It's a space station. As you may or may not know, the t-shirt was invented in 1722 by a Mr. Nathanial T. Shirk to keep your nipples from falling off. One misnomer at the London patent office later and the rest, my friends, is history. A history I just made up. Which let's be honest, is far more interesting than the real thing. Did I ever tell you the one about how our solar system was created by two magicians fighting over a turtle? Okay that one's actually true.
Thanks to Alex, L3g3ndQ, mike469x and wulk, who all would have bought it if it came in a rayon blend.