Satellite Systems

Japan has sent various satellites in different categories to the outer space till date, and they have varying roles to play. Information in this regard is available in various sources. The purpose here is not to intend to detail every Japanese satellite that is in orbit but to take a macro view of Japan’s efforts. Like any other spacefaring nation, Japan also has sent satellites basically for the purposes of remote sensing, communication and meteorology.

Normally, it has been observed that the Japanese space agencies tend to give two names to their satellites one in Japanese and other in English. The most interesting (or confusing!) part is that mostly these names are unrelated. One agency NASDA had named satellites after flowers, while in other cases, diverse names have been used. The other interesting aspect is that agency like ISAS had a policy of using the English name before launch, and subsequently, it used to switch to Japanese name after launch but only if the launch is successful!10 In view of this, following paragraphs discuss the Japanese investments into satellites only based mainly on the role for which they are launched and names of satellites are used only at few places where it was found essential.

The early priority for Japan was development of communication services for telephone and television. Over a period of time, satellite systems were put in place which were capable of providing transmission to the areas where reception of clear signal was problematic. Initially much of work was undertaken to provide high-definition television signals. A dedicated series of communications satellites were also launched to support domestic telecommunications, and this entire process further enabled the process of new technology development.

Initially satellite development was carried by buying expertise from abroad. Few launches were also carried out through foreign rockets because of certain limitations of Japanese rockets. Japan being a bit geographically isolated island nation and one periodically affected by typhoons obviously has a need for investments in meteorological satellites. The first meteorological satellite was launched during July 1977 [4, pp. 24-29].

The first few Japanese satellites could be categorised as demonstration or scientific satellites. The payloads were designed to measure ambient temperatures and undertake solar and cosmic radifation measurements and ionosphere and solar activity studies. Also, there was a programme constituting of resources satellites to observe the planet from space in an integrated way. Studies in the recent past

were undertaken for better understanding of global circulation of energy and water. To promote sustainable development, land observing satellite was launched (2006) which helped towards better understanding of cartography, monitoring of natural disasters and surveying land use and natural resources. A series of astronomical satellites were launched to carry out observations of cosmic sources at various wavelengths.11