A robot driving 100 meters in a day can seem like mechanical snail. The world's fastest human sprinters, after all, cover the same ground in less than 10 seconds. But the modest distance marks the longest one-day journey yet for NASA's Mars Rover Curiosity as it roams across the Red Planet in search of once-habitable spots.
The day-long journey of 100.3 meters (329 feet) on July 21 was more than double the rover's previous record of 49 meters, according to SPACE.com. NASA engineers manually plotted out a safe driving route across the Martian terrain—a warm-up before they begin using the rover's autonomous navigation system to calculate safe routes by itself.
"What enabled us to drive so far on Sol 340 [340th Martian day of the mission] was starting at a high point and also having Mastcam images giving us the size of rocks so we could be sure they were not hazards," says Paolo Bellutta, a rover planner at NASA's Jet Propulsion Laboratory in Pasadena, Calif, in a press release. "We could see for quite a distance, but there was an area straight ahead that was not clearly visible, so we had to find a path around that area."
NASA planners can use the images taken by the Navigation Camera (Navcam) on Curiosity's mast as well as the ones from the telephoto-lens Mast Camera (Mastcam) to calculate driving distance. The rover has covered 1.23 kilometers (0.81 miles) in total on Mars as of 23 July, NASA officials say.
After spending almost a year on the Martian surface, Curiosity has already completed its main mission of showing that the planet was once habitable. (Part of the rover's toolkit for that job involved using a laser to zap Martian rocks and analyze the chemistry of the samples.) But NASA plans to keep Curiosity roving in search of other areas where ancient life may have once existed.
Turning on Curiosity's autonomous navigation will allow the robot to go on drives beyond the safe routes manually plotted out by its human handlers. Self-driving is crucial for Mars missions because it takes 14 minutes for command signals from Earth to reach Curiosity—meaning that routes cannot be changed in real time by NASA planners back on Earth.