How are you landing your rovers?

[satcharna]

Sometimes the simple is beautiful as well. You've certainly accomplished it.

[GalaxyGryphon]

gunna go explore that mountain looking thing over there

(sorry for large images, last one)

[Ells]

I use the Skycrane method to drop all of my big Munar bases, next i'm building a rover but I like the H method some of you use.

[Mikeboy]

I just build them very small and stick them on the side of a regular lander.

[Crush]

On planets with an atmosphere, paradropping the rover shortly before touchdown is also an option:

Test flight of the whole craft on Kerbin:

[Crush]

Or just add wheels to the lander itself and call it a rove-lander. Often, the simple solutions are the best:

Edited May 24, 2013 by Crush

[wolfedg]

All my rovers have always used a vertical landing followed by a gravity topple. My newer rovers all have landing struts on the front to prevent damage to the front wheels from falling.

My first rover the Mark 1. I had to manually lift one of the legs to allow it to topple.

My later versions self topple on landing by eliminating one of the landing struts from the design as it is unnecessary, thus no screenshots of them vertical.

Mark II-The struts on the side made this one very hard to accidentaly roll while driving.

My latest revision, the Mark IIIB Incorporates parachutes for atmospheric landings.

Edited May 24, 2013 by wolfedg

[stupid_chris]

A lot of people are having the same issue I had: If the CoT is directly above the CoM, the controls are inverted. Well for a skycrane stage like this at least. I had a rover build similarly, and when I flew it it went totally the opposite of where it should: when I wanted to go left it went right, right was left, up was down, etc. So when you activate an ASAS, the computer tries to correct it... but it's actually making it worse. Which is causing the total breakdown. The only fix I found for this is to install a normal SAS module for extra control and disable the gimbal on the engines. Because it's the real issue there, the gimbal is inversed.

[satcharna]

Flip the command module upside down.

[ZedNova]

Not always. If you're a big fan of stability, like me, putting the thrust over the mass makes it "balance" on its own. It fights your commands, but it does so to keep pointing upward.

Well if it works for you, fine. But for me it doesn't, i assume it's because of this.

http://en.wikipedia.org/wiki/Pendulum_rocket_fallacy

[Vostok]

Not always. If you're a big fan of stability, like me, putting the thrust over the mass makes it "balance" on its own. It fights your commands, but it does so to keep pointing upward.

If I might link you here: http://en.wikipedia.org/wiki/Pendulum_rocket_fallacy

A rocket hovering will need thrust vectoring to keep itself pointed upwards. It will never 'balance' on its own due to the fact that the rocket thrust is relative to the rocket itself, rather than a fixed point in space.

EDIT: Oh fiddlesticks, I got Ninja'd!

[satcharna]

Oh, I know that. I just find it easier to keep my relative velocity low and stable easier with a high centre of thrust.

[Vostok]

If by centre of thrust you mean the line of action of the thrust, then surely it makes no difference where the rockets are placed? I didn't think that thrust had a centre point as you refer to, rather a line of action which should pass through the centre of mass.

[Retsof]

you can also build a box out of the armor plates to drop it with, and use decouplers and seperatrons to open it.

(screen from v19)

[Sir Nahme]

upside down usually lately lol

nah it depends on the rover, if I have a lander (ie manned mission), they are mounted underneath with a docking point to be reconnected on if I so choose.

if they are going in solo either they are capable of landing themselves, come in on a rig that they drive off of, or a skycrane

[stupid_chris]

No I tried flipping the command module upside down. Nothing to do it won't work no matter what I do :l

[Mokmo]

A stage mounted on top of the rover with thrusters that slow it down, hover it slightly above the ground, and then decouple. The rover drops down safely, and the skycrane flies off and crashes somewhere.

That folding action: How ?/Which mod ?

[magnemoe]

Or just add wheels to the lander itself and call it a rove-lander. Often, the simple solutions are the best:

This works nice, only downside is that the rover get very heavy. However if you land and want to explore a bit around the area, perhaps driving to an abnormality then you land three km away this is an good solution.

Added bonus if you design it to take off and return it to an mothership or station.

It also work nice for very small probe landers/ rovers, has one desing with 500-1200 m/s dv and weight less than an ton for the largest version.

If you want to drive a lot I recommending an separate rover with an skycrane as lighter rovers handles far better and is less likely to break. At least If you use mechjeb landing its no problem landing on the wheels outside of Tylo.

[magnemoe]

All my rovers have always used a vertical landing followed by a gravity topple. My newer rovers all have landing struts on the front to prevent damage to the front wheels from falling.

My first rover the Mark 1. I had to manually lift one of the legs to allow it to topple.

My later versions self topple on landing by eliminating one of the landing struts from the design as it is unnecessary, thus no screenshots of them vertical.

Mark II-The struts on the side made this one very hard to accidentaly roll while driving.

My latest revision, the Mark IIIB Incorporates parachutes for atmospheric landings.

Smart, I liked the extra landing legs, you know on an low gravity world you should be able to take that back to orbit if you keep the engine, if the main body was fuel this might even work on Mun.

Jump on an hill, optional use rocket for this, then airborne just burn a bit upward and start gravity turn.

Has to test this.

[lighthaze]

Rover on top of rocket, land, decouple rover, use small thrusters on rover to land it on the surface. Not really aerodynamic, but it works just fine.

[Qumefox]

As promised now that i'm home.. This is how I got three variants of these rovers to Mun.

First two were taken in the process of getting to orbit and after doing munar injection burn. Notice the drop tank on the bottom that keeps the mass symmetrical, as well as the probe body on top. It's important. Also both 'lifter' and droptank are aligned on the rover's CoM.

This was taken right after landing. After using the last of the fuel in the injection stage, It was jettisoned leaving only the rover and it's crane/droptank.. Then I switched control to the probe body on top, so I wouldn't have to deal with the controls being 90 degrees off. About 1k up the tank under the rover was decoupled, then I just landed the rover on the wheels, then decoupled the 'lifter' then flew it off, leaving the rover to do it's thing.

As I said.. Probably more complicated than it needed to be, but it worked three times in a row without problems. Or mechjeb.

[magnemoe]

even though mine isnt that off balance, when i apply thrust, it goes out of control, ive tried skycrane method but i just cant control this damn thing!!

what do you guys do?

First don't put the engines on struts longer than they need to be, second don't put them so high.

Last you use way to much engines, keep the large fuel tank for now, use two or four of the small orange radial engines, make sure they don't hit the rover, you might want to put two an two on the sides.

[stupid_chris]

First don't put the engines on struts longer than they need to be, second don't put them so high.

Last you use way to much engines, keep the large fuel tank for now, use two or four of the small orange radial engines, make sure they don't hit the rover, you might want to put two an two on the sides.

That doesn't fix the balance problem lol

[Qumefox]

From playing with it.. Apparently KSP has no clue how to operate gimbaling engines if the CoT is above the CoM... you can put ASAS anywhere, or pods/probes anywhere (though sometimes pod torque will overcome the problem if the ship is light enough)

For instance.. If you launch this with ASAS enabled.. it goes up straight every time

However, if you launch this with ASAS enabled.. it wipes out every time.

It doesn't matter where the probe body and ASAS is. I tried them on the bottom as well. It behaved the same.

However, if you lock the gimbals on the engines while they're on top.. the second example goes up straight as well.. well as straight as the miniscule probe body torque can keep it anyway.

So it's an issue with KSP not correctly gimbaling engines that are mounted higher than CoM.

[stupid_chris]

Alright since I'm not the only one with this problem, I'm gonna report in on the development page.

Edit: the bug is already on the bug tracker. The only fixes available for now is to turn of the gimbal, add SAS modules and run with torque, or control with RCS. But theres no fix for the gimbal for now.

Edited May 25, 2013 by stupid_chris