Satellite Modules

The satellite’s functional versatility is imbedded within its technical components and its operations characteristics. Looking at the “anatomy” of a typical satellite, one discovers two modules. Note that some novel architectural concepts such as Fractionated Spacecraft somewhat upset this taxonomy.

Spacecraft bus or service module

This bus module consist of the following subsystems:

• The Structural Subsystems

The structural subsystem provides the mechanical base structure, shields the satellite from extreme temperature changes and micro-meteorite damage, and controls the satellite’s spin functions.

• The Telemetry Subsystems (aka Command and Data Handling, C&DH)

The telemetry subsystem monitors the on-board equipment operations, transmits equipment operation data to the earth control station, and receives the earth control station’s commands to perform equipment operation adjustments.

• The Power Subsystems

The power subsystem consists of solar panels and backup batteries that generate power when the satellite passes into the earth’s shadow. Nuclear power sources (Radioisotope thermoelectric generators) have been used in several successful satellite programs including the Nimbus program (1964-1978).

• The Thermal Control Subsystems

The thermal control subsystem helps protect electronic equipment from extreme temperatures due to intense sunlight or the lack of sun exposure on different sides of the satellite’s body (e.g. Optical Solar Reflector)

• The Attitude and Orbit Controlled Control Subsystems

Main article: Attitude control

The attitude and orbit controlled subsystem consists of small rocket thrusters that keep the satellite in the correct orbital position and keep antennas positioning in the right directions.

Communication payload

The second major module is the communication payload, which is made up of transponders. A transponders is capable of :

• Receiving uplinked radio signals from earth satellite transmission stations (antennas).
• Amplifying received radio signals
• Sorting the input signals and directing the output signals through input/output signal multiplexers to the proper downlink antennas for retransmission to earth satellite receiving stations (antennas).

End of life

When satellites reach the end of their mission, satellite operators have the option of de-orbiting the satellite, leaving the satellite in its current orbit or moving the satellite to a graveyard orbit. Historically, due to budgetary constraints at the beginning of satellite missions, satellites were rarely designed to be de-orbited. One example of this practice is the satellite Vanguard 1. Launched in 1958, Vanguard 1, the 4th manmade satellite put in Geocentric orbit, was still in orbit as of August 2009.

Instead of being de-orbited, most satellites are either left in their current orbit or moved to a graveyard orbit. As of 2002, the FCC now requires all geostationary satellites to commit to moving to a graveyard orbit at the end of their operational life prior to launch.

Launch-capable countries

Main article: Timeline of first orbital launches by nationality

Launch of the first British Skynet military satellite.

This list includes countries with an independent capability to place satellites in orbit, including production of the necessary launch vehicle. Note: many more countries have the capability to design and build satellites — which relatively speaking, does not require much economic, scientific and industrial capacity — but are unable to launch them, instead relying on foreign launch services. This list does not consider those numerous countries, but only lists those capable of launching satellites indigenously, and the date this capability was first demonstrated. Does not include consortium satellites or multi-national satellites.

First launch by country

Order	Country	Year of first launch	Rocket	Satellite
1	Soviet Union	1957	Sputnik-PS	Sputnik 1
2	United States	1958	Juno I	Explorer 1
3	France	1965	Diamant	Astérix
4	Japan	1970	Lambda-4S	Ōsumi
5	China	1970	Long March 1	Dong Fang Hong I
6	United Kingdom	1971	Black Arrow	Prospero X-3
7	India	1980	SLV	Rohini
8	Israel	1988	Shavit	Ofeq 1
-	Russia[1]	1992	Soyuz-U	Kosmos-2175
-	Ukraine[1]	1992	Tsyklon-3	Strela (x3, Russian)
9	Iran	2009	Safir-2	Omid

Notes

1. Russia and Ukraine were parts of the Soviet Union and thus inherited their launch capability without the need to develop it indigenously. Through Soviet Union they also are on the number one position in this list of accomplishments.
2. France, United Kingdom launched their first satellites by own launchers from foreign spaceports.
3. North Korea (1998) and Iraq (1989) have claimed orbital launches (satellite and warhead accordingly), but these claims are unconfirmed.
4. In addition to the above, countries such as South Africa, Spain, Italy, Germany, Canada, Australia, Argentina, Egypt and private companies such as OTRAG, have developed their own launchers, but have not had a successful launch.
5. As of 2009, only eight countries from the list above ( Russia and Ukraine instead of USSR, also USA, Japan, China, India, Israel, and Iran) and one regional organization (the European Space Agency, ESA) have independently launched satellites on their own indigenously developed launch vehicles. (The launch capabilities of the United Kingdom and France now fall under the ESA.)
6. Several other countries, including South Korea, Brazil, Pakistan, Romania, Taiwan, Indonesia, Kazakhstan, Australia, Malaysia^{[citation needed]} and Turkey, are at various stages of development of their own small-scale launcher capabilities.
7. South Korea launched a KSLV rocket (created with assistance of Russia) in 25 August 2009, but it failed to put satellite STSAT-2 into precise orbit and the satellite did not start to function.
8. North Korea claimed a launch in April 2009, but U.S. and South Korean defense officials and weapons experts later reported that the rocket failed to send a satellite into orbit, if that was the goal. The United States, Japan and South Korea believe this was actually a ballistic missile test, which is a claim also made after North Korea's 1998 satellite launch, and later rejected.

Launch capable private entities

On September 28, 2008, the private aerospace firm SpaceX successfully launched its Falcon 1 rocket in to orbit. This marked the first time that a privately built liquid-fueled booster was able to reach orbit. The rocket carried a prism shaped 1.5 m (5 ft) long payload mass simulator that was set into orbit. The dummy satellite, known as Ratsat, will remain in orbit for between five and ten years before burning up in the atmosphere.

First satellites of countries

First satellites of countries including launched indigenously or by help of other

Country	Year of first launch	First satellite	Payloads in orbit in 2008[23]
Soviet Union ( Russia)	1957 (1992)	Sputnik 1 (Cosmos-2175)	1398
United States	1958	Explorer 1	1042
United Kingdom	1962	Ariel 1	0025
Canada	1962	Alouette 1	0025
Italy	1964	San Marco 1	0014
France	1965	Astérix	0044
Australia	1967	WRESAT	0011
Germany	1969	Azur	0027
Japan	1970	Ōsumi	0123
China	1970	Dong Fang Hong I	0083
Poland	1973	Intercosmos Kopernikus 500	0000?
Netherlands	1974	ANS	0005
Spain	1974	Intasat	0009
India	1975	Aryabhata	0034
Indonesia	1976	Palapa A1	0010
Czechoslovakia	1978	Magion 1	0005
Bulgaria	1981	Intercosmos Bulgaria 1300	0001
Brazil	1985	Brasilsat A1	0011
Mexico	1985	Morelos 1	0007
Sweden	1986	Viking	0011
Israel	1988	Ofeq 1	0007
Luxembourg	1988	Astra 1A	0015
Argentina	1990	Lusat	0010
Pakistan	1990	Badr-1	0005
South Korea	1992	Kitsat A	0010
Portugal	1993	PoSAT-1	0001
Thailand	1993	Thaicom 1	0006
Turkey	1994	Turksat 1B	0005
Ukraine	1995	Sich-1	0006
Chile	1995	FASat-Alfa	0001
Malaysia	1996	MEASAT	0004
Norway	1997	Thor 2	0003
Philippines	1997	Mabuhay 1	0002
Egypt	1998	Nilesat 101	0003
Singapore	1998	ST-1	0001
Taiwan	1999	ROCSAT-1	00009
Denmark	1999	Ørsted	0004
South Africa	1999	SUNSAT	0001
Saudi Arabia	2000	Saudisat 1A	0012
United Arab Emirates	2000	Thuraya 1	0003
Morocco	2001	Maroc-Tubsat	0001
Algeria	2002	Alsat 1	0001
Greece	2003	Hellas Sat 2	0002
Nigeria	2003	Nigeriasat 1	0002
Iran	2005	Sina-1	0004
Kazakhstan	2006	KazSat 1	0001
Belarus	2006	BelKA	0001
Colombia	2007	Libertad 1	0001
Vietnam	2008	VINASAT-1	0001
Venezuela	2008	Venesat-1	0001
Turkey	2009	ITUpSAT1[24]	0001
Switzerland	2009	SwissCube-1[25]	0001

While Canada was the third country to build a satellite which was launched into space, it was launched aboard a U.S. rocket from a U.S. spaceport. The same goes for Australia, who launched on-board a donated Redstone rocket. The first Italian-launched was San Marco 1, launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (VA,USA) with an Italian Launch Team trained by NASA. Australia's launch project (WRESAT) involved a donated U.S. missile and U. S. support staff as well as a joint launch facility with the United Kingdom.^[28]

Attacks on satellites

For more details on this topic, see Anti-satellite weapon.

In recent times satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks.

Satellites in low earth orbit have been destroyed by ballistic missiles launched from earth. Russia, the United States and China have demonstrated the ability to eliminate satellites. In 2007 the Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008.

Jamming

Due to the low received signal strength of satellite transmissions they are prone to jamming by land-based transmitters. Such jamming is limited to the geographical area within the transmitter's range. GPS satellites are potential targets for jamming, but satellite phone and television signals have also been subjected to jamming. It is trivial to transmit a carrier to a geostationary satellite and thus interfere with any other users of the transponder. It is common on commercial satellite space for earth stations to transmit at the wrong time or on the wrong frequency and dual illuminate the transponder rendering the frequency unusable. Satellite operators now have sophisticated monitoring that enables them to pin point the source of any carrier and manage the transponder space effectively.