I think the question might have been misinterpreted. The "galactic" instruments don't actually exist. They are just a fun interpretation of synthesizer noise, like the NES horn. Synths can sound futuristic and spacey, hence the galactic instruments are chrome to match.........Actually, an NES horn would be cool....
(by the way, if the question wasn't actually misinterpreted, then I've just wasted a bit of time.)