The Lion of Mars by Jennifer L. Holm
The trip to Mars was the hardest thing they’d ever experienced. That’s what the grown-ups said. The small, cramped ship. The constant fear of something going wrong. The knowledge that they could never return to Earth. But honestly, it sounded like a cakewalk compared to sharing a bedroom with Albie. Because he snored. I hadn’t had a decent night’s sleep since Albie started bunking with me. I’d tried just about everything to block the noise: earplugs, sleeping under the blanket, even a thick hat with earflaps. But none of them worked.