NASA’s Ingenuity Mars helicopter rests on the sand dunes of the Red Planet’s surface following a crash on its last flight in January. Credit: NASA/Jet Propulsion Laboratory-Caltech/LANL/CNES/CNRS
The National Transportation Safety Board (NTSB) and the FAA oversee investigations of aviation accidents in U.S. airspace. But what happens when an accident occurs hundreds of millions of kilometers away in space?
Engineers at NASA’s Jet Propulsion Laboratory (JPL) in California and unmanned aerial systems (UAS) manufacturer Aerovironment, a major aerospace and defense contractor, are conducting what the space agency said Wednesday is the first investigation into plane crashes on another world. Staff are reviewing the final flight of NASA’s Ingenuity Mars helicopter, which crashed on the surface of the Red Planet and was retired in January.
Designed to perform five experimental test flights over the course of a month, Ingenuity ultimately flew 72 missions over three years of operation, covering 30 times more ground than expected. Now, NASA knows what caused the project to end.
A Martian helicopter
Tethered beneath NASA’s Mars Perseverance rover, Ingenuity launched towards the Red Planet in July 2020 and made its maiden voyage the following April, becoming the first aircraft to fly under its own engines on another planet. The “Wright Brothers moment” kicked off a campaign that exceeded the space agency’s wildest expectations.
The battery-powered rotorcraft weighs about 4 pounds on Earth but only 1.5 pounds on Mars due to the planet’s thin atmosphere. Flying in those conditions was expected to be challenging: Ingenuity had a projected range of 980 feet and a flight altitude of just 15 feet. In April 2022, however, the plane set an extraplanetary distance record by covering 2,000 feet at 12 miles per hour. On a different flight, it reached a maximum altitude of about 79 feet.
Undoubtedly, Ingenuity outperformed. But he eventually returned to Mars.
Flight 72 was intended as a vertical “pop-up” flight to test the rotorcraft’s systems and take photos of Mars’ Jezero Crater. As it descended from an altitude of about 40 feet, however, NASA lost contact with the Perseverance rover, which was transmitting communications to mission control. When communications were restored, images showed “severe damage” to Ingenuity’s rotor blades.
Without the assistance of investigators on site or live footage of the accident, NASA was unable to determine what went wrong. Using what little information the space agency has, however, engineers believe they have pieced together a timeline.
“When you do an accident investigation from 100 million miles away, you don’t have black boxes or eyewitnesses,” said NASA JPL’s Håvard Grip, Ingenuity’s lead pilot. “Although several scenarios are viable with the available data, we have one that we think is most likely: the lack of surface structure gave the navigation system too little information to work with.”
What went wrong
Investigators believe Ingenuity’s visual navigation system, used to help the helicopter track the landscape below and identify safe landing areas, malfunctioned, causing a “chain of events” that led to the crash.
The navigation system used a downward-facing camera to help Ingenuity fly over flat terrain, and was sufficient for the helicopter’s five planned missions, according to NASA. But on Flight 72, he had reached a section of Jezero Crater characterized by “steep, relatively featureless sand undulations.” The navigation system tracked surface features to help Ingenuity adjust its speed for landing. But according to data analyzed by NASA engineers, it had no more features to track.
Based on photos of the helicopter after the flight, researchers theorize that it crashed into the crater’s sandy slope at high speed, causing its blades to break off. The damage created vibrations that broke one of the blades at the root and the resulting demand for energy on the other blades caused a communications blackout.
Although Ingenuity is on the ground, the helicopter continues to transmit data from the Martian surface to NASA about once a week. Avionics data, for example, is helping engineers develop smaller, lighter avionics that could be integrated onto vehicles that will bring back samples from Mars.
Ingenuity alumni are also researching a much larger version of the Mars helicopter called the Mars Chopper. The concept design is approximately 20 times larger than its predecessor and would be capable of carrying several kilos of equipment. Its projected range – about 2 miles – would be more than four times longer than Ingenuity’s longest flight.
“Because Ingenuity was designed to be affordable while requiring massive amounts of computer power, we became the first mission to fly commercially available cellular processors into deep space,” said JPL’s Teddy Tzanetos, Ingenuity’s project manager and one of the leader on the Mars Chopper. “We are approaching four years of continuous operations, suggesting that not everything needs to be bigger, heavier and more radiation-hardened to function in the harsh Martian environment.”
FAA and NTSB accident investigations are critical to improving the safety of U.S. airspace. Likewise, NASA’s investigation into otherworldly incidents could help future engineers develop the technology the space agency needs to explore for the benefit of humanity.
Editor’s Note: This article first appeared on Fly.
