Russia launches its latest GLONASS-M navigation satellite into orbit
A Russian Soyuz-2.1b rocket thundered into space from Site 43/4 at the Plesetsk Cosmodrome in the Arkhangelsk Region of Russia. Its payload was the latest GLONASS-M satellite for the country’s homegrown GLObal NAvigation Satellite System (GLONASS). Liftoff took place at 7:21 p.m. EST on Saturday, Feb. 6 (00:21 GMT on Sunday, Feb. 7).
“All the pre-launch operations and the rocket launch were normal. Ground-based automatic control aids monitored the space vehicle launch and flight,” Russian Defense Ministry said.
The launch of the mission was initially scheduled for Dec. 28, 2015, but was postponed two times due to operational difficulties. In mid-November, the spacecraft was delivered to Plesetsk. The mission’s launch campaign started in late-December 2015 with first checks of the satellite.
Final preparations and checkouts were carried out during an eight-hour count that preceded the liftoff. The launch vehicle was loaded with propellants and the Automated Countdown Sequence began, handing over control of the launch to the onboard computers.
After liftoff, the Soyuz-2.1b rocket commenced a short vertical climb, lasting only a few seconds before it started heading southeast. The vehicle’s four boosters were jettisoned nearly two minutes into the flight.
Shortly thereafter, the rocket’s core stage burned its engine for approximately two minutes and 50 seconds, before separating from the Fregat-M upper stage. Nearly three-and-a-half hours later, the satellite was injected into a medium-Earth orbit (MEO).
The spacecraft, named GLONASS-M No. 51, received the designation Kosmos 2514 when it reached its targeted orbit. It will replace the Kosmos 2419 satellite, which was sent aloft in 2005.
GLONASS-M satellites, also known as Uragan-M, are the second generation of Uragan satellite design used as part of the Russian GLONASS radio-based navigation system.
A typical GLONASS-M spacecraft, developed by the Reshetnev Information Satellite Systems (ISS Reshetnev), is about 7.87 by 12.14 feet (2.4 by 3.7 meters) and has a launch mass of some 1.4 metric tons. With a total power of 1250 W, these satellites are designed to operate for up to seven years. Equipped with three caesium clocks, GLONASS-M can provide the accurate timing that is required for navigational purposes. The first spacecraft in the series was launched in December 2003, while the final satellite is expected to be sent aloft in late 2017.
Operated by the Russian Aerospace Defence Forces, GLONASS is currently the only global alternative to the U.S. GPS in terms of operational capability and global coverage. The development of the program started in 1976 with the first launch being conducted in 1982.
It took more than a decade for the system to become operational as it struggled with funding issues. In December of 1995, the system became fully operational for the first time as the constellation then consisted of 24 satellites that were needed to provide global coverage.
GLONASS provides real time position and velocity determination for both military and civilian users. The satellites are located in a middle circular orbit at about 11,900 miles (19,100 kilometers) altitude with a 64.8-degree inclination at a period of 11 hours and 15 minutes. It provides an accuracy of 328 feet (100 meters) as part of the public segment and 33 to 66 feet (10 to 20 meters) for military purposes.
The system operates in three orbital planes, with eight evenly-spaced satellites on each. While a fully operational constellation with global coverage needs 24 satellites, 18 are necessary to cover the expansive territory of Russia.
The Soyuz-2.1b rocket that was used for Saturday’s launch is an upgraded version of the three-stage Soyuz-2 booster. The 151 feet (46.1 meters) tall launch vehicle has a total mass of 672,000 lbs. (304,814 kg) and is designed to put satellites into a variety of orbits. The Soyuz-2.1b is capable of putting up to 18,100 lbs. (8,210 kg) into low-Earth orbit (LEO), 10,800 lbs. (4,899 kg) into a Sun-synchronous orbit (SSO), and 7,170 lbs. (3,252 kg) 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 2 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 Saturday’s mission, the Soyuz-2.1b rocket was 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 second flight for Russia, the first launch from Plesetsk, and the first Soyuz mission of 2016. The country plans to conduct its next launch on Feb. 16 when a Rokot booster is slated to send an ESA Earth observation satellite, named Sentinel-3A, to orbit.
Video courtesy of SciNews
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