SiriusXM Radio and Space Systems/Loral have donated a digital radio broadcasting satellite to the Smithsonian Institution’s National Air and Space Museum for display at the Udvar-Hazy Center in Chantilly, Va., the Smithsonian announced Oct. 18.

The flight-model FM-4 satellite was built by Space Systems/Loral of Palo Alto, Calif., as a backup for the original Sirius system, consisting of three satellites in highly elliptical orbit. Sirius eventually acquired rival XM Satellite Radio and elected to adopt XM’s geostationary-orbiting satellite system architecture, which made the FM-4 satellite expendable.

“The availability of a flight unit like Sirius FM-4, which was never launched, is extremely rare and will be a significant addition to the museum’s collection,” Martin Collins, space history curator at Udvar-Hazy, said in a prepared statement. “Whether experienced in our cars or homes, the remarkable innovations offered by satellite services are often taken for granted — one indicator of how the space age has changed our lives.”

New York-based SiriusXM is preparing to retire its three original elliptical-orbit satellites, all of which were launched in 2000. Programming currently carried by those satellites is slated to be transferred to two geostationary satellites in 2013, a move that will require SiriusXM to augment its ground-based repeater network to ensure services in hard-to-reach areas such as urban canyons.