You hit the nail pretty good. I do sense an Outer-Space vibe to the song. I feel the entire song doesn't do that vibe justice though. When the beat comes in...it loses a bit of it's Space appeal.
The whistling sounds you have work nicely for it...I'd like to hear this song without the beat as I think that distracts the space age feel to it. Your song reminds me of this one SPAM Flash made by a SPAM FLASH Artist that resubmitted the same Flash for weeks non-stop it seemed of a a cut-and-paste picture of a real life geeky guys head and he's just bobbing up and down outter space doing nothing and it's like a 3 second loop lol....random I know. I tried to find the link for like 15 minutes but couldn't so I guess I can only put it in writing.
For the most part it's a pretty decent tune.