The Black and Diffuse Auroral Science Surveyor successfully launched on February 9 at 3:29 a.m. AKST (7:29 a.m. EST), reaching an altitude of approximately 224 miles (360 kilometers). Principal investigator Marilia Samara confirmed that all onboard instruments, including technology demonstrations, functioned flawlessly, yielding high-quality data.
Following this, the GNEISS mission executed a striking pair of launches on February 10 at 1:19:00 a.m. and 1:19:30 a.m. AKST (5:19:00 a.m. and 5:19:30 a.m. EST). The rockets achieved peak heights of around 198.3 miles (319.06 kilometers) and 198.8 miles (319.94 kilometers). Principal investigator Kristina Lynch expressed satisfaction with the operations of ground stations, subpayloads, and instrument booms, along with the data gathered thus far.
The Formation of an Electrical Circuit in the Aurora
As the auroras illuminate the night sky, they are energized by electrons descending from space into Earth's upper atmosphere. These charged particles excite atmospheric gases, creating a beautiful glow, much like electricity flowing through a wire to illuminate a bulb.
However, the phenomenon extends beyond just the visible glow. Electricity circulates in loops. Similar to how a lightbulb is part of a complete circuit, the aurora represents one segment of a larger electrical pathway. The electrons entering the atmosphere must also return to space to complete the circuit.
The incoming particle streams are relatively concentrated, akin to current flowing through a wire. Conversely, the return flow is more dispersed. After igniting the aurora, electrons scatter in various directions, influenced by collisions, shifting winds, pressure fluctuations, and changing electric and magnetic fields. Ultimately, they navigate back to space, albeit after traversing the dynamic upper atmosphere.
GNEISS: Mapping Auroral Electricity in 3D
To comprehensively grasp the workings of auroras, scientists must trace how this returning current completes the circuit, necessitating the mapping of numerous potential routes electricity travels through the sky--an exceptionally challenging task.
"Our interest extends beyond the rocket's trajectory," stated Kristina Lynch, principal investigator for GNEISS and a professor at Dartmouth College in New Hampshire. "We aim to understand how the current disperses downwards through the atmosphere."
Lynch designed GNEISS with this objective in mind. Employing two rockets and a coordinated network of ground receivers, the mission constructs a three-dimensional representation of the aurora's electrical environment.
"It's akin to performing a CT scan of the plasma beneath the aurora," Lynch elaborated.
The two rockets launched concurrently into the same aurora, each following slightly distinct paths. Once within the auroral region, each rocket deployed four subpayloads to gather data at various points.
As they soared overhead, the rockets transmitted radio signals through the surrounding plasma to ground-based receivers. The plasma altered these signals as they passed through, resembling how body tissues modify X-rays during a medical CT scan. By analyzing these alterations, scientists can ascertain plasma density and pinpoint where electrical currents can flow, resulting in a large-scale CT-style scan of the aurora.
The Importance of Mapping Auroral Currents for Space Weather
Understanding these electrical currents transcends mere academic curiosity; auroral currents play a crucial role in how energy from space is distributed throughout Earth's upper atmosphere. When these currents disperse, they heat the atmosphere, generate winds, and create turbulence that can impact satellites traversing that region.
Traditionally, researchers have relied on ground-based instruments to study auroras. NASA's EZIE satellite mission, set to launch in March 2025, will measure auroral electrical currents from an orbital perspective. By integrating satellite observations, ground imagery, and direct measurements from sounding rockets, scientists can analyze the system from multiple perspectives simultaneously.
"By combining in situ measurements with ground-based imagery, we can learn to interpret the aurora," Lynch noted.
Exploring Black Auroras and Current Reversals
The GNEISS rockets were not the only participants in this launch campaign. The Black and Diffuse Auroral Science Surveyor focused on intriguing dark regions within auroras, known as black auroras, which may indicate areas where electrical currents abruptly reverse direction.
This mission marked its second flight attempt after a previous effort in 2025 was delayed due to weather and scientific conditions. With this successful launch, researchers now possess new data to investigate how these enigmatic dark patches integrate into the broader auroral circuit.
Auroras emerge from the interaction between space and Earth's atmosphere, where electric currents, streams of charged particles, and countless collisions converge to create these stunning displays. Sounding rockets offer a rare chance to traverse directly through them, positioning instruments precisely where the action unfolds. Through brief yet meticulously timed missions, NASA is transforming fleeting flashes of light into profound insights about how space weather influences our planet's upper atmosphere.