Van Allen Belt

How science and tech led to an exciting discovery in one of the most dangerous areas of space.

Physicist Mona Kessel knows that turning on a pair of satellites takes fortitude. After thousands of hours of planning, building and testing, the new instruments are orbiting Earth. And to add to the worry, the probes are going to one of the most dangerous parts of the Solar System — the Van Allen Radiation Belts. The two Van Allen Belts were discovered in 1957. They’re collections of energized particles near Earth. Most satellites rocket quickly through the area with all their shielding down around the delicate instruments. Her team wanted to slow down and actually examine that part of space.

So it was with patience, and some trepidation, that she and her team turned on the two Van Allen Probes on August 30, 2012. The probes worked! The crew celebrated, but they were still in for a big surprise.

Kessel and the rest of the team chose to study the Van Allen Radiation Belts because they are important. Every time our Sun sends a burst of particles and energy toward Earth, the radiation belts fill up and expand, as part of a geomagnetic storm.

These storms are part of as space weather, and they can affect all of our satellites including GPS, weather and communication satellites. Airlines don’t fly near the North pole if they know a solar storm is coming because the radiation hurts the people on the plane.

The team designed the Van Allen probes for the radiation fray.

They knew that radiation belt’s high-energy particles would destroy a normal computer. And fancier computers, such as computers made for gaming or showing videos, are more likely to be damaged because they have a lot of small transistors that could be short-circuited by the high-energy particles.

So the Van Allen Probe designers used low-power computers with limited memory (the computers have 50 times less memory than a cell phone). These custom-made computers are better able to withstand the storms of high-energy particles. Then they put the electronics in shielded boxes. Finally they designed watchdog timers that automatically reset the system when needed.

About three weeks after the probes started up, the team received their first set of data.

“We saw something very unusual.” Kessel says, who still sounded excited even years after the event.

The probes’ new instruments were like putting on a better pair of glasses. Suddenly they could see clearly that the belts aren’t always made up of two bands of radiation as everyone had thought. Sometimes there are three!

In human-terms, that would be like finding a new mountain on the way to school. You’ve made that trip a thousand times before. The mountain wasn’t there. And suddenly it is.

The physicists were gob smacked.

Physicists who study space usually have long and drawn out studies. Often the information they find changes our understanding of the universe in incremental ways. This discovery was much more dramatic. They found the third Van Allen Radiation Belt and then found out it is not always there. It ebbs and flows with space weather, which is another reason to keep studying it and learn how to predict when it will reappear.

The probes themselves were expected to last two years. But there again, the team was surprised. The shielding and careful electronics have worked and the satellites are still working in early 2019. The study will end in soon when the probes run out of fuel.

Learn More

Mona Kessel

Van Allen Probes Mission Overview

van allen probes

van allen probes mission

van allen mission coming to an end

NASA Van Allen probes discover PARTICLE HURRICANES


  • Amy S Hansen

    Amy writes about science for kids, for adults, for cats, for anyone who will listen. She has more than 25 books out, including the award-winning Fire Bird: The Kirtland’s Warbler Story (Arbutus Press, 2017) and Bugs and Bugsicles: Insects in the Winter (Boyds Mills Press 2010). Amy lives in Maryland along with her husband, two sons, two cats (who really don’t listen very well) and her dog.

Also In The April 2019 Issue

Use SketchUp to create this fascinating mathematical pattern that appears everywhere in nature.

Learn about the STEAM star’s amazing journey onto Mythbusters Junior and beyond.

What’s the best way to choose a classroom lunch? Or the best way to elect a leader? The answer isn’t so simple.

Keep your passwords at the tip of your fingers, or maybe at the back of your eyes!

Bring your coding skills and your desserts to new levels in this simple Python coding activity.

Learn about the shiny new technology that allows us to be connected like never before.

Squares, checkerboards, and hollow boxes… what pattens can you imagine in Python?

A fun, DIY electronics project that’ll keep you from bumping around in the dark!

Use your favourite block language to animate this fascinatingly odd game.

Can we make a computer using only three simple rules?

How science and tech led to an exciting discovery in one of the most dangerous areas of space.

How did video games become popular before the internet? It’s all about shareware, floppy disks, and human cleverness!

Links from the bottom of all the April 2019 articles, collected in one place for you to print, share, or bookmark.

Interesting stories about science and technology for April 2019.

Interested but not ready to subscribe? Sign-up for our free monthly email newsletter with curated site content and a new issue email announcement that we send every two months.

No, thanks!