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- Elon Musk's SpaceX launched a mysterious military spaceplane into orbit Thursday.
- The X-37B spaceplane holds the record for the longest time spent in orbit.
- SpaceX dominates the industry and the US government is increasingly dependent on Musk's rockets.
A mysterious military spaceplane has blasted off on the back of one of Elon Musk's rockets.
The billionaire's rocket company SpaceX launched X-37B, a top-secret spaceplane operated by the US Space Force, into orbit using one of its Falcon Heavy rockets on Thursday.