Simplify the following text for a Grade 7 native English-speaking person.
Original: The Defense Support Program ( DSP ) is a program of the U.S. Air Force that operates the reconnaissance satellites which form the principal component of the Satellite Early Warning System currently used by the United States .
Simplified: The Defense Support Program ( DSP ) is a group of satellites that orbit the Earth . They are owned by the United States Air Force to run the Satellite Early Warning System used by the United States .