SpaceX makes launching a secret satellite and landing a rocket booster look easy

It's a good day for a rocket launch.

A SpaceX Falcon 9 rocket took flight into a partly cloudy sky from Cape Canaveral, Florida, on Monday at 7:15 a.m. ET, delivering a secret satellite for a U.S. spy agency to orbit before turning around and heading back to Earth for a picture perfect daylight landing at the Cape.

This marks the fourth time SpaceX has brought one of its Falcon 9 rocket stages back to land on solid ground and the first time Elon Musk's private spaceflight company has launched a mission for the U.S. National Reconnaissance Office (NRO), which is responsible for procuring the country's spy satellites.

People as far away as Orlando reportedly heard the sonic boom from the Falcon 9 landing.

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Because of the secretive nature of these kinds of launches, no one is quite sure what the Falcon 9 launched to space for the NROL-76 mission.

However, the fact that SpaceX was able to land back on the ground actually provides some clues about the nature of the payload.

SpaceX can only perform these kinds of landings if the Falcon 9 has a fair bit of fuel leftover from launch. This happens when the rocket is carrying a light satellite to a high orbit, or a heavy satellite to a low one.

Musk's SpaceX has been performing these kinds of landings for some time. The whole point in these types of landings is not to show off, but to eventually create a fleet of reusable rockets that can fly multiple missions to orbit and come back home.

This kind of reusability will eventually help to reduce the cost of launching to space, allowing governments, private entities, and even regular people more access to orbit.

SpaceX made a huge stride toward this goal on March 30 when the company used a previously flown rocket to launch another mission to orbit.

We should keep seeing more of these reusable rockets launch and land in the coming years if SpaceX has its way.