Europe's classic ode to space exploration dukes it out with a signature number from the Yes songbook when "The Final Countdown" goes up against "Starship Trooper" in the semifinals of our Rock Star Wars tournament.

To try and fill our days between now and when Star Wars: The Force Awakens opens Dec. 18, we’ve tracked down 32 space-themed classic rock songs and paired them off against each other in a series of intergalactic battles. The field will be halved every week based on your votes, until only the spaciest song in rock history is left.

The competitors in this round have left some impressive songs in their wake. Europe cruised to victory against Iron Maiden's "Starblind" in the opening round before racking up nearly 65 percent of the vote against Kiss' "Rocket Ride" in Round Two.

Meanwhile, Yes crushed Aerosmith's "Spaced" and then made similarly quick work of the Rolling Stones' "2000 Light Years Away."

Now it's time for these two heavyweights to go head to head. Which 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 Dec. 7 at 11:59PM ET. Your choice for our Rock Star Wars champion will be revealed on Dec. 22, 2015.

Watch Europe Perform 'The Final Countdown'

Listen to Yes Perform 'Starship Trooper'

See Yes in the Top 100 Rock Albums of the '70s