The year 1502 in science and technology included many events, some of which are listed below.

Exploration

• January 1 – Portuguese explorers, led by Pedro Álvares Cabral, sail into Guanabara Bay, Brazil, mistaking it for the mouth of a river, which they name Rio de Janeiro.
• May 11 – Christopher Columbus leaves Cadiz, Spain for his fourth and final voyage to the New World.^[1]
• May 21 – Portuguese navigator João da Nova discovers the uninhabited island of Saint Helena.^[1]
• August 14 – Columbus lands at Trujillo and names the country 'Honduras'.^[1]
• September 18 – Columbus lands in Costa Rica.
• Amerigo Vespucci, on his return to Lisbon from a voyage to the New World, writes a letter, Mundus Novus, to Lorenzo de' Medici indicating that South America must be an independent continent.^[1]
• The Cantino planisphere is the first known world map showing Portuguese discoveries.

Technology

• In Germany, Peter Henlein of Nuremberg uses iron parts and coiled springs to build a portable timepiece, the first "Nuremberg Eg".^[1]

Births

• Pedro Nunes, Portuguese mathematician (died 1578)
• approx. date – Jorge Reinel, Portuguese cartographer (d. after 1572)