Canada Post has issued a pair of commemorative stamps to mark the 50th anniversary of the Apollo 11 mission that landed humans on the moon for the first time — highlighting the Canadian minds and technology that made it happen safely.

Neil Armstrong's first steps on July 20, 1969, were watched by half a billion people worldwide and became a well-known milestone in human space exploration.

But Canadian engineers working for NASA played a big part in the mission, including Jim Chamberlin, the first to realize first that flying directly to the moon wasn't the best option. He would help develop the lunar orbit rendezvous — which involved descending to the surface aboard a landing module connected to the main spacecraft.

Owen Maynard, one of Canada's top aircraft engineers, sketched early designs of the command module used in Apollo and is credited as the person at NASA most responsible for the lunar lander.

And a company based in Longueuil, Que., Heroux-Devtek, built the landing gear components for the lunar module, which technically were the first thing to touch the ground. They remain on the moon to this day at the Apollo 11 landing site.

Sons of both Canadian engineers were on hand for the unveiling at a Heroux-Devtek plant today, alongside Gov. Gen. Julie Payette and dozens of collectors looking to snag the new stamp.