| Kosmos 37 | |
| Names List: | Zenit 2-21 |
| Mission Type: | Optical imaging reconnaissance |
| Operator: | OKB-1 |
| Cospar Id: | 1964-044A |
| Satcat: | 848 |
| Mission Duration: | 8 days |
| Spacecraft Type: | Zenit-2 |
| Manufacturer: | OKB-1 |
| Launch Mass: | 4730 kg[1] |
| Launch Date: | 14 August 1964, 09:36:00 GMT |
| Launch Rocket: | Vostok-2 |
| Launch Site: | Baikonur 31/6 |
| Launch Contractor: | OKB-1 |
| Disposal Type: | Recovered |
| Landing Date: | 22 August 1964 |
| Orbit Epoch: | 14 August 1964 |
| Orbit Reference: | Geocentric[2] |
| Orbit Regime: | Low Earth |
| Orbit Periapsis: | 207 km |
| Orbit Apoapsis: | 287 km |
| Orbit Inclination: | 65.0° |
| Orbit Period: | 89.5 minutes |
| Apsis: | gee |
| Programme: | Zenit programme Zenit-2 |
| Previous Mission: | Zenit 2-20 |
| Next Mission: | Zenit 2-22 |
| Programme2: | Kosmos (satellites) |
| Previous Mission2: | Kosmos 36 |
| Next Mission2: | Kosmos 38 |
Kosmos 37 (Russian: link=no|Космос 37 meaning Cosmos 37) or Zenit-2 No.21 was a Soviet, first generation, low resolution, optical film-return reconnaissance satellite launched in 1964. A Zenit-2 spacecraft, Kosmos 37 was the twentieth of eighty-one such satellites to be launched[3] and had a mass of 4730kg (10,430lb).
Kosmos 37 was launched by a Vostok-2 rocket, serial number R15001-04,[4] flying from Site 31/6 at the Baikonur Cosmodrome. The launch took place at 09:36 GMT on 14 August 1964,[5] and following its successful arrival in orbit the spacecraft received its Kosmos designation, along with the International Designator 1964-044A and the Satellite Catalog Number 00848.
Kosmos 37 was operated in a low Earth orbit, it had a perigee of 207km (129miles), an apogee of 287km (178miles), inclination of 65.0° and an orbital period of 89.5 minutes.[6] During the mission one of the satellite's film reels snapped, resulting in the associated camera only taking some of the images it had been programmed to produce.[7] The mission has been partially complete because there was a break in the film of the SA-10 camera.[8] On 22 August 1964, after eight days in orbit, Kosmos 37 was deorbited with its return capsule descending by parachute for recovery by Soviet forces.[9]