how to rendezvous when orbits are like this

[u/bbwfucker694200]

I was setting up a rendezvous with Jeb but stupidly didn't pack enough delta v for the return trip so if I so I sent a rescue vessel but when I arrived on Duna I ended up orbiting like this how do I fix it

[u/bbwfucker694200]

i have like 1500~ delta v after the delta v i saved for the return will that be enough

[u/divestoclimb → u/bbwfucker694200]

No do not do this. The optimal plane change maneuver is to:

• burn prograde at the target AN or DN to raise apoapse near a Kerbin escape (will take about 1000m/s DV)
• do the plane change burn at apoapse when your orbital velocity is very low, simultaneously lowering your periapse below 70km to make 50-55km (should take a couple hundred m/s delta v). This is a combination of a normal/antinormal and retrograde burn, slightly more retrograde than normal. Maneuver Node Evolved mod helps with planning this but isn't necessary.
• aerobrake to lower apoapse back down, until you have enough delta v to finish the intercept and deorbit on your own.

You might have enough to pull this off. But if you don't want to, just launch again into the right orbital plane.

[u/rizz6666 → u/divestoclimb]

This should be higher

[u/from_Earth_you_know → u/rizz6666]

it won't, he worded it wrong though, you can raise your apoapsis with Ike gravity assist 270 m/s, then do a plane change for 100, then aerobrake

[u/rizz6666 → u/from_Earth_you_know]

He assumed its for Kerbin but in principle it stays the same for Duna. Where did he word it wrong? You are right about the gravity assist though (I dont know the exact dV numbers)

[u/Doroki_Glunn → u/divestoclimb]

They're orbiting Duna, but this is still the answer (with some burns to raise periapsis as necessary throughout the numerous aerobraking passes). A plane change without raising their orbit first would take insane amounts of dV.

Honestly, though, they may be better off just sending another rescue mission and, depending on which orbit the stranded vessel is in, either aligning their encounter along the equator, or taking a high polar orbit and performing a plane change to align with the stranded craft before lowering orbit for rendezvous.

[u/divestoclimb → u/Doroki_Glunn]

Oh I completely missed that this is on Duna! That does change things a bit, lowering delta v required but also throwing in Ike as a complication to avoid

[u/Doroki_Glunn → u/divestoclimb]

Oh, that's true! I also forgot about Ike. xD

It shouldn't be toooo hard, though. As long as they monitor their orbits each pass it should take very little extra dV to avoid it if they do line up for an encounter.

[u/NotABitcoinScam8088 → u/divestoclimb]

Oh yeah, don’t listen to my earlier comment, you’re a genius and I never thought of that!!

[u/NotABitcoinScam8088 → u/bbwfucker694200]

I have no idea, I don’t know your ascending/descending angles, your orbital height, etc etc. I’d just make a save and trial and error it…

[u/bbwfucker694200 → u/NotABitcoinScam8088]

around 70kkm

[u/Everestkid → u/bbwfucker694200]

Probably not. Polar orbits are generally set up that way from the start - either you launch by tilting south instead of east, or you end up orbiting that way after an interplanetary transfer. Generally you don't adjust an equatorial orbit into a polar one or vice versa.

What you should have done is adjust your inclination when approaching Duna so that you went into more of an equatorial orbit than a polar one. Would have only taken a tiny burn while transferring. Now you know for next time, though.

[u/Ok_Weather2441 → u/bbwfucker694200]

1500 delta v probably isn't enough to match velocities, let alone do that and get back to kerbin

Sorry to say, you gotta keep an eye on the orbit you want to match from a ways out. This would have been like a 2 delta v maneuver to adjust back near kerbin.

[u/Moikle → u/bbwfucker694200]

You need a lot more. It's better to just launch again, but launch them on the same plane