Minmus Rover won't stop sliding!

[Blue]

Meet MOLLY.

Minmus Operations Load Lifter (Y)unit. She weighs 15.6 tons and can be crewed by 1 or unmanned. However, I've never gotten a screenie of her being crewed, because of what follows:

Minmus has a ridiculously low amount of gravity, I understand that. To compensate for this, I can understand that the wheels will not let me drive faster than 2.5m/s. However, I think Minmus has some friction (or rather, lack of) that makes it very difficult to use this rover. Specifically, it stops like a freight train, taking often more than 80 meters to slow to a standstill, and even when its speed is appreciably negligible, the game refuses to let me save because it's about to Crash: due to ice, or something, its velocity is never totally zero. I can switch to a nearby base module, but then if I save and try to do something else by going to the space center, say, using the space center to switch to another lander vehicle that's about a kilometer away, MOLLY disappears, as if she's crashed.

I guess my issue is, is there any way around the friction aspect? Or is there some other problem I'm unaware of?

It would be ridiculously hard at this point to try and make MOLLY heavier. And I have tried just letting the rover sit and settle out-- it doesn't work either. She just gently idly slides side to side, about the speed and distance of swinging one's arm back and forth in slow motion.

[Answer]

Well, I guess sticking landing legs on it will have to suffice until Minmus gets its friction levels improved.

Edited August 22, 2013 by Blue
other symptom

[OtherDalfite]

My guess would be that you are using those gigantic wheels with almost no mass for them to lift. If say, a big fat orange tank full of fuel was stuck under there, then a lot of your problems would disappear. Wheels and the ways in which they work are pretty wonky right now, I just hope they are fixed in a later version.

[Procyon]

with the amount of mass that rover has it shouldn't have that much trouble getting a little TRACTION

[Spica]

Since the game says its about to crash, you should make sure its state is set to LANDED in the save file.

That should work.

Spica

[lincourtl]

A couple of suggestions:

1) As others have noted, with that high a center of mass and almost no weight, you're not going to get very good friction, especially going over uneven terrain or making tight turns.

2) Switch to docking mode, and make sure you have translation turned on. That will help keep your wheels on the ground.

3) I can't tell from your screencap, but if you don't have one, put a reaction wheel under your docking port, and try turning that on when you're driving. It might help stabilize it some more, and keep it from losing contact with the ground.

Sorry, I don't have a video of driving this rover on Minmus but it does very well. I can get it up to about 12 m/s on flat terrain. It weighs about 4.7 tons without fuel. Note: I used part clipping to build it for cosmetic purposes, and so I could get extra fuel on board.

[Blue]

Thanks for your suggestions errybody. I'll see what I can do about sending a large fuel tank to Minmus to see if it can carry things.

The save file already does have it set to Landed.

[Scarecrow88]

I find turning SAS off on low grav moons can help stop unwanted oscillating and when leaving MOLLY have you tried putting the brakes on to stop it wandering?

[MrPopcup]

Just one thing, make the center of mass CLOSER to the ground, that way you won't slide and you'll be able to get 20+ m/s, I once started a topic like this one and on minmus, but the good community helped me solve this, you can see this topic here: http://forum.kerbalspaceprogram.com/showthread.php/44994-A-good-rover-for-Minmus

[Blue]

I find turning SAS off on low grav moons can help stop unwanted oscillating and when leaving MOLLY have you tried putting the brakes on to stop it wandering?

If you'll notice in the picture, the brakes are active and locked, and the SAS is off. Despite this, my speed is still 0.2m/s.

I'm going to revise the design, turning on part-clipping, and putting some ballast down near the ground. Perhaps right near the wheels, so I don't lose much of the spaciousness of its carrying underside.

[shand]

if memory serves - it might not - the brake button (up top) doesnt activate all brakes, unless you tweak it with action groups. have you tried a combination of that and pressing the button that does braking?

[Tiron]

if memory serves - it might not - the brake button (up top) doesnt activate all brakes, unless you tweak it with action groups. have you tried a combination of that and pressing the button that does braking?

actually, it just activates the 'brake' action group, which by default has everything with a brake in it. It's common for people to remove wheels from the brake action group though to prevent the brakes from flipping the rover.

[Boffinbox]

i have your answer

put landing legs on it

in minmus' gravity, large rovers don't "land" properly. they register as still in orbit

when you switch to another vehicle, physics is turned off and the rover goes on rails, on it's orbit

that orbit of course, is inside the ground

when you switch to it again, the game tries to load your rover from inside minmus

source: experience

and before i had put landing legs on...

edit: put landing legs on, at a point where the legs extend further down than the wheels. with them in firm contact with minmus the game will register the vehicle as landed.

[Zeroignite]

So that's what my problem is! My Minmus base modules are all wheeled into place, and half the time it won't let me quicksave, thinking I'm "about to crash".

I wonder if sending up a shipment of KAS anchors would work, so I don't need to do a full redesign.

[Tiron]

So that's what my problem is! My Minmus base modules are all wheeled into place, and half the time it won't let me quicksave, thinking I'm "about to crash".

I wonder if sending up a shipment of KAS anchors would work, so I don't need to do a full redesign.

Grappling hooks maybe? Kerbals can manually place them on the ground if you can't fire one downward.

[Blue]

So John Kerbin wet on the Minmus to his other more faster motorcycle that had gas in it this time.

I implemented all the suggestions made that I could, and there was no improvement. In fact, now my top speed is only 1.8m/s.

MOLLY is now twice the original weight with a much lower center of mass. However, I did think of a workaround for making it so that I could save and retain the rover again.

MOLLY now has retractable landing legs installed. If she won't cooperate, I can just put her on time-out stilts to make her hold still.

The extra 24 ASAS modules also enable me to flip myself over on any axis, if I need to in an emergency :|

[Tiron]

Well, some people have been known to put thrusters on their rovers that push it into the ground... >.> <.<

[Traches]

You could try pointing ion engines, ant engines, or linear RCS ports straight up to generate downforce and improve traction.