Zenit (Russian: Зени́т, Zenith) is the name of a series of military spy satellites launched by the Soviet Union between 1961 and 1994. To conceal their nature, all flights were given the public Kosmos designation. Over a 33 year period, over five hundred Zenits were flown making it the most numerous type of satellite in the history of spaceflight. KH-4B Corona satellite Lacrosse radar spy satellite under construction A spy satellite (officially referred to as a reconnaissance satellite or recon sat) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ... Cosmos is name of a series of satellites which were launched by the Soviet Union and are being launched now by Russia. ...

Description

The basic design of the Zenit satellites was similar to the Vostok manned spacecraft. It consisted of a spherical re-entry capsule 2.3 m in diameter with a mass of around 2400kg. 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 5 m and the total mass was between 4600 kg and 6300 kg. Vostok (Russian: , translated as East) may refer to one of the following. ...

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 weight of the satellite. An advantage was that cameras could be reused. KH-4B Corona satellite Recovery of Discoverer 14 return capsule (typical for the Corona series Diagram of J-1 type stereo / panoramic reciprocating Corona reconnaissance satellite camera system used on KH-4A missions from 1963 to 1969. ...

Early Zenits were launched using the Vostok rocket; later versions used the Voskhod and the Soyuz rockets. The first flights were launched from the Baikonur Cosmodrome but subsequent launches also took place at the Plesetsk Cosmodrome. The Vostok rocket (Russian Восток, translated as East) was a derivative of the Soviet R-7 ICBM designed for the human spaceflight programme but later used for other satellite launches. ... The Voskhod rocket (Russian: Восход, translated as Sunrise) was a derivative of the Soviet R-7 ICBM designed for the human spaceflight programme but later used for launching Zenit reconnaissance satellites. ... The Soyuz launch vehicle (Western designation: A-2) is an expendable launch system designed by the Korolev Design Bureau (Soviet Union) and used as the launcher for the manned Soyuz spacecraft, as part of the Soyuz program. ... The Baikonur Cosmodrome (Russian: Космодром Байконур, Kosmodrom Baykonur), also called Tyuratam, is the worlds oldest and largest working space launch facility. ... Plesetsk Cosmodrome is a Russian spaceport, located about 800 km north of Moscow and south of Arkhangelsk (coordinates vary in different sources, but 62. ...

Most Zenits flew in a slighty elliptical orbit with an apogee of around 200km and a perigee between 250km and 350km; the missions usually lasted between 8 and 15 days. In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ...

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 (Sputnik 1 was a simplified spin-off of the Object D program.) 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. 1956 was a leap year starting on Sunday of the Gregorian calendar. ... Mission profile Sputnik 3 was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by a modified R-7/SS-6 ICBM. It was a research satellite to explore the upper atmosphere and the near space. ... Sputnik 1 was the first artificial satellite to be launched into orbit, on October 4, 1957. ...

By 1958, the OKB-1 design bureau was simultaneously working on Object OD-1 and Object OD-2 - an early design for the Vostok manned 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 unmanned photo-reconnaissance satellite. This may have been a political manoeuvre that would enable him to continue the manned space program and avoid diverting more of OKB-1’s resources into Object OD-1. 1958 was a common year starting on Wednesday of the Gregorian calendar. ... S.P. Korolev Rocket and Space Corporation Energia (also known as RKK Energiya) is a Russian manufacturer of spacecraft and space station components. ... Vostok (Russian: , translated as East) may refer to one of the following. ... Sergei Pavlovich Korolev (Серге́й Па́влович Королёв) (December 30, 1906– January 14, 1966) was the head Soviet rocket engineer and designer during the space race, known only as the chief designer during his lifetime. ...

Despite bitter opposition from the military, the Soviet government endorsed Korolov’s approach and issued decrees on 22 May and May 25, 1959 that 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 manned 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'. May 22 is the 142nd day of the year in the Gregorian calendar (143rd in leap years). ... May 25 is the 145th day of the year in the Gregorian calendar (146th in leap years). ... 1959 was a common year starting on Thursday of the Gregorian calendar. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... Yuri Alekseyevich Gagarin Yuri Alekseyevich Gagarin (Russian: Юрий Алексеевич Гагарин; YOO-ree a-lek-SE-ye-veech ga-GA-reen; March 9, 1934 – March 27, 1968), was a Soviet cosmonaut who in 1961 became the first human to travel into space. ...

The first Zenit launch attempt took place on the 11 November 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 Cosmos 4 - was successfully launched on the 26 April 1962 and re-entered three days later. However a failure in the orientation system meant no useful pictures were obtained. The third Zenit (Kosmos 7) was launched on the 28 July 1962 and successfully returned with pictures eleven days later. A further ten flights (including two more launch failures) took place before the system was considered operational. November 11 is the 315th day of the year (316th in leap years) in the Gregorian Calendar, with 50 days remaining. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... April 26 is the 116th day of the year in the Gregorian Calendar (117th in leap years). ... 1962 was a common year starting on Monday (link will take you to calendar). ... July 28 is the 209th day (210th in leap years) of the year in the Gregorian Calendar, with 156 days remaining. ... 1962 was a common year starting on Monday (link will take you to calendar). ...

Many versions of the satellite were developed for different reconnaissance missions and flights continued until 1994. 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ...

Zenit Variants

Zenit 2

Zenit 2 was the first version to be launched in 1961 (there was no Zenit 1.)

The arrangement of cameras varied, but most flights carried four cameras of 1000mm focal length, and one of 200mm 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 200km, each frame held an image of a 60km by 60 km square. The ground resolution was stated to be 10-15m 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. Curiously, this was also where the popular Zenit SLR cameras were made. Saint Basils Cathedral and Spasskaya Tower of Moscow Kremlin at Red Square. ... Zenit Cameras are SLR cameras (Single lens Reflex) and are produced by KMZ (Krasnogorskiy Mekhanicheskiy Zavod) near Moscow and by BelOMO in Byelorussia (since 1970s). ...

Zenit 2’s also carried ELINT equipment to receive NATO radar signals, these were recorded and transmitted to the ground using a parabolic antenna, around 1m in diameter, mounted on the side of the satellite. ELINT stands for ELectronic INTelligence, and refers to intelligence-gathering by use of electronic sensors. ... The flag of NATO NATO 2002 Summit in Prague The North Atlantic Treaty Organisation (NATO), sometimes called North Atlantic Alliance, Atlantic Alliance or the Western Alliance, is an international organisation for defence collaboration established in 1949, in support of the North Atlantic Treaty signed in Washington, D.C., on April... The Parabolic antenna is a high-gain, reflector antenna used for radio, television and data communications, and also for radiolocation (RADAR), on the UHF and SHF frequencies. ...

There were 81 Zenit 2 launches, 58 were successful and 11 were partially successful. There were 12 failed missions, 5 because of a satellite malfunction and 7 because of a failure in the launch vehicle.

First flight - Kosmos 4, 1962. Last flight - Kosmos 344, 1970. 1962 was a common year starting on Monday (link will take you to calendar). ... 1970 was a common year starting on Thursday. ...

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 and Soyuz rockets.

First flight - Kosmos 208, 1968. Last flight - Kosmos 1044, 1978. 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ... 1978 was a common year starting on Sunday (the link is to a full 1978 calendar). ...

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 3000mm focal length as well as a 200mm 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 1-2m.

The Zenit 4 weighted 6300kg - around 1500kg more than the Zenit 2. So, instead of the Vostok rocket, it was launched by the heavier Voskhod rocket. A probable total of 76 Zenit 4’s were flown.

First flight - Kosmos 22, 1963. Last flight - Kosmos 355, 1970. 1963 was a common year starting on Tuesday (link will take you to calendar). ... 1970 was a common year starting on Thursday. ...

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. Mission duration was 13 days.

First flight - Kosmos 251, 1968. Last flight - Kosmos 667, 1974. 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ... 1974 is a common year starting on Tuesday (click on link for calendar). ...

Zenit 4 MK / Zenit 4 MKM

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.

First flight - Kosmos 371, 1970. Last flight - Kosmos 1214, 1980. 1970 was a common year starting on Thursday. ... 1980 is a leap year starting on Tuesday. ...

Zenit 4 MT

A special version of the Zenit 4M intended for topographical photography. It carried a SA-106 topographic camera, a laser altimeter and Doppler apparatus. Surface of the Earth Topography, a term in geography, has come to refer to the lay of the land, or the physiogeographic characteristics of land in terms of elevation, slope, and orientation. ...

First flight - Kosmos 470, 1971. Last flight - Kosmos 1398, 1982. 1971 is a common year starting on Friday (click for link to calendar). ... 1982 is a common year starting on Friday of the Gregorian calendar. ...

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 96 launches.

First flight - Kosmos 867, 1976. Last flight - Kosmos 1685, 1985. 1976 is a leap year starting on Thursday (link will take you to calendar). ... 1985 is a common year starting on Tuesday of the Gregorian calendar. ...

Zenit 8

This was intended for military cartographic photography. It used a Soyuz launch vehicle and launches took place from both Baikanur and Plesetsk. It had a 15 day orbital life. Similar satellites were referred to using the ‘Resurs’ designation. Cartography or mapmaking (in Greek chartis = map and graphein = write) is the study and practice of making maps or globes. ...

Kosmos 2281, was the last Zenit flight.

First flight - Kosmos 1571, 1984. Last flight - Kosmos 2281, 1994. 1984 is a leap year starting on Sunday of the Gregorian calendar. ... 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ...

References

• ‘Eye in the Sky: Story of the Corona Spy Satellites’; ed. by Dwayne Day; Smithsonian, 1998.
• Peter A Gorin: Zenit - The First Soviet Photo-Reconnaissance Satellite, Journal of the British Interplanetry Society, Vol. 50, 1997, pg 441.
• 'Korolov' James Harford John Wiley 1997.
• http://www.astronautix.com/index.html
• [‘Sven’s Space Place’]
• [‘Gunters Space Page’]

External links

• Zenit at astronautix.com