Ingenuity seems to be recovering from a communication problem on Mars.
NASA’s Jet Propulsion Laboratory (JPL) restored contact with the miniature Mars helicopter Thursday (May 5) after missing a scheduled call about two days earlier, the agency reported Friday (May 6).
Engineers suggest the helicopter may have entered a low power state due to a combination of high levels of dust in the atmosphere and low local temperatures. The situation rendered the solar-powered Ingenuity unable to communicate with its base station, the Perseverance rover, which sends the helicopter’s status to Earth via a Martian satellite.
“Dust decreases the amount of sunlight hitting the solar panel, reducing Ingenuity’s ability to recharge its six lithium-ion batteries,” JPL continued. “When the battery’s state-of-charge fell below a lower limit, the helicopter’s field-programmable gate array (FPGA) was powered down.”
Related: 1 year later, the Ingenuity helicopter continues to operate on Mars
Ingenuity was recently cleared to fly until at least September and has now racked up 28 sorties. This is well beyond its original flight plan, five excursions planned after landing on the Martian surface in February 2021, with Perseverance. Ingenuity’s rotor revolutions per flight were increased last September to account for decreasing atmospheric density due to seasonal changes in the mission’s landing zone, Mars’ Jezero Crater.
So far, the plan has worked well. The rotorcraft has accumulated a total of 6.9 kilometers of flight distance and is now serving as a scout for perseverance activities as the mission enters an ancient delta in search of potential signs of Martian life. Recently, the mini-helicopter even took valuable photos of Perseverance’s scrapped landing system to help spacecraft engineers plan future missions.
But the helicopter is battling dust, seasonal changes and conditions beyond its design plan, meaning it will face more hurdles to continue flying in the months to come.
The FGPA unit is crucial to ensuring that Ingenuity remains operational, including controlling power to avionics and running heaters to keep Ingenuity alive during cold Martian nights. He is also responsible for the timing of the spacecraft, including for calls scheduled with Perseverance.
Controllers suspect that after the loss of power to the FGPA, which occurred during a Martian night, the helicopter’s clock reset and the heaters went out.
“When the sun rose the next morning and the solar panel began charging the batteries, the helicopter’s clock was out of sync with the clock on board the rover,” JPL said. “Essentially, when Ingenuity thought it was time to contact Perseverance, the rover base station wasn’t listening.”
To try and catch Ingenuity again, engineers ordered Perseverance to listen for the signal for nearly an entire Martian sol (day) on May 5, and finally heard from the helicopter around 11:45 a.m. local Mars time. Ingenuity was limited in what it could send to preserve power, but controllers were able to determine that the base health of the helicopter appeared to be good.
“The radio link between Ingenuity and Perseverance was stable, spacecraft temperatures were as expected, the solar panel was charging the battery at an expected rate for this season, and the battery was healthy, holding 41% of a full charge” , said JPL.
The dust, however, will remain a lingering threat to the solar-powered mission and will make it more difficult to recharge the batteries to keep the vital heaters and clock running during the freezing night. JPL officials said Ingenuity turned on its heaters whenever the battery temperature was below 5 degrees Fahrenheit (minus 15 degrees Celsius) for the past three sols. (A Martian floor is about 40 minutes longer than an Earth day.) However, engineers fear that if this approach continues, the battery won’t be able to keep the heaters running all night.
The engineers now have a new plan. As of last week, a new set of controls changed the point at which the battery turns on, to minus 40 degrees F (minus 40 degrees C). The helicopter will also be instructed to shut down immediately, instead of draining the “precious” battery charge, JPL said.
“The team hopes this strategy will allow the battery to retain the charge it has collected during the day. Ingenuity engineers hope that after several days of soaking the helicopter’s array in the limited rays, the battery will have reached a point where the spacecraft can return to normal operations,” JPL said.
The risk is that Ingenuity will carry off-the-shelf commercial parts not optimized to stay active in the deep cold of Mars, estimated at minus 112 degrees F (minus 80 degrees C) on Ingenuity’s site. So JPL played it safe while saying engineers hoped they would sustain more battery power (and communications) for at least a few more Earth weeks.
“We always knew that the Martian winter and dust storm season would present new challenges for Ingenuity, especially colder ground, increased atmospheric dust, and more frequent dust storms,” said Teddy Tzanetos. , head of the Ingenuity team at JPL, in the same statement. . “Every flight and every mile of distance traveled beyond our original 30 sol mission has pushed the spacecraft to its limits at every sol on Mars.”
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