Soyuz rocket launches Russian missile warning satellite

A Soyuz booster and Fregat upper stage successfully carried a missile warning satellite into orbit Friday for the Russian military.

Launched from the Plesetsk Cosmodrome in far northern Russia, the Soyuz-2.1b rocket lifted off at 0731 GMT (3:31 a.m. EDT; 10:31 a.m. Moscow time) Friday and arced toward the southeast.

A statement from the Russian Defense Ministry did not identify the payload, but information about the mission’s trajectory released in warning notices to pilots and mariners suggested the satellite was likely the fourth EKS, or Tundra, missile warning satellites for the Russian military.

The defense ministry said the spacecraft was launched into the targeted orbit, and ground controllers established stable communications with the new satellite. The spacecraft will receive the designation Kosmos 2546, keeping with the Russian government’s naming scheme for military satellites.

The satellite was expected to be deployed in an elliptical orbit ranging between approximately 1,000 miles and 24,000 miles (1,600 kilometers and nearly 39,000 kilometers) from Earth’s surface. The EKS, or Tundra, satellites fly in orbits inclined about 63.8 degrees to the equator.

Russia has launched four EKS-class early warning satellites launched on Soyuz/Fregat rockets in November 2015, May 2017, and September 2019. The new generation of EKS satellites replace Russia’s Oko series of missile warning spacecraft, the last of which launched in 2012.

The flight profile for Friday’s launch included separation of the Soyuz rocket’s four kerosene-fueled boosters around two minutes into the mission, followed by jettison of the rocket’s payload fairing and core stage. A third stage powered by an RD-0124 engine ignited next, followed by deployment of a Fregat upper stage on a suborbital trajectory around nine minutes into the mission.

The Fregat upper stage fired multiple times to place its satellite payload into the targeted orbit, and the spacecraft separated from the Fregat space tug several hours after liftoff.

Russia uses the missile warning satellites, along with ground-based radars, to track missiles that approach the country’s territory. The Molniya-type orbits used by the EKS satellites give the spacecraft’s thermal infrared sensors long views over the northern hemisphere on each 12-hour loop around Earth.

The orbits provide the satellites the ability to detect missile launches from North America, and detect incoming missiles that threaten Russian territory.

Friday’s mission was the seventh flight of a Soyuz rocket so far this year, and the third launch from the Plesetsk Cosmodrome in 2020.

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.