Free Astronomy Magazine March-April 2021

22 MARS ROVERS finished, defining the completion of the mission. Even Opportunity, after having ex- plored targets similar to those as- signed to Spirit and after having overcome difficulties of various kinds, ultimately surrendered to the adverse Martian conditions. Due to a massive 2018 planetary sandstorm on Mars, the rover cut off communications and went into hi- bernation on June 10. It was ex- pected to restart once the atmos- phere cleared, but it did not, per- haps due to a technical fault or the deposition of a thick layer of dust on the solar panels that prevented the batteries from recharging. NASA hoped to reestablish contact with the rover thanks to a windy period that could have potentially cleaned L eft, sulfur-rich rocks in the Columbia Hills stand out in bright blue in this false-color image from the Spirit rover. Spirit used its Rock Abrasion Tool (RAT) to grind a hole in the rock, nicknamed “Peace.” The rock's high sulfur con- tent and softness are probably evidence of past alteration by water. Right, Opportunity used its RAT on a rock informally named “Gagarin” at a tar- get called “Yuri”. The circle is about 1.8 inches (4.5 centimeters) in diameter. The view is presented in false color to emphasize differences among materials in the rocks and the soils. [NASA/JPL-Caltech/Cornell Univ./ASU]