Boeing X-37 - Wikipedia
The U.S. Air Forces X-37B Space Plane has been orbiting the Earth for 719 consecutive days. What is it doing, and what is its mission goal? - Quora
US military launches secret space plane X-37B - China.org.cn
Boeing X-37B unmanned spacecraft successfully completes first flight
X-20 Dyna-Soar Spaceplane Was Decades Ahead of Its Time | Defense Media Network
Boeing X-37 - Wikipedia
The US Space Force's secretive X-37B space plane: 10 surprising facts | Space
File:X-37B orbital test vehicle landing-2.jpg - Wikimedia Commons
USA-212 - Wikipedia
Boeing X-37B | Spacecraft Wiki | Fandom
US Military's 'Most Secretive Craft' Has Been 'Flying Non-Stop' For Over Two Years & Has No Plans To Land
X-37B orbital test vehicle concludes sixth successful mission > United States Space Force > News
What do you think the X-37B space plane actually does? - Quora
Boeing X-37 - Wikipedia
X-37B after landing photos. – sUAS News – The Business of Drones
US military's mysterious X-37B space plane passes 500 days in orbit, but we still have no clue what it's actually doing up there | Extremetech
X-37B OTV (Orbital Test Vehicle) - eoPortal
USA-299 - Wikipedia
X-40: Bust or Birth of Space Force? | The National Interest
Secret Mini Space Shuttle Could Launch April 19 - Universe Today
China Space Plane launched! Is China overtaking the US, or it is just an X-37B copy? - YouTube
X-37B secret spaceplane returns after record-breaking flight
File:X-37B OTV4 landed at Kennedy Space Center (170507-F-LD992-006).jpg - Wikimedia Commons
US Space Force's X-37B spaceplane returns to Florida after over 900-day mission : r/space
