Saturday, December 2, 2017

Soyuz 2.1b Launches Military Satellite into Orbit

Soyuz 2.1b launch on December 2, 2017. Credit: Russian Defense Ministry

The recent failure of Soyuz 2.1b mission, which was unable to place a fleet of 19 satellites into target orbit, has not stopped Russia from sending another such booster into space. This time, lifting off from the Plesetsk Cosmodrome at 10:43 GMT (5:43 a.m. EST) on Saturday, December 2, Soyuz 2.1b orbited the Lotos military spacecraft for the Russian Defense Ministry.

Although the failure of Tuesday’s Soyuz 2.1b mission that was tasked with launching Meteor-M 2-1 Earth-observing spacecraft and 18 smaller payload is still being investigated by a space accident commission, Roscosmos decided to go on with its orbital launch schedule approved earlier.

“The accident commission has made a decision to allow Soyuz 2 carrier rocket launches under the schedule approved earlier,” the press office of Roscosmos announced Friday.

Initial reports reveal that the satellites may have been lost due to a failure in the GLONASS equipment on board the rocket that was lifting off from the Vostochny Cosmodrome on Tuesday. This could result in the Fregat-M upper stage not being able to inject the payload into desired orbit. When it comes to today’s launch, the Soyuz 2.1b flew without Fregat-M, what allowed to suspect that this malfunction will not occur for the second time.

Today’s mission was initially planned for October 25 but was postponed to mid-November and then once again, to December 2, due to some problems with the payload.

On Saturday, the Soyuz 2.1b rocket thundered off the launch pad powering by its RD-107A engines, what signaled the start of its short vertical climb. The four boosters were responsible for accelerating the launch vehicle during the initial phase of the flight and were then jettisoned at approximately two minutes after liftoff.

The launch vehicle continued the ascent being powered by its core stage until it was detached at about four-and-a-half minutes into the flight. Afterward, the third stage took control over the mission for about four minutes what ended in the orbital injection of the payload.

Saturday’s launch and flight was controlled by a ground-based automatic control system, with the commander of Russia’s Aerospace Defense Forces, Lt. Gen. Alexander Golovko, in charge of administrating the launch of the rocket.

“The Soyuz 2.1b carrier at the designated time took successfully to the target orbit the space apparatus for interests of the Russian Defense Ministry,” the state-run TASS press agency reported about half an hour after launch.

The mission’s sole passenger was the Lotos-S1 electronic signals intelligence (ELINT) satellite. The spacecraft is based on the Yantar bus and features two deployable solar arrays. After injection into orbit, the satellite received official designation Kosmos 2523.

Lotos satellites belong to Russia’s Liana program, which aims to modernize the country’s signals intelligence (SIGINT) capabilities. Lotos network replaces the former Tselina series of satellites, launched between 1967 and 2007. First prototype Lotos satellite, designated Lotos-S, was orbited in November 2009.

The Soyuz 2.1b rocket employed for Saturday’s launch is an upgraded version of the three-stage Soyuz 2 booster. The 151-foot (46.1-meter) tall launch vehicle has a total mass of 672,000 pounds (304,814 kilograms) and is designed to put satellites into a variety of orbits.

The booster is capable of putting up to 18,100 pounds (8,210 kilograms) into low-Earth orbit (LEO), 10,800 pounds (4,899 kilograms) into a Sun-synchronous orbit (SSO), and 7,170 pounds (3,252 kilograms) into a geostationary transfer orbit (GTO). The first launch of this version of the rocket took place from Plesetsk on July 26, 2008, with a classified military payload.

This rocket uses four RD-107A engines at liftoff, which burn for about two minutes. The first stage, 88.9 feet (27.1 meters) long and 9.7 feet (2.95 meters) in diameter, is equipped with a lone RD-108A engine. The rocket’s second stage has a length of 22 feet (6.7 meters) and is 8.7 feet (2.66 meters) in diameter. The 2.1b version of Soyuz has an upgraded RD-0124 engine with a second stage that has improved performance over previous iterations of the design.

For some launches the Soyuz 2.1b rocket is used in a configuration with a Fregat-M third stage. This upper stage measures approximately 4.9 feet (1.5 meters) long and is 11 feet (3.35 meters) in diameter. Its S5.92 engine is designed to burn for about 18 minutes.

Fregat-M is responsible for the orbital insertion of the satellite. However, it can also be used as an escape stage to send probes on interplanetary trajectories. Fregat stages are currently used as the fourth stage for some Soyuz-FG launch vehicles as well.

Saturday’s launch was the 18th flight for Russia and the fourth launch from Plesetsk in 2017. Next mission of a Russian booster is currently scheduled for December 17, when Soyuz-FG will send the Soyuz MS-07 spacecraft with Expedition 54 trio to the International Space Station (ISS).

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