The thin metallic sheets that periodically scramble long-distance radio signals are far less uniform inside than a single measurement track suggested, according to results NASA published from a sounding rocket that carried five sensors through one of the layers at the same moment. The findings appeared on the agency's site on September 2 and were last updated September 3.

The layers, called sporadic E, form roughly 60 miles up from the vaporized remains of burned-up meteors. When one appears, radio signals intended for space can bounce back toward the ground instead. Until this mission, in-place measurements had come from a single instrument flying a single line through a layer.

For pilots, mariners, shortwave operators, and anyone whose phone relies on satellite positioning, the practical takeaway is not a new hazard. It is a better description of an old one. The peer-reviewed study appears in the Journal of Geophysical Research: Space Physics, from a team led by Embry-Riddle Aeronautical University.

Five Sensors Instead of One Narrow Slice

The mission was called the Sporadic-E ElectroDynamics Demonstration, or SpEED Demon. It flew on a Terrier-Improved Malemute from NASA's Wallops Flight Facility on Virginia's Eastern Shore, reaching an apogee near 100 miles before falling into the Atlantic. NASA's recent release gives the launch date as August 24, 2022; the agency's launch announcement at the time recorded liftoff at 9:16 p.m. Eastern on August 23, which is the same moment expressed in local rather than universal time.

Once the rocket reached the layer, it released four ejectable probes known as dropsondes. Each flew away from the main payload and from the others, measuring plasma along its own track and transmitting to ground stations. Combined with the payload itself, that gave five simultaneous sampling points inside a single layer, a first for this kind of research.

Aroh Barjatya, the mission's principal investigator and a professor of engineering physics at Embry-Riddle in Daytona Beach, Florida, has compared single-rocket measurements to viewing a scene through a crack in a wall. Everything to the left and right of that narrow line goes unrecorded.

Now with multiple sensors, we've turned that crack into a picket fence, Barjatya said in the NASA release.

Metal from Burned-Up Meteors, 60 Miles Overhead

Sporadic E forms in the ionosphere, the region of the upper atmosphere that begins around 40 miles, or 60 kilometers, up, where neutral gases start converting into electrically charged plasma. Meteors burning up in that zone leave behind iron, magnesium and other metals.

Those metals occasionally clump into dense, cloud-like sheets near 60 miles, or 100 kilometers. That altitude is the core of the measurement problem. It sits too high for weather balloons and too low for satellites, which is why sounding rockets have been the primary tool for studying it.

The layers also form and dissipate unpredictably, which is where the name comes from. Sounding rockets can be launched on short notice, making them one of the few instruments capable of catching a layer while it exists.

One point deserves emphasis because it is frequently muddled in coverage. Sporadic E is not a product of solar storms. It arises from meteoric metal and atmospheric winds, and Barjatya says the layers follow a seasonality, with peak occurrence during local summer. That makes them a different phenomenon from the geomagnetic storms that produce aurora and grid concerns, even though both involve the ionosphere.

Signals That Bounce Where They Should Not

When a sporadic E layer is present, it acts as a reflector. Barjatya has described the layers as giant mirrors for radio frequency waves in the sky.

The consequences are specific and documented. Air traffic controllers and marine radio users can pick up distant transmissions as though the source were nearby. Radars designed to scan beyond the horizon can register false targets, sometimes called ghosts. Long-distance shortwave propagation can open and close without warning.

Satellite positioning is affected as well, though the framing matters. Henry Valentine, the study's lead author, who did the work at Embry-Riddle and is now a researcher at the U.S. Naval Research Laboratory, has said the largest source of error in a phone's GPS comes from ionospheric plasma generally, and that sporadic E can contribute to that uncertainty. The study does not claim sporadic E is the dominant driver of positioning error.

What the five-point measurement changed is the picture of the layer's interior. Instead of a smooth, dense sheet, the layer SpEED Demon flew through was uneven and structured, shaped by turbulent winds moving through the surrounding neutral air. Valentine has described the result as closer to a cinnamon roll than a flat pancake.

The Billow Explanation Remains Unconfirmed

On the descent, the layer split into two distinct density peaks. The team found that the shape is consistent with modulation by Kelvin-Helmholtz billows, the curling instability that produces breaking-wave patterns in ordinary clouds.

That interpretation carries an explicit limitation, and the researchers state it themselves. The flight could not measure local winds and electric fields directly, so the billow explanation is described as plausible rather than confirmed. Readers should treat it as a leading hypothesis, not a settled finding.

The mission's original purpose also frames how much weight the science should carry. SpEED Demon was designed as a technology demonstration, a test of whether the dropsonde technique would work at all, and it launched near the tail end of the northern hemisphere sporadic E season without waiting for ideal conditions. The structural findings came from one layer on one flight, so they describe what that layer looked like rather than what all sporadic E looks like.

Follow-On Flights and the Data Still Coming

The technique worked, and the team applied it quickly. Barjatya's group used a similar multi-probe approach for rockets flown into the paths of the annular eclipse and the total solar eclipse that followed, studying how sudden darkness disturbs the upper atmosphere.

In June 2025 the team flew SpEED Demon's most direct descendant, the SEED mission, from Kwajalein Atoll in the Marshall Islands, targeting layers at lower latitudes. NASA says papers from those missions are in preparation, without giving a publication date.

There is no action for readers to take. No alert is in effect, no agency has changed guidance, and sporadic E is a recurring natural condition rather than an emerging threat.

Barjatya has said the research community is in the final stretches of understanding these layers. That is an assessment from the mission's own principal investigator, and independent confirmation of the interior structure will require additional flights through additional layers.

Nature World News will report on results from the SEED mission and the eclipse flights when those papers are published.

What Readers Want to Know

What is a sporadic E layer?

A thin, dense sheet of metallic particles that forms roughly 60 miles above the ground, made largely from the vaporized remains of meteors. The layers appear and dissipate unpredictably and can reflect radio signals back toward Earth.

Does this mean radio or GPS problems are getting worse?

No. The study describes the internal structure of one layer in more detail than before. It does not report any increase in frequency, intensity or disruption, and no agency has issued new guidance based on it.

Is sporadic E caused by solar storms?

No. It arises from meteoric metals and atmospheric winds and peaks during local summer. That makes it distinct from geomagnetic storms, even though both involve the ionosphere and both can affect radio.

Who is most affected by these layers?

Long-distance shortwave and amateur radio operators, marine radio users, air traffic controllers who may receive distant transmissions as though they were local, and operators of over-the-horizon radar, which can register false targets.

How confident are researchers in the findings?

The measurements are peer-reviewed and published in the Journal of Geophysical Research: Space Physics. The proposed explanation involving Kelvin-Helmholtz billows is explicitly labeled plausible rather than confirmed, because the flight could not measure local winds and electric fields.

Why are results from a 2022 flight appearing now?

Sounding rocket data require extensive analysis, and the mission was a technology demonstration first. The team flew follow-on missions before this paper was finished, and papers from those flights are still in preparation.