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superseded by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
http://www.fas.org/spp/military/program/nav/transit.htm
http://sd-www.jhuapl.edu/Transit/index.html
Frequencies: uplink 149.982 / 149.988 (operational channel) MHz and
downlink 399.9413 / 399.952 / 399.968 (operational channel) MHz