A hovercraft is a device that moves by floating on a cushion of air.

NASA uses hovercraft to test spacecraft and the ways they need to move. This is because the objects we put in space experience hardly any friction – and the same is true of hovercraft.

Friction is the force that makes it so materials or objects have a hard time moving. So when friction is low, objects can move around pretty well without getting slowed down or stuck.

The image above shows the Formation Control Testbed at NASA’s Jet Propulsion Laboratory. It works kind of like a giant air-hockey table. But instead of pucks, the objects sliding around are spacecraft suspended on pillows of air – hovercraft. This reduced-friction environment lets the spacecraft move with ease, much like they will in space.

You can make your own hovercraft using simple supplies!

› Educators, explore how to turn this into a lesson for students

Hovercraft materials

Materials

1. Safety first

Put on safety glasses and fill a small bowl with cold water to dunk your fingers in case you get any hot glue on them.
Cutting the water bottle top and using sandpaper to sand it

2. Prepare the bottle top

Use scissors to cut the flip-top off the bottle top. Use sandpaper to roughen the circumference of the narrow opening of the bottle top.
Placing a bead of glue along the circumference of the bottle top

3. Place a bead of glue on the bottle top

Place a bead of glue around the circumference of the narrow opening of the bottle top. Allow it to cool before moving to the next step.
Glueing the bottom of the bottle top

4. Glue the bottom of the bottle top

Place glue along the circumference of the wide opening of the bottle top. Press the bottle top onto the center of the CD or DVD – centered over the disk opening.
Adding glue between the disk and bottle top

5. Seal with glue

Add glue along the circumference of where the bottle top meets the disk to ensure an air-tight seal. Allow all the glue to cool completely.
Attaching the balloon to the bottle top

6. Inflate and attach the balloon

Inflate a balloon and twist the neck to prevent air from escaping. While pinching the neck of the balloon, stretch the mouth of the balloon over the bottle top.
Animated gif of a hovercraft sliding across a smooth surface

7. Watch it go!

Place your hovercraft, disk-side down, on a flat surface. Untwist the balloon, give your hovercraft a little push and watch it go!

8. Experiment

Experiment with your hovercraft's design. For example, you can place paper dot stickers on the bottom of the hovercraft, over the disk hole, to control the airflow. Then, experiment with poking holes in the sticker using different size holes or different numbers of holes.

9. Challenge your friends

Can you get your hovercraft to travel farther than your friends' designs? Who can get closest to a target? Create games to keep the hovercraft fun going and going.
JPL fellow Becca Foust stands in a spacecraft testbed at Caltech. Image credit: Evan Kramer

10. Explore More

Find out more about how NASA uses hovercraft technology to test spacecraft!