Select the correct answer from each drop-down menu. study this model of a gravitational slingshot then answer the questions. in this model, the velocity of the spacecraft of the position 2 is (equal to - greater than- less than) the velocity of the craft at position 4. at point 1, the direction of the spacecraft changes because of ( the gravitational force between earth and the spacecraft - the momentum of the space craft - secondary fuel tanks). position 3 represents the (final destination of the spacecraft - gravitational force of the spacecraft on earth - orbital path or a of earth).

This is due the gravity field of the Earth is used to accelerate the craft. This is true when in a specific point the direction of the movement of the craft is the same direction of the movement of the planet.

In this case the craft will be “catched” by the Earth’s gravitational field, making the craft  to enter a circular orbit.

As explained in the first answer, this is the exact point where the trajectory of the spacecraft enters into a circular orbit because of the attraction due gravity of the Earth and therefore changes its direction.

Being this the orbital path of the Earth and considering the trajectory of the craft, the condition of accelerating the craft is accomplished. If the orbital path of the Earth were the opposite from the shown in the figure, the effect on the craft would be braking.

Note all of these is related to the gravitational assistance, this consists in a maneuver in which the energy of the gravitational field of a planet or satellite is used to obtain an acceleration or braking of the probe or craft, changing its trajectory.

This maneuver is also called slingshot effect, swing-by or gravity assist.