Heat Shield

Spacecraft like the one carrying the Perseverance rover are equipped with special materials to protect them from extreme heat as they enter a planet's atmosphere. Can you design a heat shield for a candy bar "spaceship"?

About Heat Shielding

Getting Started

When a spacecraft enters a planet’s atmosphere at high speeds, such as the atmospheres of Earth, Venus, or Mars, it experiences a lot of heat. This heat is caused by air resistance, or friction between air molecules and the surface of the spacecraft, and by a process called adiabatic heating, in which the spacecraft compresses the air in front of it as it travels. In other words, as the spaceship slows down, its kinetic energy is converted to heat energy in the atmosphere around it.

Heat shields work to protect the spacecraft by reflecting, absorbing, or redirecting heat. This is extremely important for any humans and temperature-sensitive equipment inside the spacecraft. For example, damage to the heat shield on the space shuttle Columbia led to the 2003 disaster that took the lives of seven astronauts. Because different materials have different abilities to absorb or reflect heat, some work better than others for heat shielding.

In this activity, you will design and test your own heat shield and determine which materials work best to protect a candy bar “spaceship”.

Start by watching the “How Do You Land on Mars?” video (left) to learn more about how a heat shield protected the Perseverance rover as it descended to the surface of Mars. You can also watch the other videos in the Mars in a Minute series to learn more about this mission.

Heat Shield Activity

Design and optimize a heat shield for a candy bar “spaceship”. 


  • Scissors
  • Tape
  • Rulers
  • Hair dryer 
  • Tongs 
  • Stopwatch 
  • Thermometer
  • Oven mitts
  • Unwrapped candy bars – mini or fun size
  • Assorted “heat shield” materials. Ideas include:
    • Cotton balls
    • Index cards
    • Steel wool
    • Cardboard
    • Electrical tape
    • White glue
    • Wire mesh/cloth
    • Sponges 

Key Concepts

  • Heat Shielding
  • Air Resistance


Phase 1: Plan

  • Examine the available heat shield materials and begin brainstorming your design.
    • Which materials do you think would make the best heat shield? Why? 
    • What shape do you think would make the best heat shield? Why? 
  • Draw a picture of your heat shield and label the components. Be sure to include measurements!

Phase 2: Build and Test 

  • Build the first version of your heat shield and place it on top of the candy bar. You may want to use the wire mesh or electrical tape to provide structure for the other materials. 
  • Measure and calculate the surface area of the design. 
  • Test the design.
    • First, put on the oven mitts.
    • Using the tongs, hold up the candy bar with the heat shield. 
    • Aim the hair dryer (on “hot” setting) toward the heat shield for seven minutes. Using the thermometer, record the external temperature (on the surface of the heat shield) and the internal temperature (the temperature of the candy bar). Observe whether the candy bar melts. 
  • Try to improve your design. Measure the new surface area and test it again with a new candy bar. What was similar or different from your first test?

Phase 3: Analyze and Reflect 

  • Graph the temperature measurements vs. time for each test. What do you notice?
  • Which design characteristics best protected the candy bar? Why do you think that was? 
  • What were the strengths and weaknesses of your design? 
  • What factors would aerospace engineers have to consider when designing the heat shield for the Perseverance rover that were not included in this experiment? 

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