Facts and/or assumptions:
• The #MarsHelicopter flew to an altitude of 12m
• At that altitude of 12m, it hovered for a while, sending telemetry
• It started looking for a clear spot to land
• After selecting the best spot for landing, it started its descent as usual
• During the descent, communication with #Perseverance was lost.

Other (almost) facts:
• Whatever was that caused the failure (mechanical, electrical or electronic), all rotor blades had their tips sheared while one of them

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detached from the assembly and flew 13-14m to the SW, bouncing once before it stopped.
• The elevation difference between the location of the helicopter and the broken off blade appears to be less than 0.5m, from the #USGS 1m DTM.
• It takes 0.37s for a body to drop 0.5m under the 3.72m/s² of Martian gravity. The initial velocity for a projectile to travel 13m in 0.37s would be ~35.5 m/s, without taking into consideration friction in the thin Martian air. If friction is to be considered for

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a very lightweight object with large surface, like the broken off part of #Ingenuity's blade, then the initial velocity should be significantly higher to cover the same distance.
• If however the blade broke off at a, let's say, 3m altitude, then the initial velocity would be ~14.5 m/s, which is much more logical, considering that a significant amount of kinetic energy would have been consumed by the tip of the blades being sheared before flying away, either by hitting the ground or by

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disintegrating in mid air. From a 12m altitude, which was the planned altitude for #Flight72, the initial velocity would need to be only 7.23 m/s.
• The fact that the ejected blade appears to have bounced only once and came to a stop a short distance away from the point of impact suggests that its velocity when it bounced was not high.

All the above appear to suggest that the failure occurred at a higher altitude rather than on the ground. The fact that NASA knows it

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lost communications *before* touchdown, as well as that there are no visible marks on the regolith, other than those probably made by the copter's feet (see https://mastodon.social/@65dBnoise/111992357079999905), seems to support this hypothesis. Is it the only possible explanation? Probably not. But it appears to me to be the most plausible one.

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#MarsHelicopter #Ingenuity #Mars2020 #NASA #Solarocks #Space