Lead
NASA-released images and instrument data from the International Space Station (ISS) show rare, colorful electrical discharges—known collectively as transient luminous events (TLEs)—occurring high above thunderstorms. Observed from orbit since the Atmosphere–Space Interactions Monitor (ASIM) was installed in 2018, these fleeting phenomena include blue jets, red sprites, ultraviolet rings and ELVES, and are visible up to about 55 miles above Earth. The new imagery and complemented CubeSat measurements reveal how these events inject energy into the upper atmosphere, with implications for radio communications, aviation safety and atmospheric chemistry. Taken together, the ISS observations are turning anecdote into a systematic record of lightning’s reach toward space.
Key Takeaways
- ASIM on the ISS has continuously monitored TLEs since 2018, capturing flashes smaller than a fingernail and briefer than a heartbeat.
- TLEs documented include blue jets, red sprites, violet halos and ELVES; some features are observed up to ~55 miles (≈88 km) above Earth’s surface.
- High-speed camera runs from Thor-Davis aboard the ISS have recorded storms at up to 100,000 frames per second, revealing sub-millisecond filamentation in lightning.
- ELVES rings seen by ASIM can extend ionospheric disturbances across hundreds of miles, posing a potential risk to long-range radio links and signal relays.
- CubeSat Light-1 (JAXA collaboration) is mapping high-energy bursts—terrestrial gamma-ray flashes—helping place those pulses in 3D relative to storms on the ground.
- Short corona discharges catalogued from orbit are enabling researchers to trace how a thundercloud’s upper layers prime conditions for full lightning strikes.
- Collective data from the ISS are being integrated into storm-charging models that inform aviation routing and power-grid lightning warning systems.
Background
Transient luminous events (TLEs) sat at the margins of atmospheric science for decades because they occur above storm tops, out of reach of most ground instruments. Pilots supplied the earliest eyewitness accounts and the occasional fortuitous photograph, but such reports were sporadic and lacked systematic coverage. That changed when the European Space Agency’s Atmosphere–Space Interactions Monitor (ASIM) was mounted on an external ISS platform in 2018 to observe Earth’s limb and nightside storms from above.
ASIM carries high-speed cameras, photometers and X- and gamma-ray detectors tuned to very short-duration optical and high-energy transients. The instrument’s perspective from low Earth orbit removes clouds and horizon obstructions that hamper ground-based sensors, letting researchers build a continuous archive of TLE occurrences. Complementary efforts—such as the Thor-Davis high-frame-rate camera placed inside the ISS cupola and small CubeSats like Light-1—expand the spectral and temporal reach of the dataset.
Main Event
Astronauts aboard the ISS captured vivid images showing red sprites—brief, jellyfish-shaped glows in the mesosphere—and blue jets that propagate upward from thundercloud tops toward the stratosphere. In some sequences, ASIM recorded ELVES: broad ultraviolet rings produced by lightning-driven electromagnetic pulses that briefly flash the lower ionosphere. The combined optical and high-energy measurements illustrate that storms can drive electrical and radiative effects well beyond the weather layer we normally consider.
Thor-Davis footage recorded from the cupola at frame rates up to 100,000 fps revealed lightning’s sub-structure, including filamentation and branching patterns that last fractions of a millisecond. These split-second features had been only imperfectly recreated in laboratory plasma experiments; the ISS observations enable direct validation against real-world events. In at least one study, orbital and ground-based data were combined to fix the altitude of a blue jet, confirming that upward discharges reach heights beyond conventional thundercloud tops.
The CubeSat Light-1, released from the ISS, carries detectors tailored to hard X-rays and gamma rays and has begun building a record of terrestrial gamma-ray flashes (TGFs). TGFs are extremely brief, intense bursts of high-energy photons; in aggregate they appear often over equatorial storm belts. Researchers intend to time-stamp CubeSat detections against global lightning networks to map where TGFs originate most frequently and how they relate spatially to optical TLEs.
Analysis & Implications
From a communications perspective, ELVES and other TLEs operate in the same ionospheric layers that reflect or modify long-range radio propagation. When ELVES rings boost ionospheric charge across hundreds of miles, they can temporarily alter signal paths used by HF radio, submarine communications and some navigation links. That makes understanding TLE cadence and geographic distribution relevant to agencies that manage critical communications infrastructure.
For aviation, the new altitude measurements of blue jets and the catalog of rapid corona discharges add nuance to hazard maps. Aircraft transiting polar or equatorial routes may encounter environments with unexpected electrical gradients; improved models informed by ISS data can refine routing advisories and enhance onboard detection thresholds. While most commercial aircraft remain well below the altitudes of typical TLEs, the interaction of aircraft-generated fields with upper-atmosphere discharges is an area under study.
On the climate and chemistry side, TLEs and corona discharges mobilize nitrogen oxides and other reactive species between atmospheric layers. Those chemical perturbations, repeated over millions of storms worldwide, could modify ozone concentrations and radiative balance in localized regions. Incorporating vertical mixing from TLEs into climate models may reduce uncertainty in projections of atmospheric composition and energy balance.
Comparison & Data
| Phenomenon | Typical altitude (approx.) | Duration |
|---|---|---|
| Red sprites | ~50–90 km | ~10 ms |
| Blue jets | ~20–50 km | tens of ms |
| ELVES | ~80–95 km (ionosphere base) | ~1 ms |
| Terrestrial gamma-ray flashes (TGF) | originate near storm tops; extend upward | sub-ms to ms |
The table above synthesizes altitude and timing ranges assembled from ASIM, Thor-Davis and Light-1 datasets. These ranges are approximate because individual events can deviate and because different instruments use varying detection thresholds. Still, the pattern is clear: many TLEs occupy mesospheric and lower ionospheric layers above conventional weather systems, and most last only milliseconds.
Reactions & Quotes
Agencies and researchers have framed the ISS findings as a breakthrough in observing storm-driven upper-atmosphere phenomena.
“ASIM’s orbiting vantage gives us a continuous, systematic look at fleeting electrical events that used to be anecdotal.”
European Space Agency (official statement)
“High-frame-rate imagery from inside the cupola has exposed lightning behavior that laboratory tests alone could not reproduce.”
ISS Thor-Davis team (research summary)
“Combining CubeSat gamma-ray detections with optical records will let us place high-energy flashes precisely within storm systems.”
JAXA / Light-1 collaborators (project note)
Unconfirmed
- The global frequency and seasonal distribution of TGFs remain under active study; current ISS/CubeSat coverage is improving but not yet complete.
- The long-term climate impact of TLE-driven vertical chemistry transport is suggested by models but has not been conclusively quantified.
- The extent to which TLEs pose direct hazards to high-altitude aircraft or spacecraft systems requires further targeted measurements and risk analysis.
Bottom Line
Observations from the ISS—and the instruments and small satellites it supports—have transformed TLEs from sporadic curiosities into a systematically documented class of upper-atmosphere phenomena. ASIM’s continuous monitoring since 2018, together with high-speed imagery from the cupola and targeted CubeSats like Light-1, are revealing how storms can reach and influence the ionosphere and radiation environment above them.
That knowledge matters beyond scientific curiosity: it feeds models used by radio operators, aviation planners and climate scientists, and it points to practical upgrades—automated detectors, faster recorders and coordinated CubeSat fleets—that could deliver near-real-time alerts for high-energy flashes. As the ISS continues to collect data through the decade, researchers expect the record to sharpen, reducing uncertainties and improving operational guidance for systems that rely on the charged layers above our storms.