"PER ARDUA AD ASTRA", the motto shown underneath the name of the new exploration vessel Searcher, is latin, meaning "through adversity, to the stars". it was originally the motto of the Royal Flying Corps, when it was formed before World War I, and used by many schools since, although it's probably more fitting on a starship.
Nitpick: When Buck first meets Thordis he addresses him by name even though Thordis hasn't yet told him his name.
The second season brings many changes to the show including an almost entirely new cast (including the voice of Twiki) and characters, as well as a new setting aboard the space vessel Searcher instead of on Earth. From this point, the show has become a complete space adventure.
Doctor Theopolis has been replaced by an ambulatory (and narcissistic) robot named Crichton, Doctor Huer by Doctor Goodfellow, and the voice of Twiki is now child-like and high-pitched (this changes back in episode 8). The biggest change however is that instead of defending Earth from invaders, the crew is now aboard a spaceship with Admiral Asimov at the helm, looking for lost Earth colonies. There was nothing that showed this development however; the second season just suddenly began aboard the ship, and there was no indication of the new direction other than Buck's talk with Hawk at the end of this episode and a few brief mentions in later episodes. Unfortunately, the changes did not help to keep the show going (in fact they probably hurt it), and the show was canceled after just half a season.
The second season's shift to a search for "lost tribes" is similar to the plot element from Glen A. Larson's earlier series, Battlestar Galactica.
The start of the second season was delayed for several months because of an actors' strike.