The Premium Beta is for players that purchased accessed after the Kickstarter funding had ended. The option is still available for those that want to gain immediate access to the game but it comes with a pretty big price tag at $150
David Braben, CEO of Frontier, said: “The start of the Premium Beta
phase is another exciting moment in our development – from today we have
over 10,000 additional people playing the game. This is a significant
and sensible step-change with which to test the next level of scaling of
our cloud-based systems and servers as we move towards the very large
numbers of people we will eventually have playing.
I once again would like to thank all those who played such an
important role in the Alpha phase, which is now at an end. We’re looking
forward to continuing to collaborate with the expanded community during
the beta phase as we deliver greater scale, richer content and ever
higher quality.”
All of the features included in the four previous alpha phases are present in the Premium Beta including 200 cubic light years of space and 5 star systems.
Source: Official Website