The Mars helicopter 'Ingenuity' recently completed its 47th, 48th, and 49th flight, NASA reports on the blog for its Mars rover 'Perseverance'. That rover is making a "long ascent" up the delta in Mars' Jezero crater, "an area where scientists surmise that, billions of years ago, a river once flowed into a lake.
On its 47th flight, Ingenuity attempted "tactical and scientific scouting" for the rover, but "just narrowly missing the main area of interest." But then...
Ingenuity's 48th flight produced a treasure trove of aerial images showing the exact area of interest at a resolution several orders of magnitude better than anything prior. All of these images were downlinked to Earth and provided to rover planners and scientists a full two weeks before the rover would reach this area... [T]he team chose to send the helicopter farther up the delta rather than perform additional scouting flights in the region... The Guidance Navigation and Control team once again managed to push the flight envelope with a 16-meter vertical popup at the end of the flight. At the peak, Ingenuity snapped the highest suborbital picture taken of the Martian surface since landing...
That downlink was the last time the team would hear from the helicopter for an agonizingly long time. Eager to continue up the delta, the team tried and failed to uplink the instructions for Flight 50 several times. Sol after sol, the helicopter remained elusive. Each time, the downlinked telemetry from the Helicopter Base Station (HBS) on the rover would come back showing no radio sign of the helicopter... When the rover emerged from the communications shadow on its way to Foel Drygarn and the helicopter was still nowhere to be found, the situation began to generate some unease... In more than 700 sols operating the helicopter on Mars, not once had we ever experienced a total radio blackout. Even in the worst communications environments, we had always seen some indication of activity...
Finally, on Sol 761, nearly a week after our first missed check-in, our communications team observed a single, lonely radio ACK (radio acknowledgement) at 9:44 LMST (Local Mean Solar Time), exactly the time when we'd expect to see the helicopter wakeup. Another single ACK at the same time on Sol 762 confirmed that the helicopter was indeed alive, which came as a welcome relief for the team. Ultimately, this first-of-its-kind communications blackout was a result of two factors. First, the topology between the rover and the helicopter was very challenging for the radio used by Ingenuity. In addition to the aforementioned communications shadow, a moderate ridge located just to the southeast of the Flight 49 landing site separated the helicopter from the rover's operational area. The impact of this ridge would only abate once the rover had gotten uncomfortably close to the helicopter. Second, the HBS antenna is located on the right side of the rover, low enough to the deck to see significant occlusion effects from various part of the rover...
Relying on the helicopter's onboard preflight checks to ensure vehicle safety and banking on solid communications from the rover's imminent proximity, the team uplinked the flight plan. As commanded, Ingenuity woke up and executed its 50th flight on the red planet, covering over 300 meters and setting a new altitude record of 18 m.
The rover had closed to a mere 80 meters by the time the helicopter lifted off in the Martian afternoon Sun.
And Flight 51 happened 9 days later...
Read more of this story at Slashdot.