Autonav’s first persistence engine: Perseverance depends on the left and right navigation cameras. The rendering shown here combines the perspective of two moving cameras during the rover’s first flight using AutoNav, an automatic navigation feature. Credit: NASA/JPL-Caltech
The agency’s latest rover orbits Mars using a recently improved automatic navigation system.
NASA’s newest six-wheeled robot on Mars, the Perseverance Probe, begins an epic journey across the crater floor in search of signs of ancient life. This means that the rover team is deeply involved in planning the navigation routes, creating the instructions that need to be sent, and even using special 3D glasses to determine the route.
But increasingly, the rover will take charge of driving alone, using a powerful automated navigation system. Called AutoNav, this enhanced 3D system maps the terrain in front of you, identifies hazards and plots a course around any obstacle without further guidance from ground controllers.
“We have a skill called ‘think while driving,'” said Vandy Verma, chief engineer, rover planner and driver at NASA’s Jet Propulsion Laboratory in Southern California.
This ability, along with other improvements, could allow Tenacity to reach a top speed of 393 feet (120 meters) per hour; Its predecessor, Curiosity, equipped with an older version of AutoNav, covers about 20 meters per hour while climbing Mount Sharp in the southeast.
“We’ve accelerated AutoNav four or five times,” said Michael McHenry, navigation leader and part of the JPL travel planner team. “We are driving much farther in much less time than Curiosity has shown.”
As Perseverance begins its first science campaign on the land of Jezero Crater, AutoNav will be an essential feature to help get the job done.
This crater was a lake when, billions of years ago, Mars was wetter than it is today, and the destination of the anchor was a dry river delta at the edge of the crater. If life early settled on Mars, then signs have been found there. The craft will collect samples 9 miles (15 kilometers) away, then prepare the samples for collection on a future mission that will bring them back to Earth for analysis.
“We will be able to get to where the scientists want to go much faster,” said Jennifer Trosper, who has worked on both NASA’s Mars rovers and is the project manager for the Mars 2020 Persevering rover. Get past it – we couldn’t do that before.”
The human element
Of course, persistence cannot have the advantage of AutoNav alone. Rover team involvement remains key to planning and managing the path of persistence. An entire team of professionals is developing a navigational route along with planning a rover activity, whether it’s studying an interesting geological feature on the way to its destination or soon, sampling.
Computer simulation of the Autonav Perseverance Engine I: This computer simulation shows NASA’s Persevering Mars spacecraft making its first command using the autonavigation feature, which allows it to avoid rocks and other hazards without the intervention of engineers on Earth. Credit: NASA/JPL-Caltech
Due to the radio signal delay between Earth and Mars, they cannot simply push the rover with the joystick. Instead, they scan satellite images, sometimes wearing those 3D glasses to view the surface of Mars near the rover. Once the team stops, they send the instructions to Mars, and the rover carries out those instructions the next day.
The Perseverance wheels have also been modified to help with the speed with which these plans can be carried out: in addition to being slightly larger in diameter and narrower than the Curiosity wheels, each has 48 segments that look like slightly wavy lines, unlike the handling. Chevron out of curiosity. The goals were to help with traction and durability.
Curiosity was unable to AutoNav due to wheel wear,” Trosper said. “At the beginning of the mission, we encountered small, pointy, thorny boulders that started making holes in the wheels and AutoNav did not avoid them.”
The increased stability distance also allows the vehicle to safely roll over more rough terrain, including well-sized rocks. Perseverance’s advanced automatic browsing features include ENav, or Advanced Browsing, which is a combination of algorithm and software that allows for more accurate risk detection.
Unlike its predecessors, the Perseverance can use only one of its computers to navigate the surface; The main computer can participate in many other activities that keep the vehicle healthy and active.
This Vision Calculation Element, or VCE, guided perseverance on Mars during its February entry, descent, and descent. It is now used full time to map the rover’s journey helping it avoid problems along the way.
The rover also keeps track of the distance it travels from one place to another using a system called an “optical odometer”. Perseverance periodically films it as it moves and compares one position with another to see if it has moved the expected distance.
Team members say they are trying to let AutoNav “take the lead”. But they will also be willing to step in when necessary.
And what does it feel like to drive on Mars? Planners and drivers say he never gets old.
“Jesero is incredible,” Verma said. “It’s a rover driver’s paradise. When you wear 3D glasses, you see more ripples on the ground. Some days, I just stare at pictures.”