The Amazonas 4A, renamed in 2016 Amazonas 4 and since 2017 known as the Hispasat 74W-1, is a Spanish commercial communications satellite developed 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 ...

and operated by Hispasat. It was successfully launched in 2014 and it is expected to have a

service life A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a product's ...

of 15 years however, shortly after its launch the satellite suffered a power failure that limited its

operability Operability is the ability to keep a piece of equipment, a system or a whole industrial installation in a safe and reliable functioning condition, according to pre-defined operational requirements. In a computing systems environment with multiple ...

and life. It is positioned to cover all of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

and during its service life the satellite has offered coverage for some important events such as the

2016 Summer Olympics The 2016 Summer Olympics ( pt, Jogos Olímpicos de Verão de 2016), officially the Games of the XXXI Olympiad ( pt, Jogos da XXXI Olimpíada) and also known as Rio 2016, was an international multi-sport event held from 5 to 21 August 20 ...

and

World Cup football The FIFA World Cup, often simply called the World Cup, is an international association football competition contested by the senior men's national teams of the members of the ' ( FIFA), the sport's global governing body. The tournament has ...

broadcasts.

Body

The satellite is based on the GEO Star-2.4 bus and has a dry mass of 1,241 kg. It is shaped like a square-faced prism 5 meters tall. Its lateral faces hold two deployable reflector-antennas and two retracting solar panels that, when fully deployed, give the satellite a

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for ...

nearing 23 meters. At launch, its mass was increased to 2,938 kg.

Propulsion

The main engine is the

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 ...

BT-4 developed by the Japanese company

IHI Aerospace , formerly known as , is a Japanese engineering corporation headquartered in Tokyo, Japan that produces and offers ships, space launch vehicles, aircraft engines, marine diesel engines, gas turbines, gas engines, railway systems, turbochargers f ...

. It is fueled by

unsymmetrical dimethylhydrazine Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...

using

dinitrogen tetroxide Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium ...

as the oxidizer. The fuel is stored in spherical tanks pressurized with

Helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

. The engine alone is 0.65 meters tall and has a

dry mass Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity. Curb or kerb weight Curb weight (U.S. English) or kerb ...

of 4 kg while capable of producing 450 N of thurst.

Attitude Determination & Control Subsystem

The attitude and control subsystem is

state of the art The state of the art (sometimes cutting edge or leading edge) refers to the highest level of general development, as of a device, technique, or scientific field achieved at a particular time. However, in some contexts it can also refer to a level ...

employing a combination of electrically powered set of

reaction wheel A reaction wheel (RW) is used primarily by spacecraft for three-axis attitude control, and does not require rockets or external applicators of torque. They provide a high pointing accuracy, and are particularly useful when the spacecraft must be ...

s and chemical-inertial

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 ...

monopropellant Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with biprop ...

thrusters in order to provide precise Earth-pointing capabilities.

Electrical Power Subsystem

The power requirements of the satellite are up to 4.8 kW although it was projected to support up to 6.2 kW. Those are provided by a combination of two independent arrays each composed by four panels featuring Ultra-Triple-Junction

GaAs Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circui ...

Solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

s and two 5,053 Watt-Hour

Li-Ion batteries 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 ...

and avionics for power storage and distribution.

Communications Subsystem

The communications subsystem is the main payload of the satellite. It consists on 24

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 german: Kurz-unten), because it is the lower part of the ori ...

transponder In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend word, blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a T ...

s subdivided in two 15-for-12 groups of Linearized Channel Travelling Wave Tube Amplifiers (LCTWTAs). In addition to two 2.5 x 2.7 meter single shell super elliptical deployable reflectors. All of them orientable and capable of working individually or grouped in order to speed up or relay communications. Nonetheless, a power failure in the electrical subsystem provoked the quick degradation of the subsystem and it has been speculated that, as a result, the satellite lost almost half of its communication potential being able to maintain only 12 of its transponders operational. In conjunction to the natural degradation of the solar panels in space, has greatly shortened the satellite's service life and its utility. Its design signal strength lies between 46 and 48.5 dBW throughout all of South America.

Launch

The satellite was launched the 22nd of March 2014, at 22:04 UTC, via an Ariane 5 ECA vehicle, from the

Guiana Space Center 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 ...

in Kourou, French Guiana. The launch was shared with the

Astra 5B Astra 5B is one of the Astra communications satellites owned and operated by SES. It was launched as SES' 56th satellite in March 2014, to the newest of the Astra orbital positions for direct-to-home (DTH) satellite television, at 31.5° Eas ...

satellite. Amazonas 4A was successfully put into a GEO orbit of 35,807.6 km of

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

and 35,780.1 km of perigee, an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 0.1º, a

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

of 1,436.1 minutes and a semi major maxis of 42,164 km. Since it was designed to cover all of South America, it initially operated on the longitude 61º W but since 2017 it has shifted to 73.9º W.

Power failure

Shortly after reaching its intended orbit the satellite suffered a partial power failure losing some of its capabilities and shortening its operational life. The loss was estimated to halve the satellite's capabilities. However, the difficulty in assessing the causes and severity of the failure forced Hispasat and the

insurance company Insurance is a means of protection from financial loss in which, in exchange for a fee, a party agrees to compensate another party in the event of a certain loss, damage, or injury. It is a form of risk management, primarily used to hedge ...

to open a joint investigation. It will remain open until the loss of the satellite, scheduled for 2029, but so far, the insured value has been estimated at 145 million

euro The euro ( symbol: €; code: EUR) is the official currency of 19 out of the member states of the European Union (EU). This group of states is known as the eurozone or, officially, the euro area, and includes about 340 million citizens . ...

s. The economic impact of the power failure has been estimated on 11 million euros of lost income during for the first quarter of 2014 for Hispasat, with further 5.4 million euros lost in

operating income In accounting and finance, earnings before interest and taxes (EBIT) is a measure of a firm's profit that includes all incomes and expenses (operating and non-operating) except interest expenses and income tax expenses. Operating income and ope ...

. In addition, the incident provoked the scrapping of the high power companion satellite, the Amazonas 4B, replaced by the future Amazonas 5 and the two renamings the satellite has undergone.

Amazonas 4B

A preliminary agreement between Hispasat and Orbital Sciences Corporation was signed the 25th of June 2012. This agreement included the construction of two new satellites, Amazonas 4A and Amazonas 4B that will be located at orbital position 61 West longitude. However, during 2014, in the wake of the partial power failure of the Amazonas 4A, the agreement was modified and the Amazonas 4B scrapped and replaced by the future project Amazonas 5. This time constructed by SSL. The Amazonas 5 was to provide the same capabilities of both the Amazonas 4A (previous to its power failure) and the Amazonas 4B. It was successfully put into orbit the 11th of September 2017. Its planned specifications are not clear since it was cancelled before construction began. However, being projected together with the Amazonas 4A it is safe to assume that they would have been similar. Consequently, the Amazonas 4B was going to use the GEO Star-2.4 or the more modern GEO Star-3 as a

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

. Its service life would have lasted about 15 years. It was projected that the engine would be the same as the Amazonas 4A: the BT-4 developed by the Japanese company

. The communications subsystem was going to be the main payload of the satellite. It consisted of 18

s, in addition to two 2.5 x 2.7 meter single shell super elliptical deployable reflectors.

References

{{Orbital launches in 2014 Satellites in geostationary orbit Satellites of Spain