A Flaw in the Plot
I think that there is actually a big flaw in the plot:
They seem to be in a hurry to get back and save their world, but don't they actually have all their lives to find whales and bring them back? Sure, they'd be older, but the world would still be saved.
They used the plot device of the dilithium crystals breaking down, but wouldn't it have been better had that been the time crunch, as in "if we don't leave within two days we won't have the power to return home."?
"Lovey-dovey. Bonk bonk on the head!"