SpaceX has finally launched the secret USSF-52 mission with a Boeing X-37B spaceplane on board. The Falcon Heavy rocket lifted off from the LC-39A launch complex at the Kennedy Space Center on December 29, 2023 at 01:07.

The launch was scheduled for December 10, but was postponed several times due to weather conditions at the launch site. At the same time, the Falcon Heavy rocket remained at the LC-39A launch complex, as the process of reconfiguring the LC-39A for conventional Falcon 9 Block 5 launch vehicles and vice versa takes several days. As a result, a number of future launches from the LC-39A complex, which were scheduled for early 2024, were postponed.

The United States Space Force-52 (USSF-52) mission, also known as OTV-7, is the seventh launch of the secret Boeing X-37 robotic mini-shuttle (Orbital Test Vehicle, OTV). The previous launch took place on May 17, 2020, when the Boeing X-37 was in orbit for a record 908 days and 21 hours. The planned duration of the OTV-7 mission is 1000 days, and the vehicle will spend them in a different, higher geocentric orbit. That is why the heavy Falcon Heavy rocket was used instead of the usual Atlas V 501 or Falcon 9 launch vehicles for Boeing X-37. The details of the USSF-52 mission are not disclosed, but it is known that, among other things, the impact of space radiation on plants during long-duration flights will be studied.

Interestingly, on December 14, 2023, China launched its own robotic mini-shuttle Shenlong (“Divine Dragon”) for the third time, which has almost the same configuration as the Boeing X-37. The mission of this ship is also classified. During its second flight in 2022-23, it spent 276 days in orbit.