Warp drive is a rare example of a technology that takes vast amounts of resources and time to develop, but then immediately offers total compensation for the effort. Vulcans have once calculated that a culture will either initiate a massive exploration and colonization program within 50 years of the invention, thus beginning the inevitable arc of galactic conquest, later complacency, and final fall to complete oblivion; or then it will hesitate with using the warp drive, and stagnate completely until awakened by warp-borne visitors. In the rare case it meets an aggressive neighbor in near-equal terms; it may also become a single-planet military power bent on isolationism and highly proficient in achieving that goal.
Earth seemed at first an example of the two latter paths. Because of the wounds of the recent nuclear war, the planet concentrated on rebuilding and development. It took thirty years before Earth behavior changed, in the years to come, several thousand vessels will leave the Solar system, and colonies will be founded on empty class M worlds. At this time, no warp-capable cultures are expanding into Earth's immediate vicinity: the Vulcans are already past their colonization phase, the Andorians mired down in their conflict with the Vulcans, the Vegan Tyranny already collapsed, the Kzinti soundly defeated and the Klingons licking their wounds from their Vulcan misadventure and undergoing a social upheaval. The earliest years of UE Starfleet thus represent a rare opportunity to observe a space navy evolving in a power vacuum, unhindered, but prepared for external threats. Whatever hindrance or inspiration Earth's Vulcan protectors provided remains a matter of some disagreement, even after several centuries of study.
The starship types developed by United Earth are in many ways exceptional for an ascending interstellar power. Races beginning their star travel amidst other FTL cultures are often forced to accept an excessively military posture to survive in the competitive environment, and this normally limits the experimentation done on high speed and long range propulsion, as well as curtailing exploration programs. The basic design of several early Earth vessels in turn places great importance on these very aspects, while featuring limited offensive and defensive armaments. The ubiquitous cargo ships of the 2100s-2140s are a remarkable exception from galactic norm, a design sacrificing everything else for the superior ability to engage in interstellar trade. The conscious choice of UE Starfleet to dedicate major resources to aiding in the creation of this nonmilitary fleet was seen as an equally unique sacrifice in galactic history, at least for those cultures that have survived beyond their first century in space. Truth to be said, it was not really a sacrifice at all. Using the rebuilding period Earth prepared a future infrastructure to launch not just a small number of ships, but to send out even whole fleets or armadas. With the long view, leaders of Earth understood that military might is not the only way to dominance. Also, even though Earth sent out lightly armed ships into the depths of space, she didn't forget to provide heavy armed escorts or patrols for them which was only a step away from establishing a military navy.
adapted from Hobbyist's Guide to the UFP Starfleet by Timo Saloniemi