Fifty years ago, a NASA astronaut snapped a photograph from lunar orbit showing Earth rising above the moon, and it helped inspire an environmental movement.
Now it is the environmentalists who are sending missions into space.
The Environmental Defense Fund on Wednesday announced a plan to build and launch a satellite that will measure major global sources of methane, including 50 oil-and-gas regions that make up about 80 percent of production, as well as feedlots and landfills.