The Meridian series of communications satellites is reported to be the replacement for all the Molniya-1T, the Molniya-3 and Molniya-3K satellite series and possibly also for the communication component of the Parus. They are launched into highly eccentric Molniya-orbits. Meridian is the highly eccentric orbit (HEO) component of the Integrated Satellite Communications System (ISSS), where they work in conjunction with the geostationary Raduga-1M (Globus-M) satellites. The bus structure is reportedly pressurized, possibly based on the Uragan-M bus. Meridian satellites carry three transponders operating in different frequency bands.