THAT is a whole lot closer to space cowboy, in my mind. The word 'cowboy' in my mind brings to mind 'Wild West', and 19th Century America. Honestly, 'Space Cowboy', to me, wouldn't have to specifically be things that are thought of as stereotypically 'cowboy', but like I said earlier think along the lines of Firefly/Serenity. 19th Century style, for the most part, with, perhaps, some slight 'futurization'.
And, yeah, looking at it again, I guess it isn't a katana, but more like a samshir. Cavalry sabers should have a basket guard, or at least a D-guard, not just a plain cross-guard.