NASA recently successfully carried out two sounding rocket launch missions in Alaska, sending three rockets directly into the gorgeous Northern Lights. For the first time, it "sneaked" into the secret and powerful current system behind this sky wonder to obtain high-quality in-situ observation data.
The operation includes the Black and Diffuse Auroral Science Surveyor mission and a twin-rocket mission called GNEISS (Geophysical Non-Equilibrium Ionospheric System Science), both launched from the Poker Flat Research Range near Fairbanks.
The "Dark and Diffuse Aurora Science Surveyor" rocket lifted off from Alaska at 3:29 a.m. local time on February 9, flying to an altitude of approximately 224 miles (approximately 360 kilometers). Project leader Marilia Samara said that all scientific instruments and technical verification loads carried by the rocket are operating normally, and the team has obtained extremely high-quality data, which provides valuable information for analyzing the "darkness" and diffuse structures in the aurora.
Immediately following was the GNEISS dual rocket mission, which was launched successively at 1:19:00 and 1:19:30 on February 10. The two rockets flew over the same aurora belt almost at the same time, with the highest flying altitudes being approximately 198.3 miles (319.06 kilometers) and 198.8 miles (319.94 kilometers) respectively. Project leader Christina Lynch, a professor at Dartmouth College, said that all ground stations, subloads, and extended instrument booms worked as expected, and the team was "very pleased" with the launch operations and preliminary data performance.
Scientists pointed out that the aurora phenomenon is essentially the flow of high-energy electrons from space into the earth's upper atmosphere and the luminescence produced after collision with gas molecules, just like the current passing through a filament to light up a light bulb. But the dazzling light is only part of the entire huge circuit: in any circuit, the current must form a closed loop. The electron beams that flow into the atmosphere to produce aurora are relatively concentrated, while the "return" electrons that complete the circuit are more chaotic and will move around under the influence of collisions, wind fields, pressure differences, and changing electric and magnetic fields, and eventually find their way back to space.
To truly understand how this huge circuit is closed, it is not enough to just know where the rocket flies. Researchers must map how the return current spreads in the atmosphere. This requires tracking many paths at the same time, which is a huge technical challenge. To this end, the GNEISS mission built a three-dimensional imaging solution similar to medical "CT scanning" through "two-arrow collaboration + ground receiving network" to reconstruct the structure of auroral current in high-altitude plasma.
During the flight, the two rockets passed through the same auroral area along similar but slightly different trajectories, and each released four sub-payloads to conduct simultaneous observations at multiple points inside the luminous area. The rocket continuously sends radio signals to the ground, which are "rewritten" as they pass through the surrounding plasma, similar to how X-rays are differentially absorbed when passing through different tissues of the human body. By analyzing small changes in signals, researchers invert the plasma density distribution and current channel locations to obtain a large-scale three-dimensional "current map" of the auroral environment.
Auroral current is not only a basic physical problem, but also closely related to "space weather". Scientists point out that these currents control how energy from space settles and is distributed in the Earth's upper atmosphere. When the currents spread, they can heat the local atmosphere, stimulate strong winds, and create turbulence, potentially affecting satellites flying or passing by that altitude. In recent years, the scientific research community has carried out multi-angle joint research through ground-based optical observations and orbiting satellites. Among them, NASA's EZIE satellite mission, launched in March 2025, is monitoring auroral currents from space, complementing this rocket's "pass-through" in-situ measurement.
During this launch window, NASA simultaneously implemented the "Dark and Diffuse Aurora Scientific Surveyor" mission, focusing on detecting the dark spots in the aurora called "black auroras". Current theory suggests that these abnormally "darkened" areas may mark local sharp reversals of current flow, playing a key role in the overall circuit. The mission was postponed in 2025 due to unsatisfactory weather and scientific conditions. This successful flight means that the scientific research team finally has the first batch of systematic data to study this area.
Researchers said that aurora is the result of the interaction between space plasma, the Earth's magnetic field and the atmosphere, which involves currents, charged particles and countless microscopic collisions. It is an important "window" for understanding the Earth's space environment. Unlike "looking up" at the aurora on the surface for a long time, sounding rockets provide scientists with a rare opportunity to directly travel through the aurora when it is most active, and send instruments into key areas to perform "short, flat and fast" precise tasks. Through such high spatial and temporal resolution observations, researchers are converting the fleeting light and shadow of the sky into deep knowledge that reveals how space weather shapes our planet.