Gravity assist for solar exit

[zapman987]

Trying to perform a solar exit.

Ive got a solar orbit intersecting a planet, and been working on my gravity assists.

Just to double check, Since Im coming from behind and will remain behind the planet but will drop below the planet (between it and the sun), this is proper to increase deltaV? or do I need to pass infront of the planet? Normally I do this from inside a planet so not quite sure coming from outside.

[Jimbimbibble]

You want to pass behind it relative to its orbit and you want your orbit to be as eccentric as possible. Doing a burn at Pe during the gravity assist is also very effective.

[Taki117]

If you are going to be doing a powered assist (With a burn at planet periapsis) you want your periapsis to be really low to make the most use of the Oberth Effect.

[MockKnizzle]

Basically you wanna swing around behind the planet in its orbit. Its gravity will tug you along behind it, accelerating you around the Sun and increasing your orbital energy. If you mess up and pass ahead of the planet, it will decelerate you relative to the Sun and decrease your orbital energy.

Imagine bouncing a ball off the front of a speeding train, and you'll have a basic picture of what's happening. The ball comes in opposite the motion of the train, bounces, and then leaves in the same direction as the train but at a higher speed.