Rockets to be launched during eclipse
Researchers hope to better understand ionosphere
The April 8 total solar eclipse stretching from Texas to Maine provides Americans with more than a fleeting perceptible phenomenon.
It’s also the setup for science. Aroh Barjatya, a professor of engineering physics and director of the Space and Atmospheric Instrumentation Lab at Embry-Riddle Aeronautical University’s Daytona Beach, Florida, campus, and a team of researchers and students from ERAU and other institutions will use the occasion to engage in a NASA-funded project called APEP, or Atmospheric Perturbations around Eclipse Path.
They will be working to gain a better understanding of the ionosphere – part of the Earth’s upper atmosphere in a belt that affects radio communications. The ionosphere starts at about 50 miles above the Earth’s surface and extends beyond 350 miles, according to NOAA.
The ionosphere is beyond the stratosphere, where the ozone layer is located. Because of the ionosphere’s more direct exposure to the sun, particles from extreme ultraviolet and X-ray solar radiation, as well as cosmic rays, become charged, or ionized.
And because the ionosphere is so high above the Earth’s surface, the pull of gravity is weakened, allowing the charged particles to be dynamic and swimming in plasma, the fourth state of matter, after solids, liquids and gasses. Barjatya compares the ionosphere to an ocean, as atmospheric conditions – thunderstorms, hurricanes, tornadoes, even bombs exploding in Ukraine and Gaza – can cause perturbations, or disturbances similar to oceanic waves.
“This layer reflects and refracts radio signals and impacts satellite communications as the signals pass through,” Barjatya said.
So when people use GPS, perturbations in the ionosphere can affect the quality of the signal. Also, some Ham radio operators can use high-frequency signals to bounce off the ionosphere and reach listeners worldwide, so ionospheric disruptions can impact those communications, as well.
“All satellite communications and GPS-type navigation signals pass through the ionosphere and are affected in different ways depending on the conditions of the plasma there,” student-researcher Nathan Graves said in a university news release. “Thus, being able to understand ionospheric perturbations, model them and predict when they can happen is critically important in a connected society.”
Eclipses, too, can cause these perturbations. And for scientists like Barjatya, the time and location of eclipses are predictable, creating a perfect environment for targeted experiments.
Measuring solar eclipse’s effect on ionosphere
In spring 2022, Barjatya and an Embry-Riddle research colleague, Shantanab Debchoudhury, were brainstorming ideas on how to take advantage of a NASA sounding rocket program, “Low Cost Access to Space,” through which it launches about 20 rocket missions annually.
NASA had launched sounding rockets during eclipses seven previous times dating back 60 years, and two would occur within two years.
And ERAU’s Space and Atmospheric Instrumentation Lab has experience launching sounding rockets and already had the design and one payload ready.
“We could design a neat experiment that involved launching three rockets in October 2023 in the annular eclipse, recovering and refurbishing the payload, and launching all three again in April 2024 during the total solar eclipse,” Barjatya said.
Plus, Barjatya said: “The 2023 and 2024 eclipses were very close to existing sounding rocket ranges.”
White Sands, New Mexico, and Wallops Island, Virginia, are two of NASA’s launching sites. Last October, an annular solar eclipse was seen across New Mexico, where the launches were toward the eclipse path. The launches from Virginia’s eastern seaboard will be away from the path, giving an additional perspective on how the ionopshere responds to the eclipse.
To collect more data from the ground and to model the findings, Barjatya found collaborators at Johns Hopkins University, Dartmouth College, the Massachusetts Institute of Technology and the Air Force Research Lab in New Mexico.
ERAU students built nine of the 10 instruments that will comprise the rockets’ payloads. Dartmouth researchers contributed the other.
What will take place after liftoff
Most of the Embry-Riddle team will be at Wallops Island to launch three rockets, each 60 feet high with 18-inch diameters. One will lift off about 45 minutes before the peak local eclipse, the second will go off at peak eclipse and the third 45 minutes later.
The rockets are expected to soar to a height of 260 miles. There, they will open up to allow 10 instruments on board to collect data. They will also eject sub-payloads the size of a two-liter bottle of soda with instruments to collect data, allowing for the capture of 15 data sets at varying times during the eclipse.
The data gathered will measure plasma density, neutral density and magnetic fields. It will be transmitted to the ground using a system built and managed by NASA, Barjatya said.
Simultaneously, one of the ERAU doctoral students will be at White Sands to rerun ground experiments, while other ground-based teams from the Air Force Research Lab and the MIT Haystack Observatory will gather largerscale measurements from the ground, using various radar technologies.
Barjatya said the team will also release student-built, high-altitude balloons that will elevate to 19 miles above Earth, to help study lower atmosphere weather changes “and help us detangle how much of the ionosphere dynamics during eclipse could be from groundbased weather changes propagating upwards.”
The ionosphere is not easy to study. Perturbations are unpredictable, but the eclipse is the exception.
“We know exactly when and where to launch the rockets to get some guaranteed scientific results. Most ionospheric missions must wait weeks to catch good science conditions to launch into, and sometimes the timing and positioning is still not perfect,” Barjatya said. “I am excited by the precise launch timing and ability to comprehensively instrument a rocket platform.”