Asia Cellular Satellite (ACeS)

Asia Cellular Satellite (ACeS) was a satellite-based mobile communications system intended to provide voice and data services across Asia, with interconnection to public switched telephone networks. The system was designed to support up to two million subscribers and approximately 11,000 simultaneous calls, offering wireless voice services via dual-mode GSM/satellite handsets, together with Internet access, paging, facsimile, and data transmission.

The ACeS system employed a single geostationary satellite, Garuda-1, launched on 12 February 2000 from the Baikonur Cosmodrome. The satellite was stationed at 123°E longitude and operated in a controlled inclined orbit with a north–south excursion of approximately ±3°, reducing station-keeping fuel requirements. Beginning-of-life electrical power was approximately 14 kW, decreasing to about 9 kW at end of life. A second satellite, Garuda-2, was planned but not built.

The spacecraft carried two 12-m deployable umbrella-type reflector antennas forming approximately 140 spot beams over South-East Asia. On-board switching enabled call handover between spot beams during active connections. User links operated in L-band (1.6255–1.6605 MHz uplink and 1.525–1.559 MHz downlink), while gateway links used C-band (6.425–6.725 GHz uplink and 3.400–3.700 GHz downlink), with multiple gateways providing connectivity to terrestrial networks.

Despite its design capacity, ACeS attracted fewer than 20,000 subscribers and proved commercially unsuccessful. The system ceased operations in 2014, illustrating the difficulties faced by early geostationary mobile-satellite systems in the presence of rapidly expanding terrestrial cellular coverage.