve lander cost. The biggest loss there will be Vector engines but total cost would probably be about 50000. (Or I might try to make an Eve SSTO??) Time won't be an issue because of recovery - I'd spam enough ore converters to mine the fuel within a day, and pack a level 5 engineer for that mining bonus.

-Does the timer stop when the kerbal reaches Kerbin, or when the last piece of hardware reaches Kerbin? If it's the first, then I'd throw my Eve transfer stage onto a crazy orbit and wait the couple decades necessary to get the right gravity assists to slow down again, while the kerbal only takes a year or so to come back home.

Yes. DLC props are allowed.

Mining on the runway? Hmm. I think not. You should at least need to pay for the fuel you use on Kerbin and I don't want this to become a "who can spam 10000 parts that will never fly?" challenge.

 

No mining on Kerbin or starting with ore.

 

Edited August 24, 2021 by Pds314

[jinnantonix]

I have done low cost to Eve before.  ISRU is mandatory, and re-usability is difficult.  Adding in the mission time makes the strategy somewhat different again.

[jinnantonix]

Is Mechjeb allowed?

[Pds314]

On 8/25/2021 at 5:51 AM, jinnantonix said:

Is Mechjeb allowed?

I would say not, as it pretty clearly provides an unfair advantage as per rule 3.

[jinnantonix]

How about information only mods like Trajectories?  Kerbal Engineer?    BetterTimeWarp?

Edited August 30, 2021 by jinnantonix

[jinnantonix]

A Quick Swim on Eve
 

Scoring:

Mission Cost:  K$  293, 048 - 134,804 - 21,618 = K$  136,626
Mission time:  UT Y1 D281 04:35:17 

Edit:
Score = 281^3 *  (136626)^2 / 10 ^12 =  414176

Spoiler

 

Launch Vehicle with Payload:  K$  293, 048

Retrieved Launch Vehicle:  K$ 134,804

Recovered Return Craft:   K$ 21,618

 

 

 

 

 

Edited August 31, 2021 by jinnantonix

[EveMaster]

Thanks for this challenge! It was fun playing it. The rules are well designed to neither encourage excessive part count nor being absolutely minimalistic.

For the number of days you need to be more precise, should they be rounded up to the next day, rounded to the nearest day or calculated as fractional days since Year 1 Day 1? I think @jinnantonix counted the days wrongly, since the game starts on day 1 and not on day 0. A mission that takes less than a day would otherwise be counted as two days long. I'll watch the video of @jinnantonix video now, and I'm excited to see it.

I managed to complete this challenge without ISRU, an plane that places a fuel depot on Eve's highest mountain, a nuclear stage for transfer to Eve and an fuel cell powered ion spacecraft for the way back.

Detailed mission report with many screenshots: https://imgur.com/gallery/8hOwRt6

Craft file: https://kerbalx.com/EveMaster/EveOceanExplorer

Mission Cost: k$ 274,918

Time at End of Mission: UT Y1 D200 04:00:00

Launch Cost: k$ 721,350

Recoverd Cost: k$ 446,432

Reovered:

• 5 launch clamps: k$ 1,000
• empty first stage excluding two exploded fuel tanks and heat shield: k$ 314,581
• inflatable heat shield detached from first stage on landing: k$ 2,400
• nuclear stage: k$ 128,420
• 39.17 Liquid fuel left in nuclear stage: k$31

Images of the mission:

Spoiler

 

[camacju]

Username checks out!

[EveMaster]

On 8/20/2021 at 12:11 PM, Pds314 said:

Scoring

Score =  ingame time in days^3 * total mission cost / 10^12

Assuming rounding up to the next integer number of days, my score would be:

200^3 * 274918 / 10^12 = 2

Jinnantonix entry would be:

281^3 * 136626 / 10^12 = 3

So my score is better than the one of Jinnantonix.

@jinnantonix The cost is not supposed to be squared in the score function:

On 8/31/2021 at 2:37 PM, jinnantonix said:

Score = 281^3 *  (136626)^2 / 10 ^12 =  414176

Squaring the cost makes a difference because then Jinnantonix entry would outperform mine.

Nevertheless, I like the fact that Jinnantonix submission is different in nearly every regard. That makes a good challenge, if there are different solutions to it.

@Pds314 Could you please clarify on the scoring rules? The example calculations in the opening post seem to be off by a factor of 1000.

Edited September 6, 2021 by EveMaster

[jinnantonix]

@EveMaster well that's weird, I am sure that it was squared.    Maybe @Pds314 decided to change it?