Satellites aren’t built to last forever, so it’s not a big surprise that the third and last laser on NASA’s Ice, Cloud and Land Elevation Satellite (ICESat) quit working on October 11, outlasting its designed mission length by three and a half years. Since its launch in 2003 ICESat has been a critical instrument for continuously monitoring how much ice sheets in Antarctica and Greenland are contributing to the rise of the world’s oceans and how much the swath of sea ice in the Arctic Ocean is thinning–both of which are occurring faster than projected. [More]