Opposition class mission to Duna, what time to depart and how much delta-v?

[CaelumEtAstra]

I'm tossing around the idea of doing an opposition class Duna mission instead of the standard kerbal way of "wait for the launch window then wait a year for the next one".

There are two parts to this question:

1. When do I need to depart from Kerbin and later on Duna?
2. How much delta-v would be required to depart, insert into Duna orbit, then return to Kerbin?

Thanks in advance!

[ibanix]

Well, you're going to have to define 'opposition class' first, or no one will be able to answer you.

 

8 minutes ago, Mrsupersonic8 said:

 

1. When do I need to depart from Kerbin and later on Duna?
2. How much delta-v would be required to depart, insert into Duna orbit, then return to Kerbin?

 

1) See: http://alexmoon.github.io/ksp

2) See: http://alexmoon.github.io/ksp

[CaelumEtAstra]

40 minutes ago, ibanix said:

Well, you're going to have to define 'opposition class' first, or no one will be able to answer you.

 

1) See: http://alexmoon.github.io/ksp

2) See: http://alexmoon.github.io/ksp

Already know about that, but I'm not sure when exaclty to depart. Besides, I tried with that and all I got was...well...nothing.

 

Nevermind, I'll just eyeball it in game.

Edited June 9, 2016 by Mrsupersonic8

[ibanix]

26 minutes ago, Mrsupersonic8 said:

Already know about that, but I'm not sure when exaclty to depart. Besides, I tried with that and all I got was...well...nothing.

 

Nevermind, I'll just eyeball it in game.

The planner lists departure right after you run it, eg:

Departure

Year 1, day 236 at 4:19:12

[PLAD]

I executed an opposition-class mission to Duna, where I flew by Eve on the way home from Duna, some time ago, here it is. Back in those days we only used Earth time (24-hour days and 365 days in a year) so you will have to translate my departure, flyby, and arrival dates into Kerbin time if you use that. You don't have to look through the album for dates, I give a summary in the post. Note that at the end of the post show a path for flying by Eve while on the way to Duna. I've written a tool that searches for flybys like the Eve flyby you will need either on the way to Duna or when coming back from it, so you can search for other opportunities. Here's an example of a Flyby Finder search that shows a Kerbin-Eve-Duna-Kerbin path. Arrowstar's TOT can also plan missions like this.

http://imgur.com/Xl67ivX

I like these because they allow an abort of the mission if some problem prevents the Duna landing, you can just fly by Duna and shoot home for no extra dV. And if you land, there is of course a window immediately available for getting home if you only spend a day or two on Duna. (though it requires higher-than-usual dV)

I personally prefer going Kerbin-Eve-Duna,  because the departure burn to get from Kerbin to Eve is not much larger than a typical Kerbin-Duna burn (maybe ~200m/s more), but the Duna-Kerbin burn is smaller than a Duna-Eve burn (for flying Duna-Eve-Kerbin) when heading home. You have a higher arrival speed at Duna though, but if you can aerobrake that eliminates that disadvantage.