HALE InSAR flies aboard a high-altitude balloon during a test-flight. This lightweight instrument will help researchers measure ground deformation and dynamic Earth systems.
A collaboration between NASA and small aerospace company Aloft Sensing has produced a compact radar system capable of detecting minute changes in Earth’s surface.
The instrument, called HALE InSAR, is small, lightweight, and consumes less than 300 watts—roughly the power of an electric bike—yet can track millimeter-scale deformations in terrain, snowpacks, and volcanoes.
What sets HALE InSAR apart is its ability to operate without GPS, using advanced positioning algorithms to locate itself with unprecedented accuracy.
“SAR is like a long-exposure camera, except with radio waves,” explained Brian Pollard, Chief Engineer at Aloft Sensing. “Precise positioning is critical, or your image smears.”
Flying high for science
HALE InSAR rides aboard high-altitude, long-endurance (HALE) platforms—lightweight aircraft designed to stay aloft for weeks, months, or even years. These vehicles can revisit the same location multiple times per hour, making them ideal for monitoring subtle changes in Earth’s geologic environment.
Interferometric Synthetic Aperture Radar (InSAR), the technology behind the system, compares repeated radar images to detect surface shifts.
Traditional InSAR instruments are too large for HALE vehicles, but HALE InSAR weighs under 15 pounds and features a flat phased-array antenna.
This allows operators to steer the radar beam electronically, eliminating bulky gimbals and other heavy components.
By tracking millimeter-scale shifts, HALE InSAR could provide early warnings for natural disasters like volcanic eruptions or landslides.
Its GPS-free navigation also makes it suitable for remote locations, increasing its utility for national security and scientific missions alike.
Lauren Wye, CEO of Aloft Sensing, highlighted the instrument’s advantages: “It’s a level of sensitivity that has eluded traditional radar sensors, without making them bulky or expensive. This technology has huge benefits for science and civil applications.”
From balloons to space
HALE InSAR has already been validated on airships flying at 65,000 feet and on small stratospheric balloons.
Next, the team plans to test it aboard fixed-wing HALE aircraft. In the future, the instrument could even be deployed on small satellites in low Earth orbit, expanding its reach beyond the stratosphere.
The project was made possible through NASA’s Earth Science Technology Office (ESTO), with previous funding supporting its novel electronically steered antenna and agile software-defined transceiver.
This “hand-in-hand” approach has allowed Aloft Sensing, a small business, to bring a prototype to a proven instrument, attracting both civil and military interest.
HALE InSAR represents a leap forward in compact radar technology, merging high-altitude endurance, GPS-independent positioning, and millimeter-scale precision.
For researchers and agencies monitoring Earth’s dynamic systems, this small but mighty radar could change how we watch our planet in real time.