In this challenge, you will build your own rubber-band-powered rover that can scramble across a room. Then, improve on your design and even test it with code!

Image showing all the materials required for the cardboard rover project


On the left is an Apollo lunar rover, which has a similar design to a go-kart. On the right is the Perseverance Mars rover, which is much taller and looks more like a wheeled robot with a head, neck, and hand.

1. Learn about rovers

Rovers are a kind of car-like spacecraft that NASA uses to explore the surfaces of other worlds, such as the Moon and Mars. In 1971, astronauts with the Apollo program became the first to drive around on the Moon using a lunar rover. Today, we use robotic rovers to explore Mars. Since we can't yet send astronauts to the Red Planet, Mars rovers are controlled remotely by operators back on Earth, but they might one day be used by astronauts to drive around on the surface.

Watch this talk to find out more about Mars rovers and get a sneak peak at how to create your own. Scroll below for written step-by-step instructions with photos.

About the image: On the left is the Lunar Roving Vehicle, or LRV, that Apollo 15 astronauts used to drive around on the Moon. On the right is the Perseverance Mars rover pictured with the Mars helicopter, Ingenuity. | + Expand image

Diagram showing the final rover prototype

2. Brainstorm

Take a close look at the prototype of a rover above. Prototypes are used all the time in engineering. They give you a basic design from which to build, test, and evaluate. Improving a design based on testing is part of the engineering design process.

Ask yourself these questions:

  • What do you have to do to make the rover move?
  • How do you think square wheels affect how the rover moves across the floor?
  • How can you make improvements to the wheels?

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Collage of images showing how to do step 2

3. Make the rover body

Fold the cardboard into thirds along – not across – the corrugation (the open veins inside the piece of cardboard), pushing up the sides of the rover body to form a trench. Each section will be about 2 inches (5 cm) across.

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Collage of images showing how to do step 3

4. Make the front wheels

On the two 5-inch (13-cm) cardboard squares, draw diagonal lines from each of the corners, forming an “X”. Poke a small hole in the center with a pencil, where the lines cross.

Important! Avoid accidentally poking yourself with the pencil. Keep your hands away from where the pencil will go through the cardboard.

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Collage of images showing how to do step 4

5. Attach the rear axle and wheels

Use a pencil to carefully poke a hole near the top of each of the two outermost sections on the rover body. Again, keep your hands away from where the pencil will go through the cardboard. Make sure the holes are directly across from each other and are big enough for the pencil to spin freely. This is where your axle will go.

Slide the pencil through the axle holes. Carefully slide the cardboard wheels onto each end of the pencil and secure them with tape.

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Collage of images showing how to do step 5

6. Make the front axle and wheels

Tape the straw across the bottom of the rover body on the opposite side from the pencil. Slip a candy onto each end of the straw. Bend and tape the ends of the axle to stop the candies from coming off.

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Collage of images showing how to do step 6

7. Make a rubber-band chain

Create a chain with the two rubber bands as shown in the image above.

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Collage of images showing how to do step 7

8. Attach the rubber band

Loop one end of the rubber band chain around the pencil, as shown in the image. Cut small slits into the front end of the rover body. Slide the free end of the rubber band chain into the slits.

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Collage of images showing how to do step 8

9. Ready, set …

Turn the back wheels to wind the rubber band around the axle and power up your rover.

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Animated image of a woman releasing a cardboard rover that jumps forward. A model of the Curiosity rover can be seen in the background.

10. Put your rover to the test

With the rover on the floor, let go! Observe what the rover does. Measure the distance it traveled.

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11. Evaluate the design

Think about how your rover performed and what could be improved. Ask yourself these questions:

  • Did the wheels turn freely?
  • Did the rover travel in a straight line?
  • How far did it go?
  • Did the wheels spin out without the rover moving much, or did they have traction on the ground and cause the rover to move?

12. Redesign and test it again

Make changes to your rover to improve its performance. After you’ve made changes, test your rover to see if the improvements worked!

13. Graph your results

The more energy in your rubber band, the more energy goes to spinning your rover's axle. Test your rover after three, six, and nine turns of the rubber band around your axle. Measure the distance the rover travels in each trial. Graph the number of rotations versus the distance travelled.

14. Go further with physics

For an extra challenge, determine the strength of your rubber band using the formula for the conservation of energy:

1/2 mv2 = 1/2 kx2

You’ll need to find the mass (m) of your rover, its velocity (v, or distance over time), and the amount your rubber band is stretched (x- be sure to watch your units!) to solve for the elastic strength (k).

Menu of different LED light patterns, a code block to make an X pattern appear on shake, and a microdevice displaying an X pattern.

15. Test your rover's drive with code

For an added challenge, you can use microdevices to ensure that your rover wheels allow for a smooth ride as they cross the terrain.

  1. Using a device such as a microbit, you can code simple parameters based on whether your rover is shaken too quickly as it goes over rough surfaces. First try using the on shake function in the input menu. Inside, place a show leds block and draw a diagram to be displayed if the event is triggered, such as an X or a frowning face.
  2. Next to this, place the on button input and set it to A+B. Place a clear screen block inside. This will allow the experiment to be cleared and repeated across all trials.
  3. With the code downloaded to your device, add a battery pack. Secure the device and battery pack to your rover to ensure they stay connected.
  4. As you refine your rover, consider how the wheel shape and rubber-band power affect how level and steady of a drive you observe.

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