HANOVER — Two NASA-funded missions launched last week and are currently in Earth’s orbit in part due to the work of two Dartmouth professors.
The two Dartmouth-affiliated missions, out of six total aboard last Wednesday’s SpaceX launch, will study different “pieces of the puzzle” to better predict Earth’s space weather, said Robyn Millan, Dartmouth professor of physics and astronomy of 20 years.
Having largely worked with high-altitude weather balloons, Millan is “super excited” to send her first satellite into space.
“I was more excited than I realized I was going to be,” Millan said Monday in a phone interview. “Seeing the thing I worked on in the lab now in space kind of blew my mind.”
Both Dartmouth-affiliated missions aim to better understand and predict our planet’s natural space conditions.
“The sort of bigger, broader goal is to try and understand the space environment around Earth, where we have all these satellites, and try to better be able to predict that environment,” Millan said in a phone interview on the evening of the launch.
Strong space weather can damage satellites as they pass through it — in addition to destroying ozone, Millan said. The ozone layer absorbs most of the sun’s ultraviolet radiation, protecting life on Earth — including protecting us from sunburns.
Millan leads one of the missions, Relativistic Electron Atmospheric Loss, or REAL. REAL aims to measure how high-energy particles are scattered throughout Earth’s atmosphere as an effect of space weather, which has occurrences analogous to wind, storms and hurricanes.
One example of space weather was the geomagnetic storm that caused Northern Lights as far as the Southern U.S. in May 2024.
The cube satellite of REAL is approximately the size of a toaster over, weighing less than 10 pounds, and will spend at least six months in low-earth orbit to better understand how high-energy particles are scattered into Earth’s atmosphere.
REAL received approximately $5 million in funding from NASA’s Heliophysics Flight Opportunities for Research and Technology program.
James LaBelle, a professor of Physics and Astronomy at Dartmouth for 36 years, is on the team for the other mission, Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites, or TRACERS.
The two TRACERS satellites will study space weather through energized particles in Earth’s magnetic field. The mission focuses primarily on the cause of space weather, namely sun-Earth interactions, and measures particles that aren’t so energized as REAL’s.
TRACERS has garnered over $165.7 million in funding and around 100 scientists from various institutions, according to the website of the University of Iowa, TRACERS’ lead institution.
The REAL Mission
At Dartmouth, Millan and her team of graduate and undergraduate students did much of the analysis to ensure the cube satellite could survive in space, and that it wouldn’t survive too long.
“You have to make sure your satellites are not going to stay up there forever and, you know, stick around as junk in space,” Millan said. The satellite is currently estimated to be in space for about a year, Millan said.
Millan’s team will analyze the data of REAL, which, beyond possible satellite protection, will provide insight into fundamental processes of astrophysics. Regular data will come in just about a month, which will then take an uncertain amount of time to analyze — depending on the nature of the data, Millan said.
REAL will measure how high-energy particles travelling near the speed of light are scattered into Earth’s atmosphere, Millan said.
REAL measures these high-energy particles near the poles at low-earth orbit. At the poles, Earth’s magnetic field lines come down towards the planet, along which the high-energy particles travel.
As the satellite passes the poles, it crosses all of the lines of Earth’s magnetic field in a matter of minutes. This gives researchers access to more data in a shorter period of time, compared to taking measurements near the equator, where the lines are further apart, Millan said.
It’s also cheaper and easier to send satellites into low-earth orbit and maintain communication with them compared to a higher altitude.
The mission will measure these particles at a much higher rate and with much more detail than has been done before, Millan said.
And as the magnetic field both creates and protects a planet from the high-energy particles, applying insights from the data to other planets can deepen scientists’ understanding of life outside of Earth.
“A lot of people (involved in the project) are interested in trying to understand what makes planets habitable. And radiation belts are an important part of that,” Millan said.
The TRACERS Mission
While REAL focuses more on the scattering of particles, as an impact of space weather, the TRACERS mission is concerned more with the cause of space weather.
Like Earth weather, space weather is largely caused by solar output, though it’s more a result of events such as solar flares as opposed to sunlight in general.
However, since a large solar flare doesn’t always create a large space storm for Earth, the complex relationship requires more scientific work to be understood, Labelle said.
To that end, TRACERS seeks to measure the relationship between solar output events, which can be measured on Earth, and the resulting space weather in Earth’s atmosphere.
The mission will focus on one of the key relationships between the sun and Earth, known as “reconnection,” which occurs when the magnetic fields of the two bodies interact, LaBelle said.
Reconnection can lead to conditions in space that cause damage to satellites in orbit and even power stations on the ground, he said.
Reconnection results in the two magnetic fields cancelling each other out, or “annihilation,” LaBelle said. The leftover energy of the two fields, needing to go somewhere, puts energy into particles — some of these being the protons and electrons that TRACERS is measuring.
Apart from another rocket experiment that LaBelle worked on — 2018’s TRICE-2 Rocket, which inspired the TRACERS mission — this kind of experiment has largely not been done before, LaBelle said.
This experiment could result in a better understanding of satellite and power grid protection. TRACERS can also help researchers to better understand reconnection, which is a phenomena that occurs all over the universe, for example, in the sun’s atmosphere, at other planets and at neutron stars, LaBelle said.
