The rover's Sample Analysis at Mars instruments analyzed atmospheric samples taken at a site dubbed Rocknest, where the rover stopped briefly for research, according to NASA. In its initial tests, the rover didn't detect measurable methane gas, a precursor to life. The instruments will analyze soil and rock samples for organic compounds in the weeks ahead.
As it goes about its scientific mission, Curiosity is able to cover a larger area over a longer period of time than previous Mars rovers. Edward Tunstel, a senior roboticist at Johns Hopkins University's Applied Physics Laboratory who contributed to Curiosity's development, said improved technology makes it possible to navigate within fields 25 times larger than the Mars Exploration rovers, which landed on Mars in 2004 and are still at work.
"The main difference is the Mars Exploration rovers were nominally able to do what we might call local navigation -- be able to navigate or plan paths through a natural environment one or two steps ahead," said Tunstel, who did robotics work with NASA's Jet Propulsion Laboratory for 18 years.
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Using data they collect, the Exploration rovers, Spirit and Opportunity, can create three-dimensional maps of an area 10 meters by 10 meters, allowing them to plan a path around obstacles and keep track of their positions. By comparison, Curiosity can map an area that's 50 meters by 50 meters, enabling it to plan longer paths and travel greater distances autonomously, Tunstel said.
Curiosity employs visual target tracking to lock onto an object and navigate to it automatically. With Spirit and Opportunity, that's been a three-step process: get the rover in close proximity, take an image, then send the images to Earth to allow engineers to analyze them and send commands to use the robotic arm. "Curiosity can do all that in one fell swoop," Tunstel said.
Curiosity's navigational capabilities are based largely on those of the Exploration rovers, which means the technology being used on Curiosity is close to a decade old. "The technology is really well-tested, and we have very high confidence in it," Tunstel said. "It's less risky."
If NASA's Mars Science Laboratory team is able to complete its research in less than two years -- the official duration of the mission -- the Curiosity team may test additional navigation and autonomy advancements for future missions.
"Some of it is more of the same, but improvements to what we currently do," Tunstel said. "For example, there's always the push to have not only faster computers, but also more efficient algorithms to process camera data and other data to allow us to make decisions onboard the vehicle. What it allows us to do is navigate safely in a rough terrain environment but at a high speed."
Following Curiosity's Aug. 5 (Pacific time) landing on Mars, NASA engineers upgraded the rover's onboard flight software with a new version, release 10, that's optimized for traveling long distances and making use of Curiosity's robotic arm.