Things are getting challenging for the Ingenuity helicopter on Mars. The latest news from Håvard Grip, its chief pilot, is that the “Little Chopper that Could” has lost its sense of direction thanks to a failed instrument. Never mind that it was designed to make only a few flights, mostly in Mars spring. Or that it’s having a hard time staying warm now that winter is coming. Now, one of its navigation sensors, called an inclinometer, has stopped working. It’s not the end of the world, though. “A nonworking navigation sensor sounds like a big deal – and it is – but it’s not necessarily an end to our flying at Mars,” Grip wrote on the Mars Helicopter blog on June 6. It turns out that the controllers have options.
It’s Not Dead, Yet
Like other NASA planetary missions, Ingenuity sports a fair amount of redundancy in its systems. It has an inertial measurement unit (IMU) that measures accelerations and angular rates of ascent and descent in three directions. In addition, there’s a laser rangefinder that measures the distance to the ground. Finally, the chopper has a navigation camera. It gives visual evidence of where Ingenuity is during flight or on the ground. An algorithm takes data from these instruments and uses it during flight. But, it needs to know the chopper’s roll and pitch attitude, and that’s what the inclinometer supplies.
Since it failed, the team had to find a way to impersonate the inclinometer. So, they applied a software patch to the code running on Ingenuity’s flight computer. It intercepts what Grip describes as “garbage packets” of data and replaces them with good data. Essentially, the flight controllers tricked the copter’s navigation algorithms into thinking that the data they have came from the inclinometer.
Amazingly, the flight team anticipated that some problem like this might arise and wrote the software patch ahead of time. Now they’re applying and testing it to make sure that the patch will do what it’s supposed to do. If it works, in a few sols, Ingenuity could be flying again, rising up to the Martian skies for Flight 29.
Ingenuity Facing Challenges
This isn’t the first problem Ingenuity has encountered lately. Early in May, the team members lost contact with it for two days (May 3 and 4). They figured out Ingenuity’s battery wasn’t charging as it should. With Martian winter coming on, that could affect the operations of the chopper. Ingenuity needs electricity to keep its electronics warm to survive the cold months. (Just to give you an idea, average temps on Mars during winter can drop as far as -125 Celsius, or -195 F.)
Based on those temps, there’s a good argument made for keeping Ingenuity down and “asleep” for a few months. However, that only works if the team can keep it warm. That’s going to be a big challenge. On top of that, the panel itself is getting coated with dust. The dust layer reduces the amount of electricity available for warming operations.
Mars Winds Play a Role
It turns out that Jezero Crater has some pretty intense windstorms. The Perseverance rover’s weather sensors have recorded daily whirlwinds that kick up a tremendous amount of dust. At least four whirlwinds a day pass by during each sol, and sometimes there are more. “Jezero Crater may be in one of the most active sources of dust on the planet,” said Manuel de la Torre Juarez, a deputy principal investigator at JPL. “Everything new we learn about dust will be helpful for future missions.”
Some of the most powerful gusts actually create huge clouds of dust covering 4 square kilometers of the surface. So, it’s no small wonder that both the rover and chopper are gaining dust coatings. It would be nice if the dust devils could “sweep off” the dust. That’s what they did for the rovers Spirit and Opportunity a few years back. (And, the InSight team is also hoping for dust devils to come by and help their lander, too. It’s also facing lower power levels thanks to dust coatings on its panels)
Winter is Coming
There’s no doubt that the change of Martian seasons will be a test of Ingenuity’s ability to survive the cold temperatures. In case it freezes, despite everybody’s best efforts, and shuts down permanently, there’s a plan. Ingenuity’s team has transferred its data and images for safekeeping. Hopefully, they will find ways to keep the chopper going so that it can continue flying “scout” for the Perseverance rover in the next Mars year.