Atomic Clocks for Space
The Naval Research Laboratory in the 1970s investigated whether atomic clocks would work in space in the TIMATION Program. Like John Harrison in the 18th century, atomic clockmakers had to find ways to miniaturize clocks without sacrificing stability in a new environment. These clocks are based on the elements rubidium and cesium. Rubidium clocks are smaller and less costly but slightly less accurate than cesium clocks.
Navigation Technology Satellite 2 Engineering Test Model
The Navigation Technology Satellite 2 (NTS-2) was launched in 1977 to test new navigation techniques. The two cesium atomic clocks on board helped to show that satellite navigation based on precise timing was possible. This engineering model was used at the Naval Research Laboratory for testing the satellite before launch.