The Open Alpha begins July 28th, 2017 at 12 PM (Noon) US Central Time. It’s free for anyone who creates an account on our website, even if you haven’t backed the game or pre-purchased it.
More details are available on the blog: https://blog.orbusvr.com/join-us-for-the-open-alpha/
If you have any questions feel free to ask them below. Thanks!