Explanation:

1st pair is correct. The Cosmic Background Explorer, also referred to as Explorer 66, was a satellite dedicated to cosmology, which operated from 1989 to 1993.
2nd pair is incorrect. The Falcon rocket family is an American family of multi-use rocket launch vehicles developed and operated by Space Exploration Technologies (SpaceX).
3rd pair is correctly matched. Space Shuttle Discovery is one of the orbiters from NASA's Space Shuttle program and the third of five fully operational orbiters to be built. Its first mission, STS-41-D, flew from August 30 to September 5, 1984.
4th pair is correctly matched. Space Shuttle Atlantis is a Space Shuttle orbiter belonging to the National Aeronautics and Space Administration (NASA), the spaceflight and space exploration agency of the United States.