XM provides digital programming directly from two high-powered satellites in
geostationary orbit above the equator: XM Rhythm at 115° west
longitude and XM Blues at 85° west longitude in addition to a network of ground-based repeaters. The combination of two satellites and a ground-based repeater network is designed to provide gap-free coverage anywhere within the continental U.S., the southern tip of Alaska, and in the southern part of Canada. The signal can also be received in the Caribbean Islands and most of Mexico (reports have stated that areas north of
Acapulco are able to receive a steady signal
[15]), however XM is not yet licensed for reception by paid subscribers living in these areas.
The original satellites, XM-1 ("Rock") and XM-2 ("Roll") suffer from a generic design fault on the
Boeing 702 series of satellites (fogging of the solar panels), which means that their lifetimes will be shortened to approximately six years instead of the design goal of 15 years.
[16][17] To compensate for this flaw, XM-3 ("Rhythm") was launched ahead of its planned schedule on
February 28,
2005 and moved into XM-1's previous location of 85° WL. XM-1 was then moved to be co-located with XM-2 at 115° WL, where each satellite operated only one transponder (thus broadcasting half the bandwidth each) to conserve energy and cut the power consumption in half while XM-4 ("Blues") was readied for launch. Subsequently, XM launched ground-spare XM-4 ("Blues") ahead of schedule on October 30, 2006 into the 115° WL location to complete the satellite replacement program. On
December 15,
2006 XM-1 was then powered down and drifted back to its original location at 85° WL, where it will remain as a backup to XM-3. XM-2 as well was powered down and remains as a backup to XM-4. This makes the current active satellites as XM-3 "Rhythm" and XM-4 "Blues" with two in-orbit spares.
[6][18]
On
June 7,
2005,
Space Systems/Loral announced that it had been awarded a contract for XM-5.
[19][20] XM-5 will feature two large unfurlable antennas. Sirius' Radiosat 5, also to be built by Loral, will have a similar single large antenna.