CAPE CANAVERAL - SpaceX has launched a top-secret spy satellite for the U.S. government.

The unmanned Falcon 9 rocket lifted off Monday morning from its NASA-leased pad at Kennedy Space Center in Florida. It hoisted a classified satellite for the National Reconnaissance Office.

Several minutes into the flight, the first stage booster - its job done - aimed for a touchdown at Cape Canaveral Air Force Station. SpaceX strives to return most of its first-stage boosters for reuse.

This was the fourth SpaceX booster landing at Cape Canaveral; even more have landed on an ocean platform. Sonic booms, as usual, rattled the area around the launch site.

The company's first recycled rocket flew last month.

Sunday's launch attempt was foiled at the last minute by a bad sensor.