Mars helicopter software update sets stage for Monday test flight

The Mars Ingenuity helicopter after release from the Perseverance rover. Following a delay to resolve a software glitch, NASA is ready to attempt the first aircraft flight on another planet. Image: NASA/JPL-Caltech/ASU

After a weeklong delay to troubleshoot a software commanding issue, engineers have uplinked a work-around to the Ingenuity Mars helicopter, clearing the way for an attempted maiden flight Monday, 19 April, to demonstrate the feasibility of flight in the ultra-thin atmosphere of the red planet.

If the software fix works — and engineers gave it an 85 percent chance of success — Ingenuity’s two 1.2-metre-long (4-foot) counter-rotating blades will spin up to 2,400 rpm, lifting the small, 1.8-kilogram helicopter off the dusty floor of Jezero Crater (in the lower gravity of Mars, the helicopter weighs just .68 kilograms, or 1.5 pounds).

For its first flight, Ingenuity was programmed to fly straight up to an altitude of about 3 metres (10 feet) where it will hover, rotate in place and then land. The Perseverance rover that carried the helicopter to Mars will be parked a safe distance away, recording the flight.

The 40-second test flight is expected around 0730 UTC. But it will take engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, about two-and-a-half hours to find out whether the software fix worked, after a Mars orbiter passes over Jezero Crater and relays telemetry to Earth.

NASA plans a live webcast as the data comes into JPL, starting at 1015 UTC.

After Perseverance’s touchdown 18 February, the helicopter was dropped to the surface and engineers prepared the craft for an 11 April maiden flight. But two days earlier, during a rotor spin-up test, the flight computer did not transition to flight mode as expected.

The problem was traced to a timing issue in the command sequence and engineers came up with two solutions. One required additional commands for the existing control software. The other would entail replacing the software with a modified version that’s already been uplinked and stored aboard Perseverance.

Testing showed the first option worked about 85 percent of the time and when it didn’t, it caused no damage. Replacing the software would take several days and introduce a slight risk of unforeseen issues. Engineers opted to go with Option No. 1.

“This solution is the least disruptive to a helicopter that, up until we identified the (timing) issue, has been behaving just as we expected,” Project Manager MiMi Aung said in a blog post. “It is the most straightforward, since we do not have to change its configuration.

“We also know that if the first attempt does not work on Monday, we can try these commands again, with good probability that subsequent tries in the days following would work even if the first doesn’t. For these reasons, we’ve chosen to pursue this path.”

Up to five test flights are planned before Perseverance presses ahead with its mission to look for signs of past microbial life, leaving Ingenuity behind.

If the test flights are successful, NASA likely will consider more advanced helicopters for future missions to Mars and elsewhere that could carry cameras and instruments to locales that are beyond the reach of rovers or even astronauts.