In this part of the lesson, you will get to launch a rocket ship to five different space missions. Each one will get a little bit harder. Complete all five missions and you're a super space navigator!

1. Go to Gravity Launch to start your space navigation.
   
2. Click on the rocket to start the game.
   
3. Click on the “How to Play” button in the lower right corner to read specific directions on how to use the interactive. You can use the arrow keys to scroll up or down the page. When done, click on the "Back" button to go back to the interactive.
   
4. Take a look around. To your right, you'll see the moon. Below earth, you'll see the space station to which you are trying to launch.
   
5. Adjust your ship's thrust and take-off angle using the lever and dial on the control panel.
   
6. Click the red "Launch" button to launch your ship.

Thrust is the force that is needed to get the rocket ship off the ground. It is working against the force/pull of gravity. So, there are two forces at play. One hint that may help you with successful missions is to know that your thrust should always be above a 6 in order to make a force that will push hard enough against earth's gravity.

When the motion of the rocket ship is changed, that motion is changed by a force. The changes can be in the speed or direction of the rocket ship. For instance, when the thrust starts, it moves the rocket ship from a standstill (which is not very fast) to go flying through the air. Also, when the rocket ship gets near the moon, it changes direction due to the moon's gravitational pull. (Even though the moon's gravitational pull is always the same, remember that when two objects are closer to one another, the pull between them is stronger.)

On some missions, you need to use the gravitational pull of the moon to direct the rocket ship. This pull of the moon is also a force.

When you experimented with plugging in the wrong numbers for space mission number 4, you observed the rocket ship orbiting the moon. It was actually falling around the moon. You may have noticed that when the rocket ship started to slow down, it crashed.