Next-gen Mars helicopter rotor blades exceed Mach 1 - Phys.org

1. Next-gen Mars helicopter rotor blades exceed Mach 1  Phys.org
2. NASA Pushes Next-Gen Mars Helicopter Rotor Blades Past Mach 1  NASA (.gov)
3. Engineers at NASA's Jet Propulsion Lab make a breakthrough in rotor technology  Ars Technica
4. Are Interstellar Helicopters Possible?  Avi Loeb – Medium
5. SkyFall helicopter for Mars breaks the sound barrier  Universe Space Tech