SpaceX's launch attempt today, February 21, was scrubbed due to high winds. The launch was scheduled for an instant (no window) launch at 9:17 A.M. ET from Vandenberg Air Force Base in California.
Elon Musk said via Twitter, "High altitude wind shear data shows a probable 2% load exceedance. Small, but better to be paranoid. Postponing launch to tomorrow, assuming winds are better then.High altitude wind shear data shows a probable 2% load exceedance. Small, but better to be paranoid. Postponing launch to tomorrow, assuming winds are better then. "
The primary payload is the Spanish PAZ military radar satellite. It will be put into a Sun synchronous dawn-dusk orbit. The X-band radar operates in different modes to provide variable width swaths from 5 kilometers to 100 kilometers, with resolution from 1 meter to 15 meters. Also onboard is a RF rain experiment and an AIS ship tracking payload.
However, a lot of attention is going to the secondary payloads, a pair of SpaceX owned-and-built small communications satellites. The two pathfinder satellites are test hardware for SpaceX's Starlink LEO broadband constellation, verifying operation in Ku-band. Starlink is expected to be a constellation of over 4,400 satellites, providing revenue to fuel SpaceX's plans to build bigger launch vehicles and ultimately go to Mars.