Space can be a terrifying place, especially when one of your fellow astronauts beams like a fool no matter what's happening. Thankfully Kerbal Space Program managers can now lark about in space with their chums, as enterprising modders have whipped together multiplayer support.
Building on another mod which added a more passive form of multiplayer, the Kerbal Multi Player mod lets Kerbals explore space together, from building space stations to racing on Eve. It only works in Sandbox mode right now, and players can't fly around in the same ship yet. Download KMP from the official website if you fancy playing or hosting a server.
Do be aware that it's only an "experimental pre-alpha" build, which may crash, freeze, and potentially mess with non-KMP games of KSP. Still, given how many rockets, orbiters, stations and landers players explode while learning how to play, this seems only fitting.