Mun Rescue

Mun Rescue

When I flew the early Tiny Titan missions, many, many (many), Kerbals were lost in fiery landing attempts. All in the name of science. Once I successfully landed, I created a whole new set of problems in Kerbal Space Program. I used too much fuel getting to the surface, so there was not enough to get back in orbit.

Turns out the Tiny Titan did not have enough fuel to return from Munar orbit anyway. A fact that escaped me at the time. What I knew was, there were three Kerbals stranded on Mun and another three on Minmus because someone (me) launched without considering the consequences.

Quickly adopting a no Kerbal left behind policy, I took it as an opportunity to develop and launch a rescue craft. I did not know at the time that if you load the ship from file on the launchpad instead of first loading it in VAB that you can choose the crew or even fly with a partial crew or no crew at all. I decided to design an unmanned craft that could carry the stranded crew back to Kerbin. Since every craft in unmodded KSP must start with a pod, I chose to use a remote guidance unit and the hitchhiker storage container.

I still had to deal with the lack of fuel issue. I had read the atomic engines were very fuel efficient but using one with landing struts proved problematic. That is when it occurred to me to continue to use side mounted engines. I used three for balance reasons. Admittedly it is overbuilt but desperate times and all you know. The lift stages, I think, are the same as the Tiny Titan.

Minmus Rescue

With the aid of this design, and Mechjeb to land along side the stranded vessels, I was able to successfully bring the trapped crews on Mun and Minmus home safely. A word of warning about MechJeb used in a rescue mission. Often it works too well and the rescue ship crashes into the stranded vessel as seen in this screen shot (note these are different ships than the Tiny Titan and Mun Rescue - I repeat my mistakes, a lot). So I had to send another rescue mission. What I finally did to solve the problem was to slightly alter the landing coordinates of the stranded ship, as provided by MechJeb, when picking the landing spot for the rescue ship.

One thing I noticed while writing this post is during original design I forgot to add thrusters and RCS propellant to the craft. Had I run out of fuel on the liquid engines before getting a periapsis well below the Kerbin atmosphere, it would have made getting home very difficult but it turns out, not impossible. Jebediah can literally get out and push, using his EVA thruster pack, to move the ship into a reentry orbit. If you watch your propellant levels, when they get low. just board the pod and you will get a full charge to try again.

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Below are the design specs for the Mun Rescue craft for posterity:

Lift Stage:
7 engines fire at launch. the outer ring uses 6 Mainsail engines each with a Rockomax X200-32 tank and a Rockomax X200-16 tank. Lower tanks have AV-T1 Winglet. This tank engine combo is mounted on TT-70 radial decouplers angled 5 degrees. It is all well strutted. Asparagus staging is used to drop 2 opposite side tanks at once. The outer ring is centered around 1 Mainsail with a Rockomax X200-32 tank and Rockomax X200-16 tank. The engines are over powered. Skippers might have been better.

Orbit Stage:
TR-18A Stack Decoupler to eject the Lift stage. Then 6 RT-10 Solid Fuel Boosters on TT-70 Radial Decouplers angled 5 degrees. 3 fire at a time. Once solid boosters are ejected the center engine fires - Rockomax Skipper with 2 Rockomax X200-16 tanks and AV-T1 Winglets

Transfer / Lander Stage:
TR-18A Stack Decoupler to eject the orbit stage. The orbit stage actually begins the transfer burn.
3 LV-N Atomic Rocket Motors with a double stack of FL-T200 Fuel Tanks. Why not one bigger tank? It kind of grew with each test. The atomic engine/tanks are mounted on Modular Girder Segments and secured with struts.

Lander / Return Stage:
3 TT-38K Decouplers are used to eject the atomic engines once emptied during moon ascent.
The stage is built around a Rockomax X200-16 Fuel Tank below a Rockomax X200-8 fuel tank.
Around the bottom of the lower tank is mounted 6 Modular Girder Segments with LT-1 Landing Struts. This is further strengthened with struts. Also mounted are 6 Illuminator Mk1 lights, and 3 Z-400 Rechargeable batteries, along with access steps. The return power comes from 6 Rockomax 24-77 Engines.

Reentry Stage:
TR-18A Stack Decoupler is used to eject the lander / return stage. Above this in order from bottom to top are an Advanced S.A.S. Module, a RC-L01 Remote Guidance Unit (the pod), a PPD-10 Hitchhiker Storage Container with room for 4 stranded space travelers.  Also mounted to the can are 3 OX-4W 2x3 Photovoltaic Panels, and 3 Mk2-R Radial Mount Parachutes. On top of the can is 1 Mk16-XL Parachute.