You can search any planet up to two times, but no planet can ever have more than two planet bonuses and one artifact. This upgrade is important because the special bonuses can make the planet more efficient and artifacts provide empire-wide bonuses. This upgrade explores the planet for any special Planet Bonuses or Artifacts a planet may possess. This upgrade is important because it gives defending fleets more time to arrive and to destroy the attacking fleet before a colony is destroyed. Thus allowing it to survive extended planetary bombardment. This upgrade increases the planet's health by allowing the populace of the planet to 'build' various shelters and emergency services to protect them from a multitude of disasters. (*) Indicates planet underdevelopment is suffered at this level. Population by Planet and Infrastructure Level Terran Planets usually support the largest infrastructure and Asteroids the least ( Dead Asteroids only stop siphoning money away with the upgrade), but it's still advisable to max this out quickly, as it will lead to increased credit production and prevent you from losing income to under-development. This upgrade is important because the larger the population of a planet, the greater the tax income it contributes to an empire. It also eliminates the planet underdevelopment penalty associated with new colonies.

This upgrade increases the maximum population a colony can sustain.

Sins of a solar empire artifacts