At 19:20 UTC on Oct. 21, Russia’s Soyuz-2.1v rocket launched from Site 43/4 at Plesetsk Cosmodrome, carrying a classified payload to a Sun-synchronous orbit (SSO). The mission was originally scheduled for launch on Oct. 18 but was delayed three days for unspecified reasons.
On board Soyuz-2.1v was a pair of satellites named Kosmos-2561 and Kosmos-2562, following the standard naming convention for classified Soviet and Russian satellites similar to the American USA designation.
Details about the payload are unknown, but there are reasons to believe the pair of spacecraft may be inspector satellites, similar to the payload of the previous Soyuz-2.1v launch. Kosmos-2558, launched in August 2022, was launched to match the trajectory and flight path of an American spy satellite, USA-326, that was launched on the NROL-87 mission in February 2022.
Today’s launch of Kosmos-2561 and 2562 also seemed to mirror the trajectory of USA-326, with the American satellite passing over the cosmodrome roughly at the time of today’s launch.
If the latest launch is an inspector mission, it is possible that Kosmos-2562 is a subsatellite that was released by 2561 shortly after launch, as previous inspector satellites have done. Kosmos-2542 was believed to have been an inspector satellite, although never confirmed by Russia, and later released Kosmos-2543.
Plesetsk Cosmodrome is one of three cosmodromes currently used by the Russian military as well as Roscosmos, Russia’s government space agency. The other two cosmodromes currently in use are Baikonur Cosmodrome, located in the former Soviet Union incorporated nation of Kazakhstan, and Vostochny Cosmodrome, located in Russia’s far east.
Plesetsk itself is located in the Arkhangelsk Oblast, north of Moscow and on the Barents Sea. Plesetsk was the second Cosmodrome built by the then Soviet Union and was initially used to test the R-7 intercontinental ballistic missile. Plesetsk’s location allowed the R-7 to target locations in the United States and North America.
During the 1960s, the former R-7 pads were repurposed to allow launches of R-7-derived launch vehicles, such as the Vostok rocket as well as the Soyuz family of launch vehicles. The first orbital launch from Plesetsk occurred on March 17, 1966, when a Vostok-2 launched Kosmos-112, a first-generation Soviet optical reconnaissance satellite to low Earth orbit (LEO).
Similar to the United State’s early Corona family of reconnaissance satellites, Kosmos-112 took its photographs on film before returning them to Earth in re-entry capsules.
By 1997, 33 years after its first launch, the cosmodrome had seen over 1,500 launches, making it the most active cosmodrome in Russia at the time. Since then, the cosmodrome has gone on to launch the R-7-derived Soyuz, Cosmos-3M, Rokot, Tsyklon, and most recently, the Angara launch vehicle.
Plesetsk is currently the host of the only operational Angara launch site, but another pad is currently under construction at Vostochny Cosmodrome, with launches expected to begin in 2023.
The Soyuz-2.1v doesn’t look like a traditional Soyuz-2 launch vehicle, and the Soyuz-2.1v was even referred to as Soyuz 1 during development, which began in the mid to late 2000s.
As the Soyuz-2.1v doesn’t use the four side boosters as the other Soyuz-2 rockets, the first stage replaces the RD-108A engine with the NK-33 engine, initially developed for the N-1 Moon rocket, as well as an RD-0110R engine with four nozzles, providing thrust vectoring control on the first stage.
Since the Soyuz-2.1v lacks the four side boosters, it is the only Soyuz rocket that does not feature a “Korolev Cross,” which occurs when the four boosters separate from the first stage. The planned Soyuz-5 rocket, which will replace all of the Soyuz-2 rockets, will also not feature the Korolev Cross.
The NK-33 engine on the first stage was initially developed for the N-1 Moon rocket, which would have featured 30 NK-33s on the first stage. The engine runs on a staged combustion cycle, and uses RP-1, a refined form of kerosene, and liquid oxygen.
The NK-33 never got a chance to fly on the N-1 but did fly on the then Orbital Sciences Antares 110 rocket as the Aerojet Rocketdyne AJ-26. Orbital Sciences has since merged with Alliant Techsystems (ATK) before later being bought by Northrop Grumman.
After an engine failure on the fifth flight on Antares, the NK-33 was replaced by the RD-181, which is derived from the RD-180 engine used on the United Launch Alliance Atlas V.
After the stockpile of NK-33s runs out, the Soyuz-2.1v will switch to the RD-193 engine, a derivative of the RD-191 currently used on Angara.
The second stage uses the same RD-0124 as the second stage of the Soyuz-2.1b. Instead of using the optional Fregat upper stage of the other Soyuz-2 rockets, the Soyuz-2.1v uses the Volga upper stage.
(Lead image: Soyuz-2.1v launches Kosmos-2558 in August 2022. Credit: Roscosmos)