Any heavily colonized world will have a number of measures in place to protect its populace from both catastrophic terrorist threats and the danger of assault and invasion. The first line of defense employed by any world is a dedicated sensor network. Similar to the sensors found on a starship these long range sensors, constantly scan for high yield neutronic, atomic, chemical and antimatter weaponry. The sensors are generally powerful enough to detect the exact location of a weapon and if it is armed or not.
Planetary sensors are also to detect if nearby shipboard weapons are active. As many starships carry significant firepower, for most situations the posture and activation level is the key factor in determining if a ship is hostile or not. On a colonized world, it is never acceptable for a ship to attempt to fire at ground based targets and is almost always considered as a hostile act against the population as a whole. Additionally civilized worlds will universally deny landing access to any ships or persons in possession of high yield explosives.Planetary defense batteries are almost always seen on any world with exceeding 10,000. Often times these weapons are massive gauss or rail weaponry and have considerable range. These weapons not only deter opportunistic raiders and pirates but serve a real and function role of shooting any incoming asteroid, space debris or missile before it makes landfall.
Planetary shields are one of the most expensive defenses and are found only on high valued worlds. These shields function just like starship shields but tend to be considerably more powerful. The greatest weakness of a planetary shield is that they take 10 times longer to activate and bring back online once they collapse. When activated these shields are so powerful they will damage or destroy structures and living creatures near them and must be placed on the surface of the world, frequently in vulnerable and exposed locations.
Found only found on worlds with ionospheres, the SHELL scrambler is a relatively simple device which harness the force of a world’s ionosphere to knockout guidance sensors, computers and firing mechanisms of explosive weapons. Despite being cheap SHELLs are not perfect, they tend to be large and can not be fully submerged in protective bunkers, one SHELL only protects 1/8th of the planets air space, and a SHELL is unable to distinguish friend from foe, finally a SHELL does not work on a craft which has an active shield. When a craft is affected by a SHELL all computers, control panels, sensors and explosive warheads instantly break and are not usable. In the case if antimatter reactors or similar high-risk energy sources the reactor containment is violently disrupted and will detonate. SHELL scramblers only work in the upper layers of a world’s atmosphere about 700 km to 30km above the world’s surface, once below this layer of effect all ships and buildings are safe from the SHELL.