Difference between revisions of "Rover"

Revision as of 21:28, 23 September 2013

A simple solar-powered, unmanned rover

A rover is a ground vehicle equipped with wheels, allowing them to travel around the surface of most celestial body, notable exceptions are Kerbol and Jool. They were introduced with version 0.19.

Constructing rovers

Basics

For a vehicle to be classified as a rover, it must have at the very least a command module and some wheels. A source of electricity is strongly recommended as no command module has enough internal supply for more than a few minutes of driving. To allow the vehicle to drive straight, the wheels must be mounted parallel to each other in the VAB. While the rover is being driven, the wheels are smart enough to steer in directions matching the control inputs.

Wheels require lots of electricity to operate, so a rover should be equipped with plenty of energy. Batteries can power a rover for a time, but sustainable energy sources in form of solar panels or RTGs are required for a rover to operate indefinitely. Often solar panels are preferred due to their lower mass, but extended solar panels can easily be destroyed by atmospheric drag when on a fast-driving rover in an atmosphere.

Rover wheels model 3, 1 and 2 with a Kerbal for size comparison

Image	Part	Radial size	Cost ()	Mass (t)	Max. Temp. (K)	Tolerance (m/s)	Tolerance (g)	Electricity (⚡/s)	Max. Motor Speed (m/s)	Brake Torque (kNm)
	RoveMax Model S2	Radial mounted	300	0.05	1 200	20	20	1.0	12	0.34
	RoveMax Model M1	Radial mounted	450	0.075	1 200	50	50	2.5	34	2
	TR-2L Ruggedized Vehicular Wheel	Radial mounted	760	0.105	1 200	100	80	3.5	58	3
	RoveMax Model XL3	Radial mounted	1 200	1.25	1 200	150	200	5.0	15.5	30

Advanced

A rover which is easy to control, should be relatively wide with a low center of mass. This makes it much harder for the rover to topple over when driving fast curves, accelerating or braking. Rovers are less stable when in low gravity, so a rover which is almost impossible to flip over on Kerbin might still require some care on Minmus, for example. Especially on bodies with low gravity like Minmus rovers with a low mass might not have enough grip to accelerate. In such case thrusters, usually RCS, pointing upwards can be used to push the rover onto the surface.

On small rovers, LT-1 Landing Struts can be used to turn them back over when they end up upside down. Larger rovers on low-gravity worlds can help themself up by using RCS thrusters.

To give rovers some more acceleration, RCS or even rocket engines can be added to them.

Piloting rovers

Per default, a rover is controlled with the keys A, D, W and S. Unfortunately these keys also control vehicle rotation, which can make a rover completely uncontrollable on planets with low gravity. As a workaround for this problem, the rover controls can be remapped to different keys in the settings menu. If a number pad is available, a good solution is to map the WASD drive controls to 8456 on the numpad. Another solution is to switch into docking mode when controlling a rover.

Using docking controls, as opposed to staging controls, it is possible to quickly switch which keys control the translation and rotation. When the controls are in "UN" mode the WASD controls rotate the rover, which can be switched with space. When IJKL rotate and WASD translate, which is usually harmless for a rover. With a single click of the space button, pitching can be easily switch between on and off, therefore giving a stable mode of acceleration/direction change and a quick way to adjust the pitch of the rover on low gravity planets, should it be tipped or launched over a hill.

To prevent rovers from driving away when they are dropped, the parking brake (in the top-center HUD, bottom icon on the right) should be applied prior to the drop. While piloting the rover the “B” (default) can activate the brake, but after releasing the button the brakes will release too.

The most flimsy part of a rover are the wheels. When they experience strong impacts, they can get “broken”. In this state they are still intact as a part, but do not work as a wheel anymore. The impact threshold for this to happen is a lot lower than the actual impact tolerance listed in the parts menu. Wheels easily break when the rover jumps, so it is recommended to reduce the speed when the rover is driving over a hill. They can also break when they get faster than the maximum speed of the wheels, which can easily happen when it drives down a slope or uses rocket thrusters to accelerate a rover to higher speeds than it could reach with its wheels only. But it is possible to raise the speed at which the wheels break by reducing the weight pushing on the wheels, for example in atmosphere by using wings.

Fortunately, broken wheels can be fixed by kerbonauts on an EVA. When a kerbonaut is close to the damaged wheel, right-click it and click on "repair". The wheel will immediately be operational again. Usually the wheel jumps a bit which can damage the rover, especially if it is moving or very light.