Free Astronomy Magazine March-April 2021

botic arm, able to move in much the same way as a human arm with an elbow and wrist, could position in- struments directly against rocks and other targets to study. The first of the mission's scientific objectives was to search for and characterize a wide range of rocks and soils related to past water activity on Mars. Both Spirit and Opportunity found evi- dence that, long ago, Mars offered an environment that could have sus- tained any existing microbial life. Using the data from the rovers, the mission scientists reconstructed an era in which Mars appeared to be flooded with water. After more than five years of explo- ration, during which Spirit visited craters, hills, valleys and analyzed many rocks and different terrains, the rover got stuck in a soft sandbar on May 1, 2009. For the next eight months, NASA carefully analyzed O pportunity passed near this small, relatively fresh crater in April 2017, during the 45 th anniver- sary of the Apollo 16 mission to the moon. The rover team chose to call it Orion Crater, after the Apollo 16 lunar module. The rover's Pancam recorded this view. The crater's di- ameter is about 90 feet (27 meters). Its age is estimated at no more than 10 million years. [NASA/JPL-Caltech/ Cornell Univ./Arizona State Univ.]