Nordic Satellite AB (NSAB) was awarded a contract in early January 2005 to Lockheed Martin to design and manufacture the Sirius 4 satellite.

Sirius 4 will be a multi-mission Ku/Ka-band satellite to be built on Lockheed Martin's reliable A2100AXS platform with a minimum service life of 15 years. The spacecraft will be designed to be compatible with all flight-proven commercial launch vehicles and NSAB intends to select the respective launch service provider later on in the year. The satellite will be deployed at NSAB's orbital position of 5° East in the second quarter of 2007.

The first mission of Sirius 4 will be to provide replacement capacity for NSAB's existing Sirius 2 and Sirius 3 satellites in the Nordic and Baltic markets as well as to enhance coverage in Eastern Europe and Russia. This mission is supported by 46 active Ku-band transponders in the BSS and FSS frequency bands.

As a secondary mission, Sirius 4 will provide one wide beam Ka-Band transponder for interactive applications in Scandinavia and the Baltic States.