High school students measure the Earth's magnetic field from the ISS

Code aboard the space station

The Earth's magnetic field also called the geomagnetic field, extends tens of thousands of kilometers into space, forming the Earth's magnetosphere.

The fluxgate magnetometer and the proton precision magnetometer are most commonly used for geomagnetic measurements. 

In 2018, researchers in Canada, the United States, and Europe have developed an innovative way to measure Earth’s magnetic field remotely. By zapping a layer of sodium atoms floating 100 kilometers above the planet with lasers on the ground.

The method employed by the students sprung up as part of a contest.

The European Space Agency had teamed up with the U.K.'s Raspberry Pi Foundation to hold a contest for high school students. 

"The students had applied to participate in the AstroPi Challenge, organized by the RaspberryPi Foundation, whose theme was to make measurements using a Raspberry Pi computer (and attached sensors) on board the ISS, and then use them to produce any result of value for science. The idea of using it to model the Earth’s magnetic field came from the students themselves. Of course, I helped with the Math," Nuno Barros e Sá, co-author, told IE.

"I saw the Astro Pi challenge as an opportunity to broaden my knowledge and skill set, and it ended up introducing me to the complex but exciting reality of the practical world," Lourenço Faria, co-author and one of the students involved in the project, said.

The space station had acquired data to map out Earth's magnetic field. The students used that data and compared their results to the International Geomagnetic Reference Field (IGRF) data.

Reconstructing the Earth's primary features

The IGRF uses observations and satellites to compute Earth's magnetic field measurements. This data is updated every five years.

So, the students compared their measurements taken in April 2021, with the latest IGRF data from 2020. Their data did differ from the IGRF results by a significant but fixed amount.

However, the difference was attributed to a static magnetic field inside the space station.

The team then repeated their analysis using another 15 orbits worth of ISS data and noticed a slight improvement in results. 

The fact that the primary features of Earth's magnetic field could be reconstructed with just three hours' worth of measurements from a low-cost magnetometer aboard the space station was somewhat surprising.

A project that could connect students

Though intended for the space station, the project can easily be adapted to ground-based measurements using laboratory equipment or magnetometer apps for smartphones.

"Taking measurements around the globe and sharing data via the internet or social media would make for an interesting science project that could connect students in different countries," said Nuno Barros e Sá.

The value of the project stands mostly at the educational level, as there are scientific programs which do the same job but with a much higher degree of accuracy, he believes.

"This project stands as a tool to introduce students to the practical application of physics, in a multidisciplinary manner, as they have to deal with physics, math and programming, using an exciting theme, with simple measurement tools and computers," Nuno Barros e Sá added.