ISIS 1 and 2 ("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 1 and 2.