Proposed Pluto Fly-By Mission. Pluto, the smallest planet, has remained enigmatic since its discovery by astronomer Clyde Tombaugh in 1930. Pluto is the only planet in our Solar System not yet viewed close-up by spacecraft, and given its great distance and tiny size, study of the planet continues to challenge and extend the skills of planetary astronomers. Most of what we know about Pluto we have learned since the late 1970s. Many of the key questions about Pluto and its satellite Charon await the close-up observation of a space flight mission. Beyond Pluto lies the recently-discovered Edgeworth-Kuiper Disk of ice dwarfs or minor planets. Its history may be connected with the Earth's atmosphere and biosphere. To address these questions, NASA is now considering a future robotic reconnaissance mission to Pluto-Charon using lightweight advanced-technology hardware components and advanced software technology.