Fair enough. But with a biosphere, that makes sense. Mars has gravity and an atmosphere, so a biosphere on Earth is a smart project to resume. I'm not saying w

Fair enough. But with a biosphere, that makes sense. Mars has gravity and an atmosphere, so a biosphere on Earth is a smart project to resume. I'm not saying we shouldn't test everything we can. We should, absolutely. But we also have to accept that the absence of gravity and operating in a vacuum are two major factors we could never adequately test on Earth.