The X-37B, also known as the Orbital Test Vehicle (OTV), is an unmanned spaceplane operated by the United States Air Force (USAF). It is a reusable spacecraft designed for a variety of missions, including space experimentation, technology testing, and space operations. Here are some key details about the X-37B:

1. Origins: The X-37B is part of a program initiated by NASA in the late 1990s and later transferred to the U.S. Department of Defense. The program’s primary goal was to develop a reusable, unmanned spacecraft for a range of purposes.
2. Boeing’s Development: Boeing Phantom Works, a division of Boeing, was the primary contractor responsible for designing, building, and testing the X-37B.
3. Size and Appearance: The X-37B resembles a smaller version of the Space Shuttle, with a length of about 29 feet (8.8 meters) and a wingspan of approximately 15 feet (4.6 meters). It is launched atop a rocket and lands horizontally like an airplane.
4. Reusability: One of the primary objectives of the X-37B program is to demonstrate the feasibility of a reusable spaceplane. After completing its mission, the X-37B can return to Earth, land autonomously, and be refurbished for future flights.
5. Classified Missions: Many aspects of the X-37B program, including its specific missions and payloads, are classified. As a result, the spacecraft has been used for a variety of classified experiments and operations.
6. Long Duration Missions: The X-37B has set records for its extended missions in low Earth orbit. It can spend months or even years in space, autonomously conducting experiments and technology demonstrations before returning to Earth.
7. Versatile Platform: While the exact nature of its missions is often undisclosed, the X-37B is known to carry a variety of experiments and payloads, including scientific instruments, materials science experiments, and technology demonstrations.
8. Launch and Landing: The X-37B is launched into space atop a rocket, typically an Atlas V or SpaceX Falcon 9. When its mission is complete, it re-enters Earth’s atmosphere, glides back to the surface, and lands autonomously on a runway.
9. Multiple Flights: The X-37B program has conducted multiple missions, with each mission building upon the knowledge gained from previous flights. The spacecraft has been used to test various technologies and concepts in space.
10. Uncertain Future: The X-37B program continues to evolve, with ongoing missions and developments. Its versatility and ability to operate in space for extended periods make it a valuable asset for the U.S. military and space research community.

While many details about the X-37B remain classified, it represents an important platform for testing and advancing technology in space and conducting experiments in a reusable spacecraft.