SpaceX Webcast of Falcon 9 DSCOVR Launch
spacex.com
spacex.com
"Air Force tracking radar went down. Launch postponed to same time tomorrow."
EDIT: The big problem was the air forces radar going down, a transmitter went down as well, but if I understand Musk correctly that was not needed.
[1] http://en.wikipedia.org/wiki/Lagrangian_point#mediaviewer/Fi...