Russia launches a Soyuz-2-1a rocket carrying a Kobal’t-M reconnaissance satellite on Tuesday. Liftoff from the Plesetsk Cosmodrome in Northwest Russia occurred at 17:49:39 Moscow Time (13:49:39 UTC). Tuesday’s mission marked the first time a Kobal’t-M satellite has been launched atop the Soyuz-2 rocket; previous missions having made use of the older Soyuz-U.
The spacecraft, No.564, is likely to be the penultimate Kobal’t, with the type being retired in favour of the more modern Persona series of satellites.
The Kobal’t-M, also known as the Yantar-4K2M or by its GRAU index of 11F695M, is a rare surviving example of a film-return photoreconnaissance satellite. As the name suggests, such spacecraft produce images of the Earth which are physically returned to earth by means of one or more small recoverable capsules.
In the early days of satellite reconnaissance, film-return spacecraft were cheaper, more reliable and could produce better quality images than their electro-optical counterparts. As technology improved, electro-optical reconnaissance became more practical, and thanks to its ability to return images for analysis almost immediately, more desirable.
Freed from the constraints of a limited supply of film or return capsules, electro-optical satellites were also able to achieve longer operational lives, with the longest-serving satellite – USA-129 – having been in orbit for seventeen and a half years.
By contrast the longest-serving photoreconnaissance satellite was probably OPS 0721, a KH-9 Hexagon satellite of the US National Reconnaissance Office, which operated for nine months between June 1983 and March 1984.
Kobal’t-M is the last in Russia’s Yantar line of reconnaissance satellites, whose development originally began in the 1960s as a longer-duration spacecraft to supplement the short-duration Zenit series. The first Yantar satellite was launched in 1974 using a Soyuz-U rocket, however it failed to achieve orbit. Initial spacecraft used the Yantar-2K configuration, with additional variants being introduced in the late 1970s and early 1980s.
The first new type to be introduced was the Yantar-4K1, or Oktan, which featured a higher-resolution camera than the Feniks. Oktan was quickly replaced by the Yantar-4K2, or Kobal’t, which first flew in 1981. Meanwhile a new lower-resolution area survey spacecraft, the Yantar-1KFT, was developed. Named Kometa or Siluet, this was a hybrid satellite consisting of a Yantar bus with a Zenit film capsule.
Another series, beginning with the Yantar-4KS1 or Terilen, was the Soviet Union’s first attempt to develop an electro-optical satellite. Later replaced by the 4KS1M, which was known as Neman, this series used geostationary Geizer satellites to transmit optical and infrared images in real-time.
Despite launches continuing until 2000, these spacecraft never replaced their film-return brethren, with the Kometa remaining in use until 2005 and the Kobal’t being replaced by the modernised Kobal’t-M.
The first Kobal’t-M to fly was Kosmos 2410, which rode a Soyuz-U into orbit in September 2004; a year and a half after the final launch of its predecessor. Further satellites followed in May 2006, June 2007, November 2008, April 2009, April 2010, June 2011 and May 2012.
The spacecraft which will be launched on Tuesday is the ninth Kobal’t-M and the 177th Yantar overall. It will be designated Kosmos 2495 upon reaching orbit successfully, becoming part of the sequence used to designate Russian, and previously Soviet, military satellites.
Each Kobal’t-M is equipped with three return capsules. Two of these, the Spuskayemaya Kapsula, are small vehicles mounted on either side of the spacecraft which are used to return images partway through the flight; while the larger central capsule returns to Earth at the end of the spacecraft’s mission.
While in orbit the 6.7-tonne (15,000 lb) spacecraft is powered by a pair of solar arrays attached to its aft propulsion module. This module also allows the spacecraft to manoeuvre in orbit, providing the ability to study particular areas of interest.
Unlike most modern reconnaissance satellites, Kobal’t-M spacecraft do not operate in sun-synchronous orbit. The first six satellites were placed into lower orbits, inclined at around 67.1 degrees, while the most recent two have gone to orbits with inclination of 81.3 degrees. Notices to Airmen associated with Tuesday’s launch suggest that it will also go to 81.3 degrees.
The Soyuz-2-1a rocket used in Tuesday’s launch is one of three Soyuz-2 configurations in service, along with the Soyuz-2-1b and Soyuz-2-1v.
The launch was the sixteenth flight of a Soyuz-2-1a, including Soyuz-STA launches from French Guiana, and the thirty-second overall for the Soyuz-2.
It was the sixth time a Soyuz-2 has been launched without an upper stage – the majority of launches use a Fregat to deliver payloads into higher or more precise orbits, however this is not required for Kobal’t-M.
The Soyuz-2 is a modernised and upgraded rocket based on the Soyuz-U, whose ancestry can be traced back to the R-7 missile. The first intercontinental ballistic missile to be successfully demonstrated, the R-7 first flew in 1957 with a modified version being used later that year to orbit the first satellite, Sputnik 1.
R-7 rockets were subsequently used to launch the first missions to the Moon, Mars and Venus, as well as every manned mission conducted by the Soviet Union and Russia to date.
The R-7 family has been used for more orbital launches than any other series of rockets, with the Soyuz branch its most-flown variant.
The Soyuz-U alone has made over 750 launches, with the total for the whole family in excess of 1,200.
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The Soyuz-2-1a consists of three stages, under the Russian system of designation where the four strap-on boosters are considered a separate stage from the core stage with which they burn in parallel. The four boosters which comprise the first stage are powered by RD-107A engines each with four thrust chambers.
These are clustered around the core stage, which is propelled by a single RD-108A. The core stage is designated Blok-A, with the boosters being designated Blok-B, V, G and D, denoting their places in the stack. These designations should not be confused with the names of Russian upper stages, such as the Blok-D series used in the Proton and Zenit series of rockets.
The third stage of the Soyuz is a Blok-I, which is powered by an RD-0110 engine. All three stages are fuelled by T-1 propellant, a refined form of petroleum similar to the US RP-1. Oxidisation is provided by means of liquid oxygen.
Tuesday’s launch took place from Site 43/4 at the Plesetsk Cosmodrome. Site 43 consists of two launch pads, 43/3 and 43/4, which are both still considered operational although 43/3 has not been used since 2002.
In practise, Site 43/4 is the only active Soyuz pad at Plesetsk, with Site 41/1 having been demolished and Sites 16/2 and 43/3 requiring renovation to support the Soyuz-2 – which is the only Soyuz variant now flying from the site.
Pad 4 was first used in July 1967, as the point of departure for an R-7A missile test. Other rockets which have used the facility include the Voskhod, Vostok-2M, Molniya-M, Soyuz-M and Soyuz-U.
In March 1980 the pad was the site of a fatal accident, when a Vostok-2M exploded during fuelling, killing 48 soldiers and engineers.
To date, Site 43/4 has been used for all Soyuz-2 launches from Plesetsk, beginning with the type’s maiden flight in November 2004.
This was Russia’s tenth orbital launch of 2014, and the twenty-fifth of the year overall. The next Russian launch is expected to take place on 15 May, with a Proton-M/Briz-M orbiting the Ekspress-AM4R satellite – a replacement for the original Ekspress-AM4 which was lost in a 2011 launch failure.
The next Soyuz launch is planned for 28 May, with a Soyuz-FG orbiting the manned Soyuz TMA-13M mission to the International Space Station, while the next Soyuz-2 will fly in mid-June with a Uragan-M navigation satellite. The next, and potentially final, Kobal’t-M launch is believed to be slated for some time next year.
(Images via Roscosmos).