Landing a Rover

[DarkHawkGames]

I'm looking into building an unmanned rover to either Minmus or the Mun, to make it easier to get science out of the biomes. Is there a specific way I should try to land it? I was thinking about building it like a rocket, and then just tilting it over onto its wheels when it landed wherever its going and decoupling, like on a fairing.

[dafidge9898]

28 minutes ago, DarkHawkGames said:

I'm looking into building an unmanned rover to either Minmus or the Mun, to make it easier to get science out of the biomes. Is there a specific way I should try to land it? I was thinking about building it like a rocket, and then just tilting it over onto its wheels when it landed wherever its going and decoupling, like on a fairing.

How I used to do it was like a sky crane. I have the rover hanging off of something by a rectangular strut or something. The thing it's hanging off of houses engines and fuel. Once the wheels touch down, I stage, and the engines + fuel tanks go flying off far away, while the lander stays tight on the surface. 

[foamyesque]

Why not just make the rover self-landing? You can do the bulk of the insertion and deorbit work with a can of fuel and a Terrier, with the rover on top, then jettison it and do your terminal burn with a few spiders and an Oscar-B.

[klesh]

Check out the pre-made skycrane rover/lander combo in the stock crafts section of the game for a neat way of doing it.  I use variations on that theme.

[bewing]

Most of my rovers have a rocket on the back end. I land them vertically on the engine bell, and then tip them onto their wheels. A slightly tricky maneuver if you have a little bit of horizontal drift, or your landing spot is not flat.

One of my rovers has a terrier on the bottom, and I just land it directly on the wheels.

 

[Aegolius13]

Another variant to the skycrane approach is to put landing legs on the crane, situated so that they stick down just past the rover when deployed.  This way, unless you hit some really bumpy topography, you'll touch down on the legs first, with the rover dangling underneath.  Then you can release the rover at your leisure, and let the rover drop the small distance to the surface.  This should provide some insurance against hitting too hard and damaging your wheels.  

[Foxster]

If you want something waaaay over-engineered then there's this idea (which is really for Eve)...

[Superfluous J]

Be prepared to be very unhappy with the utility of your rover once on the surface, especially on Minmus. Driving there is more like skiing. Or trying to run on ice with tap shoes on. Mun's not much better, except your tires will get a little grip, allowing you to go much faster before losing total control.

[Magzimum]

I typically install some upwards-pointing RCS (the Place-Anywhere RCS), so that it pushes me onto the surface in case I really need it... and for the rest, I make sure I it is a low vehicle that does not tip over quickly... (Testing is fun, as I get to drive around the Space Center like a maniac, trying to tip it over.)

As for the lander, I always made a skycrane-type of ship, with 2 rockets on the side of the rover, and something (a flat Mk2 fuel tank, or girders) overhead that the rover hangs on (I use docking ports for the connection). One time, I equipped my rover with wheels as well as landing legs, so that it would be pushed up a little by the landing legs when they are extended. That allowed me to dock my rover again with the skycrane, so that I could rove on multiple locations on Minmus. It was a little over-engineered for its original task, but that's what KSP is all about, isn't it?

[Aethon]

 

 

Here's my Standard science rover with the skycrane still attached.

 

[storm_soldier2377]

My favorite way of landing rovers:

The reason I do it that way is that you only need one probe core and is somewhat simpler to build than a traditional skycrane.

5 hours ago, Aethon said:

 

 

Here's my Standard science rover with the skycrane still attached.

 

What mod are you using for that camera?

[klesh]

Here's one where I had enough fuel in the transfer stage to land my rover with it still attached.  Fortunately I had the skycrane, and just hopped it off a few feet.

 

[Geschosskopf]

23 hours ago, DarkHawkGames said:

I'm looking into building an unmanned rover to either Minmus or the Mun, to make it easier to get science out of the biomes. Is there a specific way I should try to land it? I was thinking about building it like a rocket, and then just tilting it over onto its wheels when it landed wherever its going and decoupling, like on a fairing.

First off, rovers are NOT the ideal way of going to other biomes on Mun or Minmus.  On Mun, in most places, you have to drive dozens if not hundreds of kms to get to another biome, and the terrain is NOT kind to rovers.  The best bet is a self-refueling (aka ISRU) lander hopping from biome to biome.  On Minmus, the gravity is so low that rovers are way more trouble than they're worth. So instead, drop a lander that has about 3500m/s still in the tank when it 1st lands, and you can hop to every biome on Minmus and get back home no problem.  Given that Minmus can be hopped without ISRU, I recommend doing that first, collecting the thousands of Science! points from all the biomes, and then going on to Duna to finish the tech tree.  There are more biomes on Mun but they're not worth as much as biomes on Minmus, and after you pillage all Minmus biomes you should be mostly done with the tech tree anyway.

That said, how to land rovers is an age-old KSP question predating the advent of career mode.  The basic problem is called the "vertical to horizontal transition", because no matter how you slice it, the rover's POV (and thus the way its navvball is oriented) must change at some point.  Given that this is a very old problem, there are many possible solutions, which I will try to outline below.

However, 1st off, you need to understand navball orientation and how the 2 different editors (VAB and SPH) deal with it.....  Rovers should always be built in the SPH, saved as subassemblies, then added to rockets started in the VAB.  But  the SPH says "forward" is towards the open doors and "up" is towards the ceiling. which means that when you launch the rover from the SPH to the runway, the navball will have brown down, blue up, and all is good for the rover.  But in the VAB  "forward" is towards the ceiling and "up" is towards the wall WITHOUT your big flag on it.  If you build a rocket in the VAB, the navball shows all blue when you launch it to the launchpad and wheel steering is reversed from the keys say.  This is why you should always build rovers in the SPH as subassemblies for the rocket in the VAB, but is also the basis for the "vertical to horizontal problem" because, unless you do something, once you separate the rover, its navball will have the VAB orientation.  That's fine for landing it but sucks for driving around.  This is where the "vertical to horizontal problem" comes from.

There are 2 main ways to work around this problem all of which assume the rover was built in the SPH with SPH navball orientation for the primary "control from here" point.

• Have 2 "control from here" points on the rover, one using default SPH orientation and the other facing up.   The other can be a probe core rotated to face up, a docking port, an MJ unit radially attached to face up, or any radially attached probe core from a mod.  The idea here is that the rover separates from the rocket in orbit and then descends with engines that will be ditched once landed.  The 2nd "control from here" part is used only during the descent and landing.  Once down you switch "control from here" to the core probe core or crew pod that you started with in the SPH.
•  The rover lands attached to a rocket built in the VAB, using the VAB navball orientation based on the root crew pod or probe core you started with in the VAB.  Once on the ground, you detach the SPH-built rover so that it rotates 90^ and ends up on its wheels with the navball oriented per SPH.

I tend to prefer the 1st option myself, so I can attach the descent engines in the SPH and then stack several rovers on the VAB rocket.  Here's an example:

In the right half of the pic, you see a the stack of 4 rovers inside the fairing.  Each has its own descent engines and fuel tanks on the sides.  To "control from here" during the landing, each has a small probe core mounted on a cubic octagonal strut, which can be seen n the top rover in the stack.  To drive once down, each has a probe core inline with the axis of the rover body.  Each rover, complete with descent engines, was a subassembly.  The rocket flew to its destination using a VAB-placed probe core below the fairing.

 

Another method (from, very long ago using mods that have been dead for years).

Here, the VAB-built rocket landed using its own vertically oriented probe core.  Once down, an action group retracted 2 lets on 1 side and extended an inverted leg  halfway up the central stack on that same side, so the lander fell over about 160^.  Then the SPH-built rover detached and drove away using its own SPH-built "control from here" part.

[bewing]

I have to disagree slightly with the above, just to say that rovers on Minmus are the greatest thing ever.

[Aethon]

5 hours ago, storm_soldier2377 said:

 

What mod are you using for that camera?

Tarsier Technologies.