20 December 2012

Adventures in KSP - Preparing Eve Exploration

In this series of posts I'll tell my progression (and my throwbacks) at the brilliant Kerbal Space Program. I have currently set my sights to the neighboring planets, Eve and Duna. Join me in my quest for exploratory glory!

So, Eve's the next target. Close to the sun than Kerbin is, Eve is a dense planet with gravity that is a bit higher than on Kerbin and an atmosphere that is quite dense too. Having landed there during a play in a previous version of the game, I know that the planet is pretty much impossible to explore with a manned vessel if you intend to get your astronaut back to Kerbin. This is what made me chose this as my next exploration target over Duna, which I intend to land a Kerbal on. Eve is going to get robotic exploration only, because the only thing I could think of that would get back out of that atmosphere and gravity-well would be some sort of really efficient space-plane and I'm horrible at designing and flying aircraft so forget it.

Eve has land as well as liquid oceans. As I intend to do a parachute-landing with my probe, I better land on land or lose the probe upon touch-down. At the same time this is a scientific program, so I should reach the oceans too, as I need to explore what they're made of and if they do contain life. Thus I will need another rover. I modified my proven rover-design, removing the cockpit in favor of more RCS-fuel tanks, adding more RCS-thruster, parachutes and a drag-chute instead of the ion-drive. Then I launched the thing with some small rockets in order to test the thing on Kerbin, as both gravity and atmosphere are somewhat similar to that on Eve. The dense atmosphere on Eve means one thing for my test: If the chutes slow it down enough for a soft landing on Kerbin, they will surely work on Eve too. It's just a question of slowing the whole thing down with the drag-chute first, in order to prevent the rover from being ripped apart once the chutes open up.
So far, so good.
So, the Eve Rover landed about 30 km from the Kerbal Space Center. I turned it nose-there, fired up the RCS-thrusters and accelerated. It turned out that driving was different from driving on Mun or Minmus. The atmospheric drag meant that I would have to fire the thrusters often to keep up the speed, using more fuel than on Mun (which I had expected - the goal is to reach the nearest ocean-shore on Eve so I'll try to land near one in the first place). The higher gravity on the other hand meant much more ground-traction and less danger of catching air when driving over bumps in the ground - I could drive three times as fast as I could on the Mun without raising the risk of an accident to much. I made it to the KSC within less than twenty minutes, then testing whether this version of the rover would be able to drive up the rocket-ramp, which the former version hadn't been able to. I want my rover to be able to traverse terrain on Eve after all.

Unmanned exploration of our own space center.
The rover did admirably, using only about a quarter of its fuel in the process. I'd assume that I can go about 100 km on Eve with the fuel I have, bearing in mind that I would mostly go downhill, as I plan to go from somewhere on land to the next ocean. So I designed a dual-rocket setup around the rover, attaching nuclear drives as a last stage to do the interplanetary travel. Ignition, let's do this.

Surprisingly, this is flying somewhat stable.
Yes, it was working well. The semi-asparagus-style setup I had built around the dual rocket-layout was working rather well and the rocket made its ascent into the higher atmosphere without issues.

Getting lighter and faster...
So when the rocket left atmosphere and it became time to jettison the last of the regular engines, wait for the ship to leave Kerbin orbit and then get the nuclear thrusters working towards Eve...

At this point, the thin gis still working properly...
Well, I realized that I had made a mistake. See, the new rover had its solar panels on its top, where the canopy of the cockpit for the original rover design had been. And I had made the mistake of not providing any other means of recharging the batteries of the thing. So once I turned off the engines, it lost power until it was drained, as one of the two fuel tanks was covering the solar panels... The dead probe shot out into the solar system and was lost forever.

So, I'll have to re-try that one. Unmanned ground mission to Eve. And after that I guess I'll have to assemble my three-part manned Duna-Explorer ship. Tune back in after Christmas. Have a merry and peaceful one, everybody.


  1. Have you considered using an Ion Drive to propell the rover? That should enable you to travel further than RCS. It will need more solar cells though to keep the engine going constantly, but you do not need to run it all the time. Recharging a battery between thrusts is fine.

    Also your rover doesn't look too heavy, It seems to me that most of your lifter is used to lift itself. You could probably do with way less. You wont need two nuclear engines, that does nothing for you except shorten the burn times, but since you already are in orbit those do not matter. One with way less fuel will suffice. This should further lower the requirements for the lifter stage.

    1. The Ion drive that is part of my original rover on Mun is pathetically weak even at the 1/6th g and no atmo on Mun. On Eve it's around 1.6 g and five bar atmo. The ion drive wasn't even able to push the rover up a light encline on Mun with its maximum of .5 thrust... As that wouldn't be much fun I'll take 100 km range with the RCS, which translates to two hours of driving in real time, more than I'd be willing to do in one sitting anyways...

      As for the dual drive: I know it's overkill BUT this version of the rover has no centered point to attach it to the tip of a rocket, as the back where my other versions would have the ion drive or the refuel/docking port is used up with a large drag chute. Also, it looks cool when flying. The next version is just going to have solar panels around the last rocket-stages.