"Liftoff of the Delta II with the NPP satellite, blazing the way in new technology for climate research and weather forecasting," said NASA commentator George Diller.
The $1.5 billion National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) took off aboard a Delta II rocket from Vandenberg Air Force Base in California at 5:48 am (0948 GMT).
The satellite will carry five instruments to study temperature and water in the atmosphere, how clouds and aerosols affect temperature, and how plants on land and in the ocean respond to environmental changes.
It is one of 14 Earth observation missions currently being managed by NASA. Project managers said they hope it will operate for about five years. (AFP)