Major space mystery solved using data from student satellite

December 13, 2017, University of Colorado at Boulder
Dozens of CU Boulder students designed and built the CSSWE CubeSat satellite, which was used to study energetic particles in the Van Allen radiation belts. Credit: University of Colorado

A 60-year-old mystery regarding the source of some energetic and potentially damaging particles in Earth's radiation belts is now solved using data from a shoebox-sized satellite built and operated by University of Colorado Boulder students.

The results from the new study indicate energetic electrons in Earth's inner radiation belt - primarily near its inner edge - are created by born from explosions of supernovas, said the study's lead author, Professor Xinlin Li of CU Boulder's Laboratory for Atmospheric and Space Physics (LASP). Earth's radiation belts, known as the Van Allen belts, are layers of held in place by Earth's magnetic field.

The team showed that during a process called "cosmic ray albedo neutron decay" (CRAND), cosmic rays entering Earth's atmosphere collide with neutral atoms, creating a "splash" which produces charged particles, including electrons, that become trapped by Earth's magnetic fields. The findings have implications for understanding and better forecasting the arrival of energetic electrons in near-Earth space, which can damage satellites and threaten the health of space-walking astronauts, said Li.

"We are reporting the first direct detection of these near the inner edge of Earth's radiation belt," said Li, also a professor in CU-Boulder's aerospace engineering sciences department. "We have finally solved a six-decade-long mystery." A paper on the subject was published in the Dec. 13 issue of Nature. The study was funded primarily by the National Science Foundation.

Six-decade-old space mystery solved with shoebox-sized satellite called a CubeSat
Researchers test the CubeSat, which is communicating with a ground station about four miles away. Credit: University of Colorado Boulder

Soon after the discovery of the Van Allen in 1958, both American and Russian scientists concluded that CRAND was likely the source of high-energy protons trapped in Earth's magnetic field. But over the intervening decades, no one successfully detected the corresponding electrons that should be produced during the neutron decay.

The CubeSat mission, called the Colorado Student Space Weather Experiment (CSSWE), houses a small, energetic particle telescope to measure the flux of solar energetic protons and Earth's radiation belt electrons. Launched in 2012, CSSWE has involved more than 65 CU Boulder students and was operated for more than two years from a ground station they built on the roof of a LASP building on campus.

Six-decade-old space mystery solved with shoebox-sized satellite called a CubeSat
The CubeSat just before it was brought into the launch facility. Credit: University of Colorado Boulder

The instrument on CSSWE, called the Relativistic, Electron and Proton Telescope integrated little experiment (REPTile) is a smaller version of REPT, twin instruments developed by a CU Boulder team led by LASP director and Nature paper co-author Daniel Baker that were launched on NASA's 2012 Van Allen Probes mission.

"This is really a beautiful result and a big insight derived from a remarkably inexpensive student satellite, illustrating that good things can come in small packages," said Baker. "It's a major discovery that has been there all along, a demonstration that Yogi Berra was correct when he remarked 'You can observe a lot just by looking.'"

Six-decade-old space mystery solved with shoebox-sized satellite called a CubeSat
Assembling the only science payload onboard; it sent back high-quality data, researchers report. Credit: University of Colorado Boulder

"These results reveal, for the first time, how energetic charged particles in the near-Earth space environment are created," said Irfan Azeem, a program director in the NSF's Division of Atmospheric and Geospace Sciences.

"The findings will significantly improve our understanding of the Earth-space environment," Azeem said. "It's exciting to see NSF-funded CubeSats built by undergraduate and graduate students at the center of a significant scientific discovery."

Explore further: FIREBIRD II and NASA mission locate whistling space electrons' origins

More information: Measurement of electrons from albedo neutron decay and neutron density in near-Earth space, Nature (2017).

Related Stories

Saturn's radiation belts: A stranger to the solar wind

October 30, 2017

The radiation belts of Earth and Saturn differ more strongly than previously assumed. In these belts, very energetic particles, such as electrons and protons, move around the planet at high velocities - captured by its magnetic ...

Recommended for you

HESS J1943+213 is an extreme blazar, study finds

June 21, 2018

An international group of astronomers have carried out multi-wavelength observations of HESS J1943+213 and found evidence supporting the hypothesis that this gamma-ray source is an extreme blazar. The finding is reported ...

'Red nuggets' are galactic gold for astronomers

June 21, 2018

About a decade ago, astronomers discovered a population of small, but massive galaxies called "red nuggets." A new study using NASA's Chandra X-ray Observatory indicates that black holes have squelched star formation in these ...

The Rosetta stone of active galactic nuclei deciphered

June 21, 2018

A galaxy with at least one active supermassive black hole – named OJ 287 – has caused many irritations and questions in the past. The emitted radiation of this object spans a wide range – from the radio up to the highest ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.