Buster Charlie

STOAT rides the WEASEL: Smallest/Lightest Rescue Craft?

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In an excuse to use weasel themed Acronyms inspired by the Lunar Escape System I started a series of light craft using Stock parts, but honestly it could be done better with mod parts.

In fact if I can work out some bugs maybe i'll try my hand at making some custom mod parts specifically to streamline this idea (better form factor, less parts) while keeping the stock balance involved... 



The name of the Project is F.E.R.R.E.T - Focused Emergency Rescue-Rrendezvous Escape Technology

The Vehicle is called the S.T.O.A.T. - Straight To Orbit Ascent Thruster

If you decide to build a lander, it falls under the project W.E.A.S.E.L. - Worst-case Emergency Ascent Surface Escape Lander

If you can think of a better name, go for it.

The Base Model STOAT can land by itself, lift off one astronaut, and circularize orbit on Gilly, Pol, Minmus, Bop, Ike, Dres, Mun, Eeloo, Vall, & Moho; This is not much of a challenge because some of these bodies you could use the EVA pack to do the same thing. In fact I was tempted to use 300 DV from the EVA pack to act as a 3rd stage (I wanted to save half the fuel for maneuvering to the rescue craft).


It uses a single Ant Engine, the probe core's reaction wheel for stability control, and a single battery (I had issues with the probe battery running out during some circulation maneuvers)

The Lander is just a test bed, you could include this with nearly anything to bring it to the surface. I used a Docking port as a decoupler for weight reasons, so if you use gravity turn or mechjeb I don't think you can use auto-stage. Also make sure you turn off fuel crossflow or your lander will suck the STOAT fuel supply dry (Ask me how I know this). Lander uses a fuelcell because it has more than enough fuel to land, it cuts down on solar panels, batteries, and it's only purpose is to keep the STOAT topped up until launch. You could always disable the battery on the STOAT until right before launch to be on the safe side.


For DUNA I actually didn't have to do much extra, just needed a little more Delta-V to get off.


This uses the same Lander as the standard STOAT, Double the fuel and a more powerful engines mounted side by side to keep it from being too tall. I found the atmosphere and shape of the rocket made flipping a issue, so I used a smaller probe core and added a larger dedicated reaction wheel, and the same battery setup still worked. I didn't have issues with overheating, and I since propulsive landing worked, I didn't bother with parachutes or any other kit for the lander. I also discovered I had to play with the ascent profile, too shallow and you just wont make it, so you pretty much have to punch through the lower atmosphere as fast as possible to get this to work.


I was going to share my TYLO STOAT, but I think I overwrote it with my prototype LAYTHE one.  Pro side is we don't need the nose cones, but I think I might have needed to make it two stage (IIRC a single 1.25m small tank and the same engine as the lander, with a docking port decoupler), and the lander needed nearly all of it's fuel to land safely.

The Laythe Lander is providing me trouble, I've got a lander that can land alright, but the STOAT stage is getting into full sized rocket territory, and its getting pretty tipsy unless on flat round, and forget water landing (it survives but can't keep it upright). I know EVE is going to be pretty much crazy in size but is still something I want to attempt. I did resort to sticking the command seat inside a 1.25m service bay (sideways) on one attempt to deal with atmospheric issues.



So I'd like some feedback and feel free to submit design or ideas.


Design goals:

Single Kerbal (I mean sure go for 2 or more, but I want to keep the footprint that will fit inside a 2.5m farring without looking like a pancake.) 

Minimum weight STOAT stage:

All it needs to do is get into a stable orbit where another ship can rendezvous and pick up the stranded kerbal, you can use the EVA pack for emergency orbital stability if needed, you need to reserve enough EVA fuel to get to the rescue ship.


The WEASEL acts as the launch platform  for the STOAT, if you just want to hyperedit something onto the planet to make a stand alone STOAT, be my guest, the WEASEL is optional but I essentially designed it to be a bare bones landable launch platform. Obviously on some planets this might be a challenge of itself, but we can assume the player gets the STOAT planetside with their own vehicle.

I really don't care if you use mods, I used all stock parts but I used hyperedit to put the test platform into a target orbit to test landings and takeoffs. 

Go ahead and use mechjeb or gravity turn, or whatever you want to launch it. This isn't a piloting contest. 

I know I could have made the STOAT lighter and smaller using some of the STOCKALIKE parts mods that provide smaller fuel tanks or smaller reaction wheels or different probe cores. I'm fine with mod builds, but I'm also curious what can be done with STOCK parts.


I will post my craft to KerbalX if anyone wants it, but it's so basic I doubt you'll need that.




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I made something similar for my Jool 5 low mass entry. 

This is a 1.8t Tylo lander.


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1 minute ago, Nefrums said:

I made something similar for my Jool 5 low mass entry. 

This is a 1.8t Tylo lander.


I like that, but what of recovery?  I guess that was my main goal, what is the smallest liferaft to get off a planet or moon.

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I like this idea, I always like to build small. Maybe I'll give it a try! :)

Check out my very old JOOL-5 low mass mission with ion drives: it was able to do an almost grand-tour, landing everywhere except Eve and the whole ship was less than 10 tons: http://imgur.com/a/Oevfg#0


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