The United States military is gearing up for the launch of its secretive X-37B space plane on its seventh mission in orbit. The uncrewed vehicle, resembling a miniature space shuttle, is scheduled to take off from NASA's Kennedy Space Center in Florida on Sunday within a 10-minute launch window opening at 8:14 p.m. ET. Notably, this mission marks the first time the X-37B will ride into orbit aboard a SpaceX Falcon Heavy rocket.

Since its debut over a decade ago, the X-37B has left the space community intrigued due to the enigmatic nature of its activities in low Earth orbit. Its true purpose and location remain unknown, despite occasional sightings and photographs of the space plane in the night sky by keen skywatchers equipped with telescopes.

The classified details of X-37B missions are typically not disclosed by the U.S. Space Force, leaving little information about the specific operations conducted by the robotic vehicle in orbit. However, for the upcoming flight, referred to as OTV-7, the X-37B is expected to carry out various tests, including experimenting with space domain awareness technologies and investigating the radiation effects on NASA materials.

On its previous mission, which lasted 908 days in orbit, the X-37B was launched using a SpaceX Falcon 9 rocket. Prior to that, it had successfully completed five missions using United Launch Alliance's Atlas V rockets. The utilization of a Falcon Heavy booster for this mission significantly increases the vehicle's power, enabling it to explore "new orbital regimes," according to statements from Space Force officials.

The duration of the X-37B's stay in space and its ultimate orbit altitude remain undisclosed by the military. However, the X-37B missions are considered crucial for ensuring safe and responsible operations in space for all users of the space domain, as stated by the Space Force. Air Force Secretary Frank Kendall expressed that the seventh flight of the X-37B demonstrates the innovative spirit of the United States Space Force.

Built by Boeing, the mini space plane measures approximately 29 feet long and, like the NASA space shuttles, is designed to return to Earth and land on a runway. Since its first mission in 2010, the X-37B has accumulated a total of 3,774 days in orbit over the course of six flights. Previous outings of the X-37B involved civilian science experiments, such as testing technology for harnessing solar energy and transmitting power to the ground, as well as studying the effects of long-term space exposure on organic materials.

As the X-37B prepares for its seventh mission, the interest and curiosity surrounding its activities continue to pique the curiosity of those within the space community, eagerly awaiting any new insights that may emerge from this mysterious venture.