When was the first space helmet invented?

== == That date is probably unknown. I suspect it was in the late 1940s or early 1950s when the military, and guys like Chuck Yeager , were testing super high performance aircraft, like the Bell X-1 and its sister ships in the series. Those aircraft flew to altitudes where the ambient air pressure was so low they were, for all practical purposes in space, though never in orbit. And it was not just a matter of a pressurized "space" helmet, as the helmet had to be attached to a pressurized "suit" to prevent the pilot's blood from "boiling" due the the near "zero" ambient pressure occasionally encountered.