Horizons-2 is a

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

owned by

Horizons Satellite Horizons Satellite is a joint venture between Intelsat and SKY Perfect JSAT Group. Originally formed in 2001, pursuant to a memorandum of understanding between JSAT Corporation and PanAmSat for the launch of Horizons-1, it was renewed for Horizons ...

, a joint venture between

SKY Perfect JSAT Group The SKY Perfect JSAT Group is a Japanese corporate group that claims to be Asia's largest satellite communication and multi-channel pay TV company. It owns the SKY PerfecTV! satellite broadcasting service and the SKY Perfect Well Think content s ...

and

Intelsat Intelsat S.A. (formerly INTEL-SAT, INTELSAT, Intelsat) is a multinational satellite services provider with corporate headquarters in Luxembourg and administrative headquarters in Tysons Corner, Virginia, United States. Originally formed as In ...

. Its orbital slot is located at 74° west longitude.

Launch

Horizons-2 was launched from the

Guiana Space Centre The Guiana Space Centre (french: links=no, Centre spatial guyanais; CSG), also called Europe's Spaceport, is a European spaceport to the northwest of Kourou in French Guiana, a region of France in South America. Kourou is located approximatel ...

— along with the

Rascom-QAF 1 The Regional African Satellite Communication Organization (RASCOM) will provide telecommunication services, direct TV broadcast services and Internet access in rural areas of Africa. Under an agreement with RASCOM, RascomStar-QAF (a private compan ...

spacecraft — aboard an Arianespace Ariane 5-GS. Launch occurred at 21:42

GMT Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a cons ...

on 21 December 2007.

Platform and payload

Horizons-2 was built by

Orbital Sciences Corporation Orbital Sciences Corporation (commonly referred to as Orbital) was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other governmen ...

based on its

STAR-2 The STAR-2 Bus is a fully redundant, flight-proven, spacecraft bus designed for geosynchronous missions. It is a satellite platform, designed and developed by Thomas van der Heyden for the Indonesian Cakrawarta satellite program in the early 19 ...

satellite platform, which will generate 3.5 kilowatts of payload power by means of two solar arrays, each equipped with three panels of UJT gallium arsenide cells. The solar arrays charge two

lithium ion A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...

batteries with capacities of at least 3,850

watt-hour A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bil ...

s. The spacecraft is 3-axis stabilized, with a zero momentum system.

Hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly toxic unless handled in solution as, for example, hydrazine ...

-fuelled monopropellant thrusters are used for stationkeeping, with an

IHI Ihi, Ehee (Nepal Bhasa:ईही) is a ceremony in the Newar community in Nepal in which pre-adolescent girls are "married" to the Suvarna Kumar which is a symbol of the god Vishnu, ensuring that the girl becomes and remains fertile. It is bel ...

BT-4 bipropellant engine used for insertion into geostationary orbit. It has a design life of 15 years, however it is fuelled for at least 16 years of operations. Its payload consists of 20 Ku-band transponders broadcasting through two dual gridded shaped reflectors.
It has 16 active transponders with 22-for-16 redundant 85 W TWTAs and four active transponders with 6-for-4 redundant 150 W TWTAs. The satellite will provide service to the continental United States, the Caribbean and parts of Canada.

References

Communications satellites in geostationary orbit Spacecraft launched in 2007 Satellites using the GEOStar bus {{Communications-satellite-stub