| Kosmos 138 | |
| Mission Type: | Optical imaging reconnaissance |
| Operator: | OKB-1 |
| Cospar Id: | 1967-004A |
| Satcat: | 02646 |
| Mission Duration: | 8 days |
| Spacecraft Type: | Zenit-2 |
| Manufacturer: | OKB-1 |
| Launch Mass: | 4730 kg |
| Launch Date: | 19 January 1967 12:39:59 GMT |
| Launch Rocket: | Vostok-2 s/n N15001-05 |
| Launch Site: | Plesetsk, Site 41/1 |
| Launch Contractor: | OKB-1 |
| Disposal Type: | Recovered |
| Landing Date: | 27 January 1967 06:14 GMT |
| Orbit Epoch: | 19 January 1967 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 191 km |
| Orbit Apoapsis: | 273 km |
| Orbit Inclination: | 65.0° |
| Orbit Period: | 89.2 minutes |
| Apsis: | gee |
Kosmos 138 (Russian: Космос 138 meaning Cosmos 138) or Zenit-2 No.43 was a Soviet, first generation, low resolution, optical film-return reconnaissance satellite launched in 1967. A Zenit-2 spacecraft, Kosmos 138 was the forty-fifth of eighty-one such satellites to be launched[1] [2] and had a mass of .
Kosmos 138 was launched by a Vostok-2 rocket, serial number N15001-05,[3] flying from Site 41/1 at the Plesetsk Cosmodrome. The launch took place at 12:39:59 GMT on 19 January 1967,[4] and following its arrival in orbit the spacecraft received its Kosmos designation; along with the International Designator 1967-004A and the Satellite Catalog Number 02646.[5] The satellite reached a slightly lower orbit than had been planned, but was still able to complete its mission.
Kosmos 138 was operated in a low Earth orbit, at an epoch of 19 January 1967, it had a perigee of, an apogee of, an inclination of 65.0°, and an orbital period of 89.2 minutes.[6] After 8 days in orbit, Kosmos 138 was deorbited, with its return capsule descending under parachute, landing at 06:14 GMT on 27 January 1967, and recovered by Soviet force.[7]