This article is about Canadian satellites launched to study Earth's ionosphere. For international studies of infarct survival, see International Studies of Infarct Survival.
ISIS 1 and 2 ("International Satellites for Ionospheric Studies") were the third and fourth in a series of Canadian satellites launched to study the ionosphere over one complete solar cycle. After the success of Canada's Alouette 1, Canada and the United States jointly sent up three more satellites in the ISIS program. The first was named Alouette 2 (after originally being named ISIS-X). As was the case for the Alouette satellites, RCA Ltd. of Montreal was the prime contractor for both ISIS 1 and 2.[1]
A third satellite, ISIS 3, was scheduled for construction, but when the government's focus shifted towards communications satellites, it was cancelled in 1969. The funds were instead used to produce the Communications Technology Satellite (also known as Hermes), which was launched in 1976.[2]
Unlike the Alouette satellites, the ISIS had complex navigational equipment and a tape recorder to record some experiments when they were out of communications range and play back the results when the satellites came over Canada again.[1] Some other experiments were not recorded but data was sent in over several stations around the globe. In total it conducted 10 experiments.
ISIS 2
ISIS 2 (1971-024A) was launched at 2h53 UTC[5] on April 1, 1971, on a Delta rocket also from the Western test range at Vandenberg AFB in California.[6] Due to budget constraints, the design of ISIS 2 was largely similar to that of ISIS I. The main difference was the addition of two experiments designed to study atmospheric optical emissions, including a photometer. This allowed images to be taken for the first time of an Aurora Borealis as seen from above.[7]James Gosling wrote some of the software to analyze data from ISIS 2, as a high school student working for the University of Calgary physics department.[7][8]
On March 13, 1984, both ISIS 1 and ISIS 2 were loaned to Japan's Communications Research Laboratory, which continued to operate the satellites until 1990, when they were shut down due to deterioration of battery capacity.[9]
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).
