Soyuz launches military payload

A Soyuz-2-1b rocket launched a classified satellite for the Russian military. The vehicle lifted off from the Plesetsk, north of Moscow, on Dec. 21, 2023.

Previous military launch: Soyuz-2-1b rocket lifts off on Nov. 25, 2023


Kosmos-2573 launch at a glance:

Spacecraft designation
Kosmos-2573 (Bars-M No. 5)
Launch date and time
2023 Dec. 21, 11:48:39 Moscow Time
Launch vehicle
Launch site
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According to the Russian Ministry of Defense, a Soyuz-2-1b rocket lifted off on Dec. 21, 2023, at 11:48:39 Moscow Time (08:48 UTC, 3:48 a.m. EST) from Plesetsk and successfully delivered a spacecraft for the Ministry of Defense.

The standard statement said that personnel of the Russian Air and Space Forces, VKS, had performed the launch of a Soyuz-2-1b rocket with a spacecraft for the Ministry of Defense. The state-controlled media also quoted the Ministry of Defense as saying that the spacecraft had reached its planned orbit on time and was taken under control by ground assets of VKS. The spacecraft maintained stable telemetry contact and all its systems functioned as planned, according to the official reports.

According to tracking data of the US Space Force, the satellite was inserted into a 338 by 499-kilometer orbit with an inclination 97.57 degrees toward the Equator. The spent third stage of the Soyuz-2-1b launch vehicle was also tracked:

Orbital period
92.94 minutes
97.57 degrees
338 kilometers
499 kilometers
92.92 minutes
97.55 degrees
338 kilometers
498 kilometers

Official photos released by the Ministry of Defense showed that the Soyuz-2-1b rocket used in the mission was topped with the same payload fairing as the one on the vehicle that had delivered a military payload into orbit on Nov. 25, 2023. Both satellites were also inserted into orbit with the same inclination toward the Equator, but the latest payload was released into a considerably higher orbit. The orbital altitude for the new satellite resembled that of initial orbits used by the Bars-M series of military cartographic satellites and the orbit also matched their orbital inclination. The payload fairing was also common with Bars-M flights. On Dec. 22, 2023, RKTs Progress, which developed the Bars-M series , also updated the public count of satellite built by the company from 998 to 999.

However, the switch from the Soyuz-2-1a to the Soyuz-2-1b variant hinted at a heavier spacecraft than previous four Bars-M satellites.

Like its predecessors, the satellite was detected maneuvering on Dec. 23 and Dec. 25, 2023, entering the 408 by 498-kilometer orbit, typical a transitional orbit used by the series. The new spacecraft was also in the same orbital plane as the Bars-M No. 3 satellite, indicating that it was a replacement of the failed satellites or a formation flying for a joint function, such as production of stereo images. On Jan. 14, 2024, Bars-M N0. 3 boosted its orbit by nearly 12 kilometers, confirming the hypothesis that it was operating in conjunction with the newly launched Kosmos-2573.


The article, graphics and illustrations by Anatoly Zak; Last update: January 15, 2024

Page editor: Alain Chabot; Last edit: December 26, 2023

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A Soyuz-2-1b rocket lifts off on Dec. 21, 2023.