Well, first you will need to find a replacement part. If you were on Homeworld, I would tell you to visit the body banks. Unfortunately, that won't help you. So, Here are some options
You can go and find parts for Micronauts on Ebay, or some of the other online auctions. You may be able to find some damaged toys to use for parts at flea markets, garage sales, antique stores, collectible stores.
Many of the Micronaut Collectors on Micropolia Embassy Suite mailing list trade regularly. We can also be found in the Micronauts Facebook pages. Perhaps one of them can help you with parts.
Finally, If in an absolute emergency, you really need the part and don't mind casted duplicate parts, drop me a line. Perhaps is is something I can reproduce for you. Just keep in mind it takes me a while to reproduce a part. I have to make sure that I have molding material and casting resin Jeff - MicroDoc