Loads and Stresses on the Mars Helicopter Ingenuity Rotor

The aeroelastic loads, stability and stresses on the Mars Helicopter rotor were predicted with a special-purpose three-dimensional rotor structural dynamic analysis. This paper documents that analysis and the insights gained from it. The thin and cold Martian atmosphere, with density 1% of Earth and speed of sound 30% lower, produced sufficient lift but unusually challenging dynamics even with one third the gravity of Earth. The aeroelastic stability was positive but low-about 10-50 times lower than Earth. The stresses and strains on the 57#x25; thin carbon fiber blades were unsteady, complex, and three-dimensional, but within material limits. The key conclusion was that the Ingenuity rotor was structurally stable and safe for Martian hover and controlled forward flight, even at the lowest Reynolds number and highest Mach number anticipated on Mars. Fundamental gaps remained in basic knowledge and tools which must be addressed for larger more capable rotorcraft of the future.