1964
and you believers still think that a gigantic vacuum chamber would be needed.
That's in interesting way to reduce the effect of gravity for testing capabilities and practicing some maneuvers for low-gravity conditions, but it creates its own issues if you want to use it to make a convincing simulation of what actually happened on the moon. The first issue is that the incline necessary to reduce g to 1/6 needs to be tilted by 80°, meaning the camera is looking almost straight down. The subject in the test moved only left and right. Moving toward or away from the camera (up and down in earths gravity) would be difficult to accomplish, if it could be done at all; even if it could, the hundreds of meters of simulated horizontal "moonscape" needs to be hundreds of meters tall instead of hundreds of meters from front to back. This makes the structure far more difficult to build. It also makes things like making footprints in regolith a serious problem, since 80° is waaay beyond the angle of repose for loose material; it would simply slide off. In addition, since the people (and everything they drop or put down) need to be supported by harnesses and wires, having them walk around each other (and things like the LM, rover, deployed equipment [which would need its own support wires], etc.) would not be possible without getting the support wires fouled - even ignoring the difficulty of keeping the support wires from being seen.
There was no need for this exercise to be done in a vacuum; the behavior of fine particles or material with a lot of air resistance isn't what's being investigated, it's how mobile a person in a pressure suit could be in simulated reduced gravity. As noted, this gravity-reduction technique wouldn't work for loose particles, anyway.
Related to the other conversation about pre-recording material and convincingly playing it back as "live", did everyone notice the artifacts that immediately identify this as film, not video (live or otherwise)? Spots on the film, scratches, a bit of up-and-down wavering, and some fuzz stuck in the upper left corner for part of it are dead giveaways. That's why convincingly faking a live telecast would require a pure video chain (no film), and videotape recorders of the time were much more limited than they are now.