In the early 1960s various ideas for dedicated application satellites were advanced including one for aeronautical communications that was being considered in the United States as well as the European nations, the latter through the European Space Research Organisation (ESRO). Unfortunately the market was not ready for this development and the proposal was cancelled. However, today and many years later, with new technology and in a different market, this may be one application that deserves revisiting.
The impetus for the use of satellites in aeronautical communications originated from the need to find better communications facilities for the ever increasing fleet or airliners. After World War II, HF communications were being used for aeronautical communications but the efficiency was poor as HF suffered from interference from electric storms making, at time, communications fade altogether. HF had, however, the advantage of being able to bounce on the ionosphere, allowing long distance communications.
Experts were looking at the use of the VHF band and the so called L-band (at around 1600GHz) as alternative frequencies. These frequencies had the advantage of being free from interference and propagation effects but, on the other hand, needed the high orbit platform that was provided by a satellite in geostationary orbit.
Research and studies started separately in Europe, where the L-band frequencies were favored, and the United States, where NASA favored the VHF band. It was just a matter of time before the two parties pooled their resources.
In a separate move, Comsat, a commercial U.S. organization, had submitted a draft plan to the U.S. Government for the development of two hybrid satellites with VHF and L-band capabilities to be deployed over the Pacific Ocean. The VHF band was seen as an immediate operational capability whereas the L-band was seen as a long range development capability. The Comsat proposal, made to the Federal Aviation Authority (FAA), envisaged one satellite to provide the service with a second satellite as a ground spare.
In 1971, the U.S. government made the decision that the FAA, and not NASA, was the appropriate agency to manage an aeronautical communications satellite project. All the previous work carried out by NASA in partnership with ESRO was, in effect, turned over to the FAA and the Aerosat project, a joint venture of the FAA and ESRO, was established in August 1974. Initially it was hoped to get Australia, the Philippines and Japan to join and represent the Pacific Ocean region, but these nations were not interested and instead the project started to focus on trans-Atlantic air traffic.
In 1974, Canada joined the venture and the percentages were ESRO and FAA each 46 percent with Canada at 8 percent. In 1975, ESROs share was taken over by the newly established European Space Agency (ESA).
By November 1975 a two phase plan had emerged. In the first phase, several experimental satellites were to be developed and launched to perform a variety of experiments to determine preferred system characteristics of an operational system. Two satellites were to be located in geostationary orbit at 15 degrees West and 40 degrees West, with launches taking place in late 1977 and early 1978. The contract would have included a third ground spare satellite as well as ground stations.
Hawker Siddeley Dynamics, a British company, headed the Mesh Consortium that was selected to develop the Aerosat satellites from the ESAs OTS platform, in a similar manner as that platform was to be used for the ESAs MAROTS experimental maritime communications satellite.
Originally, the satellites were to carry only L-band equipment to meet the European requirement, in which case the satellites could have been launched by a Delta 2914 launch vehicle. The inclusion of the VHF equipment necessitated a shift to a Delta 3914 launch vehicle.
Each satellite was to have six L-band channels and two VHF channels for applicational use, with one C-band channel for groundstation-to-satellite service communications.
An integral part of the Aerosat experimental satellites was the fitting of new communications equipment to nine European and 12 U.S./Canadian aircraft. The subsequent operational phase was anticipated to be run on a commercial basis by a private concern with launches commencing in the late 1980s.
Comsat, which had made earlier proposals, as well as RCA, ITT and Western Union had expressed their interest. Eventually Comsat won the development contract in 1975.
Up to this point the potential users of the system, the airlines, had not been asked for their opinions. This proved to be a recipe for disaster especially since in 1973/74 the prospects of civil aviation looked gloomy. Global inflation and the dramatic increase in the oil price, and hence aviation fuel costs, as well as the introduction of the wide body Boeing 747, reduced the number of flights across the North Atlantic. In addition there was the cancellation of the American supersonic SST aircraft and the reduction in the number of Concordes, both of which had been used to justify the Aerosat program. All this caused airline companies to withdraw their support.
At the same time the cost of the Aerosat project was increasing and, eventually, in 1977, the FAA pulled out and ESA decided to cancel further work.
With this decision, the dream of a satellite system completely devoted to aviation died, then and there, never to be revived. At that point, maritime applications were to take center stage.
About the author
Jos Heyman is the Managing Director of Tiros Space Information, a Western Australian consultancy specializing in the dissemination of information on the scientific exploration and commercial application of space for use by educational as well as commercial organisations. An accountant by profession, Jos is the editor of the TSI News Bulletin and is also a regular contributor to the British Interplanetary Society's Spaceflight journal. Jos is also a Contributing Editor for SatNews Publishers' SatMagazine and MilsatMagazine.
Heymans Focus: Aerosat: A Brilliant Idea Gone Wrong
by Jos Heyman, Contributing Editor