EDITOR’S NOTE: Updated Nov. 26 with video and orbital elements.
A modified Soyuz rocket delivered a top secret Russian military payload into orbit Monday from the Plesetsk Cosmodrome in northern Russia, according to the country’s defense ministry.
The mission lifted off from the Site 43 launch complex at Plesetsk at 1752 GMT (12:52 p.m. EST; 8:52 p.m. Moscow time) Monday. A Soyuz 2-1v rocket carried a Volga upper stage and the classified military satellite into space, and the Volga stage successfully delivered its payload into the targeted orbit, Russian officials said.
The Russian Ministry of Defense said the spacecraft launched Monday will monitor the condition of other Russian satellites in orbit, suggesting the satellite has a space surveillance mission. The satellite’s optical instrument will also allow it to take pictures of Earth, according to a Russian Interfax news report quoting the defense ministry.
The satellite was expected to be designated Kosmos 2542, keeping with defense ministry’s naming scheme for Russian military spacecraft.
Analysts noted similarities between Monday’s launch and a Soyuz 2-1v flight in June 2017 that deployed a similarly-secretive payload into orbit. Observers believed the June 2017 launch carried a military spacecraft into orbit to collect geodetic measurements, but the satellite later released a smaller craft in orbit described by the Russian military as an inspector probe capable approaching and imaging other objects in orbit, according to RussianSpaceWeb.com, a website run by the respected Russian space journalist Anatoly Zak.
Russian authorities did not announce the launch of the clandestine payload in advance, but airspace warning notices informing pilots of downrange booster and payload fairing drop zones suggested a Soyuz launch was planned Monday.
Trajectory information deduced from the airspace warning notices indicated the Soyuz 2-1v rocket was expected to head north from Plesetsk over the Arctic Ocean. Such a flight path would result in the mission’s satellite payload entering an orbit taking it on a north-south track over Earth’s poles.
U.S. military tracking data indicated the rocket deployed its satellite payload in an orbit ranging between 226 miles (365 kilometers) and 531 miles (855 kilometers), with an inclination of 97.9 degrees to the equator.
The Soyuz 2-1v rocket is a modified version of the Russian Soyuz rocket that flies without the four liquid-fueled strap-on boosters used on standard Soyuz configurations. A single kerosene-fueled NK-33 main engine replaces the four-nozzle core stage engine flown on other Soyuz rocket variants.
The NK-33 engine was originally developed for the Soviet-era N1 moon rocket, which was canceled in the 1970s after four test launches failed. Russia kept NK-33 engines in storage after the cancellation of the N1 rocket program. Some of the powerplants were exported to the United States and flown on Northrop Grumman’s Antares rocket to launch supplies to the International Space Station.
But Northrop Grumman redesigned the Antares booster to use newly-manufactured Russian RD-181 engines. Investigators blamed an Antares launch failure in 2014 on one of the NK-33 engines — known as AJ26s in the United States — stored for decades after Russia ended development of the giant N1 rocket.
The Soyuz 2-1v first stage also includes four vernier steering engines mounted around the NK-33 main engine. The modified launcher’s second stage is powered by an RD-0124 engine, the same type of powerplant also used on the modernized Soyuz 2-1b version of Russia’s classic Soyuz rocket.
Monday’s launch marked the sixth flight of a Soyuz 2-1v rocket since 2015, and it was the 20th flight of a Russian-made satellite launcher this year.
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