About two months ago, executives of NASA’s Ingenuity Mars helicopter were in a sweat. Ingenuity Chief Engineer Travis Browne wrote in an update on May 26 that the small helicopter was unable to communicate with the mission crew for about six days in early April.

At first, this was not a concern. Since January of this year, when winter began at Ingenuity’s excavation site at the bottom of Martian Crater Lake, the solar-powered helicopter “unfortunately went into and out of survival mode at night (it has enough power to prevent nighttime power outages),” Brown wrote in an update.

This led to uncertainty about Ingenuity’s daily wake-up time, making it difficult to call the helicopter and plan its actions. Additionally, during this yawn, a rocky ledge created a “shadow of communication” between Ingenuity and its robotic partner, the Perseverance rover, that transmitted commands to the 4-pound (1.8-kilogram) rotorcraft.

But when Perseverance, which was searching for life and collecting samples, returned to communication range, “and with the helicopter still out of sight, the situation started to sound a little alarming,” wrote Brown of NASA’s Jet Propulsion Laboratory. Southern California.

“Poor telecommunications performance was considered a plausible explanation, but there was reason to doubt it,” he added. “For the more than 700 sols working in a helicopter on Mars, we have never once encountered a complete interruption of radio communications. Even in the worst communication conditions, we have always seen certain signs of movement.”

A solar or Martian day is slightly longer than an Earth day, lasting about 24 hours and 40 minutes. Ingenuity’s shutdown began on Sol 755, or April 5. The 761 finally ended on the left when the mission crew saw a signal during the expected helicopter wake-up window. A second signal simultaneously on Sol 762 “confirmed that the helicopter was indeed alive, which was a welcome relief for the crew,” Brown wrote.

Ingenuity made its 50th flyby to Mars the next day at 763 sols, or April 13. During this flight, it reached a maximum altitude of 59 feet (18 meters), higher than ever before.

“To say that the helicopter crew was relieved to see successful flight telemetry on Sol 763’s downlink the next morning would be an understatement,” Brown wrote.

Creativity took off again on April 22, but has remained on the ground ever since. Summer will soon return to Crater Lake, but Brown said communication problems can persist even after the seasons change. This is because Ingenuity’s solar cells contain large amounts of Martian dust, and this will likely keep the helicopter in its current “transient power state” for a while.

“This means we haven’t finished playing this high-stakes game of hide-and-seek in the fun little helicopter enough to upset his team,” Brown wrote.