(RussianSpaceweb)– The Russian military personnel in Plesetsk orbited an operational spacecraft for electronic intelligence, known as Lotos-S1 or 14S145. A part of the Liana constellation, the mission lifted off on a Soyuz-2-1b rocket on Dec. 2, 2017, or just four days after another Soyuz-2 rocket lifted an ill-fated mission from Vostochny spaceport.
Preparations for launch
The Lotos-S1 No. 803 mission was previously planned for Oct. 25, 2017, but had to be postponed until the beginning of November and then until November 18, at the earliest, due to problems with the satellite.
On Oct. 25, space officials were expected to hold a meeting in Moscow on the status of the mission. The launch was then postponed until December 1, 2017, and by Nov. 21, 2017, it was set for December 2.
In the hours immediately following the botched launch of the previous Soyuz-2-1b rocket from Vostochny on November 28, preparations for the Lotos mission continued as scheduled in Plesetsk. Because the upcoming flight carried a low-orbiting satellite without the Fregat upper stage, the fresh Soyuz-2-1b launch could proceed as long as space officials could isolate the problem to the Fregat.
According to the latest schedule, on November 29, military personnel in Plesetsk were ready to integrate the upper composite, including the 14F145 satellite and the third stage, with the already assembled first and second stages of the launch vehicle.
On the morning of November 30, the Soyuz-2-1b rocket was rolled out to the launch pad at Site 43 and was installed into a vertical position. By the end of the day, preparations of the rocket on the pad continued as scheduled. The launch vehicle had passed routine tests and it was to be prepared for fueling during December 1.
On the same day, Roskosmos announced that the accident commission looking into the November 28 failure, had cleared the Soyuz-2 series for future missions.
How Lotos is launched
A Soyuz-2-1b rocket carrying the 14F145/Lotos No. 803 military satellite for the Liana electronic intelligence network lifted off from Site 43 in Plesetsk on Dec. 2, 2017, at 13:43:26.331 Moscow Time (5:43 a.m. EDT), as snowfall was showering the facility.
After a few seconds in vertical ascent, the rocket was programmed to head northeast to align its ascent trajectory with an orbit inclined around 67.1 degrees toward the Equator. The four boosters of the first stage separated after around two minutes in flight and fell at the S15 drop zone around 350 kilometers from the launch site.
The payload fairing protecting the payload was probably 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 fired through the interstage lattice structure, which then separated along with the second stage.
Around five seconds later, 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 aimed 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.
According to the official Russian media, Col. General Aleksandr Golovko, the commander of the Russian space forces, oversaw launch operations in Plesetsk.
Soon after the launch, Roskosmos announced that the newly launched spacecraft had functioned well and it had receieved an official designation Kosmos-2524.
In previous launches of Lotos satellites, the spacecraft and its empty third stage would first enter a 200 by 900 kilometer elliptical orbit, but the satellite would then fire its engine in apogee to circularize its orbit at a safe altitude of around 900 kilometers. The satellite would then be ready for operation.
NORAD listed two objects associated with the mission – spacecraft itself and the third stage of the Soyuz rocket that had delivered it into orbit: