“Time is a flat circle,” Matthew McConaughey’s Det. Rust Cohle says in the first season of HBO’s “True Detective,” smoke in hand and a can of beer perched before him. “Everything we’ve ever done or will do, we’re gonna do over and over and over again.” Whether or not this Nietzschean proclamation holds true in most of our lives, it’s certainly an apt metaphor for the long, snaking history of Hawkwind since it first came together in 1969 — 53 years, countless ex-members and three-dozen-odd studio albums ago.