Slingshot/Gravity Assist planner

[szputnyik]

I would like it if there was a planner tool, that would calculate optimal launch windows for planetary slingshots for you. It could be an extension of TriggerAu's Transfer Window Planner, or a separate, similar program.

For example, let's say you want to do a free return mission to Eve, in which you launch a spacecraft to Eve, it swings by Eve, and returns to Kerbin with minimal orbital adjustments. The planner would give you a launch window to Eve, where the date of the Eve periapsis corresponds with an Eve-->Kerbin transfer window, so the spacecraft would return to Kerbin with a minimum of dV.

More complicated arrangements could be using the gravity assist of a planet, to reach a more distant planet with less dV. This time for example, it would give you a launch window to Eve, where the time of the Eve periapsis corresponds with a transfer window to Moho, so you could go to Moho with less dV than by directly burning to a Moho-encountering orbit from Kerbin.

An even more complicated arrangement would be a "Grand Tour" where the planner would give you a launch window, with which you could visit multiple planets with gravity assists.

[Red Iron Crown]

Trajectory Optimization Tool has advanced mission planning tools, including a gravity assist planner.