Engineers at NASA's Jet Propulsion Laboratory (JPL) and AeroVironment are conducting a detailed investigation into the last flight mission of the "Ingenuity" Mars helicopter on January 18, 2024, and will release the first technical report on flight accidents occurring on other planets in the next few weeks.
Caption: A photo taken by Perseverance on February 24, 2024. The Ingenuity Mars helicopter (right) stands near the top of the ripples in the sand, with part of the rotor blades 15 meters away (left). Source: NASA/JPL-Caltech/LANL/CNES/CNRS
Ingenuity was the first aircraft to fly on another planet. It was originally designed to conduct up to five flight experiments in 30 days. However, Ingenuity worked for nearly three years and carried out 72 flights, flying 30 times farther than originally planned and accumulating flight time of more than two hours.
The investigation results indicate that the inability of the Ingenuity's navigation system to provide accurate data during flight may be the main cause of the accident. The 72nd flight plan was a simple vertical ascent to check the status of the Ingenuity's flight system and take pictures of the area. Flight data showed that the Ingenuity ascended to a height of 12 meters, hovered and took photos, began to descend after 19 seconds, and returned to the ground and stopped communicating 32 seconds later. The next day, the mission team restored communications and found in the returned pictures that the blades of the Ingenuity's rotor had suffered severe damage.
Video: Video taken by Ingenuity using a black-and-white navigation camera on February 11, 2024. The video shows the shadow of the rotor blades, which were confirmed to have been damaged during the 72nd flight. Source: NASA/JPL-Caltech
Håvard Grip, the first pilot of the Ingenuity mission, said: "There are no black boxes and no witnesses to investigate an accident 100 million miles away, but we think the most likely cause is the lack of surface texture that lacks sufficient information for the navigation system." Ingenuity's navigation system uses downward-shooting cameras to track features on the surface. This works well in flat pebble terrain, but by the 72nd flight Ingenuity was already in the Jezero impact crater, which is full of steep, relatively featureless sand terrain. Flight data showed that about 20 seconds after takeoff, the navigation system was unable to find enough surface features to track, and the error resulted in high levels of speed during landing. The Ingenuity may have made a hard landing on the sand, causing the fuselage to tilt and roll. The rapid attitude change overloaded the high-speed rotating rotor blades, causing the four blades to break at their weakest point about one-third from the blade tip. The damaged blade caused excessive vibration in the rotor system, tearing off the root of one blade and creating excessive power demands that disrupted communications.
Caption: The Ingenuity Mars Helicopter made its 72nd flight on January 18, 2024. The excessive landing horizontal speed caused the impact to tilt the fuselage and damage the rotor blades. Source: NASA/JPL-Caltech
Although the accident on Flight 72 prevented Ingenuity from flying again, the helicopter continued to transmit weather and avionics test data to the Perseverance rover on a weekly basis. This weather data will be of great help in designing future Mars spacecraft and rovers. Because Ingenuity was designed to be small, affordable, and capable of handling massive amounts of calculations, and proving that not everything needs to be bigger, heavier, and radiation-proof to operate long-term in the harsh environment of Mars, NASA engineers have now been testing lighter avionics that could potentially be used in the Mars sample return program. (Compiled by Wang Tingxuan)
Video: Ingenuity’s successor mission to Mars, MarsChopper, is still in conceptual design stage. In addition to reconnaissance, the helicopter can carry scientific instruments to study remote areas that cannot be reached by rovers, and can fly up to 2 miles (3 kilometers) in a day.