NASA is finishing its first off-world accident report

NASA is about to publish the world’s first off-world aircraft accident investigation. Aside from making history, the report will help the agency plan ahead for the next generation of flying vehicles that will help humanity explore Mars.

NASA engineers only intended the Mars Perseverance Rover’s Ingenuity helicopter to complete a maximum of five experimental test flights over 30 days in 2021. The experimental vehicle, however, proved much more durable than expected. Over nearly three more years, Ingenuity ultimately flew 72 more times, racking up more than two hours of aerial travel and traveling 30 times farther than planned.

[Related: RIP Mars Ingenuity, the ‘little helicopter that could’]

The rotorcraft’s flying career ended on January 18, 2024, however, when a botched landing appeared to fatally damage its blades. But what caused Ingenuity to miscalculate its 72nd flight remained a mystery to NASA. Since then, a collaborative research team from the Jet Propulsion Laboratory (JPL) and AeroVironment have spent months analyzing the available evidence and data.

“When running an accident investigation from 100 million miles away, you don’t have any black boxes or eyewitnesses,” Ingenuity’s first pilot, Håvard Grip, said in the JPL’s December 10th report announcement.

Grip explained that, while there are now multiple possible scenarios given the data, the team believes one explanation is the likeliest for Ingenuity’s landing failure: The aircraft navigation system couldn’t properly calculate its flight trajectory from the sparse information provided by its camera while traveling over relatively smooth Martian ground.

As JPL explains, the reviewed data indicates the helicopter’s navigation system began to lack enough trackable surface attributes roughly 20 seconds after takeoff.  Subsequent photographic analysis suggests Ingenuity’s computer errors generated a high horizontal velocity that exceeded the design limits of its rotor blades. This caused all four blades to snap at their weakest points, while the resulting vibrations tore the remainder of one blade from the copter. It then rolled across the sands after crashing on Mars as an excessive onboard power demand downed Ingenuity’s communications array for roughly six days.

In a sense, Ingenuity’s demise is also a testament to its resiliency. NASA never expected the helicopter to travel as far as that particular area in Jezero Crater on January 18th. Instead of traveling over a rocky terrain covered in plenty of visual coordinating cues as originally designed, Ingenuity was forced to attempt handling a region with steep and comparatively featureless sand ripples.

Despite all this, Ingenuity isn’t totally dead. Since engineers helped reestablish a link from Earth, the downed helicopter’s computer regularly transmits avionics and weather data to the Perseverance rover—information that may help human astronauts one day reach Mars.

In the meantime, NASA is using all this knowledge to plan for future Mars aerial vehicles, some of which may be as much as 20 times heavier than Ingenuity. On December 11th, team members previewed the Mars Chopper rotorcraft project, which would be capable of transporting several pounds of equipment while also autonomously exploring as much as 2 miles Mars per day. For comparison, Ingenuity traveled about 2,310 feet on its longest flight.

But scaling up isn’t always necessary. Aside from the Mars Chopper, engineers are also working on designs for vehicles that are smaller and lighter craft than Ingenuity’s four-pound, 19-inch-tall frame. According to Ingenuity project manager Teddy Tzanetos, the aircraft’s lifespan and accomplishments shows just how tough tiny packages can be on Mars.

“We’re now approaching four years of continuous operations, suggesting that not everything needs to be bigger, heavier, and radiation-hardened to work in the harsh Martian environment,” he said.