How do I fix my orbit for a rendezvous?

[Aphox]

My space station had a little trouble staying upright in sub-orbital flight, so it went on a light skew in it\'s orbit, causing this to happen. They come across eachother very closely-- around 300m, but I can\'t judge which direction it\'s going and what direction I need to burn to keep my orbit and speed exact with it.

Anyone have any tips on how to get these two in sync?

For reference, the ISS is at 403KM Pe and Ap @ 1876.3 m/s. I\'m using a MechJeb for the rendezvous since I\'m terrible at rocket surgery, but it can\'t compensate for the slight skew of the orbit.

[Aphox]

Well, I\'ve completed the mission. I found it near impossible to get my rendezvous craft to orbit in perfect sync with the station; as with every orbit, it would slowly drift further and further.

I EVA\'d two of the kerbals and got them into the crewpod on the station, leaving one to return the shuttle home.

A rescue vehicle will be deployed to him, as well as Bob and Bill, who\'ve been trapped on the other side of Kerbin for years, as soon as I figure out how to get something that heavy that far.

[sgtblazing]

Mechjeb makes this very easy (even without the rendezvous add-on)

What you want to do is called a plane change maneuver, as you need to get your orbital inclination to match your target.

Find out what inclination you want to have(you are using mechjeb, so its very easy, it tells you in the orbital information window)

Find a point where the two orbits intersect (form an x)

When they intersect, you want to 'push' your orbit towards your target\'s orbit, you do this by thrusting along the normal and anti-normal. The MechJeb Smart ASS has buttons for this. You do this as close to the intersection as you can, and it may take a few times. To tell which direction to thrust (normal or anti-normal) you can simply see which way you need to thrust. If at the intersection your orbit will be passing above the target orbit (moving from south of the orbit to the north), you need to thrust downward (south)at the intersection. This is done by thrusting upon the anti-normal. The opposite is true when you need to 'push' the orbit upward, you use the normal to thrust upward. keep doing this until you get the same inclination as your target (or just eyeball the orbits in the map)

I like to get my inclination to match my target before trying to sync up with it, mainly because when burning to fix the tilt you can accidentally unsync. Be warned, changing your inclination takes a ton of fuel.

If anything here is incorrect or does not make sense, I apologize as it is very late. I hope this helps!

[Aphox]

Mechjeb makes this very easy (even without the rendezvous add-on)

What you want to do is called a plane change maneuver, as you need to get your orbital inclination to match your target.

Find out what inclination you want to have(you are using mechjeb, so its very easy, it tells you in the orbital information window)

Find a point where the two orbits intersect (form an x)

When they intersect, you want to 'push' your orbit towards your target\'s orbit, you do this by thrusting along the normal and anti-normal. The MechJeb Smart ASS has buttons for this. You do this as close to the intersection as you can, and it may take a few times. To tell which direction to thrust (normal or anti-normal) you can simply see which way you need to thrust. If at the intersection your orbit will be passing above the target orbit (moving from south of the orbit to the north), you need to thrust downward (south)at the intersection. This is done by thrusting upon the anti-normal. The opposite is true when you need to 'push' the orbit upward, you use the normal to thrust upward. keep doing this until you get the same inclination as your target (or just eyeball the orbits in the map)

I like to get my inclination to match my target before trying to sync up with it, mainly because when burning to fix the tilt you can accidentally unsync. Be warned, changing your inclination takes a ton of fuel.

If anything here is incorrect or does not make sense, I apologize as it is very late. I hope this helps!

It makes perfect sense, actually. I figured that out after a little bit of messing with it. Got it within 25 meters of the station for a few minutes, but had to constantly adjust.

What I\'m having trouble with is getting the rendezvous craft going the exact same direction and speed as the station. They were on the exact same orbit on the map, even at maximum zoom, but they still seemed to go in and out from eachother a kilometer or two. It\'s hard to judge which exact direction you need to burn when you\'re that far out.

[pebble_garden]

Even if two spacecraft are in exactly the same orbit (same altitude, same speed) with one trailing the other by a few meters, they are going to slowly spin around each other, once per orbit.

Imagine this in map view, looking down on Kerbin\'s North Pole. On one side of the orbit, ship A will be above ship B because the orbit is going up. Half an orbit later, their positions will be reversed. But they shouldn\'t drift any further apart, so that\'s good.

You can\'t separate by orbital inclination, because the ships will bang into each other at the two crossing nodes.

The only way to make them to co-orbit without that slow spin is to dock, or put one ship inside the other. Or you could (theoretically) lash them together and spin it all around a common center, useful for artificial gravity perhaps.

[Aphox]

Yeah, kinda noticing that now. Even with the Orbital Construction mod and the jump drive that teleports me straight to the station, they still kinda noodle around eachother. But I guess it\'s easy enough to EVA to the thing when you get close. EVA is incredibly easy to control at short range.

[pebble_garden]

But I guess it\'s easy enough to EVA to the thing when you get close. EVA is incredibly easy to control at short range.

EVA is the most fun EVAR. Squad really hit a home run when they created those delightful Kerbals, and gave us the ability to scoot them around.