NASA engineers at the Jet Propulsion Laboratory have completed crucial environmental testing on a featherweight, flexible radar antenna designed for the planned SkyFall Mars helicopter mission. The ultra-light apparatus, built to withstand extreme thermal swings and repeated landings, will enable low-flying autonomous aircraft to map subsurface ice.
Following the performance of the Ingenuity helicopter, space agency planners turned their attention toward more capable autonomous aircraft designed to search for resources like water on the Red Planet. That ambition takes physical shape in the proposed SkyFall mission, which is penciled in to launch in late 2028. The mission relies on a deployment aboard the Space Reactor-1 Freedom spacecraft, using elements derived from the discarded Lunar Gateway station to carry three autonomous helicopters to Mars.
Engineering a Featherweight Vivaldi Antenna for Martian Regolith
Equipping autonomous helicopters with ground-penetrating radar presents an immediate mechanical contradiction: the antenna must extend beyond the vehicle’s landing legs to capture useful data, yet it cannot interfere with touchdown or snap upon impact. To solve this challenge, engineers adapted an existing antenna design known as Vivaldi, scaling it down specifically for shallow surveying under 16 feet (5 meters) in dry Martian regolith.
Because the dry Martian soil blocks radio waves far less than Earth’s soil, the radar system could be heavily miniaturized. Even after downsizing, however, the antenna remained about one and a half times longer than the helicopter’s landing legs. This requires the structure to flex during landing and spring back into position for data collection once airborne.
“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
Materials and Environmental Testing at JPL
To protect the downsized Vivaldi array from structural fatigue, development teams sheathed the component in polyester followed by multiple layers of Vectran, a high-performance manufactured fiber used for the landing airbags that protected the Spirit and Opportunity rovers. Engineers further reinforced the assembly using flexible fiberglass tape springs and a lightweight magnesium mounting structure. The complete apparatus weighs roughly 5 ounces (150 grams), or slightly more than two violin bows.
Proving the hardware could survive Martian conditions required rigorous trials inside the Environmental Test Laboratory at the Jet Propulsion Laboratory. Technicians bent the antenna to simulate landing orientations and subjected the hardware to dramatic thermal cycles where daily temperatures swing by as much as 170 degrees Fahrenheit (94 degrees Celsius). The testing protocol paused six times to transfer the hardware to an electromagnetic test chamber, verifying that the repeated physical flexing and radiation exposure did not diminish its signal transmission or reception capabilities.
Mission Operations and Subsurface Mapping Objectives
When deployed, the three SkyFall aircraft will operate with more autonomy and investigative hardware than Ingenuity. While Ingenuity relied upon the Perseverance rover as a communications relay, SkyFall aircraft are designed to transmit collected information independently to spacecraft orbiting Mars.
Newly released artist concepts depict the green frequency waves from the flexible antennae gathering subsurface radar data, while red beams capture near-infrared imagery of crushed rock, dirt, and other surfaces. That proximity to the ground is the core requirement for detecting hidden water resources.
“The only way to detect shallow subsurface ice remotely is to fly close to the ground,”
Adrian Tang, SkyFall’s ground-penetrating radar lead instrument scientist
By executing low-altitude flights, a SkyFall helicopter can capture radar images that resolve fine geological layering where dry soil gives way to ice, allowing scientists to map its extent across the Martian landscape.
Uncertainties Surrounding the 2028 Schedule
Despite the successful clearance of recent antenna testing at the Jet Propulsion Laboratory, the timeline for the broader mission carries notable caveats. Because the mission relies on the fission reactor-powered Space Reactor-1 built around elements of the discarded Lunar Gateway station, scheduling remains subject to change. Even so, the engineering milestones achieved inside the test chambers ensure that the hardware itself is advancing independently of spacecraft deployment hurdles.
