A NASA suborbital sounding rocket deployed five simultaneous sensors into a sporadic E layer, uncovering complex, turbulent structures inside the radio-reflecting ionospheric clouds, NASA reported.
The mission, called the Sporadic E Electrodynamics Demonstration, or SpEED Demon, launched on Aug. 24, 2022, from NASA’s Wallops Flight Facility in Virginia. Led by a team at Embry-Riddle Aeronautical University, the rocket flew into the layer roughly 60 miles above Earth and released four ejectable dropsonde probes. The four probes flew away from the main payload and one another, allowing five instruments to take plasma measurements along separate tracks at the same moment and transmit the data to ground stations.
The study, published in the Journal of Geophysical Research: Space Physics, revealed that the metallic cloud was structured rather than uniform. Lead author Henry Valentine, who carried out the work at Embry-Riddle before joining the U.S. Naval Research Laboratory, said the layer interacted with neutral winds and swirling atmospheric turbulence. On descent, the layer separated into two distinct peaks, a structure consistent with Kelvin-Helmholtz billows. The team could not directly verify the billow mechanism because the rocket payload was unable to measure local winds and electric fields directly.
Sporadic E layers gather in the ionosphere, where neutral atmospheric gases turn into plasma starting roughly 40 miles up. Vaporized dust from meteors contributes particles of iron, magnesium, and other metals that clump into dense formations. These clouds act as giant mirrors for radio waves, causing signals to bounce back toward the ground, generating false radar targets, and introducing errors into GPS systems.
Principal investigator Aroh Barjatya of Embry-Riddle said sporadic E layers peak during the local summer. His team later used the dropsonde multi-probe technique on rockets launched during the October 2023 annular solar eclipse and the April 2024 total solar eclipse. In June 2025, the team launched a successor mission, Sporadic-E ElectroDynamics, from the Kwajalein Atoll in the Marshall Islands to examine the layers at lower latitudes.
