<P> Other nations are racing to colonize space, and they would stop at nothing, not even sabotage, to thwart the United States's effort . It turns out that Dr. Zachary Smith (Jonathan Harris), Alpha Control's doctor, and later said to be a psychiatrist and environmental control expert, is secretly an agent for one of those competing nations . After disposing of a guard who catches him on board the spacecraft, Smith reprograms the Jupiter 2's B - 9 environmental control robot (voiced by Dick Tufeld) to destroy critical systems on the spaceship eight hours after launch . Smith, however, unintentionally becomes trapped aboard at launch and his extra weight throws the Jupiter 2 off course, causing it to encounter a meteor storm . This, plus the robot's rampage that causes the ship to prematurely engage its hyperdrive, causes the expedition to become hopelessly lost in the infinite depths of outer space . </P> <P> Smith's selfish actions and laziness frequently endanger the expedition . After the first half of the first season, Smith's role assumes less sinister overtones, although he continues to display many character flaws . In "The Time Merchant" Smith shows he actually does care about the Robinsons, when he travels back in time to the day of the Jupiter 2 launch, with the hope of changing his own fate by not boarding the ship, so allowing the Robinsons to start the mission as originally planned . However, he learns that without his weight altering the ship's course, the Jupiter 2 will be destroyed by an uncharted asteroid . So he sacrifices his chance to stay on earth, electing to re-board the ship, thus saving the lives of the family and continuing his role amongst them as the reluctant stowaway . </P> <P> The fate of the castaways is never resolved, as the series was unexpectedly canceled at the end of season 3 . </P> <P> The astronaut family of Dr. John Robinson, accompanied by an Air Force / Space Corps pilot and a robot, set out in the year 1997 from an overpopulated Earth in the spaceship Jupiter 2 to travel to a planet circling the star Alpha Centauri with hopes of colonizing it . The Jupiter 2 mission is sabotaged by Dr. Zachary Smith--an agent for an unnamed foreign government--who slips aboard the spaceship and reprograms the robot to destroy the ship and crew . However, when he is trapped aboard, his excess weight alters the craft's flight path and places it directly in the path of a massive meteor storm . Smith manages to save himself by prematurely reviving the crew from suspended animation . The ship survives, but consequent damage caused by Smith's earlier sabotage of the robot leaves them lost in space . In the third episode the Jupiter 2 crashlands on an alien world, later identified by Will as Priplanus, where they spend the rest of the season and survive a host of adventures . Smith, whom Allen had originally intended to write out, remains through all three seasons, as a source of comedic cowardice and villainy, exploiting the eternally forgiving nature of Professor Robinson . Smith was liked by the trusting Will, and tolerated by the women, but he was disliked by both the Robot and the suspicious Major Don West . </P>

Lost in space where did they end up
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