Although there are some delays on planning, today I could do a small stress test.
On this video the alien ships are not attacking the player yet, but I could do a good performance estimation. On the RX580 I use to develop, with 64 ships plus a few dozens asteroids, frame rate was still solid and well above the minimal 90hz required for a smooth experience on the Oculus Rift.
Worth to remember that this is always perfectly possible to enter a ship, take off and combat in the air as well. And, of course, all stars, planets and asteroids are freely explorable. There are no fake backgrounds or loading interruptions on this game.
I would say that this test succeeded, as there is a lot of breath yet for the upcoming features.