Hermes
Communications Technology Satellite
![[Picture of the Hermes Satellite]](hermes.jpg)
Hermes |
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1975: CRC developed a family of small Earth stations for communications experiments with the high-power Hermes satellite. John Day, manager of the engineering group that designed the stations, stands beside a 1-metre antenna used to provide a telephone link at remote sites. The 1-m Earth station was the forerunner of Earth stations that are now used worldwide. The 9.1m antenna in the background was part of the network control station. |
1976: An experiment sponsored by the Quebec government demonstrated that CRC's 1m Earth station could provide high quality telephone link via the Hermes satellite to remote campsites in the James Bay development region. In one instance the satellite link was used to plan an evacuation when a camp was threatened by a forest fire. |
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1978: The Alberta Native Communications Society pioneered the concept of native people producing their own telecision programs for broadcast by satellite to native communities. |
1979: Canadian and Peruvian officials in the garden of a Canadian diplomat in Lima, Peru watch a Stanley Cup playoff game thanks to Hermes. This was the first demonstration of the feasibility of direct-to-home broadcasting. The Earth station is on display at the National Museum of Science and Technology, Ottawa. |
1987: Communications Minister Flora MacDonald accepted an Emmy awarded to the Department of Communications and NASA recognizing their joint role in developing Ku-band satellite technology through the Hermes program. |
Canada's entry into space with the Alouette satellites was at a time when HF radio was the only means of communication for people in many remote locations. With the Alouette and ISIS satellites, scientists learned much about the upper atmosphere, which helped to predict the behaviour of HF communications. In the meantime, engineers in the USA were developing satellite communications. In 1967, John Chapman conducted a study to determine the direction Canadian space research should take. The recommendations, published in a report, "Upper Atmosphere and Space Programs in Canada", were that Canada should solve its communications problems by developing its own satellite network, research should focus on communications satellites and the last scientific satellite, ISIS C, should be cancelled.
Hermes was an experimental satellite built to test a new concept for communications satellites; that is, high power in the satellite and small dishes on earth. Early communications satellites adapted technology already in use for microwave systems (at 6/4 GHz) and hence were limited to transmitting at low power to avoid interfering with the terrestrial systems already in place. As a result very large dish antennas were required on the ground to pick up the weak signals. Hermes transmitted with high power so that TV broadcasts could be received by low-cost earth stations small enough to be used at individual homes. This concept, called a Direct Broadcast Satellite (DBS), was championed by John Chapman as a means of delivering high quality TV transmissions to Canadians outside urban centres.
New technical approaches were required to achieve the goals:
- Large flexible panels of solar cells generated the high power (1200W) required for the transmitter (panels provided by ESA). The power of earlier satellites was limited by the number of solar cells that could be placed on the surface of the spacecraft.
- A system to stabilize the satellite body in three axis enabled the solar panels to face the sun at all times and ensured that the narrow transmit beams could be kept accurately pointed towards the earth. Earlier satellites were "spinners". The whole body spun to stabilize the satellite.
- The high power tranmitter was equipped with a new design travelling wave tube (TWT) that generated 200 watts of power (NASA provided the TWT).
- A new, higher frequency band (14/12 GHz) did not interfere with microwave systems on earth and hence earth stations could be used in urban environments.
On April 20, 1971, DOC and NASA announced a joint mission to build an experimental satellite - the Communications Technology Satellite (CTS). CRC would build the satellite and NASA would launch it. CTS was successfully launched on January 17, 1976 from Cape Canaveral. On May 21, 1976, it was officially inaugurated and named Hermes by Madame Sauvé. Designed for a two-year life, it was used for an extensive program of experiments until November 1979.
DOC was responsible for the overall management of the project. It designed and built the spacecraft at CRC. 80% of the industrial contracts, by value, went to Canadian industry. The David Florida Laboratory was built with facilities to integrate and test the satelllite. NASA provided an experimental, high-powered (200-watt) transmitting tube, conducted pre-launch testing and launched the satellite from Cape Canaveral. The European Space Agency also provided the low noise receiver and the 20 watt Ku band travelling wave tubes.
Canadian objectives were :
- To enhance in Canada a capability in the design and manufacture of spacecraft subsystems for domestic use and for export.
- To maintain a Canadian capability to specify, assess and construct space application systems for domestic use.
- To develop and flight test spacecraft subsystems and components for use in future communications satellites.
- To advance the technology for space and ground components of satellite systems that use high-radiated radio frequency power.
- To conduct communications experiments to explore the use of future high-power communications satellites in Canada, to low cost ground stations in the 14- and 12-GHz bands.
- To explore by means of communications experiments the social, cultural and economic impact of the eventual introduction of services that might be provided.
The USA and Canada each conducted programs of experiments to test Hermes communications capabilities. The experiments were in the form of field trials to demonstrate new communications services using both broadcast and point-to-point modes. There were trials of tele-education, tele-health, tele-conferencing, community communications and direct-to-home broadcasting (DBS). Many of these trials later developed into operational services.
Many people from Canada, the United States, as well as Europe participated in this project. CRC took responsibility for systems engineering and for program management of the project, with industry carrying out the design and manufacture of the subsystems of the satellite. David Florida was the first Program Manager, and on his death, Irvine Paghis assumed the role. Dr. Colin Franklin was the Project Manager. He was experienced in building satellites from the Alouette-ISIS program. The Canadian program of experiments was developed by Bert Blevis and implemented by a team led by George Davies.
When Hermes was launched, it was the most powerful communications satellite in the world with a 200 watt transmitter. It was also the first to operate in the Ku band. Hermes was intended to be a geostationary satellite. After reaching the 116W longitude, spacecraft control was transferred to DOC. The transition between the spin mode and three-axis mode of control was complex and constituted a significant mission hazard particularly since this manoeuver had not yet been successfully demonstrated for a geosynchronous satellite. The necessary technology for this operation was developed within Canada. The CTS/Hermes satellite occupies an important place in the evolution towards high-power satellites, because it permitted future communications systems to realize the resulting benefits of small, low cost ground stations and incidentally opening the way to a variety of direct broadcasting applications.
The transponder design allowed several types of experiments to be carried out, including:
- TV broadcast to small communities in remote areas;
- TV transmission, using a transportable terminal, of special events from a remote region to a central area for network distribution or for retransmission to other remote regions. This introduced the term Satellite News Gathering (SNG);
- Broadcast of radio program material to small earth stations;
- Telephone service including voice, facsimile and data, to and between small transportable earth stations;
- Digital data transmission and exchange;
- Investigation of high-speed satellite data transmission;
- Investigation of time division multiple access (TDMA) techniques.
In 1987, an EMMY was awarded to the Department of Communications and NASA recognizing their joint role in developing the Ku band satellite technology through the Hermes program. Communications Minister Flora MacDonald referred to the Hermes satellite as "one of the most important milestones in Canadian space history" when she loaned the award for engineering achievement to the National Museum of Science and Technology. Hermes was the first satellite to operate in remote areas by people with no technical training. In 1976, John Day designed a way to connect telephones via Hermes.
After the success of Hermes, Telesat Canada acquired the world's first hybrid satellite, Anik B, to provide service in both 14/12 GHz and 6/4 GHz bands. Telesat has continued to provide service in both bands. Field trials of social services initiated with Hermes were continued with Anik B. Several of these trials were continued as operational services. These included education networks in Ontario (TVO), BC (Knowledge Network), Alberta and Saskatchewan.
The Hermes engineering model and many associated artifacts, including the DOC's Emmy Award are currently on display in the "Canada in Space Exhibit" at the National Museum of Science and Technology.
The Birth of Hermes
In 1970, the Department of Communications (DOC) and the Department of Northern Affairs sponsored a conference on Northern communications. The conference was held in Yellowknife and northerners were invited to attend. The objective was to seek input about communication needs from northerners and to unveil plans for the first Anik communications satellite.
John Chapman, the leader of the conference, was surprised by the vehement rejection of the idea of broadcasting television from the south into the norht. Spokesperson Nellie Cournoyea emphasized that northerners required communications that addressed their needs.
As a result, John Chapman approved the concept of the Hermes experimental program, in which user groups were given access to the satellite for trials in telemedicine, tele-education, community communications, and broadcasting. The programs was a huge success.
First direct-to-home satellite television
In May 1978, the world's first direct-to-home satellite television broadcast carried a Stanley Cup hockey game from Canada to the home of a Canadian diplomat in Lima, Peru, via the Hermes satellite.
From Smoke Signals to Satellites
The Alberta Native Communications Society (ANCS) pioneered the concept of Native people producing their own television programs for broadcast by satellite to native communities. CRC provided earth stations and access to the Hermes satellite for the project. The ANCS project was called "Ironstar," which they subtitled with the quote, "From Smoke Signals to Satellites."
Telephone Link
The Québec government sponsored an experiment that proved the one metre earth station provided by CRC could successfully provide a high quality telephone link via Hermes to remote campsites in the James Bay development region. In one case, the satellite link was used to plan an evacuation when a forest fire threatened a camp.
Sources
Almond, J., C. Franklin, and E. Warren, A Perspective on the Canadian Satellite Program Canadian Electronic Engineering Journal. vol. 1 no. 1, 1976.
Hartz, T and I. Paghis. Spacebound. Ottawa; Canadian Government Publishing Centre, 1982.
Jelly, D. and P. Townsend. Hermes Satellite, Engineering Model: Summary. 1993.
Jelly, D. Canada: 25 Years in Space. Ottawa; Polyscience Publications and NMST, 1988.
McNally, J.L. Alouette to Mobilesat - A Review of Canadian Space Programs. Department of Communications, 19--.
Lucas, M., L. Lafleur, P. Dumas. Hermes Press Release. Information Services, 1987.
Page created on July 8, 1996 by Cynthia Boyko
Last updated on February 5, 2001 by Stu McCormick
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