NASA Rocket Samples Radio-Disrupting Clouds at Five Points

On Aug. 24, 2022, a sounding rocket — a suborbital research rocket — rose from NASA’s Wallops Flight Facility in Virginia and flew through an invisible metallic cloud. The SpEED Demon mission carried five detectors through the same sporadic E layer at once, giving researchers the first concurrent, multi-point view of a phenomenon that can bend radio signals in unexpected directions.

Sporadic E layers form in the ionosphere, which begins around 40 miles (60 kilometers) above Earth as neutral gases start turning into plasma, or ionized gas. Some of that material comes from meteors burning up and leaving iron, magnesium and other metals behind. Those metals can gather into dense, cloud-like sheets around 60 miles (100 kilometers) up. When a sheet forms, it can reflect radio waves back toward Earth: distant transmissions may sound nearby to air traffic controllers or marine radio users, while radar can register false targets. Plasma in the ionosphere is also the biggest source of error in phone GPS, according to the study’s lead author, Henry Valentine.

Before SpEED Demon, a rocket could sample only one narrow line through a layer. The new mission released four dropsondes, ejectable probes that flew away from the main payload and from one another, each transmitting measurements to ground stations. Together with the rocket’s main instrument, they sampled five places at the same moment. A team led by Embry-Riddle Aeronautical University described the results in the Journal of Geophysical Research: Space Physics.

The measurements found more structure than the team expected. Instead of a smooth, dense sheet, the layer appeared uneven and shaped by turbulent winds in the surrounding neutral air. It split into two distinct peaks during the descent. The pattern was consistent with Kelvin-Helmholtz billows, curling wave-like instabilities also seen in ordinary clouds, but Aroh Barjatya’s team stops short of calling that cause proven: the flight could not directly measure the local winds and electric fields.

So what changes, concretely? Five simultaneous tracks reveal movement and structure that one rocket path could miss, giving researchers more context to study how sporadic E affects radio signals. The mission was a technology demonstration designed to test whether the dropsonde technique would work. A similar multi-probe strategy was used for the October 2023 annular eclipse and April 2024 total eclipse, while a direct descendant flew from Kwajalein Atoll in June 2025; papers from those missions are in preparation.