At 15:17 UTC on Nov. 28, a Soyuz-2.1b launched from Site 43/3 at the Plesetsk Cosmodrome, carrying the final GLONASS-M satellite to orbit, designated Kosmos-2564.

This is the first of two planned launches from the Plesetsk Cosmodrome in just three days, with a classified payload scheduled to launch onboard a Soyuz-2.1a on Wednesday, Nov. 30.

The GLONASS (Globalnaya Navigationnaya Sputnikovaya Sistema, or Global Orbiting Navigation Satellite System) is a Russian radio-based satellite navigation system comparable to the American GPS (Global Positioning System) satellites, the European Galileo constellation, or the Chinese BeiDou system. The operational GLONASS system consists of 21 satellites in three orbital planes, with three on-orbit spares.

GLONASS satellites provide 100-meter accuracy with their C/A (deliberately degraded) signals and 10-20 meter accuracy with their P (military) signals.

The Uragan-M spacecraft are three-axis stabilized, nadir pointing with dual solar arrays. The payload consists of L-Band navigation signals in 25 channels separated by 0.5625 MHz intervals in two frequency bands: 1602.5625 – 1615.5 MHz and 1240 – 1260 MHz.

The first generation of GLONASS satellites was created under the ban on foreign radiation-hardened components, and therefore had an inferior design life of three years. With the degraded average life of just 22 months, it was necessary to launch at least seven satellites per year to keep the constellation in operational status. After the ban on foreign radiation-hardened components was lifted, the GLONASS-M satellite was designed with parts available through ITAR control, and now has a design life of seven years.

The first GLONASS-M satellite, Kosmos-2404, was launched by a Proton-K/Briz-M on Dec. 10, 2003. The second satellite launched a year later on Dec. 26, 2004. Previously launched in trios, the first trio of only GLONASS-M satellites was launched on Dec. 25, 2006.

With four more launches by 2009, there were 18 satellites in orbit, and a planned launch in 2009 would have brought the constellation to operational status.

Render of a GLONASS satellite. (Credit: Roscosmos)

The only planned launch of 2009 was on a Proton-M/DM-3 and ultimately ended in failure. The launcher deviated from its planned trajectory, leading the Blok DM-3 upper stage and the three satellites to fall back into the Pacific Ocean, 1500 km northwest of Honolulu.

Two years later, a single satellite launch onboard a Soyuz-2.1b/Fregat-M, the launcher used today, brought the constellation to operational status, delivering the 24th operational satellite to orbit.

The Soyuz-2.1b is one of three active variants in the Soyuz family of rockets, and looks the most like the early Soyuz rockets, using four liquid-fueled boosters surrounding a central core. This design is also used on the Soyuz-2.1a but is not used on the Soyuz-2.1v, which doesn’t use the four side boosters and instead uses only a single core.

First introduced in 1996 and derived from the Vostok rocket, the Soyuz launcher initially had a poor launch record, with the first four flights ending in failure. The first successful flight of the Soyuz rocket occurred on Nov. 28, 1966 wi,th the launch of the first Soyuz spacecraft.

The first launch was planned to be an “all-up” test of the Soyuz spacecraft, including a docking to a lunar version of Soyuz. The docking never occurred, as the spacecraft was destroyed in an explosion on the launch pad after its launch was scrubbed.

The first and second stages of Soyuz-2.1b ignite before liftoff from Plesetsk.

Monday’s launch also made use of the Fregat upper stage. Plans to redesign the Soyuz rocket with this new stage were introduced in the 1990s, based on the propulsion module of the Phobos interplanetary probes. Despite being endorsed by Roscosmos, the Russian state space agency, and the Russian Ministry of Defense, a lack of funds prevented the plans from being implemented.

The eventual founding of Starsem, a company marketing Soyuz launches internationally, allowed for the creation of a less ambitious rocket, the Soyuz-U/Fregat, also known as Soyuz-Fregat. The Soyuz-U/Fregat consisted of a Fregat upper stage being used on the already existing Soyuz-U launcher, allowing the rocket to carry 1,350 kg to a geostationary transfer orbit (GTO).

Monday’s mission lifted off from Site 43/3 at the Plesetsk Cosmodrome. Plesetsk is one of three cosmodromes currently used by the Russian military as well as Roscosmos, Russia’s state-owned 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.

During the 1960s, the former R-7 pads were repurposed to allow launches of R-7-derived launch vehicles, including the first Soyuz launcher. The first orbital launch from Plesetsk occurred on March 17, 1966, when an R-7-derived Vostok-2 launched Kosmos-112, a first-generation Soviet optical reconnaissance satellite to low Earth orbit (LEO).

(Lead photo: Soyuz-2.1b lifts off from Plesetsk with Kosmos-2564.)