[TeMPOraL]

There are four additional experiments listed under this link:

https://en.wikipedia.org/wiki/Biosphere_2#See_also

So that's at least five.

In Poland, there's a Mars-like base being built right now, though not aimed at testing self-sufficient ecosystems but equipment and work procedures of potential off-world colonists. My guess is there's more of such little-known projects happening.

The point being, the number of projects related to living off-world is slowly increasing, and my guess it will only go up as the perspective of Mars mission comes closer (SpaceX is doing a lot of good work making this close to "very soon" in peoples' minds). So we're definitely not "giving it one little shot".