Official name COSMOS 2546
Alternative name Cosmos-2546
Cospar ID 2020-031A
Norad ID 45608
Launch date 2020-05-22
Launch site PKMTR
Launch vehicle Soyuz-2-1b Fregat
Country/Organization Russia
Type application Early warning, communication
RCS size LARGE
Decay date ON ORBIT
Period (min) 717.75
Inclination (deg) 63.11
Perigee (km) 2428
Apogee (km) 37926
Eccentricity 0.879664965059226
Mean motion (revs. per day) 2.00626959247649
Semi-Major axis (km) 26555.135
Raan (deg) 153.9168
Arg of perigee (deg) 265.164
Shape Box + 2 Pan
Mass (kg) 2550
Height (m) 4
Width (m) 2
Depth (m) 2
Lifetime 7.5 years
Contractors TsNII Kometa (prime); RKK Energiya (bus)
Configuration USP Bus
Power Deployable solar arrays, batteries

The Tundra, Kupol or EKS (Edinaya Kosmicheskaya Sistema) series of satellites is the next generation of Russian early warning satellites to replace the US-K and US-KMO early warning satellites of the Oko-1 system. The new early warning system is called Kupol.

The development of the EKS started in 2000. The Russian Ministry of Defence awarded in 2007 a contract for the EKS system to RKK Energiya with a first test launch planned in 2009. Several problems, changing requirements and a court case led to long delays, postponing the first mission to the end of 2014.

Reportedly the Tundra satellites carry also a secure emergency communications payload to be used in case of a nuclear war.

They are launched on Soyuz-2-1b Fregat boosters into Molniya-orbits, inclined highly elliptical 12 h orbits. A geostationary version is also planned.

The first Tundra satellite was launched in the last quarter of 2015 on a Soyuz-2-1b Fregat booster. Until 2020, six satellites were planned to be orbited. At then end of 2020, four were on orbit.

Satellite COSPAR Date LS Launch Vehicle Remarks
COSMOS 2510 2015-066A 2015-11-17 PKMTR Soyuz-2-1b Fregat
COSMOS 2518 2017-027A 2017-05-25 PKMTR Soyuz-2-1b Fregat
COSMOS 2541 2019-065A 2019-09-26 PKMTR Soyuz-2-1b Fregat
COSMOS 2546 2020-031A 2020-05-22 PKMTR Soyuz-2-1b Fregat
COSMOS 2552 2021-113A 2021-11-25 PKMTR Soyuz-2-1b Fregat