Landing Rovers

[Omicron314]

Hey, everyone. I've been playing this game for a bit more than 2 months, and love it to death. I've managed to land on the Mun and Minmus, as well as performing several successful dockings, but I cannot for the life of me figure out how to land a rover on a low gravity body. I've managed it once with a skycrane/lander hybrid (which ultimately failed due to the fact that it kept flipping forward whenever it moved, whoops), but is there any other way to do it? The skycrane/lander thing is quite unstable and isn't going to work when better aerodynamic models are implemented.

[Specialist290]

One method you could try is just to build a lander around the rover in such a way that the rover just has a short drop to the ground.

(I probably could have done that better with a normal rover by using just one fuel tank and attaching the rover to the bottom, but the kethane sensor (mod part) was already taking up that node and couldn't take anything on top.)

Another way you could do it is by copying the Lunokhod profile and putting the rover on top of the craft, then drive it down using a ramp of some sort. I've also seen rovers slung to the side of a normal lander that just drop down to the surface, though you'll need some sort of counterweight on the other side as well to keep the lander balanced.

[BobTheYoungFish]

When slinging a rover on the side of lander you could use symmetry to put one on either side. It'll balance the weight and you'll have an extra rover.

[masTerTorch]

This way it worked for me. But the thing is, you can only ship small rovers. I had a few problems with rovers like the one on the picture, with only 4 wheels. They had not enough power to drive forward. The one on picture is much better, but when I accelerate he will go to one side instead just forward.

[Lexif]

Omicron, I guess your problems with flipping over are because you have the rover controls mapped to WASD, so probe torque wants to rotate your rover if you try to drive? Try to remap the rover controls to IJKL and see if that helps.

I used a small skycrane with four RCS thruster blocks and two small round RCS tanks for the final landing phase on my Mün and Minmus attempts. A 909 powered rocket stage was used until ~300 m height, and the RCS skycrane for the final touchdown. After landing, I decoupled the skycrane and flew it away (it has a probe body). Worked very well. I'll see if can find out how to post screenshots via imgur.

masTerTorch, I like your lander and might copy that for higher-gravity bodies! Never thought of using those radial mounted engines that way. Looks very sleek!

Specialist, any success with building a top-mounted, Lunochod-style rover? I never quite managed to find a good way to drive them off the top. I would be very interested in such designs. I found that the decoupler or docking port got in the way, and I couldn't quite find a good design for a ramp without using mods to make moving parts.

[ThreeMartiniLaunch]

Small Rovers? Check out this bad boy I recently put on the surface of Duna...

and

[Joe_Bender]

Change to docking mode, the button below the green rocket ship button and set it to lin.....this should help.

[Mihara]

There are basically only five methods of rover delivery possible within the limitations of KSP -- only five I can think of, at least -- each with their own limitations and advantages:

1. Rover below the landing stage which either lands onto the rover wheels themselves or suspends the rover underneath the body of the lander and releases it from a very short drop.

I.e. the explicit skycrane that lowers the rover down with a cable and the non-explicit skycrane where the landing stage is detached from the top of the rover after landing. Paradoxically, in real life, skycrane was created not because it's superior in terms of energy or engineering -- it isn't -- but because they didn't want to mess up the dust on the landing site if at all possible. In KSP this is apparently the lightest and the most generally applicable method, the stock "Rover + Skycrane" is made this way, and it's especially suitable for small automated rovers which are meant to be used unattended. I've been using the Kerbal Attachment System plugin to suspend rovers underneath the body of a piloted lander (which, when using LV-N engines, will often have them mounted on the sides of the body and have the bottom free to get some clearance from the ground) with it, or hold them by a docking port and winch them up by two symmetrical winches until the docking port sucks them in, and retain the ability to take them with me when relocating to another landing location. That works moderately well.

2. Rover above the landing stage, a-la Lunokhod.

Has the advantage that the lander can be much heavier and has no chance to mess up the top of the rover, which would be important on a higher-gravity body. The disadvantage then is that you need to make the landing stage flatter, (or wider) and provide a ramp for the rover to drive down -- either prebuilt this way and descending in an open configuration (never actually seen that done) or opening after landing. The latter can be done with the Damned Robotics plugin which provides you with a servo-controlled hinge, or another means to lower a ramp, but the examples I've actually seen done just landed onto the bottom of the box the rover was in and blew a wall open with a decoupler.

3. Rover suspended off the side of a lander.

You will need two of them to balance the lander's center of mass, and this method is suitable for very big landers which you don't want to make even bigger or taller and relatively light rovers. That will typically give you a much taller drop, so the only practical method to do that I can think of involves suspending it off a Kerbal Attachment System winch and gently lowering it down. That works perfectly -- getting it back up, howerver, in my experience, does not, as interpenetrating objects that can result will disintegrate the lander. If you don't expect to get the rover back up, it works fine.

4. Rover with integrated landing stage.

Basically, a rover that includes it's own engines, lands under it's own power onto it's wheels or extra landing legs, sometimes with parachutes, and keeps some fuel just in case it needs to navigate an extra-steep climb. People don't seem to commonly do that, but when they do, that's usually for monster piloted rovers weighing upwards of 20 tons. Sometimes they land on one end and later tip over with the use of Damned Robotics tools, other times they transfer to target lengthwise but turn horizontally for landing. I've yet to see one explicitly balanced to land and do interplanetary transfers horizontally.

5. Rover moved from a cargo bay to the ground by one or another kind of robotic arm.

I've yet to see that done actually, and I suspect it's because it's the least mass-efficient method. It's probably the coolest one, though.

[Designer225]

By default the rover controls are assigned to the rotation control. Before you even drive I suggest that you reassign the control.

[etse]

By default the rover controls are assigned to the rotation control. Before you even drive I suggest that you reassign the control.

isn't this fixed by just going into docking-mode while driving the rover - which will infact turn off the rotational movement of the probe-body and let the wheels control the turning.

[maltesh]

4. Rover with integrated landing stage.

Basically, a rover that includes it's own engines, lands under it's own power onto it's wheels or extra landing legs, sometimes with parachutes, and keeps some fuel just in case it needs to navigate an extra-steep climb. People don't seem to commonly do that, but when they do, that's usually for monster piloted rovers weighing upwards of 20 tons. Sometimes they land on one end and later tip over with the use of Damned Robotics tools, other times they transfer to target lengthwise but turn horizontally for landing. I've yet to see one explicitly balanced to land and do interplanetary transfers horizontally.

It's not that difficult to build them that way. Just start with the probe brain, and use either six-way nodes, or radial attatchment points to place the rover's "body" at right angles to the primary axis.

Care needs to be taken when using the six-way node with fuel tanks, though. They do allow fuel crossfeed, and if you don't place them the correct way, they'll leave you unbalanced if your spacecraft burns the fuel in the rover.

And of course, there aren't any clues on the six-way nodes themselves to let you know which node is the "Top" and which one's the bottom.

Or are you referring to rovers more like this?

That one uses a radial attatchment point atop the center fuel tank to mount a probe-brain for proper orientation when landing wheel-side down.

Admittedly I have not yet taken either design interplanetary, though plans are in the works for that.

[Temstar]

I've yet to see one explicitly balanced to land and do interplanetary transfers horizontally.

It's actually not too difficult, but you will need subassembly saver/loader to do this:

For low gravity worlds you also have the option of building rover with propulsion system, put it on top of a lander and then fly it off the lander once on the ground. So the Lunokhod method but without requiring a flat lander with ramp.

Edited May 14, 2013 by Temstar

[Mihara]

Reorienting control by using a different 'control from here part' and using subassembly loader to get symmetry right go without saying. I just meant to say that I've never seen heavy rovers built horizontally for both landing and interplanetary transfers. It's usually either flying and landing on the bottom and then tipping over, or flying on the bottom but then landing on the side with small engines.

Nice idea with the six-way node, though.

[Tristavius]

For mid-sized rovers there's nothing wrong with landing them veridically... I've deployed a design like this on almost every world in the system. The image below is my new version (slightly longer, a bigger wheel base and a few other tweaks) which I landed on Duna for trials last night. The frame starts with 3 tanks on each of the 3 arms.. this picture isn't great as I ejected the 3rd at some point when it emptied, but forgot to eject the second before landing (this thing has enough delta v to go anywhere, so Duna barely emptied 1 tank on each). It's only supposed to land with 1 tank left, regardless of how many were actually used or they get in the rovers way. It lands upright and then releases the rover in one of three methods...

Ideally I land in the correct orientation on a slight slope which causes the rover to fall forwards onto its wheels once released

Or when it's released I use the rovers top RCS to push it forward and again falls on its wheels

Or at worst the frame can be sacrificed and two engines turned off, the third can then topple the frame over, once again landing the rover on it's wheels

On paper it may not look as efficient as ramps and skyframes but the landing system has got me almost everywhere incredibly easily. The frame also contains a 1-man pod to return to orbit (in the 3300 delta v range, so works on most worlds) If there's plenty of fuel on the nukes the whole thing can lift off on most worlds, then deploy the pod later if needed.

[masTerTorch]

Change to docking mode, the button below the green rocket ship button and set it to lin.....this should help.

WoW... it really helps! And I thought my rover design is just crap. Wasn´t thinking about the rotation of the core. Tanks!

[magnemoe]

I have been experimenting with roverslander combinations. For unmanned rovers this has the benefit that you save weight.

800 kg, 1000m/s, a bit top heavy then full but manageable with asas, you can stack the oscar tanks inside each other but not sure if this is safe.

Adjust tanks for wanted dV. Bonus is that you can jump around with it.

Manned version, this weight 20 ton, and have 2500 m/s, main benefit is that its fully reusable, you get an rover with 20m/s ground speed and you don't have to return to the lander before taking off.

[RoboRay]

There are basically only five methods of rover delivery possible within the limitations of KSP -- only five I can think of, at least -- each with their own limitations and advantages:

Good write-up and assessments. You've covered pretty much all the options, I think, so I'll just add some illustrations...

1. Rover below the landing stage which either lands onto the rover wheels themselves or suspends the rover underneath the body of the lander and releases it from a very short drop.

I.e. the explicit skycrane that lowers the rover down with a cable and the non-explicit skycrane where the landing stage is detached from the top of the rover after landing.

My version was slightly different... I detached the rover from the skycrane from approximately a hover 1-2m off the ground because I didn't want the full weight of the descent package coming to rest on top of the rover.

2. Rover above the landing stage, a-la Lunokhod.

3. Rover suspended off the side of a lander.

You will need two of them to balance the lander's center of mass

Maybe, maybe not. I did it the other way around... Rather than two rovers hanging off a lander, I did two landing-packages hanging off a single rover.

Detach one package, move away and turn prior to detaching the other package, so you don't get stuck between them.

4. Rover with integrated landing stage.

5. Rover moved from a cargo bay to the ground by one or another kind of robotic arm.

Ok, you got me on those... I don't have any pictures of that style landing in KSP. I actually did #4 on the Mun once, but that was early in my KSP adventures when we didn't have all the capabilities we have now. It was pretty crude.

I do have one other recent design that's somewhat in the spirit of #5, in that the rover has a designated "carrier bay" on another vehicle and is deployed then redocked for long-range transportation...

Edited May 14, 2013 by RoboRay

[automcdonough]

Try mine, I just landed it on Bop (low grav just like minimus)

http://forum.kerbalspaceprogram.com/showthread.php/25339-stock-99-isplore-rover

If you decide the skycrane isn't working for you there's always the "screw it I'll just use RCS" option. Low grav is fun like that.

[magnemoe]

There are basically only five methods of rover delivery possible within the limitations of KSP -- only five I can think of, at least -- each with their own limitations and advantages:

1. Rover below the landing stage which either lands onto the rover wheels themselves or suspends the rover underneath the body of the lander and releases it from a very short drop.

I.e. the explicit skycrane that lowers the rover down with a cable and the non-explicit skycrane where the landing stage is detached from the top of the rover after landing. Paradoxically, in real life, skycrane was created not because it's superior in terms of energy or engineering -- it isn't -- but because they didn't want to mess up the dust on the landing site if at all possible. In KSP this is apparently the lightest and the most generally applicable method, the stock "Rover + Skycrane" is made this way, and it's especially suitable for small automated rovers which are meant to be used unattended. I've been using the Kerbal Attachment System plugin to suspend rovers underneath the body of a piloted lander (which, when using LV-N engines, will often have them mounted on the sides of the body and have the bottom free to get some clearance from the ground) with it, or hold them by a docking port and winch them up by two symmetrical winches until the docking port sucks them in, and retain the ability to take them with me when relocating to another landing location. That works moderately well.

2. Rover above the landing stage, a-la Lunokhod.

Has the advantage that the lander can be much heavier and has no chance to mess up the top of the rover, which would be important on a higher-gravity body. The disadvantage then is that you need to make the landing stage flatter, (or wider) and provide a ramp for the rover to drive down -- either prebuilt this way and descending in an open configuration (never actually seen that done) or opening after landing. The latter can be done with the Damned Robotics plugin which provides you with a servo-controlled hinge, or another means to lower a ramp, but the examples I've actually seen done just landed onto the bottom of the box the rover was in and blew a wall open with a decoupler.

3. Rover suspended off the side of a lander.

You will need two of them to balance the lander's center of mass, and this method is suitable for very big landers which you don't want to make even bigger or taller and relatively light rovers. That will typically give you a much taller drop, so the only practical method to do that I can think of involves suspending it off a Kerbal Attachment System winch and gently lowering it down. That works perfectly -- getting it back up, howerver, in my experience, does not, as interpenetrating objects that can result will disintegrate the lander. If you don't expect to get the rover back up, it works fine.

4. Rover with integrated landing stage.

Basically, a rover that includes it's own engines, lands under it's own power onto it's wheels or extra landing legs, sometimes with parachutes, and keeps some fuel just in case it needs to navigate an extra-steep climb. People don't seem to commonly do that, but when they do, that's usually for monster piloted rovers weighing upwards of 20 tons. Sometimes they land on one end and later tip over with the use of Damned Robotics tools, other times they transfer to target lengthwise but turn horizontally for landing. I've yet to see one explicitly balanced to land and do interplanetary transfers horizontally.

5. Rover moved from a cargo bay to the ground by one or another kind of robotic arm.

I've yet to see that done actually, and I suspect it's because it's the least mass-efficient method. It's probably the coolest one, though.

Very good written.

1) have three versions even without cable, one who uses landing legs and often wrap around the rover, perfect for Tylo.

Subtype with two or more side mounted engines and fuel tanks, this is nice for large rovers.

The simple one with fuel tank and radial engines on top,

2) an very small probe rover can be mounted upside down on top of an probe and flip down. I have used this a lot with bobcat solar powered rover.

3) This is nice for an rover on a manned lander Mun lander. done it a lot with the ant rover. balance with an small fuel tank you empty and drop. Also used this metod with KAS to make an ant rover able to redock after use. http://i.imgur.com/oVludaR.jpg

4) This can also be used to make very light probe rovers for low gravity worlds. I have an picture of it over.

Can also be used to make the combined rover and lander reuseable who is nice for an grand tour type expedition.

5) using an robotic arm would be an easy way to make an rover redockable. KAS can also be used but I have had issues with it on low gravity worlds.

[Specialist290]

Specialist, any success with building a top-mounted, Lunochod-style rover? I never quite managed to find a good way to drive them off the top. I would be very interested in such designs. I found that the decoupler or docking port got in the way, and I couldn't quite find a good design for a ramp without using mods to make moving parts.

Not in particular, unfortunately. In theory you could do it by just angling a few 2x2 structural panels off the sides and call that a ramp, but I'll have to experiment a bit to see how practical that really is.

[automcdonough]

every time i've tried was a fail, the wheels don't treat the parts as a ramp, they are frictionless and fall thru

[Designer225]

isn't this fixed by just going into docking-mode while driving the rover - which will infact turn off the rotational movement of the probe-body and let the wheels control the turning.

You do know that rotation controls and rover controls aren't the same. When going into docking mode, the rotation mode will be disabled yes, but because the rover control is separate from rotation control, the rover control aren't really disabled. You can might as well test this theory.

[automcdonough]

i always map rover controls to numpad so no overlap on anything

[DerekL1963]

You do know that rotation controls and rover controls aren't the same. When going into docking mode, the rotation mode will be disabled yes, but because the rover control is separate from rotation control, the rover control aren't really disabled. You can might as well test this theory.

Disabling the rotation mode *is the entire point*.

[Specialist290]

every time i've tried was a fail, the wheels don't treat the parts as a ramp, they are frictionless and fall thru

After doing some testing, it seems you're right. Every method I've used to try and get a rover off the top of the craft with a ramp has failed horribly. Seems like the "pure" Lunokhod option is out, at least with stock only