In the first of three launches within the space of several hours, a Russian Soyuz-U kicked of a busy Thursday with the launch of the Kobalt-M spy satellite. Launch of the veteran rocket was conducted at launch pad 16/2 at the Plesetsk cosmodrome, with the lift off time given as 3:05pm GMT. This was the last Soyuz-U to launch from the Plesetsk launch site.
With an interesting appearance, the Kobalt-M is classed as a modernized version of the Yantar spacecraft. It is understood to be a military reconnaissance spacecraft by nature.
The design of the spacecraft is such that it has two small capsules on board, allowing it to return film back to Earth inside the main – cone-shaped – reentry vehicle. Kobalt-M satellites are typically launched into the 170 by 370-kilometer orbits with the inclination 62.8 – 67.2 degrees toward the Equator.
Very little is known about the spacecraft, given it’s military nature, although it is understood to have the classification of Cosmos-2450, and will be the last such spacecraft of this range to be launched.
Its launch vehicle is a derivative of the R-7 Semyorka, the world’s first intercontinental ballistic missile. The R-7 made its first flight in 1957, and a modified version was used to launch Sputnik 1, the first artificial satellite, later that year.
In addition to Soyuz, the R-7 has served as the basis of the Vostok, Molniya and Voskhod rockets as well as several other variants which made small numbers of flights.
Vostok rockets launched early Soviet manned spaceflights, reconnaissance satellites, and a modified version launched the first Soviet lunar probes. Molniya was used to launch missions beyond Earth orbit, as well as military, communications and scientific satellites into high Earth orbits. The Voskhod rocket, which first flew in November 1964, was the predecessor to the Soyuz.
It incorporated the Blok I third stage developed for the Molniya rocket, powered by an RD-0108 engine. Voskhod was used to launch reconnaissance satellites, and missions of the manned Voskhod programme.
The Soyuz, meaning “Union”, first flew on 28 October 1966. Derived from the Voskhod, it incorporated upgraded engines, including an RD-0110 on the third stage, as well as a lower-mass and improved telemetry system.
The original Soyuz was used exclusively for launches of Soyuz spacecraft, both manned and unmanned. Not including one which exploded on its launch pad after its launch had been delayed, thirty one were launched, the last of which flew in 1975 carrying the Soyuz 23 spacecraft.
Between 1970 and 1971, three Soyuz-L rockets were launched, incorporating reinforcements to the core stages and a larger payload fairing to accommodate prototypes of the LK spacecraft, the spacecraft the Soviet Union intended to use to land men on the Moon.
Another Soyuz variant, the Soyuz-M, was developed to launch the Soyuz 7K-VI; the military version of the Soyuz spacecraft, which was heavier than the civilian version. After the cancellation of the military Soyuz programme, eight Soyuz-M rockets were used to launch Zenit-4MT reconnaissance satellites, with launches occurring between 1971 and 1976.
The Soyuz-U was developed as a standardised launch system, to replace the Voskhod and Soyuz and provide commonality with the Molniya-M. It first flew in May 1973, and in 1976 the original Soyuz, Soyuz-M and Voskhod were all retired, with subsequent launches of their payloads being conducted by Soyuz-U rockets.
The Soyuz-U2 configuration, which was optimised to use synthetic propellant allowing it to carry more payload, was introduced in 1982, and used for around 90 launches before being retired in 1995.
With around 750 flights, the Soyuz-U is the most-flown orbital launch system ever developed. It remains in service, and in the last few years it has mostly been used to launch Progress missions to the International Space Station, as well as occasional military payloads such as Thursday’s mission.
Recent launches have used the Soyuz-U PVB version, which features additional fireproofing.
(Images via Tsenki).