Launch of X-37B spaceplane for US Space Force in May.

A United Launch Alliance Atlas V 501 configuration rocket will launch the USSF-7 mission for the U.S. Space Force. This will mark the sixth flight of the X-37B Orbital Test Vehicle (OTV-6).

The X-37B has a lifting body-style and landing profile that is similar to the Space Shuttle, but the vehicle is one-fourth the size (Picture source: Boeing)

OTV is an experimental test program to demonstrate technologies for reliable, reusable, unmanned space test platform for the U.S. military. The primary objectives of the X-37B include reusable spacecraft technologies for America's future in space and operating experiments which can be returned to and examined on Earth.

The X-37B is an advanced re-entry spacecraft, designed to operate in low-earth orbit, 150 to 500 miles above the Earth. The vehicle is the first since the Space Shuttle with the ability to return experiments to Earth for further inspection and analysis. This United States Air Force unmanned space vehicle explores reusable vehicle technologies that support long-term space objectives.

The vehicle features many elements that mark a first use in space, including:
- Avionics designed to automate all de-orbit and landing functions.
- Flight controls and brakes using all electro-mechanical actuation; no hydraulics on board.
- Built using a lighter composite structure, rather than traditional aluminum.
- New generation of high-temperature wing leading-edge tiles and toughened uni-piece fibrous refractory oxidation-resistant ceramic (TUFROC) tiles.
- Advanced conformal reusable insulation (CRI) blankets.
- Toughened uni-piece fibrous insulation (TUFI) impregnated silica tiles.

The USSF-7 mission will be the 139th mission for ULA. It is the 84th for an Atlas V rocket and the 7th in the 501 configuration.

ULA recently launched the AEHF-6 military communications satellite abroad an Atlas V 551 configuration rocket marking U.S. Space Force’s first dedicated mission.