A worker monitors the solid rocket motor as it is moved into position in the mobile service tower at Space Launch Complex 2.

A worker monitors the solid rocket motor, or SRM, for NASA's Orbiting Carbon Observatory-2 mission, or OCO-2, as it is moved into position in the mobile service tower at Space Launch Complex 2 on Vandenberg Air Force Base in California. Operations are underway to attach the Delta II rocket's three SRMs, known as graphite epoxy motors, to the rocket's first stage in place in the tower.

OCO-2 is scheduled to launch into a polar Earth orbit aboard a United Launch Alliance Delta II 7320-10C rocket in July. Once in orbit, OCO-2 will collect precise global measurements of carbon dioxide in the Earth's atmosphere and provide scientists with a better idea of the chemical compound's impacts on climate change. Scientists will analyze this data to improve our understanding of the natural processes and human activities that regulate the abundance and distribution of this important atmospheric gas. To learn more about OCO-2, visit http://oco.jpl.nasa.gov. Photo credit: NASA/Randy Beaudoin