The US Air Force initially launched the X 37B drone on April 22 2010. It has been on many missions since then
CHAPTER 1 Exploring Space It is August 2019. A figure glides down from the dark sky Its wheels hit the runway The X 37B spacecraft has returned from an orbit around Earth It spent two years in space The X 37B is a drone A drone is an unpiloted aircraft or ship
The X 37B drone landed at the Kennedy Space Center in Florida The X 37B drone is shaped like a bullet It is 29 feet 9 m long Short wings stick out on its sides It has no windows The X 37B is the first drone to return from space and land on
its own It travels at about 17,500 miles per hour 28,200 km h The US Air Force owns the X 37B The drone's first flight was in 2010. Since then it has orbited Earth many times The drone has spent more than 1,000 days in orbit The Air Force says drone could be used to bring experiments back the from space Flying in Space All planets have atmospheres An atmosphere is the layer of gases that surrounds a planet Some drones have spinning blades to help them fly The blades push against air as they spin When a planet's atmosphere is thin the blades have to spin faster to lift the drone Space drones must be lightweight If they are too heavy they will not be able to fly
