Zenit (satellite)


Zenit was a series of military photoreconnaissance satellites launched by the Soviet Union between 1961 and 1994. To conceal their nature, all flights were given the public Kosmos designation.

Description

The basic design of the Zenit satellites was similar to the Vostok crewed spacecraft, sharing the return and service modules. It consisted of a spherical re-entry capsule in diameter with a mass of around. This capsule contained the camera system, its film, recovery beacons, parachutes and a destruct charge. In orbit, this was attached to a service module that contained batteries, electronic equipment, an orientation system and a liquid-fuelled rocket engine that would slow the Zenit for re-entry, before the service module detached. The total length in orbit was around and the total mass was between.
Unlike the American CORONA spacecraft, the return capsule carried both the film and the cameras and kept them in a temperature-controlled pressurised environment. This simplified the design and engineering of the camera system but added considerably to the mass of the satellite. An advantage was that cameras could be reused. The camera would either land on the ground or be recovered in midair by a modified Mil Mi-8 helicopter.
Early Zenits were launched using the Vostok rocket; later versions used the Voskhod and the Soyuz rockets. The first flights were launched from Baikonur Cosmodrome but subsequent launches also took place at Plesetsk Cosmodrome.
Most Zenits flew in a slightly elliptical orbit with a perigee of around and an apogee between ; the missions usually lasted between 8 and 15 days.

History

In 1956, the Soviet government issued a secret decree that authorised the development of "Object D" which led to the program to launch Sputnik 3 The text of the decree remains secret, but it apparently authorised another satellite program – "Object OD-1" – which was to be used for photo-reconnaissance from space.
By 1958, the OKB-1 design bureau was simultaneously working on Object OD-1 and Object OD-2 – an early design for the Vostok crewed spacecraft. The development of Object OD-1 was experiencing serious difficulties so the head of OKB-1, Sergei Korolev, initiated work to see if a design based on Object OD-2 could be used for an uncrewed photo-reconnaissance satellite. This may have been a political manoeuvre that would enable him to continue the crewed space program and avoid diverting more of OKB-1's resources into Object OD-1.
Despite bitter opposition from the military the Soviet government endorsed Korolev's approach and issued decrees on 22 and 25 May 1959 which ordered the development of three different spacecraft, all based on the same basic, Object OD-2, design. Spacecraft 1K would be a simplified prototype, 2K was to be a reconnaissance satellite and 3K was to be for crewed flights. The name Vostok was also initially used for all three of these craft. But in 1961 the name became publicly known as the name of Yuri Gagarin's spacecraft so the "Vostok 2" reconnaissance satellite was renamed "Zenit 2".
The first Zenit launch attempt took place on 11 December 1961, but there was a fault in the rocket's third stage and the spacecraft was destroyed using its destruct charge. The second attempt — publicly referred to as Kosmos 4 — was successfully launched on 26 April 1962 and re-entered three days later. However a failure in the orientation system meant few useful pictures were obtained; usable pictures had a resolution of about 5 to 7 meters. Launch #3 on 1 June 1962 failed dramatically when one of the 8A92 booster's strap-ons shut down at liftoff and fell onto the pad, exploding on impact. The rest of the launch vehicle crashed 300 meters away. This accident caused considerable damage to Site 1, delaying the flights of Vostok 3 and Vostok 4 by two months.
On 28 July 1962, Site 1 was back in service to host the next Zenit flight, which performed successfully. Testing continued over the next year largely without incident but on 10 July 1963, another launch accident occurred in practically identical fashion to the June 1962 failure. Once again, one of the strap-ons shut down at liftoff, separated from the booster, and exploded on impact with the pad while the rest of the launch vehicle crashed a few hundred feet away.
Examination of telemetry from the booster indicated that some sort of electrical failure occurred, but subsequent investigation took three months and finally concluded that a switch designed to cut power to the strap-ons at staging had malfunctioned, possibly due to liftoff-induced vibration. The electrical circuit in the 8A92 was redesigned and it never again experienced problems with the strap-ons shutting down at launch.
Many versions of the satellite were developed for different reconnaissance missions and flights continued until 1994.

Zenit variants

Zenit 2

Zenit 2 was the first version to be launched between 1961 and 1970.
The arrangement of cameras varied, but most flights carried four cameras of 1000 mm focal length, and one of 200 mm focal length. The single lower resolution camera was intended to provide low-resolution pictures that would help give a context to the high-resolution pictures.
Each camera had 1500 frames of film and from, each frame held an image of a square. The ground resolution was stated to be although some unofficial sources claim it was much better—one source claims the number of cars in a car park could be counted. The cameras were developed at the Krasnogorsk Optical-Mechanical Factory near Moscow. The Krasnogorsk factory, which had been producing a variety of optical equipment for the military since 1942, was also the manufacturer of the popular Zenit SLR cameras.
Zenit 2s also carried ELINT equipment called Kust-12M to receive NATO radar signals. The satellites carried a parabolic antenna, around in diameter, that is associated with this equipment. However, it is unclear if the antenna transmitted recorded signals to the ground or was for intercepting radar signals. In the latter case they would have been recorded on magnetic tape, to be retrieved after the return capsule landed.
There were 81 Zenit 2 launches. 58 were successful and 13 were partially successful. There were 9 failed missions, 2 because of a satellite malfunction and 7 because of a failure in the launch vehicle.
No.MissionLaunch date
Landing dateCOSPAR IDOrbitDuration
Outcome
1-11 December 1961
09:39
---
2Kosmos 426 April 1962
10:02
29 April 19621962-014A285 x 317 km
3-1 June 1962
09:38
---
4Kosmos 728 July 1962
09:18
1 August 19621962-033A197 x 356 km
5Kosmos 927 September 1962
09:39
1 October 19621962-048A829 x 981 km
6Kosmos 1017 October 1962
09:00
21 October 19621962-054A178 x 376 km
7Kosmos 1222 December 1962
09:23
30 December 19621962-072A202 x 385 km
8Kosmos 1321 March 1963
08:30
29 March 19631963-006A214 x 303 km
9Kosmos 1522 April 1963
08:30
27 April 19631963-011A194 x 336 km
10Kosmos 1628 April 1963
08:50
8 May 19631963-012A201 x 379 km
11Kosmos 1824 May 1963
10:33
2 June 19631963-018A212 x 269 km
12-10 July 1963---
13Kosmos 2018 October 1963
09:29
26 October 19631963-040A201 x 296 km
14-28 November 1963---
15Kosmos 2419 December 1963
09:28
28 December 19631963-052A204 x 391 km
16Kosmos 284 April 1964
09:36
12 April 19641964-017A213 x 373 km
17Kosmos 2925 April 1964
10:19
2 May 19641964-021A203 x 292 km
18Kosmos 3210 June 1964
10:48
18 June 19641964-029A205 x 322 km
19Kosmos 3323 June 1964
10:19
1 July 19641964-033A205 x 279 km
20Kosmos 3515 July 1964
11:31
23 July 19641964-039A218 x 258 km
21Kosmos 3714 August 1964
09:36
22 August 19641964-044A208 x 240 km
22Kosmos 4624 September 1964
12:00
2 October 19641964-059A211 x 264 km
23Kosmos 4814 October 1964
09:50
20 October 19641964-066A204 x 284 km
24Kosmos 5028 October 1964
10:48
5 November 19641964-070A190 x 233 km
25Kosmos 5211 January 1965
09:36
19 January 19651965-001A203 x 298 km
26Kosmos 6425 March 1965
10:04
2 April 19651965-025A205 x 250 km
27Kosmos 667 May 1965
09:50
15 May 19651965-035A285 x 397 km
28Kosmos 6815 June 1965
10:04
23 June 19651965-046A208 x 306 km
29-13 July 1965---
30Kosmos 7814 August 1965
11:16
22 August 19651965-066A330 x 379 km
31Kosmos 9827 November 1965
08:24
5 December 19651965-097A205 x 547 km
32Kosmos 9910 December 1965
08:09
18 December 19651965-103A203 x 309 km
33Kosmos 1047 January 1966
08:24
15 January 19661966-001A195 x 379 km
34Kosmos 10522 January 1966
08:38
30 January 19661966-003A203 x 311 km
35Kosmos 10710 February 1966
08:52
18 February 19661966-010A216 x 313 km
36Kosmos 11217 March 1966
10:28
25 March 19661966-021A214 x 664 km
37Kosmos 11520 April 1966
10:48
28 April 19661966-033A189 x 283 km
38Kosmos 1176 May 1966
11:02
14 May 19661966-037A200 x 314 km
39Kosmos 1208 June 1966
11:02
16 June 19661966-050A201 x 331 km
40Kosmos 12414 July 1966
10:33
22 July 19661966-064A202 x 282 km
41-16 September 1966
09:30
---
42Kosmos 12914 October 1966
12:13
21 October 19661966-091A199 x 288 km
43Kosmos 13219 November 1966
08:09
27 November 19661966-106A202 x 257 km
44Kosmos 13619 December 1966
12:00
27 December 19661966-064A202 x 282 km
45Kosmos 13819 January 1967
12:39
27 January 19671967-004A190 x 273 km
46Kosmos 14327 February 1967
08:45
7 March 19671967-017A202 x 390 km
47Kosmos 14713 March 1967
12:10
21 March 19671967-022A195 x 298 km
48Kosmos 1534 April 1967
14:00
12 April 19671967-030A199 x 279 km
49Kosmos 15712 May 1967
10:30
20 May 19671967-044A249 x 262 km
50Kosmos 1648 June 1967
13:00
14 Jun 19671967-057A185 x 317 km
51Kosmos 1684 July 1967
05:59
12 July 19671967-067A223 x 230 km
52-1 September 1967
10:30
---
53Kosmos 17716 September 1967
06:06
24 September 19671967-088A201 x 267 km
54Kosmos 18026 September 1967
10:20
4 October 19671967-093A206 x 350 km
55Kosmos 18111 October 1967
11:30
19 October 19671967-067A198 x 325 km
56Kosmos 19325 November 1967
11:30
3 December 19671967-117A745 x 756 km
57Kosmos 19516 December 1967
12:00
24 December 19671967-124A204 x 352 km
58Kosmos 19916 January 1968
12:00
1 February 19681968-003C206 x 363 km
59Kosmos 2055 March 1968
12:30
13 March 19681968-016A197 x 293 km
60Kosmos 2103 April 1968
11:00
11 April 19681968-024A200 x 373 km
61Kosmos 21620 April 1968
10:30
28 April 19681968-034A198 x 267 km
62Kosmos 2231 June 1968
10:50
9 June 19681968-045A221 x 317 km
63Kosmos 23110 July 1968
19:49
18 July 19681968-058A206 x 311 km
64Kosmos 2359 August 1968
07:00
17 August 19681968-067A201 x 281 km
65Kosmos 24014 September 1968
06:50
21 September 19681968-075A203 x 283 km
66Kosmos 24711 October 1968
12:05
19 October 19681968-088A199 x 345 km
67Kosmos 25313 November 1968
12:00
18 November 19681968-102A216 x 337 km
68Kosmos 25529 November 1968
12:40
7 December 19681968-105A197 x 317 km
69Kosmos 25810 December 1968
08:25
18 December 19681968-111A205 x 298 km
70Kosmos 26312 January 1969
12:10
20 January 19691969-003A200 x 325 km
71Kosmos 26625 February 1969
10:20
5 March 19691969-015A202 x 336 km
72Kosmos 27322 March 1969
12:15
30 March 19691969-027A200 x 336 km
73Kosmos 2789 April 1969
13:00
17 April 19691969-034A198 x 310 km
74Kosmos 28113 May 1969
09:15
21 May 19691969-042A191 x 303 km
75Kosmos 28724 June 1969
06:50
2 July 19691969-054A189 x 265 km
76Kosmos 29022 July 1969
12:30
30 July 19691969-060A195 x 332 km
77Kosmos 30124 September 1969
12:15
2 October 19691969-081A203 x 271 km
78Kosmos 30912 November 1969
11:30
20 November 19691969-098A185 x 364 km
79Kosmos 3254 March 1970
12:14
12 March 19701970-015A200 x 327 km
80Kosmos 32613 March 1970
08:00
21 March 19701970-018A208 x 232 km
81Kosmos 34412 May 1970
10:10
20 May 19701970-038A204 x 326 km

Zenit 2M

Improvements included a new camera system and the addition of solar panels. As the spacecraft mass was increased to 6300 kg, the Vostok rocket was replaced by the Voskhod rocket and
Soyuz rockets. In common with Zenit 2 satellites this also had an ELINT payload.
A total of 101 Zenit-2M satellites were launched between 1968 and 1979

Zenit 4

Unlike Zenit 2, little information on Zenit 4 has been released. The Zenit 4 was intended for high-resolution photography and carried one camera of 3000 mm focal length as well as a 200 mm camera. The focal length of the main camera was greater than the diameter of the capsule so the camera made use of a mirror to fold the light path. The ground resolution is not publicly known but it is believed to have been 1–2 metre.
The Zenit 4 had a mass of 6300 kg — around 1800 kg more than the Zenit 2. So, instead of the Vostok rocket, it was launched by the heavier Voskhod rocket. A total of 76 Zenit-4 satellites were flown between 1963 and 1970.

Zenit 4 M

An improved version of the Zenit 4, the Zenit 4M carried a new camera, solar panels, and a restartable engine so the satellite's orbit could be altered during the course of its mission. The mission duration was 13 days.
A total of 61 Zenit-4M satellites were launched between 1968 and 1974.

Zenit 4 MK

These may have been versions of the Zenit 4 designed specifically to fly in lower orbits to improve image resolution. Some sources claim they were fitted with devices to compensate for aerodynamic drag and to withstand the effects of aerodynamic heating.
A total of 80 Zenit-4MK satellites were launched between 1969 and 1977.

Zenit 4 MKM

Intended to replace the 4MK design, the 4MKM may have been a low altitude variant of the later Zenit-6U and have similar equipment to it
No.MissionLaunch date
Landing dateCOSPAR IDOrbitDuration
Outcome
1Kosmos 92712 July 1977
09:00
25 July 19771977-063A153 x 361 km
2Kosmos 93220 July 1977
07:35
2 August 19771977-069A150 x 358 km
3-10 August 1977
10:40
---
4Kosmos 93824 August 1977
14:30
6 September 19771977-078A181 x 340 km
5Kosmos 95316 September 1977
14:30
29 September 19771977-089A180 x 330 km
6Kosmos 95730 September 1977
09:46
13 October 19771977-098A171 x 361 km
7Kosmos 9644 December 1977
12:00
17 December 19771977-110A171 x 362 km
8Kosmos 96920 December 1977
15:50
3 January 19781977-120A180 x 317 km
9Kosmos 9746 January 1978
15:50
19 January 19781978-001A178 x 334 km
10Kosmos 98624 January 1978
09:50
7 February 19781978-010A172 x 318 km
11Kosmos 98731 January 1978
14:50
14 February 19781978-013A189 x 322 km
12Kosmos 98914 February 1978
09:30
28 February 19781978-017A169 x 318 km
13Kosmos 99310 March 1978
10:42
23 March 19781978-027A190 x 325 km
14Kosmos 99930 March 1978
07:50
12 April 19781978-033A174 x 352 km
15Kosmos 100320 April 1978
15:30
4 May 19781978-040A178 x 328 km
16Kosmos 100716 May 1978
10:40
28 May 19781978-048A168 x 350 km
17Kosmos 102110 June 1978
08:35
23 June 19781978-057A173 x 313 km
18Kosmos 102212 June 1978
10:30
25 June 19781978-059A171 x 344 km
19Kosmos 102929 August 1978
15:00
8 September 19781978-082A194 x 316 km
20Kosmos 10319 September 1978
15:00
22 September 19781978-085A182 x 329 km
21Kosmos 10426 October 1978
15:30
19 October 19781978-092A179 x 299 km
22Kosmos 104715 November 1978
11:45
28 November 19781978-104A171 x 354 km
23Kosmos 104921 November 1978
12:00
4 December 19781978-107A169 x 338 km
24Kosmos 10597 December 1978
15:30
20 December 19781978-110A180 x 338 km
25Kosmos 106826 December 1978
15:30
8 January 19791978-123A191 x 389 km
26Kosmos 107113 January 1979
15:30
26 January 19791979-002A179 x 339 km
27Kosmos 107330 January 1979
15:15
12 February 19791979-006A182 x 328 km
28Kosmos 107822 February 1979
12:10
2 March 19791979-016A168 x 280 km
29Kosmos 108014 March 1979
10:50
28 March 19791979-023A169 x 294 km
30Kosmos 109815 May 1979
11:40
28 May 19791979-040A170 x 354 km
31Kosmos 111310 July 1979
09:00
23 July 19791979-064A173 x 330 km
32Kosmos 111725 July 1979
15:20
7 August 19791979-068A177 x 325 km
33Kosmos 112011 August 1979
09:15
24 August 19791979-073A170 x 362 km
34Kosmos 112814 September 1979
15:30
27 September 19791979-081A173 x 328 km
35Kosmos 114828 December 1979
13:00
10 January 19801979-106A170 x 340 km
36Kosmos 116521 February 1980
12:00
5 March 19801980-017A170 x 350 km
37Kosmos 11701 April 1980
08:00
12 April 19801980-025A178 x 379 km
38Kosmos 117317 April 1980
08:30
28 April 19801980-029A174 x 352 km
39Kosmos 121410 October 1980
13:10
23 October 19801980-082A170 x 347 km

Zenit 4 MKT

Another variant of the Zenit-4 design equipped with a Priroda-3 camera, intended for the investigation of natural resources in the interests of the Soviet economy and international cooperation.
No.MissionLaunch date
Landing dateCOSPAR IDOrbitDuration
Outcome
1Kosmos 77125 September 1975
09:50
8 October 19751975-090A203 x 219 km
2Kosmos 82021 May 1976
07:00
2 June 19761976-046A209 x 217 km
3-4 October 1976
11:00
---
4Kosmos 91226 May 1977
07:00
8 June 19771977-040A217 x 225 km
5Kosmos 9482 September 1977
09:00
15 Sept 19771977-083A217 x 235 km
6Kosmos 101023 May 1978
07:30
5 June 19781978-052A217 x 230 km
7Kosmos 10333 October 1978
11:00
16 October 19781978-089A212 x 231 km
8Kosmos 109917 May 1979
07:10
30 May 19791979-041A215 x 247 km
9Kosmos 11058 June 1979
07:10
21 June 19791979-052A212 x 254 km
10Kosmos 110822 June 1979
07:00
5 July 19791979-041A214 x 245 km
11Kosmos 111513 July 1979
08:25
26 July 19791979-066A217 x 235 km
12Kosmos 112321 August 1979
11:10
3 September 19791979-076A211 x 236 km
13Kosmos 118223 May 1980
07:10
5 June 19801980-040A211 x 251 km
14Kosmos 120115 July 1980
07:30
28 July 19801980-061A213 x 243 km
15Kosmos 120722 August 1980
10:00
4 September 19801980-070A211 x 256 km
16Kosmos 121226 September 1980
10:10
9 October 19801980-078A205 x 244 km
17Kosmos 127322 May 1981
07:10
5 June 19811981-040A205 x 258 km
18Kosmos 127616 June 1981
07:00
29 June 19811981-055A211 x 233 km
19Kosmos 13149 October 1981
10:40
22 October 19811981-101A209 x 223 km
20Kosmos 135323 April 1982
09:40
6 May 19821982-036A207 x 238 km
21Kosmos 138713 July 1982
08:00
26 July 19821982-071A201 x 229 km
22Kosmos 14068 September 1982
10:20
21 September 19821982-089A207 x 238 km
23Kosmos 145828 April 1983
08:30
11 May 19831983-040A207 x 238 km
24Kosmos 14953 September 1983
10:15
16 September 19831983-092A205 x 221 km
25Kosmos 155722 May 1984
08:30
4 June 19841984-048A208 x 245 km
26Kosmos 159713 September 1984
10:25
26 September 19841984-099A208 x 241 km
27Kosmos 16816 September 1985
08:30
19 September 19851985-080A206 x 225 km

Zenit 4 MT

A special version of the Zenit 4M intended for topographical photography. It carried an SA-106 topographic camera, a laser altimeter and Doppler apparatus.
No.MissionLaunch date
Landing dateCOSPAR IDOrbitDuration
Outcome
1Kosmos 47027 December 1971
14:04
6 January 19721971-118A192 x 259 km
2Kosmos 50213 July 1972
14:30
25 July 19721972-055A203 x 262 km
3Kosmos 54127 December 1972
10:30
8 January 19731972-105A218 x 348 km
4Kosmos 57627 June 1973
11:50
9 July 19731973-044A204 x 332 km
5Kosmos 61617 December 1973
12:00
28 December 19731973-102A206 x 332 km
6Kosmos 66429 June 1974
12:50
11 July 19741974-049A205 x 341 km
7Kosmos 6934 November 1974
10:40
16 November 19741974-088A219 x 243 km
8Kosmos 72021 March 1975
06:50
1 April 19751975-019A212 x 273 km
9Kosmos 75912 September 1975
05:30
23 September 19751975-084A231 x 276 km
10Kosmos 81131 March 1976
12:50
12 April 19761976-030A206 x 338 km
11Kosmos 85521 September 1976
11:40
3 October 19761976-095A221 x 321 km
12Kosmos 91610 June 1977
08:00
21 June 19771977-046A255 x 304 km
13Kosmos 9888 February 1978
12:15
20 February 19781978-015A201 x 335 km
14Kosmos 10461 November 1978
12:00
13 November 19781978-102A202 x 324 km
15Kosmos 106928 December 1978
16:30
10 January 19791978-124A254 x 289 km
16Kosmos 11193 August 1979
10:45
15 August 19791979-071A213 x 245 km
17Kosmos 11395 October 1979
11:30
18 October 19791979-088A199 x 329 km
18Kosmos 118015 May 1980
05:35
26 May 19801980-038A245 x 279 km
19Kosmos 121123 September 1980
10:30
4 October 19801980-077A211 x 236 km
20Kosmos 123916 January 1981
12:00
28 January 19811981-004A210 x 231 km
21Kosmos 130918 September 1981
09:30
1 October 19811981-092A212 x 257 km
22Kosmos 133212 January 1982
12:30
25 January 19821982-002A207 x 251 km
23Kosmos 13983 August 1982
11:30
13 August 19821982-077A211 x 231 km

Zenit 6U

A "universal" version of the Zenit, intended for both low-altitude, high-resolution missions and higher-altitude, general observation missions. All flights used the Soyuz launch vehicle. There were a total of 97 Zenit-6U satellites launched between 1976 and 1984.

Zenit 8

This was intended for military cartographic photography. It used a Soyuz launch vehicle and launches took place from both Baikonur and Plesetsk. It had a 15-day orbital life. Similar satellites were referred to using the "Resurs-DK No.1" designation.
A total of 102 Zenit-8 satellites were launched between 1984 and 1994, in addition to one sent into a suborbital trajectory during the maiden flight of the Soyuz-2 rocket in 2004.

Foreign assessment

By the late 1960s, American intelligence was not only able to distinguish between reconnaissance Kosmos missions and other satellites launched under the Kosmos label, but also which launch complex they lifted off from, and even when the film capsules were deorbited for recovery. Given the increase in spy satellite launch tempo that preceded and succeeded the major clashes during the 1969 Sino-Soviet border conflict, it was suggested that the pace of surveillance missions could indicate when Sino-Soviet tensions were elevated.

In popular culture

A Zenit satellite was mentioned in the movie Mission: Impossible – Dead Reckoning Part One.