You might already know that NASA uses spacecraft and satellites to explore space, but did you know we also use balloons? In this project, you'll find out how NASA uses balloons to explore Earth and space and then take on a challenge to design your own balloon explorer inspired by what you've learned!

Picture of the materials for this activity


An illustration shows a reflective balloon floating in Earth's stratosphere carrying a device covered in metal scaffolding and solar panels.

1. Learn about scientific balloons

When people think of NASA, they don’t usually think of balloons. But NASA has been using balloons to explore Earth and space since 1983! NASA launches 10-15 balloons a year from locations around the world for technology development, scientific research, and education purposes.

Balloon missions are cheaper than space missions and they also take less time to plan and develop than a spacecraft. Because of this, NASA can test out new technologies on balloon missions before sending the technology all the way to space.

NASA uses balloons in many different ways. In 2014, they used a balloon to test technology for landing on Mars.

In 2019, the first detection of an earthquake from a balloon was made using sensors floating about 16,000 feet (4.8 kilometers) high. In the future, NASA hopes to use balloons floating in Venus' atmosphere to detect quakes – something that can’t be done on Venus’ incredibly hot, high-pressure surface.

In 2023, NASA plans to launch a telescope aboard a balloon as part of the ASTHROS mission – short for Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimeter-wavelengths. The ASTHROS balloon will spend three to four weeks floating about 130,000 feet (40,000 meters) above Antarctica observing star-forming regions of space as well as planets forming around newborn stars.

NASA is also studying the use of balloons to explore places like Mars, Venus, and Saturn's moon Titan. Balloon missions to these places could allow for measurements at different altitudes that other types of spacecraft can't reach.

About the image: This illustration shows a balloon ascending into Earth's upper atmosphere while carrying a small scientific device. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab/Michael Lentz | + Expand image
Inside a drawing of a balloon, an arrow is shown pointing down. Above the arrow, a person writes the word "gravity."

2. Think about forces

Now, it's your turn to design your own balloon explorer. But before you begin, consider this: When a balloon floats, rises or falls, different forces act on the balloon. Think about how a force like gravity will pull on a balloon, and how a force like lift will push on a balloon. Then, draw a balloon and add arrows representing gravity and lift. Draw the arrows so that they point in the direction that each force acts on the balloon.

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A person sketches a balloon on graph paper.

3. Brainstorm and sketch your design

Think of ways you can combine the materials you have (balloon, cup, string or ribbon, and tape) to make a gondola that will hang from your balloon. Note: Your gondola will need to stay attached to the balloon and hold the items you place inside of it in Step 6.

Sketch your design, but be ready to make changes as you build and test.

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A pile of small wooden beads is shown next to a pile of larger wooden beads. A person holds one of the beads as if to decide whether or not to use it.

4. Choose your mission

Decide which of the following three mission challenges you want to complete.

  • Maintain altitude: Find the right amount of objects to place in the gondola that will cause the balloon to float and maintain a steady altitude, or height above the surface, of approximately 36 inches (1 meter) for 30 seconds.
  • Controlled ascent: Find the right amount of objects to place in the cup that will cause the balloon to slowly rise at a rate between 10 and 20 inches per second (0.25 to 0.5 meters per second).
  • Controlled descent: Find the right amount of objects to place in the cup that will cause the balloon to fall at a slow rate between 10 and 20 inches per second (0.25 to 0.5 meters per second).

Predict how many objects you will need to successfully complete your challenge. You can attempt other challenges after completing one and compare your results.

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A person tapes ribbon to a cup filled with wooden beads.

5. Build your balloon and gondola system

Build your balloon and gondola system according to your design. Note: So your balloon doesn't pop or float away and contribute to land and air pollution, remember to build and fly your balloon indoors.

While you build, place several objects such as beads, metal washers, or coins in the gondola as it hangs from the balloon to make sure the items stay inside. (These items will act as ballast – material that stabilizes balloon flight and controls the rate of rise and fall.) If you need to, adjust your design so it can better support ballast placed in the gondola. Remember, you may need to use more than one balloon to support the weight of your gondola as well as the objects placed inside of it.

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A collage of images shows a person dropping a wooden bead into a cup, writing a measurement on painters tape stuck to the wall, and holding their balloon and gondola system in preparation for launch.

6. Complete the challenge

With your balloon and gondola system built, add the number of objects you predicted to the gondola and observe how your design performs. You may need to add or remove objects from the gondola, depending on what you notice about how it performs.

You can measure the performance of your design to see if you met the goals of the challenge using one of these methods:

  • Tape a meter stick against a wall, or tape height markings on the wall that you can use to measure the height of your balloon during your test flights.
  • Use a stopwatch to measure the time it takes your balloon to rise or fall and calculate the rate (inches / seconds).
  • Use the camera on a mobile device to record your balloon’s rise or fall and calculate the rate using the time count of your video.

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The gondola, with the ribbon and tape still attached and the wooden beads inside, sits on a small digital scale.

7. Analyze your results

How close was your prediction to the number of items you actually needed?

If you have a scale, remove the balloons from the gondola system. Weigh the gondola with the objects inside. When measuring the weight of your gondola, be sure to include any ribbon or tape that you used.

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8. Fly again

Animated image showing a balloon and gondola system ascending

Think about your balloon flight and think back to the forces you drew in Step 2. Can you improve your balloon’s flight? Try one of the following ideas for your next flight!

  • Speed up your balloon: Increase the speed at which your balloon moved up or down while maintaining a controlled float.
  • Slow down your balloon: Decrease the speed at which your balloon moved up or down while maintaining a controlled float.
  • Choose one of the other challenges in Step 4 and use what you learned from your first flight to better predict how much ballast you’ll need to add.

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