Ingenuity’s last flight: an accident investigation

Ingenuity accident investigation conclusions
Click for original image.

Using all the data available, engineers at JPL have done a more detailed accident investigation into Ingenuity’s last flight on Mars on January 18, 2024, and are about to publish their report. Their conclusions however were published today by NASA, with the graphic to the right the main conclusion.

One of the navigation system’s main requirements was to provide velocity estimates that would enable the helicopter to land within a small envelope of vertical and horizontal velocities. Data sent down during Flight 72 shows that, around 20 seconds after takeoff, the navigation system couldn’t find enough surface features to track.

Photographs taken after the flight indicate the navigation errors created high horizontal velocities at touchdown. In the most likely scenario, the hard impact on the sand ripple’s slope caused Ingenuity to pitch and roll. The rapid attitude change resulted in loads on the fast-rotating rotor blades beyond their design limits, snapping all four of them off at their weakest point — about a third of the way from the tip. The damaged blades caused excessive vibration in the rotor system, ripping the remainder of one blade from its root and generating an excessive power demand that resulted in loss of communications.

The reason Ingenuity’s system couldn’t find enough features to track was because it was flying over a dune field, the ground almost all smooth sand. The only features were the soft changes of topography caused by the dunes, which were not small.

Not surprisingly, these same engineers are working on a larger drone-type helicopter for a future mission, dubbed Mars Chopper, which based on an short animation released by NASA, is the mission targeting Valles Mariner that I first described in June 2022. The investigation into Ingenuity’s failure will inform the design of Chopper.

Another Mars location being considered for future helicopter mission

Global overview of potential Mars helicopter missions

Floor of Degana Crater
Click for original picture.

In today’s May download of new photos from Mars Reconnaissnce Orbiter (MRO) I came across the picture to the right, reduced and sharpened to post here, and taken on April 2, 2024 by MRO’s high resolution camera. The scientists labeled it “Sample Rim Traverse Hazards at Possible Mars Helicopter Landing Site.” It was clearly taken as part of preliminary research to determine some potential landing sites for a future Mars helicopter mission.

Nor is this the first such location or region on Mars targeted for such a mission. As shown in the global map above of Mars, colored by the elevation data from MRO (blue is low and orange is high), two other candidate sites are being looked at as well. About a half dozen pictures have been taken inside the eastern end of Valles Marineris, exploring a helicopter mission there. In addition, MRO took for the same purpose a recent photo of the floor of Terby Crater, on the northern interior slope of Hellas Basin.
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NASA/ESA revise plan to recover Perseverance core samples from Mars

NASA and ESA yesterday announced that the agencies have revised their plan to recover Perseverance core samples from Mars, dropping the launch of a rover to pick up the samples.

Instead, they have decided to use Perseverance to bring the samples to the return vehicle, which will also carry two small helicopters.

In 2030, if all goes as planned, the NASA lander will touch down near where Perseverance is working. The rover will drive over to the lander, and an ESA-built robot arm will extract the tubes one by one and place them inside a spherical container the size of a basketball. In early 2031, a rocket on the lander will loft the container into Mars orbit, where a return craft built by ESA will snare it, enclose it in several layers of shielding for safety, and then head for home. In 2033, a saucer-shaped descent pod will carry the samples down to the Utah desert.

If Perseverance gets into difficulties during its 9-year wait for company, controllers can instruct it to drop its cargo of sample tubes onto the ground, creating a second depot. If that happens, the helicopters come into play: they can fly up to 700 meters, land next to a sample tube—each weighs up to 150 grams—and, with wheels on the bottom their feet, roll over the tube and pick it up with a grabber. On returning to the lander, they will drop the tubes on the ground for the arm to pick up.

The change means that the rover the United Kingdom was planning to build will either be abandoned, or repurposed as a lunar rover.