NASA has awarded United Launch Alliance and SpaceX contracts worth nearly $500 million to launch four Earth-observing mission spacecraft.

The contracts provide $412 million to ULA for three Delta II launches and $82 million to SpaceX for a Falcon 9 mission, all from Vandenberg AFB, Calif., in 2014-16.

The ULA lineup is: NASA’s Orbiting Carbon Observatory-2 (OCO-2) mission, a spacecraft designed to monitor natural and man-made sources of carbon dioxide accumulations in the global atmosphere, set for a July 2014 launch; NASA’s Soil Moisture Active Passive mission, a global flood-prediction and drought-monitoring initiative scheduled for an October 2014 launch; and the NASA/National Oceanic and Atmospheric Administration (NOAA) Joint Polar Satellite System-1 (JPSS-1) spacecraft for weather forecasting and the monitoring of sea surface temperatures and ozone levels, planned for a November 2016 liftoff.

OCO-2 replaces the original Orbiting Carbon Observatory mission that was lost in a February 2009 launch accident while climbing to orbit atop an Orbital Sciences Corp. Taurus XL from Vandenberg. JPSS-1 will succeed the Suomi-NPP mission launched in October 2011.

SpaceX was selected for the December 2014 launch of Jason-3, a joint mission for observations of global sea levels and ocean circulation led by NOAA and the European Organization for the Exploitation of Meteorological Satellites, in collaboration with NASA and CNES, the French space agency. The Jason spacecraft observations will be used to monitor sea surface levels, ocean circulation and hurricane intensification, as well as for climate change research.