NASA’s first successful mission to another planet, Mariner 2 to Venus in 1962, marked the beginning of what NASA Chief Scientist Jim Green describes in this volume as “a spectacular era” of solar system exploration. In its first 50 years of planetary exploration, NASA sent spacecraft to fly by, orbit, land on, or rove on every planet in our solar system, as well as Earth’s Moon and several moons of other planets. Pluto, reclassified as a dwarf planet in 2006, was visited by the New Horizons spacecraft in 2015.

What began as an endeavor of two nations—the United States and the former Soviet Union—has become a multinational enterprise, with a growing number of space agencies worldwide building and launching planetary exploration missions—sometimes alone, sometimes together.

In this volume, a diverse array of scholars addresses the science, technology, policy, and politics of planetary exploration. This volume offers a collection of in-depth studies of important projects, decisions, and milestones of this era.