Illustration of spacecraft on a light purple background that reads "NASA Pi Day Challenge"

Update: March 16, 2020 – The answers to the 2020 NASA Pi Day Challenge are here! View the illustrated answer key (also available as a text-only doc).

In the News

Our annual opportunity to indulge in a shared love of space exploration, mathematics and sweet treats has come around again! Pi Day is the March 14 holiday that celebrates the mathematical constant pi – the number that results from dividing any circle's circumference by its diameter.

Infographic of all of the Pi in the Sky 7 graphics and problems

Visit the Pi in the Sky 7 lesson page to explore classroom resources and downloads for the 2019 NASA Pi Day Challenge. Image credit: NASA/JPL-Caltech | + Expand image

Overhead view of Mars with a comparison of the smaller landing ellipse made possible by Range Trigger technology

A new Mars landing technique called Range Trigger is reducing the size of the ellipse where spacecraft touch down. Image credit: NASA/JPL-Caltech | › Full image and caption

Composite image of the Kuiper Belt object Arrokoth from NASA's New Horizons spacecraft. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko | › Full image and caption

Diagram of an airplane flying over a section of ocean with an example of the spectral data that CORAL collects

The CORAL mission records the spectra of light reflected from the ocean to study the composition and health of Earth's coral reefs. Image credit: NASA | + Expand image

Rays of bright orange and red shoot out diagonally from a blue circle surrounding the star Beta Pictoris

The star Beta Pictoris and its surrounding debris disk in near-infrared light. Image credit: ESO/A.-M. Lagrange et al. | › Full image and caption

Besides providing an excuse to eat all varieties of pie, Pi Day gives us a chance to appreciate some of the ways NASA uses pi to explore the solar system and beyond. You can do the math for yourself – or get students doing it – by taking part in the NASA Pi Day Challenge. Find out below how to test your pi skills with real-world problems faced by NASA space explorers, plus get lessons and resources for educators.

How It Works

The ratio of any circle's circumference to its diameter is equal to pi, which is often rounded to 3.14. But pi is what is known as an irrational number, so its decimal representation never ends, and it never repeats. Though it has been calculated to trillions of digits, we use far fewer at NASA.

Pi is useful for all sorts of things, like calculating the circumference and area of circular objects and the volume of cylinders. That's helpful information for everyone from farmers irrigating crops to tire manufacturers to soup-makers filling their cans. At NASA, we use pi to calculate the densities of planets, point space telescopes at distant stars and galaxies, steer rovers on the Red Planet, put spacecraft into orbit and so much more! With so many practical applications, it's no wonder so many people love pi!

In the U.S., 3.14 is also how we refer to March 14, which is why we celebrate the mathematical marvel that is pi on that date each year. 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.

The NASA Pi Day Challenge

This year's NASA Pi Day Challenge poses four puzzlers that require pi to compare the sizes of Mars landing areas, calculate the length of a year for one of the most distant objects in the solar system, measure the depth of the ocean from an airplane, and determine the diameter of a distant debris disk. Learn more about the science and engineering behind the problems below or click the link to jump right into the challenge.

› Take the NASA Pi Day Challenge
› Educators, get the lesson here!

Mars Maneuver

Long before a Mars rover touches down on the Red Planet, scientists and engineers must determine where to land. Rather than choosing a specific landing spot, NASA selects an area known as a landing ellipse. A Mars rover could land anywhere within this ellipse. Choosing where the landing ellipse is located requires compromising between getting as close as possible to interesting science targets and avoiding hazards like steep slopes and large boulders, which could quickly bring a mission to its end. In the Mars Maneuver problem, students use pi to see how new technologies have reduced the size of landing ellipses from one Mars rover mission to the next.

Cold Case

In January 2019, NASA's New Horizons spacecraft sped past Arrokoth, a frigid, primitive object that orbits within the Kuiper Belt, a doughnut-shaped ring of icy bodies beyond the orbit of Neptune. Arrokoth is the most distant Kuiper Belt object to be visited by a spacecraft and only the second object in the region to have been explored up close. To get New Horizons to Arrokoth, mission navigators needed to know the orbital properties of the object, such as its speed, distance from the Sun, and the tilt and shape of its orbit. This information is also important for scientists studying the object. In the Cold Case problem, students can use pi to determine how long it takes the distant object to make one trip around the Sun.

Coral Calculus

Coral reefs provide food and shelter to many ocean species and protect coastal communities against extreme weather events. Ocean warming, invasive species, pollutants, and acidification caused by climate change can harm the tiny living coral organisms responsible for building coral reefs. To better understand the health of Earth's coral reefs, NASA's COral Reef Airborne Laboratory, or CORAL, mission maps them from the air using spectroscopy, studying how light interacts with the reefs. To make accurate maps, CORAL must be able to differentiate among coral, algae and sand on the ocean floor from an airplane. And to do that, it needs to calculate the depth of the ocean at every point it maps by measuring how much sunlight passes through the ocean and is reflected upward from the ocean floor. In Coral Calculus, students use pi to measure the water depth of an area mapped by the CORAL mission and help scientists better understand the status of Earth's coral reefs.

Planet Pinpointer

Our galaxy contains billions of stars, many of which are likely home to exoplanets – planets outside our solar system. So how do scientists decide where to look for these worlds? Using data gathered by NASA's Spitzer Space Telescope, researchers found that they're more likely to find giant exoplanets around young stars surrounded by debris disks, which are made up of material similar to what's found in the asteroid belt and Kuiper Belt in our solar system. Sure enough, after discovering a debris disk around the star Beta Pictoris, researchers later confirmed that it is home to at least two giant exoplanets. Learning more about Beta Pictoris' debris disk could give scientists insight into the formation of these giant worlds. In Planet Pinpointer, put yourself in the role of a NASA scientist to learn more about Beta Pictoris' debris disk, using pi to calculate the distance across it.


Join the conversation and share your Pi Day Challenge answers with @NASAJPL_Edu on social media using the hashtag #NASAPiDayChallenge

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TAGS: K-12 Education, Math, Pi Day, Pi, NASA Pi Day Challenge, Events, Space, Educators, Teachers, Parents, Students, STEM, Lessons, Problem Set, Mars 2020, Perseverance, Curiosity, Mars rovers, Mars landing, MU69, Arrokoth, New Horizons, Earth science, Climate change, CORAL, NASA Expeditions, coral reefs, oceans, Spitzer, exoplanets, Beta Pictoris, stars, universe, space telescope

  • Lyle Tavernier

Mariah Woody poses for the camera with her hands clasped behind her back in front of a metal starburst screen.

This past month, intern Mariah Woody joined her team in mission control at NASA's Jet Propulsion Laboratory to say goodbye to the Spitzer Space Telescope, a mission that provided never-before-seen views of the cosmos for more than 16 years. Woody has only been interning with the Spitzer team since June, but she played a key role in planning the mission's final moments. And now that the mission has ended, she's helping document its legacy. While her internship has largely been about bringing the Spitzer mission to a close, the experience is marking a new beginning for Woody. Even as a master's student in engineering, Woody never thought her skills would qualify her for a career in space exploration. It wasn't until she heard about an internship opportunity with JPL through an initiative designed to foster connections with historically black colleges and universities, or HBCUs, that she decided to apply. Now at JPL, she's getting a whole new perspective on where her career path might lead. We caught up with Woody to find out what it was like to join the team for Spitzer's final voyage, how she's archiving the mountain of mission images and data, and where she's hoping to go from here.

What are you working on at JPL?

I'm working on the Spitzer Space Telescope mission. Spitzer was a telescope that was designed to observe and study the early universe. It used infrared light, which can capture images of a wide range of objects that are found in the universe. It studied and observed new galaxies, stars and exoplanets. It was launched on Aug. 25, 2003, and it was one of NASA's four Great Observatories. It was originally planned for five years, but it was extended multiple times, so it lasted for more than 16 years. We just had the end of the mission on January 30. When I started, I was working on implementing a plan to archive all the data at the end of the mission and learning about spacecraft operations. Now, I'm working on the end-of-mission closeout activities.

What was your average day like when you were working on the final days of the mission?

I didn't have an average day when I was working on the operations team. We did a lot of different tasks, so each day was different. But usually, I would meet with my mentor and co-mentor to discuss the tasks that I was working on or the timeline and deliverables for the project. I learned about mission operations for the spacecraft and the systems on the ground that support the spacecraft. The spacecraft is controlled by programmed commands that we send through various antennas on the ground. The Spitzer team would have status and coordination meetings every week. All the team leads within the project would come together and discuss updates about the spacecraft, science details and other closeout tests that needed to be completed after the mission ended.

Even though the spacecraft is no longer operational, there's still more to do on the mission. What does closing out the mission entail?

The closeout team has to archive all the information into a repository where it can be looked at later, including the information that different team members have. It could be anything from documentation to images to any records, scripts or tools that were used. Once that information has been submitted, then I go in and audit the list and make sure that all of the products that need to be delivered are there and archive them.

You got to be in mission control for Spitzer's final moments. What was that experience like?

That experience was really fun for me. We called it Spitzers' final voyage, and I was able to be a part of the operations team in mission control, monitoring the status of the spacecraft in real-time as we all said goodbye. It was amazing to see all the different team members for the Spitzer mission come together on the last day to collaborate and do all of our work at once. It was a wonderful day in history, and I was proud to be a part of it.

Have there been any other standout moments from your time at JPL?

Meeting and learning from other people at the Lab. It's very nice to be able to just reach out to someone and sit down for lunch to learn about what they do and what experiences they have. I'm able to learn a little bit about all the different things that are going on here.

You're working toward your Ph.D. at North Carolina A&T State University. What's your research focus, and what got you interested in that field?

I'm studying industrial and systems engineering. It came to my attention because it's a broad area. You can do so much with it. I wasn't quite sure what industry I wanted to go into, so that's one of the reasons that I chose it. The fact that I can work in space exploration is very cool. I know that I like to explore different areas, improve things and make things more efficient. So I thought that this would be the perfect field for me to study.

What made you interested in engineering in the first place?

I've always loved math and science, and I performed very well in those subject areas when I was in school. When it comes to new ideas, I'm very creative. So I always wondered, "What can I do with this?" A lot of my teachers mentioned that I should look into becoming an engineer, so that's what I did.

What brought you to JPL for this internship?

I heard JPL was coming to my campus – they had an info session. I was notified about it at the last minute, so I missed out. I told myself, "I should still apply even though I missed the info session." So I applied, and then I received a call and got the offer.

But I feel like there was more to what brought me here than just applying and receiving the offer. I know that the offer was based on my hard work and saying yes to the challenges and opportunities that have come my way. I've always known about JPL, but I never pictured myself actually working here. I thought that it would be challenging, and I would be coming from so far away. It was a lot all at once, but I accepted the opportunity because I wanted to be exposed to and have the experience to work in space exploration. It's an area that I'd never really thought I'd go into coming from industrial and systems engineering. Now that I have some experience in the aerospace field, I have realized how much it impacts the industry in general and the economy of this country. It's a great field for my background.

Now that you've got some experience at JPL, how has it shaped your career path?

It's provided focus for my career path. I really want to stay within this industry. It's opened my eyes to see where I can branch off and where I can contribute and apply my skills. There's so much I can do with my background just in space exploration. I'm happy that my career path went in this direction.

What did you imagine that you would be doing before you came to JPL?

I wanted to be a part of designing something to improve a process at an organization or company. I didn't really have a specific job in mind. I've always thought that I'd maybe work in the medical industry, designing and improving medical devices. I've always had a lot of different ideas of what I wanted to do. I've kind of just explored and applied to many areas that were of interest.

Now for the fun question: If, you could have any role in NASA's plans to send humans to the Moon or on to Mars, what would you want it to be?

I think that I'd want to be involved in the training process – not necessarily me going through the training, but maybe coming up with ideas or requirements to get astronauts ready to go to space efficiently and safely.

Explore JPL’s summer and year-round internship programs and apply at:

Career opportunities in STEM and beyond can be found at:

The laboratory’s STEM internship and fellowship programs are managed by the JPL Education Office. Extending the NASA Office of STEM Engagement’s reach, JPL Education seeks to create the next generation of scientists, engineers, technologists and space explorers by supporting educators and bringing the excitement of NASA missions and science to learners of all ages.

TAGS: Higher Education, Internships, STEM, Engineering, Interns, College, Black History Month, Spitzer, Universe, HBCU

  • Kim Orr

In the News

On Jan. 30, 2020, the venerable Spitzer Space Telescope mission will officially come to an end as NASA makes way for a next-generation observatory. For more than 16 years, Spitzer has served as one of NASA’s four Great Observatories, surveying the sky in infrared. During its lifetime, Spitzer detected planets and signs of habitability beyond our solar system, returned stunning images of regions where stars are born, spied light from distant galaxies formed when the universe was young, and discovered a huge, previously-unseen ring around Saturn. Read on to learn more about this amazing mission and gather tools to teach your students that there truly is more than meets the eye in the infrared universe!

How It Worked

Human eyes can see only the portion of the electromagnetic spectrum known as visible light. This is because the human retina can detect only certain wavelengths of light through special photoreceptors called rods and cones. Everything we see with our eyes either emits or reflects visible light. But visible light is just a small portion of the electromagnetic spectrum. To "see" things that emit or reflect other wavelengths of light, we must rely on technology designed to sense those portions of the electromagnetic spectrum. Using this specialized technology allows us to peer into space and observe objects and processes we wouldn’t otherwise be able to see.

Infographic showing the electromagnetic spectrum and applications for various wavelengths.

This diagram shows wavelengths of light on the electromagnetic spectrum and how they're used for various applications. Image credit: NASA | + Expand image

Infrared is one of the wavelengths of light that cannot be seen by human eyes. (It can sometimes be felt by our skin as heat if we are close enough to a strong source.) All objects that have temperature emit many wavelengths of light. The warmer they are, the more light they emit. Most things in the universe are warm enough to emit infrared radiation, and that light can be seen by an infrared-detecting telescope. Because Earth’s atmosphere absorbs most infrared radiation, infrared observations of space are best conducted from outside the planet's atmosphere.

Learn more about the infrared portion of the electromagnetic spectrum and how NASA uses it to explore space. Credit: NASA/JPL-Caltech | Watch on YouTube

So, to get a look at space objects that were otherwise hidden from view, NASA launched the Spitzer Space Telescope in 2003. Cooled by liquid helium and capable of viewing the sky in infrared, Spitzer launched into an Earth-trailing orbit around the Sun, where it became part of the agency's Great Observatory program along with the visible-light and near-infrared-detecting Hubble Space Telescope, Compton Gamma-Ray Observatory and Chandra X-ray Observatory. (Keeping the telescope cold reduces the chances of heat, or infrared light, from the spacecraft interfering with its astronomical observations.)

Over its lifetime, Spitzer has been used to detect light from objects and regions in space where the human eye and optical, or visible-light-sensing, telescopes may see nothing.

Why It's Important

NASA's Spitzer Space Telescope has returned volumes of data, yielding numerous scientific discoveries.

Vast, dense clouds of dust and gas block our view of many regions of the universe. Infrared light can penetrate these clouds, enabling Spitzer to peer into otherwise hidden regions of star formation, newly forming planetary systems and the centers of galaxies.

A whisp of orange and green dust bows out beside a large blue star among a field of smaller blue stars.

The bow shock, or shock wave, in front of the giant star Zeta Ophiuchi shown in this image from Spitzer is visible only in infrared light. The bow shock is created by winds that flow from the star, making ripples in the surrounding dust. Image credit: NASA/JPL-Caltech | › Full image and caption

Infrared astronomy also reveals information about cooler objects in space, such as smaller stars too dim to be detected by their visible light, planets beyond our solar system (called exoplanets) and giant molecular clouds where new stars are born. Additionally, many molecules in space, including organic molecules thought to be key to life's formation, have unique spectral signatures in the infrared. Spitzer has been able to detect those molecules when other instruments have not.

Bursts of reds, oranges, greens, blues and violets spread out in all directions from a bright center source. Reds and oranges dominate the left side of the image.

Both NASA's Spitzer and Hubble space telescopes contributed to this vibrant image of the Orion nebula. Spitzer's infrared view exposed carbon-rich molecules, shown in this image as wisps of red and orange. Image credit: NASA/JPL-Caltech/T. Megeath (University of Toledo) & M. Robberto (STScI) | › Full image and caption

Stars are born from condensing clouds of dust and gas. These newly formed stars are optically visible only once they have blown away the cocoon of dust and gas in which they were born. But Spitzer has been able to see infant stars as they form within their gas and dust clouds, helping us learn more about the life cycles of stars and the formation of solar systems.

A blanket of green- and orange-colored stellar dust surrounds a grouping of purple, blue and red stars.

Newborn stars peek out from beneath their natal blanket of dust in this dynamic image of the Rho Ophiuchi dark cloud from Spitzer. The colors in this image reflect the relative temperatures and evolutionary states of the various stars. The youngest stars are shown as red while more evolved stars are shown as blue. Image credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA | › Full image and caption

Infrared emissions from most galaxies come primarily from stars as well as interstellar gas and dust. With Spitzer, astronomers have been able to see which galaxies are furiously forming stars, locate the regions within them where stars are born and pinpoint the cause of the stellar baby boom. Spitzer has given astronomers valuable insights into the structure of our own Milky Way galaxy by revealing where all the new stars are forming.

A bright band of crimson-colored dust stretches across the center of this image covered in tiny specs of light from hundreds of thousands of stars.

This Spitzer image, which covers a horizontal span of 890 light-years, shows hundreds of thousands of stars crowded into the swirling core of our spiral Milky Way galaxy. In visible-light pictures, this region cannot be seen at all because dust lying between Earth and the galactic center blocks our view. Image credit: NASA/JPL-Caltech | › Full image and caption

Spitzer marked a new age in the study of planets outside our solar system by being the first telescope to directly detect light emitted by these so-called exoplanets. This has made it possible for us to directly study and compare these exoplanets. Using Spitzer, astronomers have been able to measure temperatures, winds and the atmospheric composition of exoplanets – and to better understand their potential habitability. The discoveries have even inspired artists at NASA to envision what it might be like to visit these planets.

Collage of exoplanet posters from NASA

Thanks to Spitzer, scientists are learning more and more about planets beyond our solar system. These discoveries have even inspired a series of posters created by artists at NASA, who imagined what future explorers might encounter on these faraway worlds. Image credit: NASA/JPL-Caltech | › Download posters

Data collected by Spitzer will continue to be analyzed for decades to come and is sure to yield even more scientific findings. It's certainly not the end of NASA's quest to get an infrared window into our stellar surroundings. In the coming years, the agency plans to launch its James Webb Space Telescope, with a mirror more than seven times the diameter of Spitzer's, to see the universe in even more detail. And NASA's Wide Field Infrared Survey Telescope, or WFIRST, will continue infrared observations in space with improved technology. Stay tuned for even more exciting infrared imagery, discoveries and learning!

Teach It

Use these lessons, videos and online interactive features to teach students how we use various wavelengths of light, including infrared, to learn about our universe:

Explore More

Also, check out these related resources for kids from NASA’s Space Place:

TAGS: Teachable Moments, science, astronomy, K-12 education, teachers, educators, parents, STEM, lessons, activities, Spitzer, Space Telescope, Missions, Spacecraft, Stars, Galaxies, Universe, Infrared, Wavelengths, Spectrum, Light

  • Ota Lutz