On April 17, SpaceX launched a classified US National Reconnaissance Office spy satellite payload into space from the Vandenburg Space Force Base in California. While the rocket launch was being streamed, a request by the NRO prevented SpaceX from broadcasting the payload and upper stage, and the broadcast was cut short to stop the disclosure of classified material. 

Interesting as that may be, the achievement of the rocket is perhaps more noteworthy. The launch marks Falcon 9’s 14th mission this year and 148th mission ever, including previous contracts with the NRO, though this is the first time the NRO has reused a Falcon 9 booster. 

Once the booster separated from the payload, it successfully returned and landed autonomously upright, marking the 114th recovery of a SpaceX booster in this manner. 

The secret spy satellite designated NROL-85, is the NRO's second launch this year, after the rocket booster launched NROL-87, the NRO said in a statement. 

It described the NROL-85 satellite as a “critical national security payload.”

The unreusable upper stage of the rocket was caught creating a mysterious "flying whirlpool" over the skies of Hawai'i a few hours after launch as it carried out a fuel vent after deorbiting over the Pacific and burning up in Earth's atmosphere.