system
Given the following post, respond as if you're commenting on Reddit:
human
[Passengers] Questions about the speed of the Avalon.

We know a few things. At the time Jim wakes up, they've been in transit for 30 years.  You can send messages via laser array, and lasers travel at the speed of light.  Jim's message will arrive at Earth 19 years after he sends it.  
Does anyone know how the math shakes out on that one?  How fast are they going?
gpt
That works out to an average speed of about 2/3 of the speed of light. The Avalon wasn't constantly accelerating, at least not significantly. It got its "gravity" from rotating the ship about its axis. If it was accelerating, it wouldn't need to rotate, it would simply use the acceleration to simulate gravity.