Orbiting Duna Forever...

[The Jedi Master]

The guy at KSC who handles interplanetary encounters is officially fired.

I sent Milholt Kerman and one other guy who's name I don't remember out to land on Ike (yes, I know it's dark due to a bug, that's why I want to go there before 0.21). I had gotten the encounter with Duna and all, but when I got there, I noticed something odd. Namely, I WAS DIRECTLY OVER THE NORTH POLE OF DUNA. I burned for orbit anyway, because orbiting Duna forever with a slim chance of rescue is a lot nicer than orbiting the sun forever with no chance of rescue.

Now Milholt and his pal are now stuck in a highly elliptical polar orbit around Duna. The ship has less than 100 units of fuel left, 98 units of RCS left and no docking ports. Chances of rescue, due to the extreme distance involved, are very slim.

But hey, we got a nice picture...

Lesson learned: Do not treat interplanetary missions like a Mun landing!

[Cashen]

What's your orbital periapsis? If it's low enough, you could expend a small amount of fuel at apoapsis to bring your periapsis down into the atmosphere, aerobreake for a few orbits to drag your apoaosis down, and then kick your periapsis back out. It would make the orbit more manageable.

After that, your only chance of a rescue is a simple rendezvous with a craft with enough empty seats for the crew, and EVA them over, leaving the empty craft in orbit forever.

In the future, you are best to match orbital planes with Duna half-way during the interplanetary coast, at either the ascending or descending node. This will mean you'll come very close to the equatorial plane. You should also aerocapture at Duna by passing through its atmosphere at periapsis, this will allow you to be captured without expending fuel. I find this online calculator useful when aerobreaking: http://alterbaron.github.io/ksp_aerocalc/

You could use that tool to aerobrake at the right altitude to have an apoapsis close to Ike's orbit, and from there an encounter is almost guaranteed if you wait an orbit or two. Don't try to brake-burn right to Ike, you'll waste a lot of fuel. Aerocapture is free.

Edited July 13, 2013 by Cashen

[TinMissileMan]

I rescued lone Dudrod Kerman from a highly eccentric orbit around Kerbin with my Remuais (pronounced Rea-mwah) craft. Rendezvous with the craft, kill the velocity relative to the target and EVA both kerbals into one of those Hitch-joker things.

[jwenting]

beware that a slingshot around Ike at some point can kick you out of your Duna orbit and back into the interplanetary void.

Had that happen with one ship I'd parked there, overnight awaiting my brain to wake up and get the orbit circularised around Duna. When I got out of bed it was gone, found it later in a solar orbit.

[Tw1]

Was this a powered capture? (As in, you performed an orbital insertion burn.)

I tried that on my first Duna visit, didn't go so well. An aerocapture saves you a lot of delta V.

Even if you forget to make corrections, and end up in a polar orbit, you could still intercept Ike. Then, you could try a gravity assist to change inclination.

Note that this was for a landing at the pole.

Then get to Ike. Better luck next time!

Then it's time for part two. The rescue, and Ike landing. I hope Milhot and friend have enough to do, with all that time on their hands.

Edited July 15, 2013 by Tw1

[The Jedi Master]

Was this a powered capture? (As in, you performed an orbital insertion burn.)

I tried that on my first Duna visit, didn't go so well. An aerocapture saves you a lot of delta V.

Even if you forget to make corrections, and end up in a polar orbit, you could still intercept Ike. Then, you could try a gravity assist to change inclination.

--sniped image--

Note that this was for a landing at the pole.

Then get to Ike. Better luck next time!

Then it's time for part two. The rescue, and Ike landing. I hope Milhot and friend have enough to do, with all that time on their hands.

Thank you for the advice! I think I'll head into KSP and try to make it happen!

I just had a good look at the first screenshot, and realized that the ship has way more than "less than 100 units of fuel left"! That will help!

Edited July 16, 2013 by The Jedi Master