In short :

> NASA engineers are assessing the data, since it's not yet clear what caused the failure. One potential cause is a software issue that first showed up during a high-speed spin test ahead of the chopper's first flight. That test failed because Ingenuity's flight computer was unable to transition from "pre-flight" to "flight" mode. Within a few days, though, NASA engineers resolved the issue with a quick software rewrite.

> But those engineers determined that their fix would only successfully transition the helicopter into flight mode 85% of the time. So Thursday's attempt may have fallen into the 15% of instances in which it doesn't work.