Satellite radio provider Sirius has announced plans for a fourth satellite to be launched at the end of 2008.

From the press release:

Construction of the satellite is expected to be completed in the fourth quarter of 2008. SIRIUS plans to launch the satellite on a Proton rocket under a contract previously announced between SIRIUS and International Launch Services (ILS). The satellite will be launched into a geostationary orbit to complement SIRIUS’ existing three satellites, which were also manufactured by Space Systems/Loral and operate in a highly elliptical geosynchronous orbit. This unique hybrid constellation will provide unparalleled redundancy, enhanced coverage and exceptional performance.

This news should mean improved service for Sirius’s subscribers, as well as more talk about their forthcoming video and data transmission plans.