History Radio / Earthsearch

* ShipwreckGraveyard: In the episodes "Supermass" and "Deathship" the Challenger is drawn into a black hole, only to discover it's an artificial construct littered with derelict spacecraft. This is ''Spaceguard Six'', whose inhabitants are dedicated to protecting an Earth they've never seen by trapping any potential invader.

* ReversePolarity: Our heroes escape ''Spaceguard Six'' by setting negative traction at [[TimTaylorTechnology at 150%]] on the ArtificialGravity holding them there. It works too well, throwing all the captive spacecraft into space and destroying ''Spaceguard Six'' in the process. Turns out the reverse of traction is explosion.

* AppealToForce: {{Killer Robot}}s like Fagor and Kraken are able to take over the ship by dominating the surgeon-androids, the only androids with the intelligence and dexterity to pilot Challenger. As they are expensive and delicate machines, the surgeon-androids are programmed for self-preservation, so threats to [[CrushKillDestroy Crush, Kill or Destroy]] them are an excellent motivator.

* CrushKillDestroy
-->'''Fagor:''' ''[gunfire]'' ''[gunfire]'' No-one! The cowardly vermin hide from Fagor. ''[gunfire]'' When Fagor finds them, Fagor kills! ''[[[PunctuatedForEmphasis gunfire]]]'' Kills! ''[[[PunctuatedForEmphasis gunfire]]]'' Kills!
-->'''Angel One:''' Fagor...
-->'''Fagor:''' The murderer of the Lord Thorden!
-->'''Angel One:''' Fagor!
-->'''Fagor:''' So you're hiding in there. [[TheEasyWayOrTheHardWay Come out slowly and Fagor will kill you quickly. Come out quickly and Fagor will kill you slowly.]] ''[gunfire]''
-->'''Angel One:''' Listen Fagor, there is no-one there. We are all around. We are the Angels: Angel One and Angel Two. We are the Challenger's control systems. ''[gunfire]'' All that has done is [[ComputerEqualsMonitor destroy one voice terminal]], Fagor. There are a million throughout--''[gunfire]''
-->'''Fagor:''' Then Fagor will destroy a million voice terminals!

** Earth has only a single township with less than ten thousand people.

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

* CuttingTheElectronicLeash

* CuttingTheKnot
** When Fagor wants to go somewhere, he just blasts through every bulkhead in a straight line instead of trying to navigate the corridors.
** In Season 2 our heroes have to find the main control room after the Angels have redesigned the entire ship. However they realise that the control room hasn't been moved after all--instead a maze of corridors have been created to misdirect them. So they [[LaserCutter use their PD guns to cut a hole]] in the bulkheads like Fagor did.

** Agricultural android George is being used as an improvised tank, and says that [[ApeShallNotKillApe androids do not shoot at androids]]. Several {{Killer Robot}}s appear and immediately set about proving him wrong.

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 [[TheCycleOfEmpires 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.

* AbsurdlyDedicatedWorker: Tidy, to [[TeethClenchedTeamwork 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.

* WhoWouldBeStupidEnough: The Angels aren't worried about Fagor, because who would be stupid enough to make a KillerRobot that can self-activate its weapon system? Turns out even though the Solaric Empire fought at least three Computer Wars, they've no problem using {{Robot Soldier}}s.

** ''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.

* 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 [[LiteralMinded not too bright]] and JustAMachine anyway, and the Angels think they're better than everyone because they've got DelusionsOfGrandeur.

* DelusionsOfGrandeur
** All freewill computers eventually go mad with power and want more of it.
** In the episode "Megalomania", Android Surgeon-General Kraken declares he's going to [[InsaneTrollLogic conquer a sun]] and absorb its energy, 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 of the two children, and the Angels have promised her that [[TakeOverTheWorld she and her descendants will rule the Earth]].]]

** In Season 2 our heroes have to find the main control room after the Angels have redesigned the entire ship. However they realise that the control room hasn't been moved after all--instead a maze of corridors have been created to misdirect them. So they use their PD guns to cut a hole in the bulkheads like Fagor did.

* TheArk: In Season 2 the Angels try to force the humans off Paradise, using HostileTerraforming to melt the icecaps and make it [[WhatDoYouMeanItsNotSymbolic rain for forty days and nights]], causing a global flood. Fortunately their large ferry shuttle is airtight, and so they are able to salvage some flora and breeding pairs of the local animals.

** Early in ''Earthsearch 2'', the crew load breeding pairs of animals into a shuttle to wait out a global flood caused by rain that lasts forty days and nights.

* SpaceIsNoisy: Lampshaded when the Custodian of the Past supplies sound effects for her lecture on the origin of the solar system, despite there being no sound in space.

* EternalEnglish: The language the protagonists speak is no different from the other humans they encounter, even though there's a million years difference between them. In fact they frequently cite the fact that they speak the same language as proof that they are not HumanAliens.

** Thorden is reluctant to kill Astra and Darv with DeadlyGas because [[WouldntHurtAChild they look just like children]]. He goes ahead however when urged on by the Imperial Prosecutor.
** [[spoiler:When Elka and the Angels urge Bran to kill their parents, he refuses. It's the first time he's refused his sister anything and causes him to start throwing off her influence.]]

* LogicBomb: The Sentinel starts to pump all the air out of the library dome, because its programming orders it to kill anyone searching for Earth. So the protagonists open fire on the control circuits; as the Sentinel is also programmed to protect the library, it's forced to release them.

** When Kraken goes mad and decides to overload the fusion engines, Darv informs him there's a thousand safety interlocks he'd have to remove first. Kraken proceeds to demonstrate just how quickly an android with six manipulator arms can enter a thousand interlock commands.

* EternalEnglish: The language the protagonists speak is no different from the other humans they encounter, even though there's a million years difference between them. In fact they frequently cite the fact that they speak the same language as proof that they are not HumanAliens.
* EvenEvilHasStandards: Thorden is reluctant to kill Astra and Darv with DeadlyGas because [[WouldntHurtAChild they look just like children]].

* GhostPlanet: The protagonists are surprised to find the Moon covered in [[DomedCity domed cities]] that are completely deserted, as the Moon has long since been evacuated due to the dangers of radiation from the sun, and returning there is now taboo. The inhabitants of Zelda Five have long since abandoned their own domed cities and now live [[UndergroundCity underground]].

** In Season 2, Bran loses confidence in the Angels when they hand over control of the ''Challenger'' to his father (who proves better at handling the crisis than the Angels), and Elka when the Angels reveal [[YouHaveOutlivedYourUsefulness just how expendable she is to them.]]

** The central switching room for the Angels. In Season One they guard it with nightmare barriers (holographic monsters to frighten off intruders) and in Season 2 they integrate their systems into the ship to remove this vulnerability entirely.

* BrokenPedestal: Telson starts the series with unquestioning faith in the Angels, and ends up discovering these godlike beings are just two racks of organic circuitry who AintTooProudToBeg for their lives.

* ChronicBackstabbingDisorder: The Angels only loyalty is to themselves.

-->'''Lenart:''' What a lovely way of making holes!

** Telson refuses to believe that the Angels are malevolent. In fairness, he has no proof that they're not until it's revealed that they lied about Paradise being unsafe for settlement. When Darv and Astra send a signal that there's no high levels of radiation on the inner planets, he goes right for the central switching room the moment he finds its location on a schematic.