NASA chose not to re-install OS and live with a 15 percent failure rate Laura Dobberstein Fri 30 Apr 2021 // 08:15 UTC Share Software issues prevented the fourth scheduled flight of NASA's Mars Ingenuity helicopter. The delay was not unexpected nor prevents future flights. In fact, NASA re-assured a waiting world that the helicopter is "safe and in good health." The reason for the failure is also known: a software bug that results in a watchdog timer expiration prior to mode transition. And if Ingenuity doesn't make it into flight mode, it doesn't fly. NASA identified the bug two weeks ago and found two ways to solve the problem. One was to change the timing of the transition by adjusting the command sequence from Earth. The other was to modify and reinstall Ingenuity's existing flight control software.