Owlcat has revealed that the Warhammer 40k: Rogue Trader closed alpha test goes live today. It'll run until the game's release, which doesn't currently have a fixed date, and will allow you to test out the CRPG if you pick up certain special editions.
Grabbing the Developer's Digital Pack or Collector's Edition of the game, which you can get right here (albeit for pretty eye-watering amounts), will grant you access to the closed alpha. There doesn't appear to be a time limit on that, so it seems you can buy either edition before the actual release and still enjoy the alpha (which will eventually turn into the beta).
According to Owlcat, when the beta does arrive, it'll be available until Rogue Trader launches in full. Bear in mind, though, that progress between the beta and the full version will not be carried over. It sounds like progress between the alpha and the beta also won't be transferred, so make sure you don't get too invested in your squad.
Originally announced in June this year, Rogue Trader is the first CRPG set in the Warhammer 40k universe. It's being worked on by Pathfinder: Wrath of the Righteous developer Owlcat Games and casts you as the titular Rogue Trader, a privateer casting about in the Imperium's fringes to make a living for yourself.
As you journey through the Koronus Expanse, you'll be able to recruit a number of companions to your side, including "holy warriors, twisted psykers and perfidious xenos", according to the devs. Combat is turn-based, and you'll be expected to make the most of your environment and your abilities in order to emerge victorious.
Warhammer 40k: Rogue Trader doesn't have a release date yet, but when it does arrive, it'll launch on PC via Steam. You'll need to buy the Developer's Digital Pack or Collector's Edition via the official Rogue Trader website if you want to join the alpha test.