Reversing Your Orbit

[Enigma179]

So more than once on my interplanetary journeys by this point I've messed up and put myself in a clockwise orbit, exactly the opposite of the one you'll want. So far I believe I've done it on 3 of 6 of my interplanetary insertions (I've been getting better). Pro-tip; when transferring to a planet/moon/whatever in an orbit higher than your own, when you're doing your adjustments after leaving Kerbin/your starting point's sphere of influence, get your periapsis to the minimum, then burn a little more to get it higher again, because if you stop *before* the periapsis reaches the minimum you'll come in on the inside edge of the planet's SOI, and end up with a clockwise orbit, but if you burn a bit further you'll be on the far side upon reaching it and you'll get the right orbit. You'll still have to adjust inclination and things but that can save you a bit of delta-V.

Wait what was I gonna say?

Oh right, so recently after a 389 day journey to jool I now have a probe with something like 2600 delta-V flying around the giant in a stable orbit (and by the way, this being my first trip to jool, that aerobrake and the fire effects were TOTALLY worth the wait), except it's going in the wrong direction. This is more a thought experiment than anything else but I'd just like to hear your ideas; how would you go about reversing the direction of your orbit? The simplest approach is burn retrograde until your retrograde magically becomes prograde but with limited fuel and a gravity well like Jool's for me I don't think that's an option. Gravity assist/steep aerobrake on laythe? Rotate the orbit in a big circle around Jool to get the inclination from 180 degrees to zero? Some other outlandish solution? What if you're around a body with no moon? What if Jool didn't have such a freakishly strong gravity well?

[Brotoro]

Try for a gravity assist from Tylo?

[Brotoro]

Aerobrake violently at Laythe, then leave Laythe orbit in the correct direction if desired?

I'd go with this one.

[Brun]

Forgive me if this is offtopic, but why does it matter what direction your orbit is? I get why you want to launch prograde/counterclockwise from Kerbin (to take advantage of Kerbin's rotation), but once you're up there what disadvantage is there to being in a retrograde orbit? I can maybe see it making it hard to land on non-atmospheric planets, since you'll need more delta-v to compensate for the higher relative velocity of the surface...

[Temstar]

What's your current orbital altitude?

Where do you want to go after you've changed to a prograde orbit?

[malkuth]

Forgive me if this is offtopic, but why does it matter what direction your orbit is? I get why you want to launch prograde/counterclockwise from Kerbin (to take advantage of Kerbin's rotation), but once you're up there what disadvantage is there to being in a retrograde orbit? I can maybe see it making it hard to land on non-atmospheric planets, since you'll need more delta-v to compensate for the higher relative velocity of the surface...

Don't know.. Thought it might effect the Hofmann but don't think it would.. Must be a reason other then the fact it takes less energy to do it the correct way.

Edited June 12, 2013 by malkuth

[dharak1]

Forgive me if this is offtopic, but why does it matter what direction your orbit is? I get why you want to launch prograde/counterclockwise from Kerbin (to take advantage of Kerbin's rotation), but once you're up there what disadvantage is there to being in a retrograde orbit? I can maybe see it making it hard to land on non-atmospheric planets, since you'll need more delta-v to compensate for the higher relative velocity of the surface...

It makes it nearly impossible to transfer to airless moons. Especially ones with tight orbits and high orbital velocities because you need to burn VERY retrograde. That's why Laythe aerobrakes are being recommended.

[Markus Reese]

When I need to reverse direction of orbit, make a burn to make an extremely high apo, ie almost escape velocity. The high Apo makes for a low velosity point that makes orbital corrections easy It also doesn't take as much fuel to do as apposed to trying to do a full retrograde burn in low orbit.

[Mokmo]

My routine whenever getting to a planet now includes "is the ship in the right inclination?" an orbit in the wrong direction being one at 180 degrees, it takes very little energy to change it if you do it as soon as you're in the planet's sphere of influence. obviously it would be easier if we could know before reaching it, but even then exiting/entering a SOI sometimes ends up giving you very different predicted trajectories than from where you were before...

[The Destroyer]

Aerobrake violently at Laythe, then leave Laythe orbit in the correct direction if desired?

I'd go with this one.

I remember when I entered the wrong way- I always do that. I aerobraked like MAD in laythes atmosphere to land with little fuel, 8 km/s at 8 km altitude

[Rickenbacker]

The higher you raise your apoapsis, the slower you'll be when you get there, and the easier it will be to reverse your orbit (or do any plane change maneuvers, really). So try raising your Ap, and do the correction burn there, to save some fuel.

[Mr Shifty]

When I need to reverse direction of orbit, make a burn to make an extremely high apo, ie almost escape velocity. The high Apo makes for a low velosity point that makes orbital corrections easy It also doesn't take as much fuel to do as apposed to trying to do a full retrograde burn in low orbit.

This, just make your orbit really eccentric, then burn retrograde at apoapsis until the direction reverses. It takes surprisingly little delta-V out there.

[birrhan]

May be too late for this trip, but in the future, if you know you're heading in the wrong direction, you can adjust normal/antinormal and incline/decline (the blue and purple arrows on your nodes) to approach in the opposite direction. Just after entering Jool's SOI you can do this for ~50 dv. The cost gets much higher the closer to a body you get (in line with everyone's comments about changing direction at a high apoapsis).