Rover on Minmus?

[Tukas]

Hello everybody! I'm new to this forum, but I'm not new to KSP, I was playing it from time to time, from the very first beta version. Still... I never got too good at it until now when I viewed all the Scott's Manley youtube videos. But still I have a lot of questions and one of them is about rovers on minmus and other low gravity moons.

Can the rovers be useful at very low gravity? How they must be designed to be driveable?

I was designing my rover for about 2hours, put a lot of things on it, then I was designing a rocket to get it lifted and get into minmus orbit and then to land it of course. And after about 4 hours in total I was on minmus with it to realize that it CAN NOT DRIVE AT THAT GRAVITY....:D:confused: Well, it has a docking port so I will lift it back to orbit and get it to Mun maybe or even Duna, it will be very interesting mission which will eat all my money in my carrier but... Still, how can I make a rover or should I be aiming for something else to explore the Minmus? I want some kind of rover/lander to be on it with Engineer and maybe Scientist so they can do contracts there, do all the science and of course extract the fuel from the miners and get it to the station which is already orbiting minmus.

Edited November 15, 2015 by Tukas

[FancyMouse]

My exploration rover on Minmus is always bringing rocket fuel and engine - meaning it's really a hopper with wheels. I only use wheel-only vessels for short-distance operations like base maintenance. Anything that leaves the physics bubble - I hop. I'm an impatient guy:)

Rover design in general. I find that those game-specific guidelines are enough for me to at least drive a short distance reasonably good on any planet/moon, at least including Minmus:

1. spam reaction wheel.

2. remap the key so that rover control and attitude control do not map together to WASD. Even better, if SAS is spammed, you can set up the mapping like, IK to wheel forward/backward, and JL to attitude left/right. This will solve the problem that wheels don't have enough traction for turns.

[technion]

At some point this is down to how you like to play the game. Fixes like "drive slowly" and "have engines" don't appeal to me - so I basically only use rovers on Eve, where I find them fun.

I've been meaning to try Tylo at some point.

[Batmanpuncher]

It is possible to have a rover on minmus but due to its low gravity it is difficult to keep the rover upright. So for a case such as minmus I would suggest a biome hopper. Basically it's a lander designed to take of and fly to another biome. So to answer your question; a rover is possible but hard to use and there are other more practical alternatives.

[Reactordrone]

Traction is the main issue and if you have the Ion engine you can mount one upside down on rovers that will operate on low grvity worlds so that they can apply down force during acceleration and braking.

e.g-

Edited November 14, 2015 by Reactordrone

[AeroGav]

My first manned mission to Minmus looked like this. The carrier plane launches the second stage on a sub-orbital trajectory. I'd bee-lined to RAPIER engines but had nothing better than a Gemini capsule at this point, so brought three of them so i could rescue a Kerbal, as well as have a pilot and scientist onboard.

The thing is, taking off and landing again vertically uses a LOT of fuel, even on Minmus.

So my next mission, I just brought the whole airplane. Figured that the fuel saved by

1) not having to kill all horizontal velocity before touchdown, and also therefore needing less vertical lift on approach due to residual orbital velocity

2) being able to taxy over the surface rather than lift off and touch down

would offset the fuel used to drag wings, landing gear and engines up to Minmus.

So it proved ! When taxying, there is almost no friction, at least without elevation change. You can cross the great flats loosing only 1 or 2 m/s in velocity.

I drove from the flats to the poles, crossing 5 biomes. After freewheeling across the flats, we headed north to the highlands. This required gaining over 5000m in elevation so I used a fair bit of fuel (300LF?) doing so. After that I was coasting downhill to the north pole, riding the brakes. I was very worried about busting off a control surface, so kept my surface velocity to about 10 m/s. That certainly increased my fuel use when climbing to the highlands, due to increased gravity losses.

As you can see from the picture we also brought a tourist. The science payout from this mission was enormous, more than i'd have got for slinging unmanned probes at Jool all week.

Maybe if your vehicle is not an airplane, you can make it more robust and stable, and taxy at higher speeds, using less fuel. I would stick to landing gear legs rather than rover wheels, they're much tougher. The only advantage of rover wheels is that they're self driving.

Edited November 14, 2015 by AeroGav

[Wanderfound]

Fast Minmus roving is certainly doable...

...but not very practical. As suggested above, you're better off using a biome hopper. Minmus' gravity is so low that suborbital flights are very easy to do.

[juanml82]

I use rovers at Minmus. I use the ruggerized wheels which I think have better traction, I've never got good results with the first non miniature wheels.

It is a good idea to add some engines and fuel tanks, specially for survey contracts, and KAS pipe connectors to refuel if you use that mod.

You will tip over, though, so you need to be ready for that: create an action group to enable/disable all reaction wheels (probes included) since disabling them makes for easier driving, but you'll need them on when you tip over. You can put an engine upside down so not only it can help you keep your rover into the ground if you lack traction, it can also take it off if you land upside down after tumbling. Your rover should also have at least to command modules (probe or unmanned): one aiming up, for suborbital hops and to correct orientation when you tip over and another one aiming horizontal to drive. Unfortunately, I don't think there is an action group to select "control from here", although the Part Commander mod can help you with that. Pack RCS and monoprop to stabilize the rover when it turns over (and to help you slow down before hitting the breakes)

Remap the rover keys to the numpad, so they don't also turn the rover around. As for engine selection, light rovers can do with monoprop or ion engines, something a bit larger can benefit from the terrier engine. Larger rovers can rely on Thuds or Aerospikes, although I think that's overkill for Minmus low gravity.

The MRS mod has some surface attachable probes which make good rover probes, as you can put them aiming horizontally.

Finally, use structural parts and other parts with high impact resistance as "bumpers", so when you tip over and hit the ground, no sensible part of the rover gets blown because of the impact.

[Van Disaster]

These wheels used to be stupidly good:

and the other element of that for light rovers is sticking a reaction wheel on it, in this case under the floor. I shifted my rover controls to IJKL as well ( I never use docking mode & it helps for steering planes too ) so I'm not going to flip the thing using the reaction wheel. I think there's a link to a stock-ized version of that in the Show your Rovers thread somewhere ( try about 2.5 years back ).

Large rovers work as usual, if a bit short of traction sometimes.

[A35K]

As others have said, on low gravity bodies like Minmus you're better off just using a rocket to 'hop' around. I really don't suggest using rovers anywhere with a gravity lower than the Mun. However, the best place for rovers by far is Tylo, since the gravity is high so you don't have control issues, but the lack of air resistance means you can reach stupidly high speeds downhill, which can also be a disadvantage (loss of control and explosion...)

[cantab]

If you want to use driven wheels:

Plenty of weight per wheel, to increase traction. Lightly loaded wheels will skitter and slide and won't go as fast.

A decent sized chassis. Very small rovers are liable to pitch and roll too much because the suspension can't be configured.

Remap the rover controls so they don't conflict with the torque controls, this is really important.

Set up a gamepad if you can, I find long drives *so* much nicer with a controller than with a keyboard.

Do have some decent torque, so you can land in a safe orientation after jumps.

Don't use a flimsy lander can for the Kerbals! The aircraft cockpits are good, and external seats do pretty well too.

Finally, relax. Driving isn't as quick as flying, Take your time, chill out and enjoy it.

Downthrust is an option, but if you're going to use thrust maybe you're better flying.

By using landing gear and thrust you can go faster than using driven wheels, but don't forget excessive speeds may be unsafe.

[Tukas]

Thank you all very much for the suggestions!

I'm going to try one last huge rover for the minmus, because I just must have a rover there, even if it wont work so well, maybe I'm just going to get some contracts near by. And also I'm going to build a "jumper" style lander which will be able to extract fuel from the outpost and get it to the station.

On the over hand, maybe I could combine both...