Like many other '70s rock greats, British space-rock pioneers Hawkwind built their legacy on-stage, rather than in the recording studio. On May 11, 1973, the band released their defining masterpiece. 'Space Ritual,' their fourth overall LP and first live album, is a mind-numbing double-album behemoth that captures the Hawkwind experience in all its demented glory.

It's called "space-rock" for a reason. Combining sci-fi lyrics, motorik pulses, and trippy sound effects, Hawkwind's music is the perfect simulation of space flight -- a turbulent rocket blast through alternate galaxies of riffage and noise. And 'Space Ritual' (recorded during a pair of performances in London and Liverpool) is their most explosive moment.

If there's a lead instrument at all, it's the distorted, brain-bullet bass guitar of Lemmy Kilmister. As a former rhythm guitarist, he brings a chordal, melodic presence to the band's low-end, while the rest of the band (woodwind player Nik Turner, drummer Simon King, guitarist/vocalist Dave Brock, the twin synthesizers of Dik Mik and Del Dettmar) offers texture and turmoil.

Hawkwind are often labeled a "prog-rock" band, and on some levels, that makes perfect sense -- as a whole, prog is saturated with spacey concept albums and indulgent textures. But Hawkwind were never virtuosos -- their playing here is too raw, too reckless, too barbaric. The sheer repetition of the riffs puts them more in line with the kraut-rock scene, and the rhythm section (particularly King's sloppy drum fills) points toward punk. Perhaps the band's easiest reference point is Pink Floyd (who released a psychedelic masterwork of their own in 1973), but Hawkwind's brand of space-rock is more aggressive and, well, nasty.

The Space Ritual Tour (in promotion of the band's third studio album, 1972's 'Doremi Fasol Latido') itself was a spectacle, filled with light shows, dancers, and spoken-word interludes delivered by sci-fi writer Robert Calvert. Through the sheer velocity of its music, 'Space Ritual' the album feels like a multi-sensory experience, from the unrelenting psychedelic throb of 'Born to Go' to the bluesy thrust of 'Orgone Accumulator' to the sound effect showcase 'Electronic No. 1.' Calvert's mood-setting poems (delivered in a campy, borderline-Shakespearian accent) are a tad off-putting without a visual counterpart, but they do offer the album a welcome respite from the aural onslaught.

'Space Ritual' was the band's most commercially successful album to date, landing at #9 in the U.K. and even cracking the Billboard Top 200 at #179. Today, it's something of a cult-classic, a relic from an age of space-age wonder. Even now, there's still nothing else quite like it.