A military space plane that is shrouded in secrecy is set to launch into space on its latest, mostly-secret mission Wednesday.
The US Air Force's X-37B space plane is due to blast off atop an Atlas V rocket for its fourth space mission from Cape Canaveral Air Force Station in Florida.
Unlike previous missions, however, the Air Force has offered details of at least part of its mission: an experimental Hall thruster.
This electric propulsion device ionizes a noble gas such as xenon. The device would allow a spacecraft to carry larger payloads and perform more orbital maneuvers than one powered by traditional rocket engines.
The craft resembles the space shuttle, but is roughly a quarter of the size of its retired cousin. Like the shuttle, it's both reusable and capable of landing like an airplane.
One of the experiments is the Planetary Society's solar sail, a project based on a design by Carl Sagan. Called LightSail and funded by donations, the mylar sheet will use radiation from the sun to maneuver.
More videos from AOL
- Israel facing suspension from world football
- Investigation into Manila shoe factory that killed 72
- Deepcut family want closure over daughter's death
- Man caught on CCTV kicking dog's head 'like a football'
- Police brutally attack father in front of son