jinnantonix

Low cost Laythe Science Mission - with a twist

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Posted (edited)
1 hour ago, Kergarin said:

I guess you all play without part pressure limits? This it turned off by default when starting a new game (no matter which type) 

Probably yes, since it's the default. I usually turn pressure limits on, because it feels more realistic that way, but I'm starting to think that actually I probably shouldn't.

The problem with pressure limits in KSP is that most stock parts don't really tolerate much pressure at all. Which makes sense, since they're presumably designed for space, not for deep sea diving. But since most stock parts are also crazy buoyant, it basically means that the only time you ever encounter high ambient pressures in KSP (short of doing crazy stuff like diving way deeper into the atmosphere of Jool than anyone ever should) is if you deliberately engineer a vessel to go underwater, at which point you realistically should be using reinforced parts designed to handle the pressure. But there are no such parts in stock KSP, and no way to reinforce parts in the editor to make them heavier but stronger, either.

(I don't know if anyone has made a mod to reinforce parts like that. Sounds like it could be neat for missions like this. Although it would also make them much easier, and would thus probably be disallowed in challenges.)

So I'm starting to think that the actual sensible compromise between realism and playability in stock(ish) KSP is to leave pressure limits off, as they are by default, and just pretend that all those extra ore tanks and RTGs you have to stick on a submersible vessel to make it sink actually represent the mass of the thicker reinforced bulkheads you'd need to make it more pressure-tolerant. :) 

Edited by vyznev

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Posted (edited)

 

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12 hours ago, Kergarin said:

I guess you all play without part pressure limits? This it turned off by default when starting a new game (no matter which type) 

It makes sense then that players may turn pressure limits off to avoid the mystery goo exploding at depth.  Adding as a rule to the OP now.

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I recommend relying on an honour system, rather than requiring mod removal, personally.

I don't use mods much, so I am very unfamiliar with them, hence I am a overly distrustful, and that is perhaps unfair to my fellow gamers.  I will add to the OP that mods may be used, but all need to be called out when submitting.  I will then rely on the forum for feedback on any entries that use mods that are potentially creating an unfair advantage.  This is ample warning to players to play fair, and yet may use their favourite mods (at their own risk).

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Mod's in question are VesselMover and Animated Attatchment.  Can I leave them installed and not use them, or must they be removed. 

@vyznev Based on feedback from other gamers in this forum, it seems I was hasty in asking you to unload these mods.  Unless anyone makes a considered argument otherwise, please consider these mods approved.

 

 

Edited by jinnantonix

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There changes sound good so far.

You could also consider splitting the challenge in a stock parts category where players aim for the lowest cost, and an open category where people just participate in the way they want.

 

Even when I won't compete for lowest mass, this challenge really got me :D

I've created something I didn't expect to work so good for this challenge, that I'm playing around with it since hours instead of going on to create the other needed parts :D:D

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You could also consider splitting the challenge in a stock parts category where players aim for the lowest cost, and an open category where people just participate in the way they want.

Great idea, will do.  I will call it Rogue's Gallery.  

 

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I have an SSTO that can do the round-trip without losing any parts. 78,813 kerbucks. Mines its own fuel from the runway so there's no recovery penalty at all.

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Posted (edited)
On 3/27/2019 at 7:31 PM, sevenperforce said:

I have an SSTO that can do the round-trip without losing any parts. 78,813 kerbucks. Mines its own fuel from the runway so there's no recovery penalty at all.

Actually it was only said we can you use isru at laythe. Initial mining usually breakes all challenges like this, as all ssto will be at a cost of 0 :D

Edited by Kergarin

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Actually it was only said we can you use isru at laythe. Initial mining usually breakes all challenges like this, as all ssto will be at a cost of 0

This raises an interesting issue.  

Firstly I never said anything about ISRU at Laythe only, and in fact I see no issue with mining at Minmus or Pol if that is what is required.  I personally have an issue with mining for ore on the runway though, it just doesn't seem right to me, and I note most challenges exclude this option.  So I am making an executive decision to allow ISRU everywhere but on Kerbin.  This will differentiate SSTO entries on Leaderboard 2 - the smaller/lighter the SSTO, the lower the cost.

@sevenperforce please proceed with your entry for Leaderboard 2, you will just need to fully fuel in the VAB and this will be the cost of your mission.  Please show a screenshot of the vehicle fully fuelled in the VAB, and also a shot of the recovery.

 

 

 

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1 hour ago, jinnantonix said:

Firstly I never said anything about ISRU at Laythe only, and in fact I see no issue with mining at Minmus or Pol if that is what is required.  I personally have an issue with mining for ore on the runway though, it just doesn't seem right to me, and I note most challenges exclude this option.  So I am making an executive decision to allow ISRU everywhere but on Kerbin.  This will differentiate SSTO entries on Leaderboard 2 - the smaller/lighter the SSTO, the lower the cost.

While I think your executive decision makes sense, I should note that it's probably still possible to do a zero (or negative!) net cost mission with it.  All you need to do is launch with a little bit of extra space available in your tanks, run your mission as usual, and on the way back stop at Minmus to refill your tanks.  (The little bit of extra space is for the small amount of fuel that you'll need to mine at Minmus and then burn to return to Kerbin, so that you can land with your tanks as full of fuel as they were at liftoff.)

Personally, if I ever do a challenge like this, I'd probably just include a depreciation rule saying that you can only deduct, say, 90% of the value of the returned craft from the launch cost. That still strongly encourages reusable designs, but makes comparing them possible. And it's also sort of realistic, since in practice you'd always have to spend some amount of money per trip on maintenance costs, and it's reasonable to assume that these are roughly proportional to the total cost of the vessel.

Also, I'd be tempted to rule that fuel is free (and worthless when returned), because with ISRU it practically speaking is, anyway.

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This mission is proving harder than expected.  Sea planes to orbit I'm fairly good at.  But, I keep having to push for more dV and more payload which means most of my designs can't cut it.  I think I need to get rid of mK2 parts and get the probe in a 1.25m payload bay if I can.  

I discovered a new trick for taking off sea planes:  Truly massive flaps to move the center of lift forward of the center of gravity.  I'm using the big spaceplane tail fin as a front wing.  With the authority limiter over 100 it would just back flip if the flaps stayed on, but for a few seconds to lift out of the water it is perfect.

eADBdRX.jpg

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16 minutes ago, farmerben said:

This mission is proving harder than expected.  Sea planes to orbit I'm fairly good at.  But, I keep having to push for more dV and more payload which means most of my designs can't cut it.  I think I need to get rid of mK2 parts and get the probe in a 1.25m payload bay if I can.  

I discovered a new trick for taking off sea planes:  Truly massive flaps to move the center of lift forward of the center of gravity.  I'm using the big spaceplane tail fin as a front wing.  With the authority limiter over 100 it would just back flip if the flaps stayed on, but for a few seconds to lift out of the water it is perfect.

Very nice!

I solved the same problem a little differently. After the splashdown and associated mission, I burned off a bunch of my fuel heading back toward land, so that my CoM could be shifted around. I pushed all my LFO to the nose to help me get the front canards underwater, then went as far down (and as fast) as my RAPIERs would push me. Then, I then transferred some of the LFO back to the back so that it would help me kick the nose up, and I did a "breaching whale" jump with a Closed-Cycle burst from the RAPIERs. Got me going high and fast enough to stay in the air, and it was a quick trip back to land.

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5 minutes ago, sevenperforce said:

Very nice!

I solved the same problem a little differently. After the splashdown and associated mission, I burned off a bunch of my fuel heading back toward land, so that my CoM could be shifted around. I pushed all my LFO to the nose to help me get the front canards underwater, then went as far down (and as fast) as my RAPIERs would push me. Then, I then transferred some of the LFO back to the back so that it would help me kick the nose up, and I did a "breaching whale" jump with a Closed-Cycle burst from the RAPIERs. Got me going high and fast enough to stay in the air, and it was a quick trip back to land.

Nice.  I've done the dolphin jump before too.  The thing is it requires TWR > 1 on oxidizing engines.  Which means a sea plane that doesn't rely on it can carry much more fuel.

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Just now, farmerben said:

Nice.  I've done the dolphin jump before too.  The thing is it requires TWR > 1 on oxidizing engines.  Which means a sea plane that doesn't rely on it can carry much more fuel.

My SSTO has TWR << 1 on LFO when full, but after I burned off the majority of my props it was easy.

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11 hours ago, vyznev said:

While I think your executive decision makes sense, I should note that it's probably still possible to do a zero (or negative!) net cost mission with it.  All you need to do is launch with a little bit of extra space available in your tanks, run your mission as usual, and on the way back stop at Minmus to refill your tanks.  (The little bit of extra space is for the small amount of fuel that you'll need to mine at Minmus and then burn to return to Kerbin, so that you can land with your tanks as full of fuel as they were at liftoff.)

Personally, if I ever do a challenge like this, I'd probably just include a depreciation rule saying that you can only deduct, say, 90% of the value of the returned craft from the launch cost. That still strongly encourages reusable designs, but makes comparing them possible. And it's also sort of realistic, since in practice you'd always have to spend some amount of money per trip on maintenance costs, and it's reasonable to assume that these are roughly proportional to the total cost of the vessel.

Also, I'd be tempted to rule that fuel is free (and worthless when returned), because with ISRU it practically speaking is, anyway.

To me it was obvious and out of question for all challenges that initial runway mining and mining before recovery just to raise founds is never a choice, even when isru is allowed. Does one really have to mention this?

 

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@vyznev says:

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Personally, if I ever do a challenge like this, I'd probably just include a depreciation rule saying that you can only deduct, say, 90% of the value of the returned craft from the launch cost. That still strongly encourages reusable designs, but makes comparing them possible. And it's also sort of realistic, since in practice you'd always have to spend some amount of money per trip on maintenance costs, and it's reasonable to assume that these are roughly proportional to the total cost of the vessel.

I agree with the depreciation rule, and have updated the rules accordingly.  It doesn't discourage SSTO, but does encourage the lowest cost/mass craft.  Also, I think we all agree, no mining on Kerbin, both at launch and on return.

 

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Just wondering could someone use hyperedit for testing purposes. 

Of course you can use Hyperedit for testing.  Just make sure you remove that H tile when it comes time to execute the mission.

 

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Posted (edited)

Hi all, just wanted to say that I have completed a full mission run through.  So I can state that the challenge is officially "doable" under the current rules.  My craft  is non-SSTO and cost just under $78k, see below.  I didn't record the mission fully with screenshots or video, and had Hyperedit turned on, and landed in the Sagen Sea (rather than DeGrasse Sea), and I lost Bill somewhere (I think he went AWOL on Pol), so this can't be submitted.  I intend to optimise the design significantly and run the mission again properly and present a video.

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Mystery Goo collected from Sagen Sea floor at 2600m, and recovered by Jebediah for return to Kerbin

OfBuKJI.png

Oops, I lost Bill on the way - oh well...

Edited by jinnantonix

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I have also done a hyperedit run through with a SSTO spaceplane with recovery at Kerbin. (near 100% recovery, I left some heavy parts on the sea floor on Laythe).  I am not too sure about the Dv calculations for this, but pretty certain it is doable.  The SSTO was about $85,000 (with some room for improvement?), overall cost of the mission (SPH cost minus 90% recovery cost) was about $9,000.  If you are getting these numbers, you have a competitive entry.

So folks, this challenge is now officially POSSIBLE.

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Posted (edited)

This is a hard mission.  It took several tries to pull it off.   The probe was not recovered worth 49,980.  I guess if I were really paying attention to cost I would not have used RTG's, but I'm just happy to finish.

Spoiler

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Edited by farmerben

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Posted (edited)

 

 

Quote

This is a hard mission.  It took several tries to pull it off.   

I hear ya.  I am just now working through my optimised solution, and found I am very short of dV, and utilising careful use of Tylo fly-by manouvres. 

I reckon landing that plane is a challenge.  Does it land in as a seaplane?  Use chutes?

Can you please provide a listing of the mods you used, I don't recognise all of the tiles.  In particular "B".

I assume this is for Leaderboard 1?  

Edited by jinnantonix

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The only mod I used was MechJeb.  I have installed, better time warp, vessel mover, and kerbal alarm clock.  All the parts were stock.

 

I had a previous version that almost did the mission, but it approached Laythe with only 400 dV remaining and I couldn't capture without exploding in the atmosphere.  After many attempts I gave up.  This version has 1000 extra dV, and is better optimized for atmospheric heat.  The Kraken killed it several times.  But, then I figured out that fast time warp was taking away my autostruts, so I started switching to the space center to let time pass for refueling etc.  

Nearly all my airplanes can land on the sea.  Only the good ones can take off from the sea at 50 m/s.  

hXklNIp.jpg

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@farmerben impressive that you can land a plane that large on the sea.  My SSTO spaceplane keeps exploding, no matter how much autostrutting is applied. 

Unless anyone else objects, your use of mods is OK.

I am just trying to work out how to score you.  Do you want to be on Leaderboard 1 or 2?  If the latter, then I just need one more screenshot in the VAB/SPH, showing the the probe that was not recovered, so confirming the cost of 49,980.  I will then score you as [launch cost] - 90% * [launch cost] + [cost of probe not recovered].

 

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tIKSTx1.jpg

This is the probe i used.  Ore tanks are much cheaper than RTG's.  I could have saved a lot of money.

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Congratulations #farmerben on being first on the leaderboard 2.  Score = 214054 - 192,648.6 + 49,980 = 90,650.26

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