NASA engineers at the Jet Propulsion Laboratory have tested a flexible, violin-shaped Vivaldi radar antenna designed for the Mars SkyFall mission, successfully surviving 200 simulated landings in an electromagnetic testing chamber ahead of a planned late 2028 launch.
Engineers clearing hardware milestones for upcoming Martian exploration face an unusual geometry problem: how to carry a ground-penetrating radar system on a mini-helicopter that sits mere inches off the ground. NASA’s Jet Propulsion Laboratory tackled this by developing a specialized antenna that looks like a tiny cape worn by the robotic drones, designed specifically to peer beneath the Martian surface in search of water ice.
Testing the Vivaldi Antenna Through 200 Mars Landings
The SkyFall mission will deploy a trio of rotorcraft based heavily on the Ingenuity-class helicopters, which completed 72 flights over nearly three years. Each SkyFall helicopter will carry four instruments, including a ground-penetrating radar system intended to locate shallow subsurface ice. Orbital spacecraft have studied Mars for decades, but their instruments remain blind to the uppermost few feet of regolith—the crucial zone where future astronauts will need to access water ice for drinking water, oxygen, and rocket propellant without heavy industrial drilling.
To reach that depth, the radar requires an ultra-wide frequency band spanning 500 to 2,500 megahertz, covering wavelengths from roughly 5 to 24 inches. A conventional rigid antenna covering that range would need to be roughly 19 inches long. However, each SkyFall helicopter rests only about 6 inches above the Martian surface at rest, meaning any rigid structure would break upon landing. To solve this, engineers utilized a design invented by engineer Peter Gibson in 1979 known as the Vivaldi antenna.
“The only way to detect shallow subsurface ice remotely is to fly close to the ground,” said Adrian Tang, SkyFall’s ground-penetrating radar lead instrument scientist at JPL. “By flying low and slow, a SkyFall helicopter could capture radar images that resolve the fine layering where dry soil gives way to ice, detecting its presence and mapping its extent.”
Adrian Tang, SkyFall’s ground-penetrating radar lead instrument scientist at JPL
To ensure the hardware could withstand repeated impacts on a rocky alien surface, the JPL team placed the antenna through an exhaustive testing campaign inside the Environmental Test Laboratory’s electromagnetic interference testing chamber. Engineers bent and flexed the structure repeatedly, subjecting it to extreme temperatures while continually verifying that the radar could still transmit and receive signals. The antenna survived 200 simulated Mars landings—more than double the number required for a successful prime mission—without any measurable loss of performance.
Miniaturization and Materials Engineering for the Red Planet
Scaling down the Vivaldi antenna required exploiting a unique physical property of the Martian environment. Because dry Martian regolith conducts electricity far less effectively than Earth soil, radar waves penetrate far more easily without rapid attenuation. This allowed engineers to shrink the antenna while preserving its target depth sensitivity between 1.6 and 10 feet below the surface.
The resulting hardware is exceptionally light, weighing a mere 5 ounces. The antenna is stitched from flexible metallic fabric covered in layers of polyester and Vectran—the same strong material used for the airbags that cushioned the Spirit and Opportunity rovers during their 2004 touchdowns. Flexible fiberglass tape springs reinforce its shape.
“Although we managed to shrink the antenna quite a bit, it is about 1.5 times longer than the helicopter’s legs. That means during landing, the Vivaldi has to bend out of the way — and if it lands on a rock, it bends even further. But when the helicopter takes off again, the antenna must spring back into place for data collection. Because SkyFall is expected to make dozens of flights exploring Mars, we needed an antenna that could repeatedly handle those pressures without losing its shape in flight.”
Christine Gebara, SkyFall ground-penetrating radar mechanical lead at JPL
Launch Timeline and Future Exploration Context
Maya Román, a SkyFall ground-penetrating radar engineer, connected coaxial cables during recent electromagnetic compatibility evaluations in Southern California, where testing chambers were configured to minimize environmental interferences. The mission itself is expected to launch aboard NASA’s Space Reactor-1 Freedom in late 2028.
By following in the exploratory path carved by Ingenuity, the three SkyFall aircraft aim to provide the Perseverance rover team and future human missions with precise mapping data for safe landing sites and accessible resources.
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