How do I higher and lower my orbit?

[Chowderpat]

Recently I wanted to create a space station in sandbox mode, and I was wondering, how do I adjust my orbit to catch up to my space station? I have the docking part in space, and all I need to do is get to my space station.

[Octa]

If your spacecraft that wants to dock with your station is behind it, lower your orbit, so it will catch up. Raise your orbit if it's in front of your station. All is assuming that the orbit of the station and the spacecraft which wants to dock is the same at the moment.

For the final roundevouz, control the spacecraft, select the spacestation as target and set up a maneuver-node that intersects the orbit of the station. You'll get the separation distance displayed. Try to set up a node to get a seperation of 5km (more is still possible if you can't get it tight on first time) and then try to get burn right.

There are plenty of tutorials out there for roundevouz (gettings 2 ships close to each other) and docking itself. My first docking mission was the one described in the wiki, the re-enacting of gimini 6A and gemini 7.

Edit: added link

[jarmund]

To increase apoapsis, burn prograde at periapsis.

To increase periapsis, burn prograde at apoapsis.

To decrease apoapsis, burn retrograde at periapsis.

To decrease periapsis, burn retrograde at apoapsis.

To catch up with your target, make sure it's shorter than it, for example, roughly the same apoapsis, but with a periapsis lower than it.

[Alshain]

To increase apoapsis, burn prograde at periapsis.

To increase periapsis, burn prograde at apoapsis.

To decrease apoapsis, burn retrograde at periapsis.

To decrease periapsis, burn retrograde at apoapsis.

To catch up with your target, make sure it's shorter than it, for example, roughly the same apoapsis, but with a periapsis lower than it.

Not entirely accurate. You can alter your orbit from anywhere if it's mostly circular, it's just most fuel efficient at Ap or Pe. However, if you're targeting something like the Mun then it's less likely you will be burning prograde at periapsis. Eventually you will be increasing Ap or Pe from any location (or even turning your Pe into Ap)

Edited March 31, 2015 by Alshain

[Invader Myk]

Being creatures that evolved under the influence of gravity orbital mechanics are very unintuitive and often counter-intuitive.

If you are behind your target you need to go slower. This shortens your orbital period allowing you to catch up to your target.

If you are ahead of your target you need to go faster. This lengthens your period allowing your target to catch up with you.

After you have caught up, meaning within 2km, then you perform the reverse of what you did to intercept your target until your velocity relative to your target is <100m/s.

From there, unless you are flying a behemoth or have severely underpowered RCS thrusters, you should be able to man handle the ship to a docking trajectory.

Also, check out the kerbal wiki. It has an excellent tutorial on docking.

[RainDreamer]

To increase orbit height, point prograde and burn. Do the reverse to lower orbit.

To rendezvous with an object in space, makes sure you are matching with their orbital plane first to make things simpler for you, as you eliminate 1 dimension that you need to deal with. Then you either catch up with the object from a lower orbit, or you let the object catch up to you from a higher orbit.

[Superfluous J]

I made a series of tutorials on YouTube that show quickly and easily how to meet your station, then how to apporach it once you've met it, and finally how to dock. You may need all 3 but you're specifically asking for what I detailed in the first video.

[Alshain]

Depending on how you think about it, rendezvous isn't that unintuitive. Forget about speed, pretend everything is going the same speed. Now, imagine two track runners running around circular track. One is on the inside lane and the other on the outside. Assuming they are running at the same speed, which one arrives at the finish lane first? The inside, because it's a shorter distance. Now, in orbital mechanics the end result is the same, even though really the craft are in fact moving at different speeds in this case.

What is unintuitive and confuses many about orbital mechanics however is the higher your orbit, the slower your speed. You can see this effect on your own. Establish a 75 km circular orbit and write down your m/s. Raise it to 300, and check the m/s again. This is a rather confounding principle because you have to accelerate more to get a higher orbit which goes slower. That is where the confusion lies. However, the lower speed is the result of weaker gravity. Even though your adding more acceleration, that velocity does not translate into the orbit. I'm sure you have heard that orbiting is just endlessly falling, well that is true but at higher orbits there is weaker gravity so you don't fall as fast. With an elliptical orbit, this principle still holds true. As you approach Pe, you get faster and faster and as you approach Ap, you get slower and slower.

[culturekills]

This history of docking at Wikipedia explains a lot of the specifics of how and why too:

en.wikipedia.org/wiki/Space_rendezvous