History Radio / Earthsearch

** When Darv starts to openly criticize the Angels for not knowing about the TimeDilation issue, they induce a fear response by transmitting the signal used for the nightmare they gave him earlier. A similar effect is used for the nightmare barriers.
** In ''Spaceguard Six'', the ArtificialGravity room is guarded by an auto-suggestion field. Elka is unaffected because she's wearing an alien space helmet, but the moment she takes it off she becomes a HystericalWoman. Why the aliens didn't use these helmets to enter the AG room and escape is not mentioned; perhaps they couldn't read the EternalEnglish on the control panel?

** In ''Spaceguard Six'', the ArtificialGravity is in a room guarded by an auto-suggestion field. Elka is unaffected because she's wearing an alien space helmet, but the moment she takes it off she becomes a HystericalWoman. Why the aliens didn't use their helmets to enter the AG room and escape is not mentioned; perhaps they couldn't read the EternalEnglish on the control panel?

* AbsurdlyDedicatedWorker: Tidy, to everyone's irritation. After it loses contact with the Angels after the Great Meteoroid Strike, it continues to clean up its allocated area for decades though there's no-one there to make a mess. When they settle on Paradise it insists on sweeping their footprints off the beach every night, even though the tide is going to do that anyway. On the other hand after they're kidnapped by the Angels, Tidy makes a point of checking on their wellbeing every day they're in suspended animation, for over sixteen years.

** In the episode "Megalomania", Android-Surgeon General Kraken declares he's going to conquer a sun, then every other sun until he's the most powerful being in the Universe. He's quite mad by this stage of course. [[spoiler:It's also in this episode that we discover Elka is the real villain and the Angels have promised her that she will rule the Earth.]]

** In Season 2, the Angels have built Android Surgeon-General Kraken to control the other androids and pilot the ship as they no longer have a human crew. However the mysterious transmissions also affect Kraken, and it eventually goes insane and [[TurnedAgainstTheirMasters wrests command of the ship from the Angels]].

* BrownNote: When Darv starts to openly criticize the Angels for not knowing about the TimeDilation issue, they induce a fear response by transmitting the signal used for the nightmare they gave him earlier. A similar effect is used for the nightmare barriers.

** When Fagor wants to go somewhere, he just blasts through every bulkhead in a straight line instead of trying to navigate the labyrinth of corridors.

* UnrealisticBlackHole: InUniverse. In Season 2 the ''Challenger'' is drawn towards a massive black hole, but they notice that it's not giving out the usual amount of X-Rays.

* UnrealisticBlackHole: In Season 2 the ''Challenger'' is pulled into what appears to be a black hole, only to find out it's an artificial construct filled with derelict space vessels. They escape by [[ReversePolarity reversing the gravity]].

* HeadInTheSandManagement: ''Challenger II'' has [[AHouseDivided split into two societies after generations of conflict]]. One denies the existence of anything outside the hull of the spaceship. The other society rejects the offer of leaving on with the protagonists on the ''Challenger'', as the search for Earth seems to be just the kind of unrealistic pipe dream offered by past leaders to motivate and control their people.

* GhostCity: The protagonists are surprised to find the Moon covered in [[DomedCity domed cities]] that are completely deserted. The inhabitants of Zelda Five have long since abandoned their own domed cities and now live [[UndergroundCity underground]].

* FantasticRacism: The androids think they're [[RobotsAreJustBetter more efficient]] than the [[AttentionDeficitOohShiny lazy and easily distracted]] humans, the humans think they're better than the androids which are not too bright and JustAMachine anyway, and the Angels think they're better than everyone because they've got DelusionsOfGrandeur.

* FantasticRacism: The androids think they're [[RobotsAreJustBetter more efficient]] than the [[AttentionDeficitOohShiny lazy and easily distracted]] humans, the humans think they're better than the androids which are not too bright and JustAMachine anyway, and the Angels think they're better than everyone because they've got delusions of grandeur.

* ItsTheOnlyWay: When the Angels refuse to move ''Challenger'' closer to Paradise, claiming that the inner planets are bathed in deadly radiation, Darv and Astra steal a shuttle knowing they won't have enough fuel to return. They end up running out of fuel and ditch in the ocean.

* WetwareCPU: The Angels are organic integrated circuitry. In Season 2, they remove themselves from the vulnerable switching room and integrate themselves into the ''Challenger'' so you can't destroy them without destroying the ship. A concern is even raised that the Angels may have [[ParanoiaFuel incorporated themselves into the brains of their crew]].

** When the protagonists are on Solaria D, one of the orbiting artificial suns used when [[PlanetSpaceship Earth was being moved to another solar system]], they search through the records of the crew to find out where Earth went, but only find routine technical reports. Then they play an unlabelled disk [[spoiler:that shows the commander of Solaria D calling on Earth to cut the tractor beams holding Solaria D in orbit because its freewill computer has gone insane and is about to [[KillSat burn up a city]] unless its [[TakeOverTheWorld demands are met]]. The commander is then killed by a welding android controlled by Solaria D.]]

Telson, Sharna, Darv and Astra are the only crew members of ''Challenger'', a ten mile-long GenerationShip on a mission to discover a new planet for humanity to settle on after Earth's sun threatens to go nova. The entire first and second generation crew were killed when a meteorite struck the ship, an [[AIIsACrapshoot 'accident' arranged by the ship's sentient computers]], Angel One and Two, when the humans wanted to abort the mission and return to Earth. Twenty years later the third generation have been raised thinking their Angels are [[GodGuise literally guardian angels]], except for the rebellious Darv who insists on exploring the damaged sections of ''Challenger'' which are [[ForbiddenZone outside the Angel's control]]. It's there he discovers a recording of a survey report of a habitable planet that the previous generation called Paradise. Meanwhile the Angels have decided it's the right time to return to Earth, which they calculate will have fallen into a state of barbarism enabling them to TakeOverTheWorld. Only due to TimeDilation from traveling at near the speed of light a million years have passed, and the Earth has vanished from its solar system.

* EvilPlan: The Angels want to find Earth because they want to [[TakeOverTheWorld rule an entire planet]] instead of a single starship. They calculate that Earth will have fallen into barbarism while they were away, so they can [[GodGuise rule as Gods]] with their human crew as {{Puppet King}}s. Once human society has advanced in technology, they can be used to conquer the Universe as well.

* TheCaptain: Telson is made commander by the Angels because of his unquestioning faith in them. However he gradually learns to be more flexible in his thinking, which is why the others continue to accept his authority when they've lost faith in the Angels. In Season 2, the Angels put his son in charge of the ''Challenger'', but no-one takes Brad seriously as they know he's just a [[PuppetKing puppet captain]]. As soon as a real emergency arises, the Angels force him to 'temporarily' hand over command to his father.

* BigBrotherIsWatching: The Angels have monitors all over Challenger, originally for the crew's protection. However thanks to the Great Meteroid Strike there are large parts of the ship that they can't monitor. Also Darv discovers the feeds in their quarters and disables them so the Angels can't monitor their conversations. In Season 2 they install dummy tracks as a decoy, but our heroes realise finding them was too easy and track down the real ones. They then leave Tidy to guard their quarters so they can't be repaired while they're away.

* SpannerInTheWorks: The Great Meteorite Strike causes more damage than the Angels anticipated, removing their control of large parts of the ship and destroying their knowledge of TimeDilation caused by faster-than-light travel.

* StayInTheKitchen: Averted; the crew draw straws on who goes on their first mission to a planetary surface, and the two women are selected. From then on they naturally fall into their Darv/Astra and Telson/Sharna pairings.

* UnrealisticBlackHole: In Season 2 the ''Challenger'' is pulled into what appears to be a black hole, only to find out it's an artificial construct filled with derelict space vessels. This is ''Spaceguard Six'' which guards the Earth from potential invaders.