Superbird-A2, known as Superbird-6 before launch, was a

geostationary A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a Transponder (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...

ordered and operated by Space Communications Corporation (SCC) that was designed and manufactured by Hughes (now

Boeing The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support s ...

) on the

BSS-601 The Boeing 601 (sometimes referred to as the BSS-601, and previously as the HS-601) is a retired communications satellite bus designed in 1985 and introduced in 1987 by Hughes Space and Communications Company. The series was extremely popular i ...

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are less customized than specially-produced satelli ...

. It had a mixed

Ku-band The Ku band () is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally ), because it is the lower part of the original NATO K band ...

and

Ka-band The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum. The designation "Ka-band" is from Kurz-above, which stems from the German word ''kurz,'' meaning "short". There ...

payload and was expected replace

Superbird-A Superbird-A, also identified as Superbird-1 before launch, was a geostationary orbit, geostationary communications satellite designed and manufactured by Ford Aerospace) on the SSL 1300 satellite bus. It was originally ordered by SKY Perfect JSA ...

at the position at 158° East longitude. It was expected to provided television signals and business communications services throughout Japan,

South Asia South Asia is the southern Subregion#Asia, subregion of Asia that is defined in both geographical and Ethnicity, ethnic-Culture, cultural terms. South Asia, with a population of 2.04 billion, contains a quarter (25%) of the world's populatio ...

East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...

, and

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. While the launch was within the margins specified by the satellite manufacturer, the trajectory analysis had been inexact and the satellite suffered severe life and power degradation. It tried to use a supersynchronous transfer strategy, but Boeing had failed to take into consideration the effect of the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

. Thus, the lowest part of the orbit dropped too fast and much propellant had to be spent on a fast transit to geosynchronous orbit. Additionally, the solar panels suffered damage from the extreme contact with the atmosphere. Given the damage to the spacecraft, it was never put into service.

Satellite description

The spacecraft was designed and manufactured by Boeing Satellite Development Center on the BSS-601 satellite bus. It had a launch mass of , a beginning of life mass of and an end of life mass of . It was designed for a 13-year life. When stowed for launch, it measured . It had two wings with four

solar panels A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

each, that generated 4378 watts at the end of its design life. When fully deployed, the solar panels spanned , with its antennas in fully extended configuration it was wide. It had a 29-cell NiH₂ battery with a power charge of 200 Ah. Its propulsion system was composed of a liquid apogee engine (LAE) with a thrust of . It also used had 12

bipropellant The highest specific impulse chemical rockets use liquid propellants (liquid-propellant rockets). They can consist of a single chemical (a monopropellant) or a mix of two chemicals, called bipropellants. Bipropellants can further be divided into ...

thrusters for station keeping and

attitude control Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle or satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, ...

. It included enough propellant for orbit circularization and 13 years of operation. It had a dual

and

payload. The Ku-band section had its dual-grid shaped antenna on the West side. It had twenty three

transponders In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a flight trans ...

powered by Traveling-wave tube#Traveling-wave-tube amplifier (TWTA) with and output power of 85 watts. It had a wide beam

footprint Footprints are the impressions or images left behind by a person walking or running. Hoofprints and pawprints are those left by animals with hooves or paws rather than feet, while "shoeprints" is the specific term for prints made by shoes. The ...

that covered Japan, South Asia, East Asia, and Hawaii. Its Ka-band section had a single-grid shaped antenna on the East side for the wide beam, and a

nadir The nadir is the direction pointing directly ''below'' a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface. The direction opposite of the nadir is the zenith. Et ...

shaped surface antenna for the steerable beam. It had four 100 MHz transponders powered by TWTA with and output power of 70 Watts. The wide beam covered Japan, South Asia, East Asia, and Hawaii, while the steerable beam could be focus on any zone that had line-of-sight to the satellite.

History

Space Communications Corporation (SCC) was founded in 1985, the same year as the original companies that later formed JSAT. In September 2001, SCC ordered its third

based spacecraft, Superbird-6. It was to use the 158° East position and offer a Japan wide beam service in Ku-band and Ka-band, plus steerable Ka-band spot beams. It was expected for a fall of 2003 launch aboard an

Atlas IIAS Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first-stage tanks, higher-perform ...

. It was decided to launch Superbird-6 into a 2895 minutes period

supersynchronous orbit A supersynchronous orbit is either an orbit with a period greater than that of a synchronous orbit, or just an orbit whose major axis is larger than that of a synchronous orbit. A synchronous orbit has a period equal to the rotational period of th ...

with an apogee of 120,679 km, a perigee of 1138 km and a 25.5° inclination. This extreme perigee and a six-maneuvers circularization program would reduce the propellant expenditure to its final position in

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

. It was launched on 16 April 2004 by an Atlas IIAS that injected in the

specified by the satellite manufacturer, at which point it was named Superbird-A2. But the orbit analysis had failed to take into consideration the influence of the

at such high apogees and the perigee started to drop dangerously fast. Most of its propellant had to be spent and the solar panels suffered damage that reduced the power production. The satellite can not enter service as planned in July 2004. One of two main fuel tanks on the spacecraft lost pressure on 28 November 2004. The satellite was never commissioned into regular service.

References

{{Orbital launches in 2004 Communications satellites in geostationary orbit Satellites using the BSS-601 bus Spacecraft launched in 2004 Communications satellites of Japan 2004 in Japan

Satellite description

History

See also

References