Star Fleet Surveys
A primary mission for Starfleet is exploration. In that role, Starfleet recognizes that there is a lot more to explore than there are resources (i.e. ships and crews) with which to do the exploration. The organization breaks up the mission into several different categories, providing assets based on priority, availability, distance, specialization and capabilities.
Initial Identification
Without a doubt, the usual first discoveries are made by long-range sensors, oftentimes long before interstellar travel was even possible. Using optical and radio telescopes, most of the members of the United Federation of Planets compiled tremendous databases on observable stellar bodies, such as stars, nebulas, black holes and the like. And, once faster-than-light interstellar travel was achievable, the number of observable entities increased substantially. Therefore, before a starship is assigned to conduct a Phase 1 mapping survey, the sector proper is defined from the central stellar databases available to the UFP, indicating where the corners are, what stars and other stellar bodies are anticipated and any indications suggesting the locations of uncommon bodies (such as rogue planets) in that sector. The completed map is then provided to the cartographers and concerned starships, as well as any other interested organizations.
Mapping (Phase 1)
Once a sector has been determined to be a timely interest to the UFP, Starfleet Command assigns an appropriate vessel (usually a cruiser or an explorer) to conduct the first venture into its borders. The starship passes through the sector on a pre-determined stellar mapping route. The purpose of the mission is to provide rough reports of the bodies present (planets, moons, asteroid belts, uncommon object identification, etc.).
As the starship approaches a solar system, long-range sensors work to identify the planetary bodies within the system and any indications of space travel (such as by probes and interplanetary or interstellar vessels). As well as being on the lookout for any items of interest (such as dilithium deposits), the starship is tasked with being particularly aware of any habitable planets, which might suggest intelligent life.
Should a Class M or O planet be detected, the starship will contact Starfleet and break off the pre-assigned route and close to investigate with short-range sensors. If no space travel can be detected from the system's demarcation orbit, the ship will approach the planet to determine if intelligent life inhabits it. If there is intelligent life detected, confirmation of a lack of interstellar capability will be made and all efforts to hide the presence of the starship from ground-based observation will be made. Landing parties will only be utilized if some condition exists to warrant further investigation.
If no intelligent life is detected, at the captain's discretion, landing parties may be sent down to conduct basic planetary surveys.
The starship will resume the sector mapping mission from where it broke off, transmitting all data acquired to Starfleet Operations.
Intensive Survey (Phase 2)
First Contact (Phase 3)