Here’s astronaut Charles Conrad Jr. as snapped by mission commander L. Gordon Cooper Jr., the “Gordo” from The Right Stuff, if you remember him. This was a few years after the Mercury missions.
One of the things they were doing on the Gemini V mission, in August 1965, was to see what would happen if people and spacecraft spent 8 days in zero-g. No one had done it.
Since then, we’ve gotten more used to weightlessness. In 1994-95, Valeri Polyakov spent almost 438 days in space, and this year, an ISS crew just completed a year-long tour of duty. And the band OKGo filmed a video while weightless, following a weightless entertainment trail blazed by bikini model Kate Upton in 2014.
But in 1965, this was dangerous stuff. These guys just made it look like it was no big deal.