STATUS UPDATES | May 27, 2021
Surviving an In-Flight Anomaly: What Happened on Ingenuity’s Sixth Flight
“On the 91st Martian day, or sol, of NASA’s Mars 2020 Perseverance rover mission, the Ingenuity Mars Helicopter performed its sixth flight. The flight was designed to expand the flight envelope and demonstrate aerial-imaging capabilities by taking stereo images of a region of interest to the west. Ingenuity was commanded to climb to an altitude of 10 meters before translating 150 meters to the southwest at a ground speed of 4 meters per second. At that point, it was to translate 15 meters to the south while taking images toward the west, then fly another 50 meters northeast and land.”
“Telemetry from Flight Six shows that the first 150-meter leg of the flight went off without a hitch. But toward the end of that leg, something happened: Ingenuity began adjusting its velocity and tilting back and forth in an oscillating pattern”.
The oscillations seem to be caused by the interaction between the helicopter’s navcam and the velocity. When the navcam was swiched off for landing the oscillations stopped. ie. a feedback loop problem.
“Approximately 54 seconds into the flight, a glitch occurred in the pipeline of images being delivered by the navigation camera. This glitch caused a single image to be lost, but more importantly, it resulted in all later navigation images being delivered with inaccurate timestamps. From this point on, each time the navigation algorithm performed a correction based on a navigation image, it was operating on the basis of incorrect information about when the image was taken. The resulting inconsistencies significantly degraded the information used to fly the helicopter, leading to estimates being constantly “corrected” to account for phantom errors. Large oscillations ensued.”
“Despite encountering this anomaly, Ingenuity was able to maintain flight and land safely”.
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