Design a Mars Rover Out of Cardboard

NASA's Mars rovers have to work 140 million miles from the nearest repair shop. If a wheel breaks or a sensor fails, there is no one to fix it. Every design decision accounts for that.

You will not be designing for 140 million miles today, but you will be working with the same kinds of constraints: limited materials, weight limits, rough terrain, and the requirement that your rover actually functions when tested.

The Mission Brief

What You Need

• Cardboard (cereal boxes, delivery boxes, any flat cardboard)
• Duct tape or masking tape
• Scissors
• Cardboard tubes (paper towel or toilet paper rolls)
• Straws
• Small paper cups
• Optional: brass fasteners, rubber bands, a ruler

Your Design Goals

Real engineers get tested against specific requirements. Here are yours:

1. 1

   Carry a payload

   Your rover must hold a small cup with 3 quarters or 3 small rocks on top without tipping over.

2. 2

   Clear terrain

   Your rover must roll over a piece of crumpled notebook paper without getting stuck or stopping.

3. 3

   Survive a drop

   Drop from knee height. The rover must stay in one piece and still roll afterward.

4. 4

   Bonus: the arm

   Add a piece that extends outward from the body, like a rover arm, that can 'reach' down toward a surface without the whole rover moving.

Your Design Constraints

Real engineering always has constraints. Working within them is the job. These are yours:

• Maximum size: must fit inside a shoebox
• No hot glue. Use tape and fasteners only
• Wheels must be round (any size, but actually round)
• Maximum build time: 45 minutes
• You must be able to explain one design decision before testing

Engineering Questions to Think Through Before You Build

1. 1

   How many wheels?

   Four wheels offer more stability than three. But more wheels mean more weight and more parts to break. Real rovers use six, with each one independently connected so one wheel hitting a rock does not tip the whole vehicle.

2. 2

   Where is the weight?

   Weight up high makes the rover easy to tip. Weight low keeps it stable. Put heavy parts as close to the ground as possible.

3. 3

   How wide is the wheelbase?

   The distance between the left and right wheels is called the track width. Wider track means harder to tip sideways. Narrower track fits through tighter spaces.

4. 4

   What happens when one wheel hits a bump?

   If your axle is rigid, a bump on one wheel lifts the entire side. Real rovers use rocker-bogie suspension so each wheel moves independently. Can you make something like that from cardboard and tape?

Test It, Then Ask These Questions

• Did it tip during the payload test? Where is the weight concentrated?
• Did it get stuck on the crumpled paper? Did a wheel sink, or did the body drag?
• Did it survive the drop? Which part failed first?
• What is the single change you would make if you had ten more minutes?

Write down or sketch your answers. That record is what separates a first build from a better second build.

“One student added a ramp on the front of his rover using a bent strip of cardboard. He said it was for pushing rocks out of the way. I asked if he had seen that on a real rover. He said no, he just thought it would help. That is the right kind of thinking.”

The Real Rover Connection

Perseverance, NASA's current Mars rover, weighs about 1,025 kilograms and has six wheels designed to each move independently. It carries cameras, a microphone, a drill, and a helicopter called Ingenuity. Every part had to be light enough to launch, strong enough to land, and reliable enough to operate for years without anyone nearby to repair it.

The design questions you are working through, including weight distribution, wheel count, terrain clearance, and payload capacity, are the same categories of question real rover engineers answer, just at very different scales.