The Alouette 1 Satellite Programme
Alouette 1 was launched on September 29, 1962, making Canada the third country in the world to design and build a satellite. The data gathered during its ten-year lifespan greatly extended our knowledge of the ionosphere and the Earth's upper atmosphere, and validated the innovative design and stringent testing used in its development. Conceived by a team of engineers and scientists at the Defence Research Telecommunications Establishment, Alouette 1 was a scientific success and an engineering feat that enabled the space programme to prosper and contributed to the emergence of a Canadian space industry.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.