Rush's deep-space song suite goes up against a heatseeking Def Leppard chart missile in the opening round of our Rock Star Wars tournament.

To try and fill our days between now and the new Star Wars: The Force Awakens movie, we’ve tracked down 32 space-themed classic rock songs and paired them off against each other in 16 first-round battles. The field will be halved every week based on your votes, until only the spaciest song in rock history remains standing.

In this round, we're pitting Rush's "Cygnus X-1" against Def Leppard's "Rocket," and while both cuts definitely belong in the competition, they couldn't be more different on musical terms. "Cygnus X-1" takes up one of the proggier chapters in the Rush songbook — and nearly half an hour of running time, split between 1977's A Farewell to Kings and 1978's Hemispheres — while "Rocket" is a classic Lep hit with barbed pop hooks and a stomping rock arrangement that's so slickly produced it's just about frictionless. "Rocket" was a Top 15 hit from the massively popular Hysteria LP, while "Cygnus X-1" was obviously never a single — but it does hold the honor of having a Rush fan website named after it.

So, which of these songs will emerge victorious from this round? It’s your choice. You can listen to both tracks below, and vote once per hour in each of the this round's Rock Star Wars battles until polls close on Nov. 23 at 11:59PM ET. Your choice for our Rock Star Wars champion will be revealed on Dec. 22, 2015.

Listen to Rush Perform 'Cygnus X-1'

Listen to Def Leppard Perform 'Rocket'