NASA has completed its investigation into the first crash of an aircraft on another planet.

NASA announced today that the investigation into the accident with the Mars helicopter Ingenuity has been completed. On January 18, 2024, the helicopter took off to assess its position on the ground, which became its 72nd flight, and soon lost contact. A few days later it became clear that he had damaged the blades. How this could have happened became clear after a thorough reconstruction of the incident.

Image source: NASA

In a few weeks, perhaps around the anniversary of Ingenuity’s last flight, NASA will release a full technical documentation package to investigate the accident. The investigation was carried out jointly with one of the helicopter developers, AeroVironment. Investigators did not have the opportunity to interview witnesses or visit the accident site – it is separated from the Earth by outer space by more than 160 million km. It was necessary to reconstruct the course of events and consequences using modest photographs from the helicopter’s black-and-white on-board navigation camera, guided by logic and engineering skills.

Apparently the following happened. On its 72nd flight, the helicopter had to rise vertically to a height of 12 m. This was necessary both to evaluate the Ingenuity avionics and for navigation surveying of the area. The helicopter rose to a predetermined altitude, hovered and took a series of photographs. He began his descent after 19 seconds, and after 32 seconds he returned to the surface, and communication was lost.

A day later, the NASA team restored communication and was able to obtain pictures and video from the helicopter. Images showed that the rotor blades were severely damaged.

Helicopter and broken blade far to the side (left)

«When you’re investigating an accident 100 million miles away, you don’t have black boxes or witnesses,” said Ingenuity first pilot Havard Grip of JPL. “While a variety of scenarios are possible given the available data, we have one that we believe is most likely: due to the lack of surface texture, the navigation system received too little information to operate.”

The helicopter’s visual navigation system was designed to track visible surface features using a downward-facing camera. At the site where the rover and helicopter descended into the Jezero Crater, there was just such a well-textured (pebble) flat terrain. This tracking capability was more than enough to carry out Ingenuity’s planned five science flights, but by the 72nd flight the helicopter found itself in the Jezero Crater region, where there are many large boulders and a completely featureless sandy surface dominates.

During the 72nd flight, the helicopter’s navigation system was unable to understand the textures and incorrectly estimated the vertical and horizontal speed. This led to an increase in horizontal speed at the moment of touching the surface of Mars during landing. The result was a blow to the sand, which broke the tips of the blades by about a third of the ends. After this, increasing vibrations of the rotor arose, and one of the blades broke at the base and flew off 15 m. This led to an increase in the number of revolutions and a jump in power consumption, which cut off communication with the rover and the Earth.

Everything that happened causes disappointment, but is many times overshadowed by the achievements of the mission. Instead of five planned flights, the helicopter made 72, spending more than two hours in the Martian atmosphere. Moreover, the Ingenuity platform and avionics have shown that even in the harsh conditions of Mars with its cold and increased radiation, simple and easy solutions can be effective. Let us remember that the helicopter’s electronics were based on a processor from a regular smartphone. All this allows us to design future aircraft for Mars, taking into account the enormous experience gained from operating Ingenuity.

By the way, such a project is already being developed. It will be a helicopter with the working title Mars Chopper. As planned, Chopper will be approximately 20 times heavier than Ingenuity and will be able to transport several kilograms of scientific equipment, as well as autonomously explore remote Martian locations, covering distances of up to 3 km per day (Ingenuity’s longest flight was 704 m).

The Ingenuity helicopter, although it has remained permanently laid up, The Ingenuity helicopter, although it has remained permanently laid up, continues to collect weather data from its home area and transmits it to the rover. Information about the weather on Mars will never be superfluous.