Livin' on reds, vitamin C, and cocaine
All a friend can say is "Ain't it a shame"
- "Truckin' " - The Grateful Dead, 1970
Ingenuity, the JPL's fantastic little helicopter on Mars, had a rough go of things through April into May and was feared lost for a while. Figuratively, Ingenuity is sort like the "Sweet Jean" from the lyrics of that 50-some year old Grateful Dead song. Well, being an inanimate object, it didn't have a rough time but its handlers at the JPL sure did. The little helicopter didn't contact the JPL for six days in April.
This was not a cause for concern at first. Since January of this year, when winter set in at Ingenuity's digs — the floor of Mars' Jezero Crater — the solar-powered chopper "had unfortunately been drifting in and out of nighttime survival mode (having enough power to avoid overnight brownouts)," Brown wrote in the update.
This led to uncertainty in Ingenuity's daily wakeup time, which made it harder to hail the chopper and to plan out its activities. In addition, during this stretch, a rocky outcrop created a "communications shadow" between Ingenuity and its robotic partner, the Perseverance rover, which relays commands to and from the 4-pound (1.8-kilogram) rotorcraft.
Discussions about time intervals on Mars are expressed in "Sols" not days. A Martian day isn't 24 hours but the difference is about 40 minutes longer per sol. As a result, the Martian calendar drifts with respect to ours and the mission milestones are expressed by sol number.
The Ingenuity blackout began on sol 755, or April 5. It finally ended on sol 761, when the mission team spotted a signal during the helicopter's expected wakeup window. A second signal at the same time on sol 762 "confirmed that the helicopter was indeed alive, which came as a welcome relief for the team," Brown wrote.
Ingenuity had its 50th flight on the next sol, 763.
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. It would be an understatement to say that the helicopter team was relieved to see the successful flight telemetry in the Sol 763 downlink the following morning.
Ingenuity flew one more time in April, Flight 51, but has not flown since then. Flight 51 lasted for just under 137 seconds and saw the small helicopter travel for a total of 617 feet (188 m). During the just over two minute flight, April 22, 2023 at the JPL, Ingenuity snapped this photo that shows the Perseverance rover in the top left corner area. Just right of and below center, in a light area, is Ingenuity's own shadow.
(Image credit: NASA/JPL-Caltech)
In addition to the other possible things mentioned that could have kept Ingenuity from charging or communicating with Perseverance properly, the big thing is that it's still in more like spring than summer there. As the days get longer, charging can improve, but balance that with an increasing amount of Martian dust on the solar panels. That has taken out other probes, like Mars Insight back at the end of '22.
"This means that, much to the chagrin of her team, we are not yet done playing this high-stakes game of hide and seek with the playful little helicopter," (Ingenuity chief engineer Travis) Brown wrote.
51 flights? On a very experimental craft meant to fly five times? Sounds pretty good to me.