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Soyuz launches military payload
Russian military personnel in Plesetsk launched a classified payload on Dec. 4, 2024. A Soyuz-2-1b rocket likely carried a satellite known as Lotos-S1 or 14F145. It is the ninth addition to the Liana constellation performing electronic intelligence and target guidance from space for the Russian military.
The ninth Lotos-S1 mission at a glance:
Preparations for launch In mid-November 2024, the authorities of the Russia's Yamalsk District issued warnings for the planned rocket boosters impacts between Yar Sale and Ports Yakha settlements and Panaevsk - Khadaty-Yakha sites. These locations were previously used for discarding the second stage and the three panels of the aft skirt from the third stage of the Soyuz rockets during missions known to be delivering Lotos satellites for the Liana constellation and Neitron radar-imaging satellites into orbits with an inclination around 67 degrees toward the Equator. Additionally, a temporary danger warnings were issued for two sites in the Komi Republic, inclduing the "Vashka" site in the Udorsky District and the Zheleznodorozhny site in Knyazhpogostsky and Kortkerossky Districts. The Ust-Tsilemsk and Izhemsky Districts were also affected. These locations matched drop zones for the four boosters of the first stage and the two segments of the payload fairing of Soyuz rockets heading to 67-degree orbits. Fresh launches into the Liana constellation had been conducted annually during the 2020s, and, in 2024, the final (ninth) Lotos-S satellite was expected to be in the production pipeline under a 2017 Ministry of Defense contract with the industry. This time, the Nov. 27, 2024, launch window was expected to have back-up launch dates on November 28, December 3, 4, 9 and 10. However, on November 25, the authorities in Yamalsk District re-issued the warning for a later launch window opening on Dec. 3, 2024. On that day, the launch window was scheduled to be open from 19:00 to 22:00 Moscow Time with back-up launch dates available on December 3, 4, 9 and 10, the local authorities said. On December 3, another update from the administration of the Yamalsk District announced that the launch had been re-scheduled for the next opportunity on Dec. 4, 2024, between 21:00 and 24:00 local time. Orbital ascent scenario
A Soyuz-2-1b rocket, likely carrying a Lotos-S1 No. 809 satellite, lifted off from Site 43 in Plesetsk on Dec. 4, 2024, at 21:03:13 Moscow Time (1:59 p.m. EST). Available information from the previous launches into the Liana constellation and advisories to air traffic allowed projecting the flight scenario for this mission. After a few seconds in vertical ascent, the rocket headed northeast to align its ground track with an orbit inclined around 67.1 degrees toward the Equator. The four boosters of the first stage separated after around two minutes into the flight and fell at the S15 drop zone around 350 kilometers from the launch site. The payload fairing protecting the payload was dropped next, likely targeting the S16 drop zone in the Komi Republic. Less than five minutes into the flight, the core booster of the rocket completed its firing and separated as well. Moments before the second stage separation, the RD-0124 engine of the third stage ignited and fired through the interstage lattice structure, which separated moments later along with the second stage. Around five seconds after that, the tail section on the third stage was dropped, splitting into three segments. Both, the second-stage booster and the segments of the tail section were expected to fall at the S18 drop zone in the Yamalo-Nenetsk Autonomous Region. The third stage then continued firing until around nine minutes into the flight, before releasing its payload into an initial orbit. The Russian Ministry of Defense confirmed the launch soon after the fact and called it successful. (The official statement accidentally reported the time of the launch as 20:59 Moscow Time, however it was the scheduled liftoff time for Dec. 3, 2024.) The ministry then confirmed that the spacecraft was released into the target orbit and established reliable communications with ground control. The payload was officially identified as Kosmos-2580. Orbital maneuvers During a typical launch of the Lotos satellite, the payload and its empty third stage first entered a 200 by 900-kilometer elliptical orbit, but the satellite fired its engine in apogee to circularize its orbit at a safe altitude of around 900 kilometers a couple of days later. The satellite would then be ready for operation. As usual, the first set of orbital parameters released by the US Space Force for the Dec. 4, 2024, launch, showed two objects typical for Lotos missions, likely representing the third stage of the Soyuz rocket and the main payload:
By Dec. 7, 2024, the US Space Force confirmed that Kosmos-2580 had circularized its orbit at an altitude of around 900 kilometers, as expected for Lotos-S1 satellites, while the orbit of the third stage which delivered the spacecraft into orbit was naturally decaying:
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