Steam is a video game digital distribution service and storefront.
Neither Star Citizen nor Squadron 42 are available on Steam and there are no plans to do so.
Cloud Imperium Games uses its own launcher, and Star Citizen can only be bought in the form of a starter package that includes the game digital download directly from the official website, where Squadron 42 is also available.
Chris Roberts has mentioned that he would like to bring Star Citizen to Steam for those who want it, but that he doesn't want to make it a requirement.[1]
