NASA’s upcoming SkyFall trio of Mars helicopters, scheduled for a late 2028 launch aboard Space Reactor-1 Freedom, will feature a revolutionary, ultra-lightweight Vivaldi antenna made of fabric to detect shallow subsurface ice beneath Martian regolith from low-altitude flights.
While NASA’s Ingenuity helicopter proved that powered flight is possible in the thin Martian atmosphere, the next generation of aerial explorers has an entirely different scientific target. Set to deploy for Mars in December 2028, the three SkyFall helicopters will actively scout for water ice at candidate landing sites for future crewed missions. Water remains the single heaviest resource required for human exploration, essential for both life support and rocket propellant production. Because orbital instruments cannot resolve shallow subsurface deposits at the necessary scale, engineers at NASA’s Jet Propulsion Laboratory faced a difficult design hurdle: building a radar antenna capable of scanning across an ultra-wide frequency band while fitting within the tight spatial constraints of a low-flying aircraft.
Engineering a Fabric Antenna for Low-Altitude Mars Radar
To map water ice buried within the top few meters of regolith, SkyFall’s ground-penetrating radar operates across a broad frequency range from 500 to 2,500 megahertz. The longest wavelengths in this spectrum penetrate several yards beneath the surface, while the shorter wavelengths reveal fine details about upper soil layers. Traditionally, operating in this electromagnetic band requires an antenna measuring roughly 48 centimeters, or 19 inches, with an unobstructed view of the ground.
The engineering challenge lay in the geometry. The minimum clearance between the helicopter fuselage and the Martian surface is only about six inches. A rigid antenna of that length would inevitably strike the ground or interfere with landings. To solve this, JPL engineers developed a downsized Vivaldi antenna—a flat, curvilinear design resembling back-to-back curved blades—weighing a mere 150 grams, roughly equivalent to two violin bows.
“Although we managed to shrink the antenna quite a bit, it is about 1½ 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.”
Christine Gebara, SkyFall ground-penetrating radar mechanical lead at JPL
To withstand repeated bending during dozens of planned flights, the antenna features a polyester sheath, outer layers of Vectran—the high-performance fiber historically used for landing airbags on the Spirit and Opportunity rovers—flexible fiberglass tape springs, and a lightweight magnesium mounting structure. The hardware recently cleared rigorous testing at the Environmental Test Laboratory at JPL, where engineers subjected prototypes to simulated day-night temperature swings, extreme mechanical flexing, and electromagnetic chambers to ensure signal performance remained steady.
Flight Profile, Instruments, and the Daring Mid-Air Deployment
The mission profile for SkyFall introduces unique operational steps compared to its predecessor. Unlike Ingenuity, which relied on the Perseverance rover as a communication relay, each SkyFall helicopter will independently transmit collected data directly to spacecraft orbiting Mars. Furthermore, NASA plans a daring mid-air deployment where the three aircraft launch directly from the descending spacecraft rather than touching down first.
This deployment strategy requires the fabric antennas to remain stowed during the initial drop and unfurl automatically once airborne. Each of the three helicopters will carry four distinct instruments to conduct comprehensive reconnaissance.
| Frequency / Instrument | Wavelength | Data Collected |
|---|---|---|
| Subsurface Radar (Longest) | About 60 cm | Penetrates several yards below the surface |
| Subsurface Radar (Shortest) | About 12 cm | Provides fine detail on upper layers and surface texture |
| Near-Infrared / Visible Light | Optical / IR Beams | Maps crushed rock, dirt, and surface temperature monitoring |
Artist concepts released by the agency depict the helicopters scanning the Martian terrain, with green frequency waves illustrating subsurface radar data collection and red beams showing near-infrared imagery capture.
“The only way to detect shallow subsurface ice remotely is to fly close to the ground, 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
Mission Timeline and Remaining Site Decisions
With antenna testing successfully wrapped up this month, the program is moving forward toward its official launch window. SkyFall is scheduled to depart Earth in December 2028 aboard Space Reactor-1 Freedom, with arrival at the Red Planet expected in 2030.
While engineering hurdles regarding the landing gear clearance and antenna flexibility have been resolved, formal landing site selection remains ongoing. Mission planners are targeting flat, low-elevation terrain free of major geological hazards, prioritizing regions where shallow water ice deposits fall within or near the planned landing ellipse.
