The Deep Space Atomic Clock, or DSAC project, managed by NASA's Jet Propulsion Laboratory in Pasadena, California, is developing -- for use aboard spacecraft -- a smaller and lighter version of the refrigerator-sized atomic clocks used at ground-based space tracking stations. That could eliminate the need to send signals from Earth to a spacecraft and back, enabling more efficient and accurate data transfer for experiments and navigation both close to home and on deep space missions. Precise timekeeping is essential to navigation and, over a typical 10-year deep space mission, DSAC would gain or lose only about a microsecond.

Credit: NASA