An Alien Affair - S1.E3

A comet is sending out artificial signals, and the Centurions are sent to check it out. When it turns out to be hollow, they beam inside. Within, it seem barren... at least at first. But then, as the comet's true nature is discovered, a new danger emerges from the shadows, a feline creature with the ability to drain anything power-generated, including the Centurions' weapon systems... The trio attempt to evade the beast by beaming to Skyvault, but the alien hitches a ride, and begins a chain of events which could end in Skyvault falling earthwards! Unless the Centurions can think of a way to cage this animal, it will sink its teeth into the best meal he's ever had: Earth's energy resources!

Science Lesson: Halley's Comet by Ace.