NASA reported that rotor tips designed for next-generation Mars helicopters reached Mach 1.08 without breaking apart during ground tests at its Jet Propulsion Laboratory in California. The tests used a chamber that simulated Martian atmospheric conditions.
The agency reported a 30% increase in lift capability, which it said could support aircraft carrying heavier scientific instruments, sensors or batteries. Shannah Withrow-Maser, an aerodynamicist at NASA’s Ames Research Center and a member of the test team, said analysis of the data was continuing.
Testing rotors beyond the sound barrier
Mars’s atmosphere is about 1% as dense as Earth’s at sea level, making lift difficult to generate. Larger rotors and faster rotation can increase thrust, but engineers must account for how blades behave as their tips approach and exceed the speed of sound.
The campaign began with a three-bladed rotor design that could be used on future Mars missions. AeroVironment, which worked with JPL on Ingenuity, also participated in developing the new rotor hardware.
NASA said engineers installed the rotor in JPL’s 25-Foot Space Simulator, removed the air and introduced carbon dioxide to approximate the Martian atmosphere. They lined part of the chamber with sheet metal to protect it if the blades broke apart.
At 3,750 revolutions per minute, the rotor tips reached Mach 0.98. Engineers then used a fan to introduce headwinds, increasing wind velocity between runs. The additional airflow took the tips beyond the sonic threshold, reaching Mach 1.08, NASA said.
A second test series evaluated the two-bladed rotor intended for SkyFall. Its slightly longer blades reached comparable tip speeds at a lower rotational speed.
JPL rotor test lead Jaakko Karras said Ingenuity’s flights had been planned around rotor tip speeds of Mach 0.7 in still air, leaving a margin for headwinds that could increase the airflow speed at the tips.
Building on Ingenuity’s flights
Ingenuity demonstrated powered, controlled flight on another world and completed 72 flights before its mission ended in January 2024. Its original demonstration goal was five flights over 30 days.
The helicopter carried two cameras rather than dedicated science instruments and used the Perseverance rover as a communications relay. Future aircraft carrying additional instruments or larger batteries would require more lift.
NASA plans to send three next-generation helicopters to Mars through SkyFall. The mission is intended to travel aboard Space Reactor-1 Freedom, a spacecraft designed to demonstrate nuclear electric propulsion. NASA’s March 24 briefing set a December 2028 launch target; the mission architecture remained in development.
Steve Sinacore, program executive for NASA’s Space Reactors Office, said during the briefing that the planned helicopters would carry cameras and ground-penetrating radar. Their intended tasks include surveying slopes and hazards at a potential human landing site and mapping the location, size and depth of subsurface water-ice deposits.
A different environment from Titan
NASA is also developing Dragonfly, a larger rotorcraft bound for Saturn’s moon Titan. Titan’s dense atmosphere and low gravity favor powered flight, giving that mission a different aerodynamic environment from the thin air that constrains helicopter designs for Mars.
