The history of Satellites. By:
Steve Adams. G0KVZ As presented to the Vange Amateur Radio Society
8th November 2007
In the October edition of the Radcom magazine, there was a one page article about the Russian satellite Sputnik, this was launched fifty years ago in October 1957.
Not being many months before my birth, this meant that the development of satellites was quite prominent in the news throughout my childhood, and I can remember the exciting newsreels reporting the early launches.
This was the spark that led to this presentation.
Although the realisation of a practical artificial satellite wasn't until the mid fifties, satellites have been foreseen by Science fiction writers and Scientists for many years.
The possibility for an aerial platform for the relaying of radio signals was proposed by Nicola Tesla during the early 1900's, but this was never achieved during his lifetime.
In 1945, Arthur C Clarke, an RAF electronics officer and member of the British Interplanetary Society, and later a SF Writer, predicted geostationary satellites for communication purposes, in a short article "Extra-Terrestrial Relays" that was published in the Wireless World - he described the use of three manned satellites in 24-hour orbits high above the world's land masses to distribute television programs.
The first person known to seriously consider the technical possibilities on satellite communications and to evaluate the financial prospects was John R. Pierce of AT&T's Bell Lab's who, envisaged the creation of a communications "mirror" in space, in his 1954 speech and 1955 article he estimated the capacity of a satellite to be 1,000 (simultaneous) telephone calls. When the limited communications capacity of the first trans-Atlantic telephone cable (TAT-1) was 36 (simultaneous) telephone calls the financial gains were seen to be enormous.
Lead-up to satellites:
Back in 1952, The ICSU (International Council of Scientific Unions) decided to establish Mid 1957, to the end of 1958, as the International Geophysical Year (IGY) because the scientists knew that the cycles of solar activity would be at a high point then. In Late 1954, the council adopted a resolution calling for artificial satellites to be launched during the IGY to map the Earth's surface.
During Mid 1955, the USA announced plans to launch an Earth-orbiting satellite for the IGY and encouraged various Government research agencies to develop a satellite. In Autumn 1955, the Naval Research Laboratory's Vanguard proposal was chosen to represent the U.S. during the IGY.
The First satellite:
(Or more accurately should be "the first artificial satellite")
On October 4, 1957, the Soviet Union launched the now famous Sputnik I, this was under 600mm in diameter, weighed around 80Kg, and had a simple array of rear facing rod aerials to relay signals back to earth.
Sputnik orbited the earth in an elliptical orbit, and completed these orbits in around 98 minutes.
That launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the U.S.-U.S.S.R space race.
Related media: sputnik20071003-480.mov
First American Satellites:
It is generally understood, the USA had some of the finest German rocket scientists assisting with their rocket development, As a simultaneous alternative to Vanguard, Wernher von Braun and his team began work on the Explorer project.
On January 31, 1958, the tide changed, when the United States successfully launched their first Earth satellite, Explorer I (Which was officially known as Satellite 1958 Alpha). It was launched as part of the United States program for the international Geophysical year. This satellite carried a small scientific payload that eventually discovered the magnetic radiation belts around the Earth, named after principal investigator James Van Allen. The Explorer program continued as a successful ongoing series of lightweight, and scientifically useful spacecraft.
Related media: LaunchofExplorer1_480x360.mov
Related media: Explorer1FirstUS_Satellite480x360.mov
The earlier Soviet success encouraged the creation of National Aeronautics and Space Administration (NASA). Which came into existance on the 1st October 1958.
Significant Early Satellite Projects:
Possibly the best known of all early communication satellites, Telstar ushered in the era of satellite communications.
The 1964 Tokyo Olympics were televised via Syncom3, although the Video signal was transmitted via this satellite, the audio signal went via the more conventional means of an undersea cable.
The Communications Satellite Corporation (COMSAT), was formed as a result of the Communications Satellite Act of 1962, and on early 1965 their first satellite, EARLY BIRD, was launched from Cape Canaveral. Global satellite communications had begun.
EARLY BIRD was to enable line of sight communications between Europe and North America. it didn't have a battery - and worked only when its solar panels were exposed to the sun.
By the time EARLY BIRD was launched, communications earth stations already existed in the United Kingdom, France, Germany, Italy, Brazil, and Japan.
By late 1965 EARLY BIRD had provided 150 telephone "half- circuits" and 80 hours of television service.
Some glimpses of the future had already been provided during experiments with TELSTAR, RELAY, and SYNCOM.
The INTELSAT II series was a slightly more capable and longer-lived version of EARLY BIRD. Much of the early use of the COMSAT/INTELSAT system was to provide circuits for the NASA Communications Network (NASCOM). The INTELSAT III series was the first to provide Indian Ocean coverage to complete the global network. This coverage was completed just days before one half billion people watched APOLLO 11 land on the moon on July 20, 1969.
From a few hundred telephone circuits and a handful of members in 1965, INTELSAT has grown to a present-day system with more members than the United Nations and the capability of providing hundreds of thousands of telephone circuits. Cost to carriers and consumers has dropped tenfold. If the effects of inflation are considered, this is a tremendous decrease! INTELSAT provides services to the entire globe.
Since these trailblazing projects, satellite development has continued at a great pace, and the NASA Advanced Communications Technology Satellites (ACTS) in 1993 have pioneered the use of spot beams, on-board storage and processing, and all digital transmission, which has made a successful communication satellite constellation more feasible. Some modern satellites are now dedicated to television broadcasting but many are multifunctional, handling international voice and data communications, video conferencing, business television as well as data broadcasting for the retail industry
These days, a growing number of companies use satellites to provide broadband Internet access to users by means of spot-beams to provide broadband services where traditional networks are unavailable.
A Summary of types of satellite:
Essentially there are two types of satellite orbit:
Low Earth orbiting (Leo) - The first type of satellite to be launched, This type of satellite is useful for Plotting physical attributes of the earth, GPS, Amateur store and forward, etc.
Geostationary - These are also known as geosynchronous or having a 24 hour orbit, these are useful for Broadcast and communications satellites.
Although, these basic orbits can be further subdivided to define the exact orbit properties.
i.e. Molniya - Quite a specialised orbit, primarily intended for telephony and TV services over high latitudes like over Russia.
Uses for satellites:
From their humble beginnings like Sputnik which only contained a pressure sensor and associated equipment to report it's status, modern satellites provide Telephone communications, Broadcast facilities, Technical experiments, and GPS signals.
Satellites have also been invaluable in crop management and fault line detection, and to track many kinds of weather such as droughts, forest fires, and ice floes. More topical uses include tropical deforestation, global warming, and climate change.
The sounds of satellites:
Recordings of received radio signals, have been saved for posterity, and are available from the internet (see AMSAT website). I have converted examples of these to the MP3 format. These recordings are:
Orbiting Satellites Carrying Amateur Radio (OSCAR) series of small satellites was initiated for radio amateurs to experience satellite tracking and participate in radio propagation experiments. The World Administrative Radio Conference (WARC) allocated frequencies for the Amateur Satellite Service, including 29 MHz (10m), 145 MHz (2m), 435 MHz (70cm), 1270 MHz (24cm) and 2400 MHz (13cm). Transmitting low-powered signals, initially battery operated and offering short lives, the satellites have become increasingly sophisticated. More recently, they have served school science groups, provided emergency communications for disaster relief, acted as technology demonstrators, and transmitted Earth imagery.
From The Satellite Experimenter's Handbook, Martin Davidoff writes:
"OSCAR I was an overwhelming success. More than 570 amateurs in 28 countries forwarded observations to the Project OSCAR data reduction centre. The observations provided important information on radio propagation through the ionosphere, the spacecraft's orbit and thermal satellite design. The OSCAR I mission clearly demonstrated that amateurs are capable of (1) designing and constructing reliable spacecraft, (2) tracking satellites and (3) collecting and processing related scientific and engineering information. Because of its low altitude, OSCAR I only remained in orbit for 22 days before burning up as it re-entered the earth's atmosphere."
OSCAR I led to the creation of The Amateur Satellite Corporation (AMSAT) in 1969.
Listen to OSCAR I's "HI-HI" from the Sounds from the First Satellites page.
OSCAR III was the first true amateur satellite relaying voice contacts in the VHF 2 meter band through a 1 W 50 kHz wide linear transponder (146 MHz uplink and 144 MHz downlink). OSCAR III's transponder lasted 18 days. More than 1000 amateurs in 22 countries communicated through the linear transponder. The two beacon transmitters continued operating for several months.
It was the first amateur satellite to operate from solar power and relay signals from Earth.
Following these early successes, over the last 45 years, the international amateur radio community have worked together launching in excess of Fifty satellites.
One of the more unusual satellites was Suitsat - or OSCAR54 launched from the ISS in early 2006.
Related media: SuitSat.wmv
Competition to Satellites:
In 1965, when EARLY BIRD was launched, the satellite provided almost 10 times the capacity of the submarine telephone cables for almost 1/10th the price. This price-differential was maintained until the laying of TAT-8 in the late 1980s. TAT-8 was the first fibre-optic cable laid across the Atlantic. Satellites are still competitive with cable for point-to-point communications, but the future advantage may lie with fibre-optic cable. Satellites still maintain two advantages over cable: they are more reliable and they can be used point-to-multi-point (broadcasting).
Cellular telephone systems have risen as challenges to all other types of telephony. It is possible to place a cellular system in a developing country at a very reasonable price. Long-distance calls require some other technology, but this can be either satellites or fibre-optic cable.
Timeline of significant events and Satellite launches: 1940's