ST-1 was Singapore’s first communications satellite.¹ Launched into a geostationary orbit in 1998, the 3.2-tonne, US$240-million satellite was a 50-50 joint venture between Singapore Telecommunications (SingTel) and Taiwan’s Chunghwa Telecom.² ST-1 provided direct-to-home broadcast, internet and telecommunications services from 1998 to 2011.³ Its area of coverage included Southeast Asia, India, Taiwan and China.⁴ The first satellite earth station in Singapore was installed on Sentosa in 1971. By the 1980s, SingTel had taken small stakes in satellite systems such as Inmarsat, Intelsat, Asia Pacific Mobile Telecommunications and Palapa.⁵ Satellite stations were added at Bukit Timah and Seletar by the 1990s.⁶ 

Seeing the commercial opportunities in owning a satellite,⁷ SingTel signed a memorandum of understanding in 1995 with Taiwan’s government-owned Directorate General of Telecommunications (Chunghwa Telecom was spun off from the directorate on 1 July 1996 following the liberalisation of Taiwan’s telecommunications market in January that year) to jointly launch a satellite system.⁸ One of the reasons for the partnership was that the International Telecommunication Union, the international organisation responsible for assigning orbital slots for satellites by nation, did not recognise Taiwan as a sovereign state.⁹A tender for the manufacture of the satellite was called in late 1995 and awarded to Matra Marconi Space in April the following year.¹⁰ The ST-1 system was built at a cost of US$240 million. Typically, 50 percent of the total system cost would be capital cost, 25 percent for the launch, 20 percent for insurance and the remaining five percent for ground equipment.¹¹

Construction and launch
Around 60 companies from 11 countries were involved in the construction of ST-1. The companies included Anglo-French satellite manufacturer Matra Marconi Space, Germany’s Daimler-Benz Aerospace and French industrial giant Aerospatiale. The launcher was produced by European rocket maker Arianespace.¹² Construction and assembly of the 3.2-tonne satellite was completed by March 1998, following which it underwent a series of heat and cold, vacuum and radiation tests.¹³ The satellite was then flown to its launch site in French Guiana, while the launcher was shipped there.¹⁴ At 7.07 am Singapore time on 26 August 1998, ST-1 was launched from a 65-metre tower at the Guiana Space Centre in Kourou, French Guiana.¹⁵ The journey to a geostationary transfer orbit took around 22 minutes and consumed two tonnes of fuel every second.¹⁶ Over the next 12 days, ST-1 moved to the orbital position allocated to Singapore at 88° east (over the Indian Ocean), 36,000 km from earth.¹⁷ The satellite began commercial operations in December 1998.¹⁸

Operations
At the time of ST-1’s launch, SingTel had found customers for all its eight Ku-band transponders and several of its seven C-band transponders on the satellite, notwithstanding an economic crisis in Asia and amid a climate of slowing demand for the lease of satellite transponders.¹⁹ In January 1999, SingTel announced a S$206-million deal with Indian company Sterlingsat Television for the lease of an unspecified number of transponders for 12 years. Sterlingsat utilised ST-1’s digital direct-to-home services to broadcast education programmes to its customers in India.²⁰ By January 2001, SingTel had leased out all of its Ku-band and C-band transponders. To meet additional demand from its clients as well as from its own telecommunications services, SingTel booked short term leases on the Apstar-I satellite and a number of Chunghwa’s transponders on ST-1.²¹ ST-1 was exempted from the Taiwan government’s ban on direct communications between Taiwan and China, and was permitted by the Chinese government to carry cross-strait communications.²²

Description
ST-1 was equipped with 16 Ku-band and 14 C-band transponders,²³ which are electrical components that receive uplink signals and amplify them for re-transmission to the earth. Ku-band transponders operate at a higher frequency compared with C-band transponders, and are used mainly for television broadcasting, the internet and direct-to-home services. C-band transponders are used mainly for data transmission, including Very Small Aperture Terminal (VSAT) services.²⁴ ST-1 was one of the most powerful satellites launched in 1998.²⁵ Its signals could be received by ground dishes as small as 90 cm, which yielded lower costs for broadcasters and consumers during its operational life.²⁶ In orbit, ST-1 faced sun-side temperature of 200 degrees Cesius and dark-side temperature of 170 degrees Cesius.²⁷ The satellite was expected to be used for a minimum of 12 years from its launch before being moved into a graveyard orbit,  an area in space for decommissioned satellites.²⁸

Second satellite
In May 2011, SingTel launched its second satellite, ST-2.²⁹ It has a wider coverage and more transponder capacity than ST-1, and took over ST-1’s operations at 88° east. SingTel then announced that it would use ST-1 for services such as maritime communications for another three years from 2011.³⁰

X-Sat
While ST-1 is regarded as Singapore’s first satellite, X-Sat is the first satellite designed and built in Singapore. The X-Sat is a 105-kilogram micro-satellite that records images of earth to track environmental changes. It was designed and built by Nanyang Technological University and DSO National Laboratories. The S$40-million X-Sat was launched into orbit on 20 April 2011.³¹

Author
Alvin Chua