jinnantonix

Low cost Laythe Science Mission - with a twist

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Posted (edited)

I now see that my clipping in my original entry was a lot more norm-violating than I had initially thought. I have recently participated in a few other challenges that don't mention clipping in the rules, but nobody is trying anything similar to my entry. Chalk it up to inexperience.

FWIW I think the most meaningful clipping in the entry was the engines being on top of each other. The 4 clipped mk1 fuel tanks improved handling and durability but not drag or afaik anything else, which means that without that clipping it would be more difficult to fly but would have similar capabilities. On the other hand the engines being on top of each other is the only way to have both with thrust pointed at center mass and allows the body to have a cross section of only a single mk1.

The non-clipping solution is to add a second Whiplash and move them to the sides. The added weight would drop the vacuum dV to ~4k, so another fuel tank is added (4k dV might be barely enough for this mission but would be very difficult). With these and a few other minor changes the overall performance on paper is mostly superior to the original version, with slightly increased dV and ~65% more atmospheric TWR, but ~20% less vacuum TWR. Final cost is just over 30k. I haven't flown it yet so some tweaks might be needed (too little air intake?) but it should be able to accomplish this mission without undue hardship. Maybe I'll give it a go after I'm done with Salvo to Eve.

XWXKeUs.jpg

Edited by bayesian_acolyte

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8 hours ago, bayesian_acolyte said:

<snip>

I would genuinely love to see a video of that performing the mission: presumably you need to refuel at Minmus? And how do you mine the science from the sea floor? I'm just finalising my submission and I thought I'd made great progress in cost efficiency, but cannot compete at a level of 30k!!!

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Posted (edited)
8 hours ago, dnbattley said:

 And how do you mine the science from the sea floor? 

Under the fairing (attached to the nose cone) is a decoupler attached to a probe core, ore container, and goo. The ore container is filled up on Laythe and then brought to the site. The decoupler is detached, and the contraption sinks to the bottom with the probe core on hibernation mode. The sample is taken at the bottom, and then the ore container is emptied, allowing it to rise and the sample to be collected.

Quote

I would genuinely love to see a video of that performing the mission: presumably you need to refuel at Minmus? 

Yep, refuel at Minmus, refuel before and after the mission on Laythe, and then refuel on Pol.

Edited by bayesian_acolyte

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1 hour ago, bayesian_acolyte said:

Under the fairing (attached to the nose cone) is a decoupler attached to a probe core, ore container, and goo. The ore container is filled up on Laythe and then brought to the site. The decoupler is detached, and the contraption sinks to the bottom with the probe core on hibernation mode. The sample is taken at the bottom, and then the ore container is emptied, allowing it to rise and the sample to be collected.

Fair enough for that part: I use a not dissimilar mechanism, though utilising the unnaturally negative buoyancy of parachutes (specifically the Mk16) rather than ore.

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@bayesian_acolyte I have been experimenting with a similar design, but it's not working.  My design looks a bit like the craft in the below video, but the weight of the ISRU rig required for the mission makes this design non-viable.  The NERVA does not have enough thrust to get the craft to orbit. 

My craft that works is larger, with 4 x RAPIERs and a NERVA.  It certainly is more than $30k.

 

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Posted (edited)

It took a few tries and some tweaks but I got to stable orbit with enough dV for Minmus. The changes from the above screenshot were adding two yaw stabilizers, tilting all lift surfaces up 5 degrees, moving the high-drag ore tank back, and emptying one liquid fuel tank.

The flight strategy was follow prograde to 20 degrees from runway, then tilt back down to horizon slightly before reaching 10km.  Next after gaining a bit of speed, gradually tilt up to around 30 degrees until engine burn out. The NERVE was started up at around 15km. At around 30km, start to gradually tilt up more, eventually going all the way to 67 degree tilt at around 60km which was held until vertical velocity mercifully stopped decreasing at around 15 m/s at ~68km. Then tilt was gradually lowered, aiming to freeze vertical velocity at 5-10 m/s once above 70km until stable orbit was achieved.

The mk1 body looks kind of crappy compared to the cool mk2 design in the above video, but I believe there are drag advantages, especially when having to tilt hard away from prograde in the atmosphere to get enough vertical thrust. Using minimal wing surface area is also important.

nhN2JJq.jpg

SuO9hJp.jpg

Edited by bayesian_acolyte

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I just want to seethe takeoff from the DeGrasse Sea.  TWR is plenty, but are the lifting surfaces going to work?

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8 hours ago, farmerben said:

I just want to seethe takeoff from the DeGrasse Sea.  TWR is plenty, but are the lifting surfaces going to work?

I would probably do it like I did the clipped version, land in the sea and then boat back to land. There's an island south west of the DeGrasse that's not overly far away.

The clipped ship was actually capable of a dolphin takeoff for most of its development, but I eliminated a pair of control surfaces on the nose in one of the last cuts for cost saving reasons, and after that it couldn't get its nose far enough down to dive. I think on this version the upward tilted wings would prevent diving, but they would be a huge help in a sea takeoff. My guess is that some control surface canards would allow the nose to come up enough to take off on water, maybe even replacing the rear control surfaces.

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Posted (edited)

I have decided to do a mission run through to set a baseline for Leaderboard 2 using a standard spaceplane design with 4 x RAPIERs and a NERVA. as below, mission cost <$60k.  There should be plenty of room for improving on the solution, @bayesian_acolyte seems to already have a solution at half my cost.  But here goes anyway ...
Edit:  Got to Laythe and discovered I can't land.  Darn, I thought I tested that thoroughly!  Trimming lifting surfaces to save $100 was a bad idea.  Anyhoo, back to drawing board...

13UI4mU.png

 

Edited by jinnantonix

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Posted (edited)

I'd like to thank OP again for this challenge, which has provided many, many hours of design and testing entertainment. While it cannot quite beat the top entry for outright price, I'm nevertheless pleased to present the Cheapo Laythe Rocket (CLR) Mk 15 a.k.a. "The Pleasuredome" for your consideration: a non ISRU, non-recoverable, "relatively-forgiving-to-fly" homage to the art of extreme cost cutting and puerile double-entendres.

riA9Pug.png

Full mission report (mission run in version 1.7):

https://imgur.com/a/G2sPZfQ

 

Craft file:

https://kerbalx.com/dnbattley/CLR-Mk15-The-PleasureDome

Edited by dnbattley
Mission report update

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@bayesian_acolyte wrote:

Quote

I would probably do it like I did the clipped version, land in the sea and then boat back to land. There's an island south west of the DeGrasse that's not overly far away.

I found this part of the mission very challenging.  I have a big craft which is quite efficient as a boat, and there is nowhere near enough fuel to get from land to the DeGrasse Sea.  I have found that the only way to do it is to land in the sea and then dolphin dive launch.  Fortunately with a little tweaking of weight distribution my craft was able to do it.  Launching with airbreathing jets did not work, I needed the extra thrust of the RAPIERs in closed cycle.

Spoiler

In amphibious configuration the craft can reach 43m/s with engines in airbreathing mode but has insufficient fuel to reach from land to the DeGrasse Sea.

jBdCg2s.png

With the Rapiers in closed cycle there is enough control for landing and also enough thrust to dive and launch.

ob9p5If.png

 

6Qs3cp0.png

 

 

@dnbattley wrote:

Quote

Full mission report to follow...

Looking forward to it.  I have tried a few non-ISRU configurations and yours looks to be very competitive.

 

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10 minutes ago, jinnantonix said:

Looking forward to it.  I have tried a few non-ISRU configurations and yours looks to be very competitive.

You beat me to posting it by 9 minutes... :)

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Posted (edited)

Jinnatonnix, I'm curious, is the mining gear on on LoL3 adequate.  Does it rely on fuel cells?

My swan2 plane started with 2 gigantor arrays and 3 RTGs which was plenty to run on Minimus.  After the probe drop I had to refill on Laythe and then Bop down 2 RTG's and electric charge was a big problem.  I found that some mining gear would run continuously if I left the convertor and drill on with the ore tank empty and let time pass from the the space center.  

I might have to run the mission again with a different probe and different electrical gear.

.... Actually my entry had one of the small fuel cells as well.  I had it set with the brakes action group and tucked away.  Maybe sending an engineer is also a bad idea if he uses electricity faster.

Edited by farmerben

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@farmerben In a nutshell, yes.  I have small converter, 1 x small drill, 1 x small radiator,  single SP-L 1x6 solar panel, 3 x fuel cells.  The trick is to turn the radiator off and on  so the thermal efficiency goes down, and the rig consumes less power and converts slower.  When its balanced hit warp.  I sent an engineer, and my rig worked fine.

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Apparently not.  System glitch?  I was sceptical myself, until I tried it.  Like you, when I discovered it, I had to scrub my mission and start again from scratch.

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Some progress on my unnecessary complicated rogue entry. :D

Recovery works better than expected :cool:

 

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Posted (edited)

OK so it doesn't quite work out as cheap as  @dnbattley's entry.  But an ISRU equipped, staged spaceplane with twin Cheetah engines, and a dolphin diving Laythe landing jet-  it's super cool, right?

 

 

 

 

Edited by jinnantonix

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Posted (edited)

Hey I am wondering, can someone provide some guidance or assistance in making a badge for this challenge.  @dnbattley and @farmerben deserve theirs.  I am a graphics gumby - no idea where to start.

Edited by jinnantonix

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5 hours ago, jinnantonix said:

Hey I am wondering, can someone provide some guidance or assistance in making a badge for this challenge.  @dnbattley and @farmerben deserve theirs.  I am a graphics gumby - no idea where to start.

I could maybe give this a try later today. Any ideas for what the badge should feature? Maybe a goo canister under water, with Jool in the background? And perhaps a rocket circling it, just to make it look suitably spacey? :) 

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@vyznev that would be awesome, thanks.  Yes I think goo canister underwater with Jool in the background would be perfect.

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5 hours ago, jinnantonix said:

@vyznev that would be awesome, thanks.  Yes I think goo canister underwater with Jool in the background would be perfect.

First draft, still missing the goo canister. I don't feel like drawing one and couldn't find a screenshot I like, so I'll have to fire up KSP and take one myself. So basically just playing with gradients so far. Feel free to suggest more / better text, too. :) 

PQTfBau.png

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...aaand here's the final version! :) 

cjerHlk.png 7RYNjqB.png D0NVC6G.png pW0HbNr.png

This was fun to do, even if I probably spent a little more time on it than I should've. It's been a while since I've done any graphic design, and it was fun to brush up the old skills.

Ps. For anyone curious, the generic spacecraft in the picture is some random old spaceplane that I happened to have a reasonably clean screenshot of lying around. It was even actually on Laythe in the screenshot, so I figured it was appropriate enough. :) 

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These look great! Thanks @jinnantonix for suggesting and @vyznev for putting them together! I'll proudly add this to my profile page :) Do you object to my putting the words "¢ertified ¢heapskate" on/around/near it :)

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