Because of the acting and plot lines. Definitely one of the better Sci-Fi productions available for our viewing pleasure. Kudos to the actors and the script writers for their efforts and energies in this under-rated television program that nobly lasted a good SEVEN seasons. The three actors in this episode, The Voyage Home, chosen as US Astronauts actually look like they could be astronauts. All granite jawed and buff - and faced with a dilemma that NO space explorer ever wants to consider... a matter of saving their home planet... or....? Yes, the costumes and special effects are often on a budget TV level of quality. Yes, Outer Limits does seem to generalize all aliens as close relations to The Creature From The Black Lagoon. Yes, most of the episodes lack the gymnastic, explosive, laser-light-show fight scenes and Special Effects so hungrily craved by Gen X, Y, Z, and the Mils. But that's not OL's mission. Their goal is to say "What if....?" (You found yourself on a returning space capsule from Mars with an Alien Life-form that had just taken over your two partner's bodies; but the alien seems to be pretty cool and promises to show earth the cure for cancer in the deal, if you'll just cooperate and let him/it land on earth with you, AND the capsule is touching earth within the hour? What would YOU do?)Outer Limits 2.0; with excellent drama techniques, tries to get the casual television viewer to stretch his or her brain cells and ponder more than the mundane thoughts of everyday life.