Update: March 15, 2024 – The answers to the 2024 NASA Pi Day Challenge are here! Take a peek at the illustrated answer key now available under each problem on the NASA Pi Day Challenge page.

This year marks the 11th installment of the NASA Pi Day Challenge. Celebrated on March 14, Pi Day is the annual holiday that pays tribute to the mathematical constant pi – the number that results from dividing any circle's circumference by its diameter.

Every year on March 14, Pi Day gives us a reason to enjoy our favorite sweet and savory pies and celebrate the mathematical wonder that helps NASA explore the universe. Students can join in the fun once again by using pi to explore Earth and space themselves with the NASA Pi Day Challenge.

Read on to learn more about the science behind this year's challenge and get students solving real problems faced by NASA scientists and engineers exploring Earth, the Moon, asteroids, and beyond!

Visit the Pi in the Sky 11 lesson page to explore classroom resources and downloads for the 2024 NASA Pi Day Challenge. Image credit: NASA/JPL-Caltech | + Expand image

What is Pi

Dividing any circle’s circumference by its diameter gives you an answer of pi, which is usually rounded to 3.14. Because pi is an irrational number, its decimal representation goes on forever and never repeats. In 2022, mathematician Simon Plouffe discovered the formula to calculate any single digit of pi. In the same year, teams around the world used cloud computing technology to calculate pi to 100 trillion digits. But you might be surprised to learn that for space exploration, NASA uses far fewer digits of pi.

Here at NASA, we use pi to map the Moon, measure Earth’s changing surface, receive laser-coded messages from deep space, and calculate asteroid orbits. But pi isn’t just used for exploring the cosmos. Since pi can be used to find the area or circumference of round objects and the volume or surface area of shapes like cylinders, cones, and spheres, it is useful in all sorts of ways. Transportation teams use pi when determining the size of new subway tunnels. Electricians can use pi when calculating the current or voltage passing through circuits. And you might even use pi to figure out how much fencing is needed around a circular school garden bed.

In the United States, March 14 can be written as 3.14, which is why that date was chosen for celebrating all things pi. In 2009, the U.S. House of Representatives passed a resolution officially designating March 14 as Pi Day and encouraging teachers and students to celebrate the day with activities that teach students about pi. And that's precisely what the NASA Pi Day Challenge is all about!

The Science Behind the 2024 NASA Pi Day Challenge

This 11th installment of the NASA Pi Day Challenge includes four illustrated math problems designed to get students thinking like scientists and engineers to calculate how to get a laser message to Earth, the change in an asteroid’s orbit, the amount of data that can be collected by an Earth satellite, and how a team of mini rovers will map portions of the Moon’s surface.

Read on to learn more about the science and engineering behind each problem or click the link below to jump right into the challenge.

› Take the NASA Pi Day Challenge

› Educators, get the lesson here!

Receiver Riddle

In December 2023, NASA tested a new way to communicate with distant spacecraft using technology called Deep Space Optical Communications, or DSOC. From 19,000,000 miles (30,199,000 km) away, the Psyche spacecraft beamed a high-definition video encoded in a near-infrared laser to Earth. The video, showing a cat named Taters chasing a laser, traveled at the speed of light, where it was received at Caltech’s Palomar Observatory. Because of the great distance the laser had to travel, the team needed to aim the transmission at where Earth would be when the signal arrived. In Receiver Riddle, use pi to determine where along Earth's orbit the team needed to aim the laser so that it could be received at the Observatory at the correct moment.

This animation shows how DSOC's laser signals are sent between the Psyche spacecraft and ground stations on Earth - first as a pointing reference to ensure accurate aiming of the narrow laser signal and then as a data transmission to the receiving station. Credit: NASA/JPL-Caltech/ASU| Watch on YouTube

Daring Deflection

In 2022, NASA crashed a spacecraft into the asteroid Dimorphos in an attempt to alter its orbit. The mission, known as the Double Asteroid Redirection Test, or DART, took place at an asteroid that posed no threat to our planet. Rather, it was an ideal target for NASA to test an important element of its planetary defense plan. DART was designed as a kinetic impactor, meaning it transferred its momentum and kinetic energy to Dimorphos upon impact, altering the asteroid's orbit. In Daring Deflection, use pi to determine the shape of Dimorphos’ orbit after DART crashed into it.

This image shows the final minutes of images leading up to the DART spacecraft's intentional collision with asteroid Dimorphos. Credit: NASA/Johns Hopkins APL | › Enlarge image

Orbit Observation

The NISAR mission is an Earth orbiting satellite designed to study our planet's changing ecosystems. It will collect data about Earth's land- and ice-covered surfaces approximately every 6 days, allowing scientists to study changes at the centimeter scale – an unprecedented level of detail. To achieve this feat, NISAR will collect massive amounts of data. In Orbit Observation, students use pi to calculate how much data the NISAR spacecraft captures during each orbit of Earth.

The NISAR satellite, shown in this artist’s concept, will use advanced radar imaging to provide an unprecedented view of changes to Earth’s land- and ice-covered surfaces. Credit: NASA/JPL-Caltech. | › Full image and caption

Moon Mappers

The CADRE project aims to land a team of mini rovers on the Moon in 2025 as a test of new exploration technology. Three suitcase-size rovers, each working mostly autonomously, will communicate with each other and a base station on their lunar lander to simultaneously measure data from different locations. If successful, the project could open the door for future multi-robot exploration missions. In Moon Mappers, students explore the Moon with pi by determining how far a CADRE rover drives on the Moon’s surface.

Engineers test the system that will lower three small rovers onto the lunar surface as part of the CADRE project. Credit: NASA/JPL-Caltech | › Full image and caption

Bring the Challenge Into the Classroom

Celebrate Pi Day by getting students thinking like NASA scientists and engineers to solve real-world problems in the NASA Pi Day Challenge. In addition to solving the 2024 challenge, you can also dig into the 40 puzzlers from previous challenges available in our Pi Day collection. Completing the problem set and reading about other ways NASA uses pi is a great way for students to see the importance of the M in STEM.

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  Collection

  Educator Guides – NASA Pi Day Challenge

  Here's everything you need to bring the NASA Pi Day Challenge into the classroom.

  Grades 4-12

  Time Varies

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  Student Activity

  NASA Pi Day Challenge

  The entire NASA Pi Day Challenge collection can be found in one, handy collection for students.

  Grades 4-12

  Time Varies

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  Downloads

  Can't get enough pi? Download this year's NASA Pi Day Challenge graphics, including mobile phone and desktop backgrounds:

  • Pi in the Sky 11 Poster (PDF, 4.0 MB)
  • DART Mission Background: Phone | Desktop
  • CADRE Project Background: Phone | Desktop
  • DSOC Background: Phone | Desktop
  • NISAR Mission Background: Phone | Desktop
  • 2024 Pi Day Medley Background: Phone | Desktop

More Pi Resources

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  Article

  How Many Decimals of Pi Do We Really Need?

  While you may have memorized more than 70,000 digits of pi, world record holders, a JPL engineer explains why you really only need a tiny fraction of that for most calculations.

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  Article

  18 Ways NASA Uses Pi

  Whether it's sending spacecraft to other planets, driving rovers on Mars, finding out what planets are made of or how deep alien oceans are, pi takes us far at NASA. Find out how pi helps us explore space.

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  Article

  10 Ways to Celebrate Pi Day With NASA on March 14

  Find out what makes pi so special, how it’s used to explore space, and how you can join the celebration with resources from NASA.

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  Infographic

  Planet Pi

  This poster shows some of the ways NASA scientists and engineers use the mathematical constant pi (3.14) and includes common pi formulas.

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  Article

  18 Maneras en Que la NASA Usa Pi

  Pi nos lleva lejos en la NASA. Estas son solo algunas de las formas en que pi nos ayuda a explorar el espacio.

Related Lessons for Educators

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  Lesson

  Collisions in Space

  Students predict and observe what happens when two objects collide to model collisions in space.

  Grades K-4

  Time 30 min to 1 hour

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  Lesson

  Moon Phases

  Students learn about the phases of the moon by acting them out.

  Grades 1-6

  Time 30 min to 1 hour

• 
  Lesson

  Modeling an Asteroid

  Lead a discussion about asteroids and their physical properties, then have students mold their own asteroids out of clay.

  Grades 3-5

  Time 30 min to 1 hour

• 
  Lesson

  Math Rocks: A Lesson in Asteroid Dynamics

  Students use math to investigate a real-life asteroid impact.

  Grades 8-12

  Time 30 min to 1 hour

• 
  Lesson

  Modeling Crustal Folds

  Students use playdough to model how Earth’s crust is bent and folded by tectonic plates over geologic time.

  Grades 6-12

  Time 30 min to 1 hour

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  Lesson

  Making Topographic Maps

  Students draw and interpret topographic maps while learning about technology used to map Earth's surface, the seafloor, and other worlds.

  Grades 6-12

  Time 30 min to 1 hour

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  Lesson

  Code a Radio Message for Space

  Students code microcontrollers to send and receive radio signals, simulating communications between Earth and spacecraft.

  Grades 6-12

  Time 30 min to 1 hour

Related Activities for Students

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  Student Project

  Draw Your Own Psyche Spacecraft

  Follow these easy instructions to draw and decorate your own model of the Psyche spacecraft.

  Type Project

  Subject Engineering

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  Slideshow

  What's That Space Rock?

  Find out how to tell the difference between asteroids, comets, meteors, meteorites and other bodies in our solar system.

  Type Slideshow

  Subject Science

Facts and Figures

• Asteroids Overview
• Didymos In Depth

Websites

• NISAR Mission
• CADRE Project
• Psyche Mission
• DART Mission
• Asteroid Watch

Articles

• How NASA Studies and Tracks Asteroids Near and Far
• NASA Cat Video Explained
• Article for Kids: Asteroid or Meteor: What's the Difference?
• Article for Kids: What Is an Asteroid?

Videos

• The Video NASA’s Laser Communications Experiment Streamed From Deep Space
• NASA's DART Mission Confirms Crashing Spacecraft into Asteroids Can Deflect Them

Interactives

• Eyes on Asteroids

TAGS: Pi Day, Pi, Math, NASA Pi Day Challenge, moon, earth, asteroid, psyche, DART, CADRE, NISAR DSOC

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  ABOUT THE AUTHOR

  Lyle Tavernier, Educational Technology Specialist, NASA-JPL Education Office

  Lyle Tavernier is an educational technology specialist at NASA's Jet Propulsion Laboratory. When he’s not busy working in the areas of distance learning and instructional technology, you might find him running with his dog, cooking or planning his next trip.