The Ingenuity Mars helicopter, a pioneering project of NASA's Jet Propulsion Laboratory (JPL), met an unexpected end earlier this year. Following an extensive investigation, project engineers have determined the cause of the crash during its 72nd and final flight.

At the American Geophysical Union's annual meeting on December 11th, JPL leaders detailed their findings, which they termed "the first aircraft accident investigation on another world". The consensus points to a failure of the navigation system, specifically its struggle with the visually monotonous terrain.

“The root cause of this was degraded navigation due to visually bland terrain, possibly in combination with high local slopes,” explained Håvard Grip, chief pilot for the first half of Ingenuity’s mission at JPL. The helicopter relied on a downward-facing camera to identify surface features, a method that proved reliable on earlier flights over more varied terrain.

However, the region where the crash occurred was characterized by sand ripples, offering insufficient features for the navigation system to reliably track. While Flight 70 showed initial signs of navigation difficulty, Flight 71 resulted in an emergency landing with a horizontal velocity five times the design limit. Although the helicopter seemed undamaged after Flight 71, the subsequent "pop-up" Flight 72 ended in another hard landing.

Initial speculation focused on rotor contact with the surface, but further analysis revealed the blades were damaged by bending loads upon landing. The resulting damage, breaking off about one-third of the way from the blade tips, suggests similar loads affected all four blades, indicating a structural weakness.

The investigation generated several recommendations, including improvements to navigation systems for handling featureless terrain and more robust telemetry handling. These findings and experience from Ingenuity are crucial for future Mars exploration.

Looking ahead, Teddy Tzanetos, Ingenuity project manager, presented the Mars Chopper concept—a significantly larger helicopter with six rotor sets, capable of carrying a 5kg payload and covering substantial distances. While currently a concept, it highlights the potential for advanced aerial exploration on Mars.

Despite the crash, Ingenuity continues to serve as a functional weather station, collecting and transmitting data via Perseverance. This capability could last up to 20 years, exceeding initial expectations. The ongoing data transmission, though nearing an end due to Perseverance's trajectory, underscores the remarkable resilience of the helicopter.