Suspsy, they're the cops, not the army/navy.
I found this thread while looking for stuff about the Solar Explorer, which I actually like (more below)
I think I would go for #7065 Alien Mothership as the worst Space set so far. Don't own, but have seen. It's more valuable as a parts pack than anything else, and hoo boy does it not live up to its name. It just looks like a rather skeletal and plain flying saucer rather than the command ship of the alien fleet. Looks can be deceiving, I know, as something that looks bad in form can still make up for it in function (As with 6951 - which by the way I actually have most of thanks to my uncle giving me his old LEGOs).... but that doesn't happen with this set either. You can't dock the other alien ships with it, it's really only got seating for the conquerers' head honcho, there's no real tools or transmitter arrays or anything... Ugh. This might have avoided the bottom spot if the name didn't make a promise the design broke, but then again it might not have. I think even a KFOL would only want this thing for parts and figs, which is a pretty damning thing for a set.
Some of the sets I've seen hated on here (like 1478, 6813 -which is SP2, Suspsy, 1195 Alien Encounter...)... You do have to bear in mind that they're impulse sets. They're designed to be cheap, little pieces of the theme's world that a kid can by with a week or two or perhaps three's allowance (unless they're one of those unlucky sods who gets $1 or less for allowance) or some recycling money, and overall they do it well and are fun to play with.
I don't think the Solar Explorer's bad at all. Mediocre at worst, and it's fun to play with. It looks and feels very much like an evolution of NASA's rockets and shuttles, which are the definite inspiration. It has a detachable probe robot, and the middle section is a detachable solar-powered shelter/research station that holds one astronaut on a little rover car, obviously designed to be left behind for a bit to get some work done and picked up again later; similar in principle to the Landing Modules used by the Apollo missions but more technically advanced. Coulda done with some greebling and control tiles on the inside but that's not a huge strike against it. The solar panel roof could have been brick-built, but a plastic sail-type piece still lends itself to other uses (if you're not a careless buffoon who loses the thing
). I also like the overall Life on Mars theme in terms of narrative, aesthetics, and designs.