Scott Palo is leading a multi-university effort to unlock a scientific mystery in near-Earth space.
He is leading a team that has earned a $4 million, four-year grant from the National Science Foundation's Ideas Lab to design and build three CubeSat nanosatellites to investigate the relationship between charged particles and neutral particles in the thermosphere, an area that extends from 95 km – 600 km (50 miles - 375 miles) above Earth's surface and includes the orbits of many satellites and the International Space Station.
The project is called SWARM-EX, or Space Weather Atmospheric Reconfigurable Multiscale Experiment. The phenomenon to be studied is known as the equatorial ionization anomaly and equatorial thermosphere anomaly.
“Their formation and behavior are not well-determined. There are competing theories, and we want to make measurements to fundamentally understand how they are related,” said Palo, the principal investigator on the project and a professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences at the University of Colorado Boulder.
Working with Palo at CU Boulder is Jeff Thayer, an aerospace professor who has done theoretical modeling of the anomalies in the past and is eager to see the results of real-world measurements.
“Understanding these anomalies is important for societal reasons. They negatively impact GPS and communications satellites, and the neutral particles cause drag on spacecraft and orbital debris,” Thayer said.
The CubeSats are small – just slightly larger than a loaf of bread – but do not let their size fool you. Advances in technology have made it possible to pack a strong scientific punch in even the smallest spaces. Each CubeSat will carry two scientific instruments in addition to communications equipment, batteries, solar cells and fuel.
CU Boulder is one of six universities working on the project, along with the Georgia Institute of Technology, Olin College, Stanford University, University of South Alabama and Western Michigan University.
By building and flying three satellites, the team hopes to better understand the development of the anomalies.
“The plasma is unstable and changes quickly. Typically, you only have one satellite, and it passes over an area every 90 minutes, but we know these processes happen faster than that. With a constellation of three CubeSats, we’ll have control over their distances and be able to see the evolution of the particles,” Thayer said.
The goal of the CubeSats is twofold, with research as only one part of the overall mission. The second objective is to push the limits of CubeSat technology by incorporating propulsion and autonomous systems so the satellites can communicate with each other to coordinate movements and adapt to changing conditions automatically.
“SWARM-EX will demonstrate how we can fly these small sensor platforms in various configurations and that the resulting instrument-formation is more than the sum of its parts,” said Marcin Pilinski, a research associate at the Laboratory for Atmospheric and Space Physics at CU Boulder and the instrument lead on SWARM-EX.
Onboard propulsion is not typically part of small satellites due to the complexity it adds, and autonomous navigation algorithms are new enough to be novel in any satellite. The team is incorporating both in an intentional effort to advance the limits of technology in small satellites. Funding big, new concepts is a deliberate goal of the NSF Ideas Lab program.
“They tell you to push the envelope,” Palo said. “They’re looking for things that haven’t been done before.”
Each university involved in the project has a different role:
The grant officially begins January 1, with launch expected during the third year of the project. The satellites’ orbital mission should last for six to 12 months after that.
The timeline is a unique feature of CubeSat projects. Unlike large communications or research satellites that can take 10 or more years and well over $100 million to build, CubeSats can go from concept to completion in just a few years, allowing college students to see all parts of the process before graduating.
“The technology and the science are both exciting,” Palo said. “But we also have students involved in ways they never could be before.”