Launch window: 2010-2108 GMT (1510-1608 EST)

Launch site: Cape Canaveral Air Force Station, Fla.

An Orbital Sciences air-launched Pegasus XL rocket will carry NASA's Solar Radiation and Climate Experiment (SORCE) satellite into orbit to make precise measurements of total solar irradiance, which is the main source of energy in the Earth's atmosphere.

more info :

http://lasp.colorado.edu/sorce/index.html