X-37B Orbital Test Vehicle

The X-37B is an uncrewed, reusable spaceplane derived from the canceled X-40 program. Launched aboard Atlas V or Falcon 9 rockets, it conducts long-duration orbital missions — the longest exceeding two and a half years — testing sensors, materials, and space-situational-awareness payloads.

The program is operated by U.S. Space Force Space Rapid Capabilities Office and remains substantially classified. Both flight vehicles continue to be rotated through mission-specific payload configurations.

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