Link here. This update, written by Bob Balaram, the helicopter’s chief engineer at JPL and Jeremy Tyler, senior aero/mechanical engineer at AeroVironment, outlines the engineering that went into building the helicopter’s legs in order to make sure they could withstand the somewhat hard landings required in the Martian environment.
To withstand these firm landings, Ingenuity is equipped with a cushy suspension system, [with a] distinctive open hoop structure at each corner of the fuselage where the landing legs attach. The lower half of this hoop is a titanium spring that can bend as much as 17 degrees to provide 3.5 inches of motion in the suspension, while the upper half is a soft non-alloyed aluminum flexure that serves as the damper or “shock absorber.” By plastically deforming and fatiguing as it absorbs energy, this flexure acts much like the crumple zone structure of a car chassis. However, unlike a car or the crumple-cushioned landing gear of the Apollo moon landers, Ingenuity’s titanium springs rebound after each impact to pull these aluminum dampers back into shape for the next landing.
The aluminum damper gets a little bit weaker with each cycle as cracks and creases develop. While it would eventually break after a few hundred hard landings, with only a few flights scheduled for this demonstration, that’s a problem we could only dream of having.
This is most likely the failure point that will end Ingenuity’s life, though at the present it is a bit in the future.
Also, the post reveals that JPL subcontracted much of the development of Ingenuity to this company.
AeroVironment designed and developed Ingenuity’s airframe and major subsystems, including its rotor, rotor blades, and hub and control mechanism hardware. The Simi Valley, California-based company also developed and built high-efficiency, lightweight propulsion motors, power electronics, landing gear, load-bearing structures and thermal enclosures for NASA/JPL’s avionics, sensors and software systems.
Good ol’ American capitalism does it again.