Ingenuity, NASA’s autonomous Mars helicopter, was only meant to complete five flights. But since its history-making first flight in April 2021, the helicopter has flown 28 times, and preparation is underway for the 29th. Depending on dust levels and the schedule of the rover Perseverance, that flight could take place as soon as later this week. But now Ingenuity faces a new challenge: It’s unclear if the helicopter will survive the coming Martian winter, which begins in July.
Since a Martian year amounts to roughly two years on Earth, and the helicopter is in the northern hemisphere, this is Ingenuity’s first winter. As the solstice approaches, days are getting shorter and nights longer, and dust storms could become more frequent. That all means less sunlight for the solar panels mounted above the helicopter’s twin 4-foot rotor blades. Dust on solar panels recently spelled the end of operations for NASA’s InSight Mars lander, and the effects of cold on electronics is believed to have played a role in the end of the Opportunity and Spirit Mars rover missions.
“We believe it’s survivable,” Dave Lavery, NASA’s program executive for the Ingenuity Mars Helicopter, told WIRED, but “every extra day is a gift.” JPL Ingenuity team lead Teddy Tzanetos recently wrote in a NASA blog post that “each sol (Martian day) could be Ingenuity’s last.”
Last month, Ingenuity briefly lost contact with Earth due to a decline in battery life, the majority of which is dedicated to heating. NASA reestablished contact with Ingenuity after two days, but due to battery levels falling below 70 percent and persistently lower temperatures, Ingenuity will suspend use of onboard heaters at night to preserve power throughout the four-month winter. Heaters typically kick in when the temperature falls below -5 Fahrenheit, a figure reduced to -40 after the battery power shortage and communications outage last month. Outdoor temperatures during the Martian winter can drop to -112 at night, increasing the likelihood of damage to electronics inside the helicopter.
On Monday, NASA announced the failure of a sensor, delaying flight 29 and requiring NASA to uplink a software patch and rely on another sensor to govern Ingenuity’s navigation algorithms.
Dust storms are an X factor. A study published in May from a team at the University of Houston examined data from NASA sensors over the span of four Martian years, and found that imbalances in solar energy and warm weather in the south increase the likelihood of massive dust storms that can blanket the entire planet. Spring and summer are known as storm seasons, but the likelihood of severe storms reduces as the north approaches the winter solstice, says University of Houston associate professor Liming Li. But there’s a caveat: The study is global and does not take into account any particular region. Conditions can also be different in craters than on the rest of the surface, and the helicopter is operating in the Jezero Crater.
“It’s tough to say,” Li said when asked whether more dust storms are on the way. “It’s hard to give a clear picture for the radiation budget in the Jezero Crater before we really measure it.”
As Ingenuity halts normal flight activity, the team will focus on transferring data like flight performance logs and high-definition images from the last eight flights and making software upgrades. Based on a climate model, NASA expects solar energy levels to rebound to a level that allows the resumption of normal activity this fall. By September or October, if Ingenuity is able to regain the ability to heat its systems at night, it could resume regular flight operations, scouting potential places for the Perseverance rover to stash a collection of rock and soil samples and explore what scientists believe used to be a river delta within the Jezero Crater.
Although Ingenuity’s first flight has been dubbed a “Wright Brothers moment on another planet,” the site of the first flight is now called the “Wright Brothers Landing Field,” and Ingenuity even carries a strip of the muslin fabric used to wrap the wings of the Wright Brothers’ 1903 plane, Ingenuity is not a plane—and it cannot be flown by a human. Because it takes anywhere from five to 20 minutes for a radio signal from Earth to reach Mars, Ingenuity must use fully autonomous flight systems and operate without sensors like lidar used by helicopters on Earth and some NASA spacecraft. A single downward-facing camera helps Ingenuity determine position, velocity, and altitude.
Improvements to these systems could be transferred during the helicopter’s winter downtime. “If Ingenuity is able to continue operations later this year, after getting through the Martian winter, the team is currently considering several flight system upgrades that would increase system robustness and/or improve the navigation capabilities of the helicopter,” Lavery wrote in an email to WIRED.
For example, Lavery says NASA will test its autonomous hazard avoidance system for known areas. Conditions for the helicopter’s initial flights on Mars were relatively harmless, but the utility of active hazard avoidance AI is increasing as the helicopter attempts to land in areas with more potential obstacles. Lavery says these systems were developed together with Ingenuity’s initial flight system, but not as part of the version launched from Cape Canaveral in 2020.
Last month, JPL researchers who helped create autonomous flight systems for the Mars helicopter shared advances in AI for predicting the best place to land in an unknown area during an emergency. These kinds of emergency landing systems will play a role on future NASA missions like Dragonfly, a 2027 mission to send a quadcopter to Titan, the moon of Saturn.
Like Ingenuity, the Saturn drone, which arrives in 2035, will take flight millions of miles from Earth, and must operate without human assistance. Unlike Ingenuity, which hitched a ride to Mars under the belly of Perseverance, Dragonfly will take flight a little over an hour after reaching Titan, detaching from a parachute and aeroshell for midair flight to start a two-year, nuclear-powered mission to search for life.
Lessons learned from Ingenuity may also help plan future missions to Mars. NASA Ames Research Center and JPL started work on a second-generation helicopter two years before the first reached the Red Planet. Lavery compares Ingenuity to Sojourner, the first rover sent to Mars, which landed in 1997. Virtually every surface mission since then has carried a rover. “We’re hoping that Ingenuity will do a similar sort of thing, that this will become a standard part of the mission toolkit,” he says.
NASA’s ROAMX project is designing improvements to be incorporated into the next helicopter, like changes to the rotor blades that reduce drag and could enable it to carry a scientific payload that weighs about 2 pounds a distance of about 4 miles. In a presentation about future flights to Mars, last year NASA principal investigator Haley Cummings said rotor blade refinements uncovered by ROAMX will be incorporated into the Mars Science Helicopter, a 66-pound hexacopter with six rotors that could lose a rotor but continue to operate. The conceptual drone was first proposed in a white paper published in early 2021.
Experimental flying craft for Mars have been under development for more than two decades. They include a helicopter shaped like a lampshade, swarms of small drones, a glider launched with a weather balloon, and tilted-rotor machines that switch between flying like a helicopter or a plane. Future concepts may explore areas that rovers can’t reach, and may eventually ferry tools and supplies for people on Mars.
Ames Research Center scientists envision automated base stations, little aircraft hangars in the shape of clamshells, to shield flying machines from cold and dust to extend their lives for years. Extending the life of drones could expand their use beyond a single mission, allowing them to become part of a network of machines, big and small, that could do tasks like explore lava tubes, volcanoes, or ice caps. The development of forms of fully autonomous flight could also have applications for commercial drones or flight systems on Earth. Today, drones typically use GPS and a return-to-home function in the event of an emergency or loss of power.
Lavery believes Ingenuity’s most important mission was achieved during that first flight in April 2021. That 39-second flight proved that people are capable of applying the principles of aerodynamics for powered flight on another planet. “Every flight since then, and all the data we're collecting with each successive flight, helps us refine that knowledge even more,” Lavery says.
At best, the first four flights traveled no further than a few hundred feet and lasted roughly a minute. By the fifth flight, Ingenuity began to venture out, eventually flying more than 4 miles. Then Ingenuity began to assist in the mission of exploring Martian geology and searching for possible forms of life. At the request of the Perseverance Mars rover science team, Ingenuity took high-definition photos of the Fortun ridgeline rocks at the bottom of the Jezero Crater, which are thought to be of volcanic origin. And Ingenuity also flew over part of the Séítah region, delivering imagery and information the rover Perseverance is unable to reach that “just would not have been possible to capture had the helicopter not been there,” Lavery says.
In April, flying at a speed of 12 miles per hour, Ingenuity flew more than 2,300 feet in a jaunt that lasted more than two minutes, making it the longest and fastest powered flight on another planet. Later that month, Ingenuity got a photo of the parachute and aeroshell used to bring Ingenuity and the Perseverance rover to the surface of Mars, images NASA wants to use to ensure safer landings for future spacecraft.
Lavery says Ingenuity’s first winter will be a challenge the team never expected to encounter—but now that they’ve shown that it’s possible to fly a helicopter on Mars, there’s potential to make flying companions a commodity for future missions to explore other celestial objects. “We haven't made a decision yet on exactly what the next one will be,” says Lavery. “But the one thing I do feel fairly confident about is there will be a next one.”
Credit belongs to : www.wired.com