Tiny satellite 'reactivated' by huge solar storm finds two new radiation belts around Earth

A small CubeSat, a type of miniature satellite built from standardized cube-shaped modules, “woke up” after a month of silence and discovered a new radiation belt around Earth.

In the wake of a huge solar storm, it recorded fresh structure in Earth’s magnetosphere, adding new layers to the familiar radiation belts.

Two temporary rings of high energy particles appeared between the permanent Van Allen belts, which are donut-shaped zones of trapped radiation that surround Earth and protect it from solar and cosmic particles.

One ring was rich in electrons, and the other carried a striking load of protons, a mix not seen in that region before.

CIRBE woken up by solar storm

On May 10, 2024, Earth was hit by a G5 geomagnetic storm, the top tier on NOAA’s scale. The disturbance pushed energy and particles deep into near Earth space and rattled the normal order of things.

Skywatchers saw bright auroras far from the poles. Satellite operators and navigation users felt temporary glitches as the storm ran its course.

NASA reported that the Colorado Inner Radiation Belt Experiment (CIRBE), a small NASA satellite designed to study high-energy particles in Earth’s radiation belts, went quiet on April 15, 2024, then unexpectedly resumed operation on June 15, 2024.

When scientists compared data collected before and after the storm, they realized it revealed something entirely new, an additional electron belt that other spacecraft had not detected.

REPTile 2 and radiation belts

The team’s paper lays out the measurements in detail. The onboard instrument, called REPTile 2, detected fast-moving electrons with energies of a few million electron volts and found them clustered close to Earth.

It also recorded powerful protons in a nearby zone, revealing two distinct layers of trapped particles.

An L shell is a way to mark the distance of a magnetic field line from Earth’s center, measured in Earth radii. In plain terms, the belts formed in a region that is usually a sparsely populated slot.

Short lived belts have turned up after other storms, but they have been dominated by electrons.

Here, the innermost of the two new rings carried a strong proton component, which points to the specific storm drivers and how particles were injected and trapped.

That difference matters because protons punch harder into materials than electrons at similar energies. Spacecraft hardware feels that punch most in sensitive electronics and solar arrays.

Studying the new radiation belts

Electron fluxes in the new ring stayed elevated for more than three months, then took a hit after storms in late June and again in August 2024.

The proton heavy ring proved more stable over the same period, according to the mission’s analysis.

The result lines up with physics that slowly saps protons through collisions with ambient gas and plasma. Electrons, on the other hand, can scatter more quickly under the right wave conditions.

The inner belt typically spans about 1,000 to 8,000 miles above Earth, while the outer belt runs from roughly 12,000 to 25,000 miles. The May event parked the extra belts between those zones, in what is usually a safer gap.

That location is not random. The storm compressed and reshaped the region where cold plasma lives, the plasmasphere, which changes how trapped particles move and decay.

Why Earth’s radiation belts matter

Many satellites take a slow path to geostationary orbit. They spend weeks to months spiraling through the belts in a geostationary transfer orbit while electric thrusters raise altitude.

Added time inside energized electron and proton populations raises cumulative dose and risk. Engineers plan for that, but extra belts can nudge margins that were based on typical conditions.

REPTile 2 is small but precise, with fine energy channels for both electrons and protons.

That resolution let the team see that the new electron ring held only higher energy electrons, not the lower energy population that often shows up after storms.

CIRBE’s attitude control kept the telescope pointed with respect to the magnetic field, improving the quality of the flux readings. That detail helped the team separate real signals from contamination.

Wave particle interactions

Earth’s magnetic field does not just deflect the solar wind. It shapes zones where charged particles get trapped and stored for weeks or months.

Small missions can deliver big discoveries when they are in the right place at the right time. CIRBE’s recovery gave scientists a second chance and yielded data that larger missions could not match that month.

The new belts offer a natural experiment in wave particle interactions inside the plasmasphere. The way the electron ring decayed with energy and location sets valuable constraints on scattering rates and lifetimes.

Models that forecast electron and proton hazards will be updated with these observations. Better forecasts mean better guidance for spacecraft design and mission planning.

CIRBE is a university built satellite, a reminder that focused instruments can punch above their weight. The satellite reentered in October 2024, but not before it sent back a clean record of a rare space weather episode.

The mission’s data now serve as a benchmark for future storms. They also give teachers and students a concrete case study in how measurements, models, and theory come together.

The study is published in the Journal of Geophysical Research: Space Physics.

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