European voyages of exploration can be facilely divided into two areas. First was the move to the East, which was pioneered by the Portuguese. And second was the diffusion westwards across the Atlantic to the New World, which was commanded by the Portuguese but eventually domineered by the Spanish counterparts. The difference was that Europe had known of India and China for centuries, whereas America was totally unsuspected. When Columbus landed in the Americas in 1492, America was more of a barrier between Europe and the true prize of the Indies across the globe.
This was by far the most motivating factor that Europeans delved into life threatening voyages in the water to gain control over that part of the world. Not much was in favor of the European explorers because they used decrepit wooden ships and were guided by crude and primitive instruments into uncharted seas, where nothing was marked and shifting currents were a grave mystery. These challenges of exploration were great but so were the motivations: a lust for gold and glory, missionary zeal for converting the “savage”, and the desire to gain knowledge. An economic cause of these voyages is primarily the competition between nations.
The position of the Spanish was that they wanted to compete with the French and the British. Spain’s expansion was limited into Europe because of France so they expanded a bit into northern Africa but this was not rewarding. With time this became apparent that gains in territorial power and wealth through colonization of the new world. The Spanish clung on the opportunity leading to the other major powers to expand their power over and above the others. The technological advances in cartography, navigation, shipbuilding, and firearms contributed to Europe globalization.
In fact these advances gave the Europeans an edge over anybody else. Technological innovations in navigation set the stage for exploration for the Europeans. Bigger, faster ships and the invention of navigational devices such as the astrolabe and sextant made extended voyages possible. All in all, these factors contributed to the success of the European voyages and were the motivation derived to actually support the cause of these voyages.
References Applied History Research Group. The European Voyages of Exploration the Fifteenth and Sixteenth Centuries- 102-104