Planetary slingshot

[nijaxx]

I thought this effect was obvious until a friend questioned it.

Can anyone explain it in simple terms.

[mibn2cweus]

A planets motion through space (around the sun) is like the throwing arm. The planets gravitational attraction is like the net pulling an object toward it and slinging it in the direction of its motion through space. The angle of attack and initial velocity of the object are critical in determining how effective this is.

[CT]

Also, the two bjects exchange a little momentum. The planet loses a little, and the spacecraft gains some. Because of the huge mass difference, the planets loss of speed is irrelevant, but spacecraft's gain is significant.

[nijaxx]

What a wonderful web site. One gets answers to the most abstruse questions.

Thakyou mibn2cweus and CT for taking the trouble to educate me.

I am going to study this some more --Wikipedia looks promising. My trip to Pluto should follow shortly.