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Program: Transit

American navigation program

First navigation program launched in 1959 and operational in 1964. These satellites were for the U.S. Navy and in particular, the Fleet Ballistic Missile Submarines, to accurately verify their location. This program was superseded by NOVA and finally by the Global Positioning Satellites. It was commercialized in 1967. First geodetic program to use the Doppler effect.

There were 7 pre-operational Transit-5xxx satellites: 3 Transit-5A launched by Scout, 3 Transit-5BN (nuclear powered) launched by Thor Able-Star, an 1 Transit-5C launched by Scout. The Transit-5C was mostly identical with the operational Transit-O series. The first 5 Transit-O's transfered to the Thor Ablestar launch vehicle, because the Scout lacked reliability at this time.

Since 1 Jan 1997 the satellite system is used for ionospheric studies (was retired from service for navigation at the end of 1996). It has been renamed NIMS (Navy Ionospheric Monitoring System).


Operator: Naval Space Command

External resources



Technical data

Frequencies: uplink 149.982 / 149.988 (operational channel) MHz and downlink 399.9413 / 399.952 / 399.968 (operational channel) MHz

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