NASA is canceling a planned satellite that was going to intensely monitor greenhouse gases over the Americas because it got too costly and complicated. But the space agency says it will still be watching human-caused carbon pollution but in different ways. Tuesday’s NASA announcement says that its GeoCarb mission, which was designed to monitor carbon dioxide, methane and how plant life changes over North and South America is now looking to cost more than $600 million. It was budgeted at $166 million.