Washington, Dec 30 : Elon Musk-run SpaceX has sent a secretive US military space plane to orbit and what all it carried aboard the mission are classified. This is the first time the US military has selected SpaceX's Falcon Heavy rocket for a mission, reports TechCrunch. The Falcon Heavy rocket launched the secretive mission to space after weeks of delays. 'The US Space Force's X-37B space plane, a reusable vehicle that acts as a classified testbed for experiments in space, was the sole payload on the massive rocket,' the report mentioned. As with the other six uncrewed X-37B missions, little is known about this mission too. 'The extra boost could suggest that this mission is heading to farther orbits, though again, the space plane's mission profile is secret,' according to the report. The US Space Force said in a statement that the mission has objectives including 'operating the reusable spaceplane in new orbital regimes, experimenting with future space domain awareness technologies, and investigating the radiation effects on materials provided by NASA'. The seventh mission of the X-37B, also known as OTV-7, has a wide range of test and experimentation objectives. 'These tests are key to ensuring safe and responsible operations in space for all users of the space domain,' according to the Space Force. Secretary of the Air Force Frank Kendall said that 'this seventh flight of the X-37B continues to demonstrate the innovative spirit of the US Space Force.' The X-37B, which first launched in April 2010, has accrued a total of 3,774 days in space. The previous missions have successfully experimented with Naval Research Laboratory technology designed to harness solar energy and transmit power to the ground; tested the effects of long-duration space exposure to organic materials for NASA; and provided an opportunity to launch a spacecraft designed and operated by cadets at US Air Force Academy. /IANS