Star Smashers of the Galaxy Rangers — Harry Harrison

The wild, galaxy-hopping adventures of brash young scientists Jerry Courtenay and Chuck van Chider are at the core of this classic space opera. When the two college students develop a faster-than-light space drive in their homemade workshed, they decide to sneak it aboard their football team's airplane as a prank. The boyish plan backfires, however, and the boys find themselves, along with their crush Sally and the seemingly loveable school caretaker, Old John, hurtling through the solar system towards Titanan icy moon of Saturn inhabited by hideous ice creatures. Titan and the 20th century are only square one as the foursome becomes embroiled in a vast, intergalactic, century-jumping battle.