It was reported on June 11 that the Mars helicopter "smart" had completed 28 flights before, far exceeding the original plan. As the Martian winter approaches, the battery power of the "smart" Martian helicopter continues to decrease. Now the mission team is most concerned about whether the helicopter can survive the four month Martian winter. The National Aeronautics and Space Administration (NASA) originally only planned to let the "smart" Mars helicopter complete five flights.
However, since its first flight on the surface of Mars in April 2021, the "smart" has flown 28 times and is preparing for the 29th. According to the dust conditions on the surface of Mars and the operation plan of the Mars rover perseverance, the flight was originally scheduled for this weekend. But now the new challenge facing the "smart" helicopter is that it can survive the long Martian winter. It is not clear whether the helicopter will survive the long Martian winter.
At present, the "smart" helicopter is located in the northern hemisphere of Mars and will usher in the Martian winter in July this year. Since one year on Mars is about the same as two years on earth, this is also the first Martian winter that the "smart" will experience (last July was not a Martian winter). As the winter solstice on Mars approaches, the days become shorter and the nights become longer. Dust storms may also make the solar panels installed above the helicopter's twin rotors collect less sunlight. Recently, the thick dust covered on the solar panels led to the end of the mission of NASA's insight Mars probe. The impact of cold on electronic equipment is one of the reasons for the end of the missions of opportunity and spirit Mars probes.
"We believe it can survive," said Dave Lavery, program director of NASA's "smart Mars helicopter," but "every day is a gift." Teddy tzanetos, head of the Jet Propulsion Laboratory (JPL) "smart" team, recently said: "every Mars day may be the last day of smart."
Last month, due to the decline of battery performance, most of the electricity was used for heating equipment, and the "smart" lost contact with the earth for a short time. Two days later, NASA reconnected with the "smart" helicopter. However, due to the fact that the battery power of the helicopter was lower than 70% and the temperature continued to drop, the "smart" helicopter suspended the use of the onboard heater at night in order to ensure the power supply in the four month winter. The heater usually starts when the temperature is below minus 20 ℃. After the battery power shortage and communication interruption occurred last month, the "smart" team lowered the external temperature of the heater to minus 40 ℃. However, the night temperature of Mars in winter can drop to minus 80 degrees Celsius, which increases the possibility of damage to the electronic equipment inside the helicopter.
On Monday, NASA announced sensor failure, delaying the 29th flight of the smart. This makes the mission team have to upload software patches and rely on another sensor to manage the navigation algorithm of the "smart".
Dust storms on Mars are also an unknown factor. In May this year, a team from the University of Houston in the United States studied the four-year data detected by NASA sensors on Mars. It showed that the imbalance of solar radiation and the warming of the southern hemisphere of Mars increased the possibility of large-scale dust storms, which can even cover the entire Mars. Liming Li, an associate professor at the University of Houston, said that spring and summer are the storm seasons on Mars, but as the northern hemisphere approaches the winter solstice, the possibility of serious storms decreases. However, it should be noted that this study is aimed at the entire Mars, without considering any specific areas. The conditions in the Jero crater may also be different from those in other parts of the Martian surface.
When asked whether there will be more sandstorms, Li Liming said: "it's hard to say." "It's hard to give a clear answer before we really test the Jero crater."
Since the "smart" helicopter stopped its normal flight activities, the mission team will focus on transmitting the flight performance log and HD images taken in the last eight flights, and upgrading the helicopter software. According to the Martian climate model, NASA expects that the amount of solar energy collected this autumn will pick up, allowing the helicopter to resume normal activities. In September or October, if the "wit" can regain the ability of the night heating system, it can resume normal flight, find a place for the "perseverance" Rover to store rock and soil samples, and explore a River Delta in the Jero crater.
Since it takes 5 to 20 minutes for the radio signals sent from the earth to reach Mars, the "smart" must use a fully automated flight control system, and there are no sensors such as ordinary helicopters and laser radars used by some NASA spacecraft. But the downward camera can help the smart determine its position, speed and height.
Task teams can upgrade systems during winter outages. "If the 'smart' can continue to operate later this year after surviving the Martian winter, the team is currently considering several flight system upgrades to increase the robustness of the system and improve the navigation capability of the helicopter," leffrey said
Leffrey said that NASA will test the automatic risk avoidance system in known areas. The conditions of the previous flights of the "smart" were relatively stable, but as the helicopter will land in areas with more possible obstacles, the role of the automatic risk avoidance system is increasing. Leffrey said that these systems were originally developed together with the flight control system of the smart, but they were not installed when they were launched in 2020.
Last month, the researchers who developed the "smart" flight control system announced the progress of the automatic risk avoidance system, which can predict the best landing location in unknown areas in case of emergency. This emergency landing system will play a role in future NASA missions, such as the dragonfly mission to Titan in 2027.
Like the smart, the dragonfly, which will arrive on Titan in 2035, has no chance to fly alone millions of kilometers away from the earth. However, the "wit" arrived at Mars by taking the "perseverance" Mars rover. In contrast, the nuclear powered "Dragonfly" had no chance to take off more than an hour after its arrival on Titan. It dropped its parachute and landing shell in midair and began a two-year search for life mission.
The experience gained by the researchers through the "wit" may also contribute to future Mars missions. NASA Ames Research Center and Jet Propulsion Laboratory started the research on the second generation helicopter two years before the arrival of the "smart" on Mars. Leffrey likened the "wit" to the first "sojourner" Mars rover to land on Mars. The Rover "sojourner" landed on Mars in 1997. Since then, almost every Mars surface exploration mission has carried a rover. "We hope that the 'smart' will play a similar role and make the helicopter a standard part of the mission," leffrey said
NASA's roamx project is designing an improvement scheme for the next generation helicopter, such as improving the rotor blades, reducing resistance, and being able to fly about 6 kilometers with a scientific load weighing about 1 kg. Last year, NASA's chief researcher Haley Cummings said in a report on future Mars flight that the rotor blade improvements of the roamx project will be used for the Mars Science helicopter. The 30 kg six rotor helicopter can continue to fly without a rotor.
The Mars test vehicle has been developed for more than 20 years. There are helicopters shaped like lampshades, groups of small UAVs, gliders launched by meteorological balloons, and tilt rotor aircraft that can switch between different flight modes. In the future, Mars helicopters may be used to explore areas that cannot be reached by Mars rovers, and eventually transport tools and materials for astronauts.
Scientists at Ames Research Center also envisioned an automated hangar to protect aircraft from cold and dust, extending the design life by several years. If the Mars helicopter runs longer, multiple devices can form a machine network to complete tasks such as exploring lava pipelines, volcanoes or ice caps.
Leffrey believes that the most important mission of the "smart" will be completed during its first flight in April 2021. The flight lasting for 39 seconds proved that human beings could fly dynamically on another planet. "Every flight since then, and all the data we have collected from every successive flight, will help mankind further improve relevant knowledge," leffrey said.
The first four flights only flew a few tens of meters at most, and each time was no more than one minute. The fifth flight of the "smart" lasted 108 seconds, with a flight distance of 129 meters. Then, the "smart" began to assist the rover in exploring the terrain of Mars and searching for possible life forms. At the request of the scientific team of the Mars rover perseverance, the "smart" took high-definition photos of the rocks of the futon ridge at the bottom of the Jero crater, and also flew over part of the s é í TAH area to provide images and information of areas that the Mars rover could not reach. "If there were no helicopters, it would be impossible to capture this information," said lefrey.
In April this year, the "smart" flew at a speed of 20 kilometers per hour. It lasted more than two minutes, flying more than 700 meters, completing the longest and fastest power flight on another planet. Later that month, "smart" captured photos of the parachute and protective shell of the landing platform. NASA hopes to use these photos to ensure the safe landing of future spacecraft.
Leffrey said that the upcoming first Martian winter of the "smart" was a challenge the team had never thought of, but now they have proved that it is possible for helicopters to fly on Mars, which may make helicopters a part of future missions to explore other celestial bodies. "We haven't decided what our next destination will be," said levery. "But there is one thing I am confident of, and that is that there will be another time."