Mars helicopter needs patch to fly again after sensor failure

NASA engineers continue to show Ingenuity as uplinking process begins

The Mars Ingenuity helicopter is in need of a patch to work around a failed sensor before another flight can be attempted.

The helicopter's inclinometer failed during a recommissioning effort ahead of the 29th flight. The sensor is critical as it will reposition the craft nearer to the Perseverance rover for communication purposes.

Although not required during flight, the inclinometer (which consists of two accelerometers) is used to measure gravity prior to spin-up and takeoff. "The direction of the sensed gravity is used to determine how Ingenuity is oriented relative to the downward direction," said Håvard Grip, Ingenuity Mars Helicopter chief pilot.

Despite the experimental nature of Ingenuity, the helicopter has redundancies. It has accelerometers which, while not designed for sensing static orientation, can be used to estimate the initial attitude of the vehicle.

"We believe," wrote Grip, "an IMU-based initial attitude estimate will allow us to take off safely and thus provides an acceptable fallback that will allow Ingenuity to resume flying."

IMU stands for inertial measurement unit.

However, a patch is needed. Engineers anticipated this and the code is waiting for its time to shine. "The patch," according to Grip, "inserts a small code snippet into the software running on Ingenuity's flight computer, intercepting incoming garbage packets from the inclinometer and injecting replacement packets constructed from IMU data."

The process of uplinking it to the helicopter is already under way and time is of the essence. Ingenuity has endured far beyond expectations, but with shorter days and dropping power levels engineers are having to work around the helicopter shutting down overnight and exposing its electronics to lower temperatures than they were designed to survive.

The uplinking of the software patch is expected to be completed within the next few sols and commissioning shortly after. Once done, Ingenuity will be able to take to the skies once more for that crucial repositioning flight. ®

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