SATELLITES

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Satellites will play an important part in the fight against marine litter. They can already identify oil spills to alert emergency response units to the latest pollution position for containment purposes.

We also use satellites for geopositioning, data sharing, navigation and communications. In short, satellites are now an everyday tool to enhance marine operations, surveys, monitoring or for exploration purposes.

All of this is only possible because of our launch capabilities, and all of that development came about because of space exploration and the space race, where large motors and fuel systems were developed by several countries to get heavy objects on earth, including humans, into space.

SOYUZ: Soyuz is a series of spacecraft designed for the Soviet space program by the Korolev Design Bureau (now RKK Energia) in the 1960s that remains in service today. The Soyuz succeeded the Voskhod spacecraft and was originally built as part of the Soviet manned lunar programs. The Soyuz spacecraft is launched on a Soyuz rocket, the most frequently used and most reliable launch vehicle in the world to date. The Soyuz rocket design is based on the Vostok launcher, which in turn was based on the 8K74 or R-7A Semyorka, a Soviet intercontinental ballistic missile. All Soyuz spacecraft are launched from the Baikonur Cosmodrome in Kazakhstan.

In context of space flight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as Earth's Moon.

In 1957 the Soviet Union launched the world's first artificial satellite, Sputnik 1. Since then, about 6,600 satellites from more than 40 countries have been launched. According to a 2013 estimate, 3,600 remained in orbit. Of those, about 1,000 were operational; while the rest have lived out their useful lives and became space debris. Approximately 500 operational satellites are in low-Earth orbit, 50 are in medium-Earth orbit (at 20,000 km), and the rest are in geostationary orbit (at 36,000 km). A few large satellites have been launched in parts and assembled in orbit. Over a dozen space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Mercury, Venus, Mars, Jupiter, Saturn, a few asteroids, and the Sun.

Satellites are used for many purposes. Common types include military and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, and space telescopes. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include low Earth orbit, polar orbit, and geostationary orbit.

A launch vehicle is a rocket that throws a satellite into orbit. Usually it lifts off from a launch pad on land. Some are launched at sea from a submarine or a mobile maritime platform, or aboard a plane (see air launch to orbit).

Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.

SATELLITE HISTORY

The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957, and initiating the Soviet Sputnik program, with Sergei Korolev as chief designer. This in turn triggered the Space Race between the Soviet Union and the United States.

Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.

Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika.

In May, 1946, Project RAND had released the Preliminary Design of an Experimental World-Circling Spaceship, which stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century." The United States had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy. The United States Air Force's Project RAND eventually released the report, but considered the satellite to be a tool for science, politics, and propaganda, rather than a potential military weapon.

In 1954, the Secretary of Defense stated, "I know of no American satellite program." In February 1954 Project RAND released "Scientific Uses for a Satellite Vehicle," written by R.R. Carhart. This expanded on potential scientific uses for satellite vehicles and was followed in June 1955 with "The Scientific Use of an Artificial Satellite," by H.K. Kallmann and W.W. Kellogg.

SOYUZ: The first Soyuz flight was unmanned and started on November 28, 1966. The first Soyuz mission with a crew, Soyuz 1, launched on 23 April 1967 but ended with a crash due to a parachute failure, killing cosmonaut Vladimir Komarov. The following flight was unmanned. Soyuz 3, launched on October 26, 1968, became the program's first successful manned mission. The only other flight to suffer a fatal accident, Soyuz 11, killed its crew of three when the cabin depressurized prematurely just before reentry. These were the only humans to date to have died above the Kármán line. Despite these early incidents, Soyuz is widely considered the world's safest, most cost-effective human spaceflight vehicle, established by its unparalleled length of operational history. Soyuz spacecraft were used to carry cosmonauts to and from Salyut and later Mir Soviet space stations, and are now used for transport to and from the International Space Station (ISS). At least one Soyuz spacecraft is docked to ISS at all times for use as an escape craft in the event of an emergency. The spacecraft is intended to be replaced by the six-person Federation spacecraft.

In the context of activities planned for the International Geophysical Year (1957–58), the White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviets announced that they intended to launch a satellite by the fall of 1957.

Following pressure by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, military interest picked up and in early 1955 the Army and Navy were working on Project Orbiter, two competing programs: the army's which involved using a Jupiter C rocket, and the civilian/Navy Vanguard Rocket, to launch a satellite. At first, they failed: initial preference was given to the Vanguard program, whose first attempt at orbiting a satellite resulted in the explosion of the launch vehicle on national television. But finally, three months after Sputnik 2, the project succeeded; Explorer 1 became the United States' first artificial satellite on 31 January 1958.

In June 1961, three-and-a-half years after the launch of Sputnik 1, the Air Force used resources of the United States Space Surveillance Network to catalog 115 Earth-orbiting satellites.

Early satellites were constructed as "one-off" designs. With growth in geosynchronous (GEO) satellite communication, multiple satellites began to be built on single model platforms called satellite buses. The first standardized satellite bus design was the HS-333 GEO commsat, launched in 1972.

The largest artificial satellite currently orbiting the Earth is the International Space Station.

SATELLITE USES

1.  Astronomy telescopes (Hubble)

2.  Bio-satellites

3.  Atmospheric studies (Polar)

4.  Communications, TV, Radio, Phones (Anik E)

5.  Navigation (Navstar)

6.  Reconnaissance/spy (Lacrosse)

7.  Recovery

8.  Remote sensing (Radarsat

9.  Search and rescue (Cospas, Sarsat)

10. Space craft (Apollo, Shuttle)

11. Space exploration (Galileo)

12. Space stations

13. Weather (Meteosat)

THE SPACE RACE

The United States Space Surveillance Network (SSN), a division of the United States Strategic Command, has been tracking objects in Earth's orbit since 1957 when the Soviet Union opened the Space Age with the launch of Sputnik I. Since then, the SSN has tracked more than 26,000 objects. The SSN currently tracks more than 8,000 man-made orbiting objects. The rest have re-entered Earth's atmosphere and disintegrated, or survived re-entry and impacted planet Earth. The SSN tracks objects that are 10 centimeters in diameter or larger; those now orbiting Earth range from satellites weighing several tons to pieces of spent rocket bodies weighing only 10 pounds. About seven percent are operational satellites (i.e. ~560 satellites), the rest are space debris. The United States Strategic Command is primarily interested in the active satellites, but also tracks space debris which upon reentry might otherwise be mistaken for incoming missiles.

SPECIFIC TASKS

Satellites are launched into the space to do a specific job. It is an expensive undertaking that each autonomous vehicle has to be designed for and costed for economic viability.

WEATHER PREDICTION

Satellites are launched to monitor cloud patterns for weather stations and others to send television signals for Sky TV. Satellites are used for oceanography, astronomy, surveillance. They help scientists get a perceptive view of all kinds of objects anywhere in the world.

Earth observation satellites can monitor the ocean and wind currents, the extent of forest fires, oil spills and airborne pollution. Satellites provide meteorologists with the ability to see the weather on a global scale. They allow them to follow the effects of phenomena like volcanic eruptions and burning gas and oil fields, to the development of large weather systems like hurricanes.

OCEAN MONITORING

Ocean surveillance satellites are used to search for ships and submarines. They can spot nuclear vessels and new advancements may allow them to scan the depths of the ocean. Early warning and Elint satellites are primarily used by the armed forces to protect their countries from the sneak attacks. They can help to detect if other countries are building or storing nuclear warheads with varying degrees of success, because of course the opposing military are sure to employ decoys. This is all negative effort in terms of human endeavour where technology works for the preservation of life on earth positively.

Marine scientists and marine biologists can detect much that goes on in the ocean. They use satellites to detect the oceans as they affect the environment, even analyzing wave patterns.

Environmentalists can monitor marine surface life to analyze ocean tendencies and the currents, and they can get a complete synoptic view of the ocean. These things help them provide information of water quality and ocean life.

Satellites can detect underground water and mineral sources. They can monitor the transfer of nutrients and contaminants from the land into the waterways and out to sea. They can measure land and water temperatures, the growth of algae in the seas and the erosion of topsoil from the land.

CLIMATE CHANGE

Satellites are one of the best sources of data for climate change research. They monitor the ocean temperatures and the prevailing currents. The data acquired by the satellite borne radars were able to show that sea levels have been rising by three mm a year over the last decade.

Imaging satellites can measure the changing sizes of the glaciers which is difficult to do from the ground due to the remoteness and darkness of the polar regions. Satellites can determine the long term patterns of rainfall, vegetation cover and the emissions of greenhouse gases.

AGRICULTURE

Remote sensing is used to observe and measure our environment from a distance. These satellites are put into space to monitor the resources that are important for humans. They may track the animal migration or locate mineral deposits, or they can watch agricultural crops for weather damage.

Remote sensing satellites can take the photographs and observe the areas all over the globe. They can monitor the areas in which the climate is very harsh or which are nearly impossible to reach by land.

RESCUE

Satellites can take the search out of search and rescue for people in the distress in the remote regions. Distress radio beacons directly linked to a search and rescue satellite can lead rescuers quickly and 
accurately to land, sea or the air emergency locations.

NAVIGATION

Satellites provide in flight phone communications on aircraft. They are the main conduit of voice communication for rural areas and areas where phone lines are damaged after a disaster. They provide the primary timing source for cell phones and the pagers.

The satellite based navigation systems like Navstar Global Positioning Systems enable anyone with a handheld receiver to determine his location to within a few meters ,They are known colloquially as GPS.

GPS locators are increasingly included in car direction services, replacing the skills of a good map reader. GPS based systems are used by civilians and the military for navigation on land, sea and air. They are crucial in situations like a ship making a difficult course to a harbor in bad weather or where troops may be lost in unknown regions.

COMMERCE

Communications satellites have the ability to rapidly share information between a number of widely dispersed locations. They help big manufacturing companies and the department stores to perform inventory management, they provide instant credit card authorization and automated teller banking services to even small towns. They are used by motorists to pay for gas at the pump at freeway petrol stations.

ASTRONOMY

Astronomy satellites are new technology that are mounted on earth orbiting satellites or in deep space 
probes where they give us an unobstructed view without the earth’s atmosphere interfering. They carry detectors to record the electromagnetic radiation at wavelengths shorter than visible light.

DECOMMISSIONING

When satellites reach the end of their mission (this normally occurs within 3 or 4 years after launch), 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 requires all geostationary satellites to commit to moving to a graveyard orbit at the end of their operational life prior to launch. In cases of uncontrolled de-orbiting, the major variable is the solar flux, and the minor variables the components and form factors of the satellite itself, and the gravitational perturbations generated by the Sun and the Moon (as well as those exercised by large mountain ranges, whether above or below sea level). The nominal breakup altitude due to aerodynamic forces and temperatures is 78 km, with a range between 72 and 84 km. Solar panels, however, are destroyed before any other component at altitudes between 90 and 95 km.

SEAGULLS: Satellites could help to prevent seabirds from eating plastic litter that pervades our beaches and oceans.

LINKS & REFERENCE

https://en.wikipedia.org/wiki/Satellite

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