ISIS I and II (International Satellites for Ionospheric Studies) were the third and fourth satellites that were launched in a series of Canadian satellites sent up to study the ionosphere. After the success of Canada's Alouette 1, Canada and the United States decided to jointly launch three more satellites which they called the ISIS program. The first of the three was named Alouette 2 (after originally being named ISIS-X). As was the case for the Alouette satellites, RCA Victor of Montreal was the prime contractor for both ISIS I and II.
There was a final satellite scheduled for construction, but when the government's focus shifted towards communications satellites, it was cancelled in 1969.
ISIS I (1969-009A) was launched at 6h46 UTC on January 30, 1969 by a Delta rocket at the Western test range at Vandenberg AFB in California. Canada stopped using ISIS I on March 13, 1984 but Japan was authorized to keep on using it and did so until 1990.
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. Some other experiments were not recorded but data was sent in over several stations around the globe. In total it conducted 10 experiments.
ISIS II (1971-024A) was launched at 2h57 UTC on April 1, 1971 on a Delta rocket also from the Western test range at Vandenberg AFB in California. Due to budget constraints, the design of ISIS II was largely similar to that of ISIS I. The main difference was the addition of two experiments designed to study atmospheric optical emissions. This allowed images to be taken for the first time of an entire Aurora Borealis as seen from above.
- ISIS program from the Canadian Space Agency
- ISIS Satellite program
- ISIS-I at NSSDC (1969-009A)
- ISIS-II at NSSDC (1971-024A)