Hubble Ultra Deep Field "HUDF"

The "HUBBLE"

CASSINI HUYGENS
entering saturn orbit THE SOLAR SYSTEM
The HUBBLE

The Hubble Space Telescope (HST; also known colloquially as "the Hubble" or just "Hubble") is a space telescope that was carried into orbit by a Space Shuttle in April 1990. It is named for American astronomer Edwin Hubble. Although not the first space telescope, the Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. The HST is a collaboration between NASA and the European Space Agency, and is one of NASA's Great Observatories, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope.Space telescopes were proposed as early as the 1940s. The Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, scientists found that the main mirror had been ground incorrectly, severely compromising the telescope's capabilities. However, after a servicing mission in 1993, the telescope was restored to its intended quality. Hubble's position outside the Earth's atmosphere allows it to take extremely sharp images with almost no background light. Hubble's Ultra Deep Field image, for instance, is the most detailed visible-light image of the universe's most distant objects ever made. Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.
The Hubble is the only telescope ever designed to be serviced in space by astronauts. To date, there have been four servicing missions. Servicing Mission 1 took place in December 1993 when Hubble's imaging flaw was corrected. Servicing missions 2, 3, and 4 repaired various sub-systems and replaced many of the observing instruments with more modern and capable versions. However, following the 2003 Columbia Space Shuttle disaster, the fifth servicing mission was canceled on safety grounds. After spirited public discussion, NASA reconsidered this decision, and administrator Mike Griffin gave the green light for one final Hubble servicing mission. This is now planned for October 2008.
The planned repairs to the Hubble will allow the telescope to function until at least 2013, when its successor, the James Webb Space Telescope (JWST), is due to be launched. The JWST will be far superior to Hubble for many astronomical research programs, but will only observe in infrared, so it would complement (not replace) Hubble's ability to observe in the visible and ultraviolet parts of the spectrum.
souce: wikipedia

The International Space Station

as seen from the departing Space Shuttle Discovery on STS-124

Station statistics
Call sign: Alpha (only by NASA)
Crew: 3
Launch: 1998-Present
Launch pad: KSC LC-39,Baikonur LC-1/5 & 81/23
Mass: 277,598 kg(612,000 lb)(2008-06-14)419,600 kg (925,000 lb) upon completion
Length: 58.2 m (191 ft)along truss(2007-02-22)
Width: 44.5 m (146 ft)from Destiny to Zvezda73.15 m (240 ft)span of solar arrays(2007-02-22)
Height: 27.4 m (90 ft)(2007-02-22)
Living volume:424.75 m³(15,000 ft³)
Atmospheric pressure: 1013 hPa (29.91 inHg)
Perigee: 331.0 km (183.2 nmi)(2008-02-15)
Apogee: 341.9 km (184.6 nmi)(2008-02-15)
Orbit inclination: 51.6410 degrees(2008-02-15)
Typical orbit altitude: 340.5 km (183.86 nmi)
Average speed: 27,743.8 km/h(17,239.2 mi/h, 7706.6 m/s)
Orbital period: 91.34 minutes
Orbits per day: 15.78224218(2008-02-15)
Days in orbit: 3512 (2 July 2008)
Days occupied: 2801 (2 July 2008)
Number of orbits: 55427 (2 July 2008)
Distance travelled: 2,000,000,000 km(1,100,000,000 nmi)
Statistics as of November 20, 2007 (unless noted otherwise).
Configuration (photo) on top.

The International Space Station (ISS) is a research facility being assembled in space. Its on-orbit assembly began in 1998. The space station is in a low Earth orbit and can be seen from Earth with the naked eye: it has an altitude of about 350 km (217 mi) above the surface of the Earth, and travels at an average speed of 27,700 km (17,210 statute miles) per hour, completing 15.77 orbits per day.
The ISS is a joint project among the space agencies of the United States (NASA), Russia (RKA), Japan (JAXA), Canada (CSA) and eleven European countries (ESA). The Brazilian Space Agency (AEB, Brazil) participates through a separate contract with NASA. The Italian Space Agency similarly has separate contracts for various activities not done in the framework of ESA's ISS works (where Italy also fully participates). China has reportedly expressed interest in the project, especially if it is able to work with the RKA. though it is not currently involved.
The ISS is a continuation of several other previously planned space stations: Russia's Mir 2, the U.S. Space Station Freedom, the European Columbus, and Kibo, the Japanese Experiment Module. The projected completion date is 2010, with the station remaining in operation until around 2016. As of 2008, the ISS is larger than any previous space station.
The ISS has been continuously staffed since the first resident crew entered the station on November 2, 2000, thereby providing a permanent human presence in space. The crew of Expedition 17 are currently aboard. At present the station has a capacity for a crew of three. In order to fulfill an active research program it will eventually hold 6 crew members. Early crew members all came from the Russian and U.S. space programs. German ESA astronaut Thomas Reiter joined the Expedition 13 crew in July 2006, becoming the first crew member from another space agency. The station has, however, been visited by astronauts from 16 countries. The ISS was also the destination of the first five space tourists.
The station is serviced primarily by Russian Soyuz and Progress spacecraft and by U.S. Space Shuttle orbiters. On March 9, 2008, the European Space Agency ESA launched an Ariane 5 with the first Automated Transfer Vehicle, Jules Verne, toward the ISS carrying over 8,000 kilograms of cargo. Successful docking took place at 14:40 GMT on April 3, 2008.

source: wikipedia

Early attempts at Human Spaceflight

In the early Christian era, a Greek satirist named Lucian wrote a book on space flight called True Histories. The book was full of tall, unbelieveable tales and travelogues on visits to the sun and the moon. Today, the book could easily be discarded as the fantasy of a people of a bygone era. But it was significant in the sense that it kindled the curiosities of the people of the day and stimulated interest in outer space and space travel.
In 1638, a Christian writer from England named Wilkins wrote a book on moon travel and suggested four methods to accomplish it. Firstly, he said, the divine soul could take man to the moon; secondly, some large and powerful birds could transport man to the moon; thirdly, man himself could make the journey by tying wings to his arms and fourthly, he said, a flying machine could transport man to the moon.
American author Herbert S. Zim claimed in 1945 that there is a Chinese legend where a scientist named Wan Hu in the early Ming dynasty attempted to travel through space with the help of rockets. In the story, Wan tied 47 rockets filled with explosives to the chair in which he was sitting and ignited them. There was a large explosion, but when the smoke cleared Wan Hu was gone and never seen again.

List of Spaceflight Records

Longest human single flight
Valeri Polyakov, launched 8 January 1994 (Soyuz TM-18), stayed at Mir LD-4 for 437.7 days[1], during which he orbited the earth about 7,075 times and traveled 300,765,000 km, (186,887,000 miles) returned March 22, 1995 (Soyuz TM-20). This record has stood for 13 years, 100 days.

Sunita Williams holds the record for the longest single spaceflight by a woman at 195 days set on the International Space Station Expedition 15 in 2007. She landed with STS-117, June 22 2007.

Longest continuous occupation of space
The Soviet Union and Russia, its successor, kept a continuous manned presence in space from the launch of Soyuz TM-8 on 5 September 1989 to the landing of Soyuz TM-29 on 28 August 1999, a span of about 3,644 days, or about eight days short of 10 years. The Soviet Union and Russia launched 22 manned Soyuz spacecraft during the time span, all of which docked with the orbiting Mir space station. The United States additionally docked the space shuttles Atlantis, Endeavour and Discovery with Mir nine times between 1995 and 1998, dropping off and/or picking up passengers eight times. This record has stood for 8 years, 307 days.

The United States and Russia
have jointly maintained a continuous manned presence in space since 31 October 2000 when Soyuz TM-31 was launched on a mission to dock with the International Space Station. The International Space Station has been in continuous use for 7 years, 243 days. Should the ISS occupation continue as planned, it will break the Mir record on 23 October 2010.

Longest solo flight
Valery Bykovsky flew for 4 days and 23 hours solo in Vostok 5, 14-19 June 1963. The flight set a space endurance record which was broken in 1965 by the Gemini 5 crew, but the solo endurance record has stood for 45 years, 11 days.

Longest canine single flight
Veterok (Ветерок, "Little Wind") and Ugolyok (Уголёк, "Ember") were launched on February 22, 1966 on board Cosmos 110 and spent 22 days in orbit before landing on March 16. This record has stood for 42 years, 06 days.

Longest time on lunar surface
Eugene Cernan and Harrison Schmitt of the Apollo 17 mission stayed for 74 hours 59 minutes 40 seconds on the lunar surface after they landed on 11 December 1972. This record has stood for 35 years, 202 days.

Farthest humans from Earth
Apollo 13 crew; Jim Lovell, Fred Haise, John Swigert while passing over the far side of the moon at an altitude of 254 km (158 miles) from the lunar surface, were 400,171 km (248,655 miles) from earth. This record breaking distance was reached at 0:21 UTC on April 15, 1970. This record has stood for 38 years, 76 days.

Highest altitude for manned non-lunar mission
Gemini 11 fired its Agena Target Vehicle rocket engine on September 14, 1966, at 40 hours 30 minutes after liftoff and achieved an apogee of 1374.1 km (854 miles). This record has stood for

Fastest
The Apollo 10 crew; Thomas Stafford, John W. Young and Eugene Cernan achieved the highest speed relative to earth ever attained by humans; 39,896 km/h (11.1 km/s, 24,790 mph, approx 0.000037 times the speed of light). The record was set May 26, 1969 and has stood for 39 years, 35 days.

Oldest
John Glenn at age 77, October 29, 1998. This record has stood for 9 years, 245 days.

Youngest
Gherman Titov, aged 25 years, 329 days, on Vostok 2 on August 6, 1961. This record has stood for46.years, 329 days.

Most flights
7 Flights
Franklin Chang-Diaz- Costa Rica/USA*
Jerry L. Ross- USA
* Costa Rican-born and honorary citizen of Costa Rica

6 Flights
Curtis Brown - USA
Michael Foale - Britain/USA*
Sergei Krikalev - Russia
Story Musgrave - USA
Gennady Strekalov - Russia
James Wetherbee - USA
John W. Young - USA
* Dual citizen.

Most time in space
Sergei Krikalev has spent 803 days, 9 hours and 39 minutes, or 2.2 years in space over the span of six spaceflights on Soyuz, the Space Shuttle, Mir, and International Space Station.
Peggy Whitson has spent 376 days, 17 hours and 22 minutes in space over the span of two spaceflights to the International Space Station.

Most spacewalks
Anatoly Solovyev, 16 spacewalks for total of 77 hours, 41 minutes (which is also the duration record).
Peggy Whitson, 6 spacewalks for a total time of 39 hours and 46 minutes (the women's spacewalk and duration records).

Most spacewalks during a single mission
Michael Lopez-Alegria, five spacewalks during Expedition 14 on the ISS
source: wikipedia

The Ansari X PRIZE

The Ansari X PRIZE was a space competition in which the X PRIZE Foundation offered a US$10,000,000 prize for the first non-government organization to launch a reusable manned spacecraft into space twice within two weeks. It was modeled after early 20th-century aviation prizes, and aimed to spur development of low-cost spaceflight. The prize was won on October 4, 2004, the 47th anniversary of the Sputnik 1 launch, by the Tier One project designed by Burt Rutan and financed by Microsoft co-founder Paul Allen, using the experimental spaceplane SpaceShipOne. $10 million was awarded to the winner, but more than $100 million was invested in new technologies in pursuit of the prize.
The second X PRIZE, the Archon X PRIZE, was announced in October 2006 by the X PRIZE Foundation. The third X Prize, the Automotive X Prize, was announced shortly thereafter. The fourth X Prize, the Google Lunar X Prize, was announced in September 2007

Motivation
The X PRIZE was first proposed by Dr. Peter Diamandis in an address to the NSS International Space Development Conference in 1995. The competition goal was adopted from the SpaceCub project, demonstration of a private vehicle capable of flying a pilot to the edge of space, defined as 100 km altitude. This goal was selected to help encourage the space industry in the private sector, which is why the entries were not allowed to have any government funding. It aimed to demonstrate that spaceflight can be affordable and accessible to corporations and civilians, opening the door to commercial spaceflight and space tourism. It is also hoped that competition will breed innovation, introducing new low-cost methods of reaching Earth orbit, and ultimately pioneering low-cost space travel and unfettered human expansion into the solar system. The X PRIZE was modeled after many prizes from the early 20th century that helped prod the development of air flight, including most notably the $25,000 Orteig Prize that spurred Charles Lindbergh to make his solo flight across the Atlantic Ocean. NASA is developing a similar prize program called Centennial Challenges to generate innovative solutions to space technology problems.
Created in May 1996 and initially called just "X PRIZE", it was renamed "Ansari X PRIZE" on May 6, 2004 following a multi-million dollar donation from entrepreneurs Anousheh Ansari and Amir Ansari.

Contestants
Twenty-six teams from around the world participated, ranging from volunteer hobbyists to large corporate-backed operations:
Acceleration Engineering
Advent Launch Services
Aeronautics and Cosmonautics Romanian Association (ARCASPACE)
Armadillo Aerospace
American Astronautics Corporation
Bristol Spaceplanes, Ltd
Canadian Arrow
The da Vinci Project
Pablo de Leon & Associates
Discraft Corporation
Flight Exploration
Fundamental Technology Systems
HARC
IL Aerospace Technologies
Interorbital Systems
Kelly Space and Technology
Lone Star Space Access Corporation
Micro-Space, Inc.
PanAero, Inc.
Pioneer Rocketplane, Inc. (now Rocketplane Kistler)
Scaled Composites' Tier One project (Winning Team)
Space Transport Corporation
Starchaser Industries
Suborbital Corporation
TGV Rockets
Vanguard Spacecraft
Whalen Aeronautics Inc.
This contestant list notably did not include traditional space access companies like Boeing and Lockheed, which many in the industry believe to be incapable of replacing their present space transportation vehicles with low-cost alternatives. These critics claim as evidence the companies' several failed attempts to do so, such as the X-33 project, on contract from NASA and other U.S. government agencies. However, the X PRIZE Foundation itself did not ban these companies from applying, so long as they could prove their efforts on this project would be free of government funding.

Competition status
Representatives of the X PRIZE Foundation symbolically presented the ten million dollar prize to Burt Rutan and Paul Allen of Mojave Aerospace Ventures on November 6, 2004. The Ansari X PRIZE trophy is on the left.
The Tier One project made two successful competitive flights, X1 on September 29, 2004 piloted by Mike Melvill and X2 on October 4, 2004 piloted by Brian Binnie. They thus won the prize, which was awarded on November 6, 2004. (Note: the winning team is referred to by several names at various times: Tier One, Scaled Composites, and Mojave Aerospace Ventures.)
The trophy is currently on display in the St. Louis Science Center in St.Louis,Missouri.

Flight attempts by teams that did not win
Although only the Tier One team actually launched a spacecraft into suborbital space, several other teams have conducted low-altitude tests or announced future plans to launch into space:
The da Vinci Project originally announced that their first flight would be on October 2, 2004, but this was postponed indefinitely on September 23, 2004, as they were unable to obtain a few necessary components in time. They have not announced a revised timetable.
The Canadian Arrow team conducted a successful full-power engine test in 2005 and announced on June 2, 2005, that it had received permission from the Canadian government to use Cape Rich as a future launch site.
On August 8, 2004, Space Transport Corporation's Rubicon 1 and Armadillo Aerospace's test vehicle, in two separate unmanned test launches, both crashed and were destroyed.
On February 1, 2005, AERA Corporation (Formerly American Astronautics) announced its plans to send seven paying passengers into space as early as 2006, a full year before the first announced speculative Virgin Galactic flight.

List of major donors by order of donation
Anousheh Ansari and Amir Ansari
First USA (J.P. Morgan Chase), $1,000,000 USD
New Spirit of St. Louis Organization
Danforth Foundation, $500,000 USD
Tom Clancy, $100K–$500K
J.S. McDonnell (McDonnell Douglas)
Andrew Taylor (Enterprise Rent-A-Car)
Andrew Beal (Beal Bank)
St. Louis Science Center

Spinoffs
The success of the X PRIZE competition has spurred spinoffs that are set up in the same way. There have been two major spinoffs at this point, the first of which is the M Prize (short for Methuselah Mouse Prize), which is a prize set up by University of Cambridge biogerontologist Aubrey de Grey which will go to the scientific team that successfully extends the life or reverses the aging of mice, which would then eventually be available to humans. The second is the NASA Centennial Challenges, which consist of (among others) the Tether Challenge in which teams compete to develop superstrong tethers as a component to space elevators, and the Beam Power Challenge which encourages ideas for transmitting power wirelessly. An independent spinoff called the N-Prize was started by Cambridge Microbiologist Paul H. Dear in 2008, designed to foster research into low-cost orbital launchers.
The X PRIZE foundation itself is developing additional prizes, including one around genomics, and another around energy -- the Automotive X PRIZE. There is also a possible "H-Prize", focused on hydrogen vehicle research, although this goal has already been addressed by H.R. 5143, an X-Prize-inspired bill passed by the House of Representatives.
source: wikipedia

The Personal Spaceflight Federation

A private spaceflight industry group, incorporated as an industry association for the purposes of establishing ever higher levels of safety for the commercial human spaceflight industry, sharing best practices and expertise, and promoting the growth of the industry worldwide.

Current members
Person Company affiliation
Eric Anderson- CEO of Space Adventures
John D. Carmack -President of Armadillo Aerospace
Peter Diamandis -CEO of XPRIZE Foundation
Art Dula -CEO of Excalibur Almaz
Jeff Greason -CEO of XCOR Aerospace
David Gump -President of t/Space
Gary Hudson -Chairman of Airlaunch LLC
Steve Kohler -President of Space Florida
Steve Landeene -Executive Director of Spaceport America
Rob Meyerson -Program Manager of Blue Origin
Elon Musk -CEO of SpaceX
Mark Sirangelo -CEO of SpaceDev
Will Whitehorn -President aof Virgin Galactic
Stu Witt -General Manager of Mojave Spaceport

The PSF staff :
Bretton Alexander -(President)
John Gedmark- (Executive Director)
James Muncy -(Senior Advisor).

Space technology and applied Science

Hubble Ultra Deep Field

Universe

Satellite

Space technology is technology that is related to entering space, maintaining and using systems during spaceflight and returning people and things from space.
Space technology has a huge impact on the everyday lives of people; and something as simple as checking the weather or watching satellite television or receiving a parcel guided by satellite, it touches most people's lives on any given day.
The universe, exclusive of Earth, is such an alien environment that attempting to work in it requires new techniques and knowledge. New technologies originating with or accelerated by space-related endeavors are often subsequently exploited in other economic activities. This has been widely pointed to as beneficial by space advocates and enthusiasts favoring the investment of public funds in space activities and programs. Political opponents counter that it would be far cheaper to develop specific technologies directly if they are beneficial and scoff at this justification for public expenditures on space-related research.
Technologies such as weather station satellites and GPS systems, satellite television, and some long distance communications systems critically rely on space infrastructure and these technologies touch the vast majority of lives in the Western world and very many people elsewhere, every single day.
Computers and telemetry were once leading edge technologies that might have been considered "space technology" because of their criticality to boosters and spacecraft. They existed prior to the Space Race of the Cold War but their development was vastly accelerated to meet the needs of the two major superpowers' space programs. While still used today in spacecraft and missiles, the more prosaic applications such as remote monitoring (via telemetry) of patients, water plants, highway conditions, etc. and the widespread use of computers far surpasses their space applications in quantity and variety of application.

Communication Sattelite

Telephony

The first and historically most important application for communication satellites was in intercontinental long distance telephony. The fixed Public Switched Telephone Network relays telephone calls from land line telephones to an earth station, where they are then transmitted to a geostationary satellite. The downlink follows an analogous path. Improvements in Submarine communications cables caused a decline in the use of satellites for fixed telephony in the late 20th century but they still serve remote islands such as Ascension Island and Saint Helena where no submarine cable is in service.
Satellite phones connect directly to a constellation of geostationary or low earth orbit satellites. Calls are then forwarded to a teleport connected to the PSTN network or another satellite phone.

Television

became the main market, its demand for simultaneous delivery of relatively few signals of large bandwidth to many receivers being a more precise match for the capabilities of geosynchronous comsats. Two satellite types are used for North American television and radio: Direct Broadcast Satellite (DBS), and Fixed Service Satellite (FSS)
The definitions of FSS and DBS satellites outside of North America, especially in Europe, are a bit more ambiguous. Most satellites used for direct-to-home television in Europe have the same high power output as DBS-class satellites in North America, but use the same linear polarization as FSS-class satellites. Examples of these are the Astra, Eutelsat, and Hotbird spacecraft in orbit over the European continent. Because of this, the terms FSS and DBS are more so used throughout the North American continent, and are uncommon in Europe.

Fixed Service Satellite

Fixed Service Satellites use the C band, and the lower portions of the Ku bands. They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, live shots, and backhauls), as well as being used for distance learnin by schools and universities, business television (BTV), Videoconferencing, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends.
Free-to-air satellite TV channels are also usually distributed on FSS satellites in the Ku band. The Intelsat Americas 5, Galaxy 10R and AMC 3 satellites over North America provide a quite large amount of FTA channels on their Ku band transponders.
The American Dish Network DBS service has also recently utilized FSS technology as well for their programming packages requiring their SuperDish antenna, due to Dish Network needing more capacity to carry local television stations per the FCC's "must-carry" regulations, and for more bandwidth to carry HDTV channels.

Direct broadcast satellite

A direct broadcast satellite is a communications satellite that transmits to small DBS satellite dishes (usually 18 to 24 inches in diameter). Direct broadcast satellites generally operate in the upper portion of the microwave Ku band. DBS technology is used for DTH-oriented (Direct-To-Home) satellite TV services, such as DirecTV and DISH Network in the United States, Bell ExpressVu in Canada, and Sky Digital in the UK, Republic of Ireland and New Zealand.
Operating at lower frequency and power than DBS, FSS satellites require a much larger dish for reception (3 to 8 feet (1 to 2.5m) in diameter for Ku band, and 12 feet (3.6m) or larger for C band). They use linear polarization for each of the transponders' RF input and output (as opposed to circular polarization used by DBS satellites). FSS satellite technology was also originally used for DTH satellite TV from the late 1970s to the early 1990s in the United States in the form of TVRO (TeleVision Receive Only) receivers and dishes. It was also used in its Ku band form for the now-defunct Primestar satellite TV service.
Satellites for communication have now been launched that have transponders in the Ka band, such as DirecTV's SPACEWAY-1 satellite, and Anik F2. NASA as well has launched experimental satellites using the Ka band recently.

Mobile satellite technologies

Initially available for broadcast to stationary TV receivers, by 2004 popular mobile direct broadcast applications made their appearance with that arrival of two satellite radio systems in the United States: Sirius and XM Satellite Radio Holdings. Some manufacturers have also introduced special antennas for mobile reception of DBS television. Using GPS technology as a reference, these antennas automatically re-aim to the satellite no matter where or how the vehicle (that the antenna is mounted on) is situated. These mobile satellite antennas are popular with some recreational vehicle owners. Such mobile DBS antennas are also used by JetBlue Airways for DirecTV (supplied by LiveTV, a subsidiary of JetBlue), which passengers can view on-board on LCD screens mounted in the seats.

Amateur radio

Amateur radio operators have access to the OSCAR satellites that have been designed specifically to carry amateur radio traffic. Most such satellites operate as spaceborne repeaters, and are generally accessed by amateurs equipped with UHF or VHF radio equipment and highly directional antennas such as Yagis or dish antennas. Due to the limitations of ground-based amateur equipment, most amateur satellites are launched into fairly low Earth orbits, and are designed to deal with only a limited number of brief contacts at any given time. Some satellites also provide data-forwarding services using the AX.25 or similar protocols.

Satellite Internet access

After the 1990s, satellite communication technology has been used as a means to connect to the Internet via broadband data connections. This can be very useful for users who are located in very remote areas, and cannot access a wireline broadband or dialup connection.

Military uses
Communications satellites are used for military communications applications,such as Global Command and Control Systems.

source: wikipedia

Communication sattelite

Satellites

As mentioned, geostationary satellites are constrained to operate above the equator. As a consequence, they are not always suitable for providing services at high latitudes: for at high latitudes a geostationary satellite may appear low on the horizon, affecting connectivity and causing multipathing (interference caused by signals reflecting off the ground into the ground antenna). The first satellite of Molniya series was launched on April 23, 1965 and was used for experimental transmission of TV signal from Moscow uplink station to downlink stations, located in Siberia and Russian Far East, in Norilsk, Khabarovsk, Magadan and Vladivostok. In November of 1967 Soviet engineers created a unique system of national TV network of satellite television, called Orbita, that was based on Molniya satellites.
Molniya orbits can be an appealing alternative in such cases. The Molniya orbit is highly inclined, guaranteeing good elevation over selected positions during the northern portion of the orbit. (Elevation is the extent of the satellite’s position above the horizon. Thus a satellite at the horizon has zero elevation and a satellite directly overhead has elevation of 90 degrees).
Furthermore, the Molniya orbit is so designed that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. Its period is one half day, so that the satellite is available for operation over the targeted region for eight hours every second revolution. In this way a constellation of three Molniya satellites (plus in-orbit spares) can provide uninterrupted coverage.
Molniya satellites are typically used for telephony and TV services over Russia. Another application is to use them for mobile radio systems (even at lower latitudes) since cars travelling through urban areas need access to satellites at high elevation in order to secure good connectivity, e.g. in the presence of tall buildings.

source: wikipedia

Geostationary Orbit

A satellite in a geostationary orbit appears to be in a fixed position to an earth-based observer. A geostationary satellite revolves around the earth at a constant speed once per day over the equator.
The geostationary orbit is useful for communications applications because ground based antennas, which must be directed toward the satellite, can operate effectively without the need for expensive equipment to track the satellite’s motion. Especially for applications that require a large number of ground antennas (such as direct TV distribution), the savings in ground equipment can more than justify the extra cost and onboard complexity of lifting a satellite into the relatively high geostationary orbit.

The concept of the geostationary communications satellite was first proposed by Arthur C. Clarke, building on work by Konstantin Tsiolkovsky and on the 1929 work by Herman Potočnik (writing as Herman Noordung) Das Problem der Befahrung des Weltraums - der Raketen-motor. In October 1945 Clarke published an article titled “Extra-terrestrial Relays” in the British magazine Wireless World. The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits for the purpose of relaying radio signals. Thus Arthur C. Clarke is often quoted as being the inventor of the communications satellite.
The first truly geostationary satellite launched in orbit was the Syncom 3, launched on August 19, 1964. It was placed in orbit at 180° east longitude, over the International Date Line. It was used that same year to relay television coverage on the 1964 Summer Olympics in Tokyo to the United States, the first television transmission sent over the Pacific Ocean.
Shortly after Syncom 3, Intelsat I, aka Early Bird, was launched on April 6, 1965 and placed in orbit at 28° west longitude. It was the first geostationary satellite for telecommunications over the Atlantic Ocean.

On November 9, 1972, North America's first geostationary satellite serving the continent, Anik A1, was launched by Telesat Canada, with the United States following suit with the launch of Westar 1 by Western Union on April 13, 1974.
On December 19, 1974, the first geostationary communications satellite in the world to be three-axis stabilized was launched : the franco-German Symphonie.
After the launchings of Telstar, Syncom 3, Early Bird, Anik A1, and Westar 1, RCA Americom (later GE Americom, now SES Americom) launched Satcom 1 in 1975. It was Satcom 1 that was instrumental in helping early cable TV channels such as WTBS (now TBS Superstation), HBO, CBN (now ABC Family), and The Weather Channel become successful, because these channels distributed their programming to all of the local cable TV headends using the satellite. Additionally, it was the first satellite used by broadcast TV networks in the United States, like ABC, NBC, and CBS, to distribute their programming to all of their local affiliate stations. Satcom 1 was so widely used because it had twice the communications capacity of the competing Westar 1 in America (24 transponders as opposed to Westar 1’s 12), resulting in lower transponder usage costs. Satellites in later decades tended to even higher transponder counts.
By 2000 Hughes Space and Communications (now Boeing Satellite Development Center) had built nearly 40 percent of the satellites in service worldwide. Other major satellite manufacturers include Space Systems/Loral, Lockheed Martin (owns former RCA Astro Electronics/GE Astro Space business), Northrop Grumman, Alcatel Space, now Thales Alenia Space, with the Spacebus series, and EADS Astrium

source: wikipedia