SpaceX just launched a top-secret spy satellite

SpaceX successfully launched yet another rocket Monday morning.

But it wasn't carrying your average SpaceX cargo.

The Falcon 9 rocket was actually used to send a top-secret U.S. government spy satellite into space.

SEE MORE: SpaceX Hits A Major Milestone On Its Way To Mars

The unmanned rocket lifted off from Kennedy Space Center in Florida around 7 a.m. Monday.

The launch was originally scheduled for Sunday, but it was scrubbed at the last minute because of a "sensor issue." SpaceX CEO Elon Musk noted in a tweet that high-altitude winds during Monday's launch almost exceeded the rocket's capability.

And after it launched the National Reconnaissance Office satellite into orbit, the rocket booster turned around and touched back down at a nearby landing pad.

The mission was SpaceX's first for the Department of Defense, a customer Musk has been trying to do business with for a while now.

SpaceX received certification to launch satellites for the U.S. Air Force in 2015.

Because Monday's mission was a national security launch, the finer details are being kept under wraps.

See images from a previous launch:

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SpaceX Falcon rocket lifts off from Space Launch Complex 4E at Vandenberg Air Force Base, California, U.S., January 14, 2017.

(REUTERS/Gene Blevins)

SpaceX Falcon rocket lifts off from Space Launch Complex 4E at Vandenberg Air Force Base, California, U.S., January 14, 2017.

(REUTERS/Gene Blevins)

SpaceX Falcon rocket lifts off from Space Launch Complex 4E at Vandenberg Air Force Base, California, U.S., January 14, 2017.

(REUTERS/Gene Blevins)

SpaceX, an American aerospace manufacturer, successfully launched a Falcon 9 rocket from Vandenberg Air Force Base this morning at 9:54 a.m. on January 14, 2017, in Lompoc, California. The SpaceX Falcon 9 rocket's payload consisted of ten Iridium NEXT satellites and was viewed by thousands of people lining roads and nearby hillsides.

(Photo by George Rose/Getty Images)

People (and dogs) gather to watch SpaceX, an American aerospace manufacturer, successfully launch a Falcon 9 rocket from Vandenberg Air Force Base this morning at 9:54 a.m. on January 14, 2017, in Lompoc, California. The SpaceX Falcon 9 rocket's payload consisted of ten Iridium NEXT satellites and was viewed by thousands of people lining roads and nearby hillsides.

(Photo by George Rose/Getty Images)

SpaceX, an American aerospace manufacturer, successfully launched a Falcon 9 rocket from Vandenberg Air Force Base this morning at 9:54 a.m. on January 14, 2017, in Lompoc, California. The SpaceX Falcon 9 rocket's payload consisted of ten Iridium NEXT satellites and was viewed by thousands of people lining roads and nearby hillsides.

(Photo by George Rose/Getty Images)

People gather to watch SpaceX, an American aerospace manufacturer, successfully launch a Falcon 9 rocket from Vandenberg Air Force Base this morning at 9:54 a.m. on January 14, 2017, in Lompoc, California. The SpaceX Falcon 9 rocket's payload consisted of ten Iridium NEXT satellites and was viewed by thousands of people lining roads and nearby hillsides.

(Photo by George Rose/Getty Images)

SpaceX Falcon rocket lifts off from Space Launch Complex 4E at Vandenberg Air Force Base, California, U.S., January 14, 2017.

(REUTERS/Gene Blevins)

SpaceX, an American aerospace manufacturer, successfully launched a Falcon 9 rocket from Vandenberg Air Force Base this morning at 9:54 a.m. on January 14, 2017, in Lompoc, California. The SpaceX Falcon 9 rocket's payload consisted of ten Iridium NEXT satellites and was viewed by thousands of people lining roads and nearby hillsides.

(Photo by George Rose/Getty Images)

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