EnceladusEnceladus is the sixth-largest moon of Saturn (19th largest in the Solar System). It is about in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon only reaches , far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain.
Voyager 2Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach gas giants Jupiter and Saturn but enabled further encounters with ice giants Uranus and Neptune. Voyager 2 remains the only spacecraft to have visited either of the ice giant planets.
Mariner programThe Mariner program was conducted by the American space agency NASA to explore other planets. Between 1962 and late 1973, NASA's Jet Propulsion Laboratory (JPL) designed and built 10 robotic interplanetary probes named Mariner to explore the inner Solar System - visiting the planets Venus, Mars and Mercury for the first time, and returning to Venus and Mars for additional close observations. The program included a number of interplanetary firsts, including the first planetary flyby, the planetary orbiter, and the first gravity assist maneuver.
NeptuneNeptune is the eighth planet from the Sun and the farthest IAU-recognized planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. Being composed primarily of gases and liquids, it has no well-defined solid surface.
Triton (moon)Triton is the largest natural satellite of the planet Neptune, and was the first Neptunian moon to be discovered, on October 11, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, an orbit in the direction opposite to its planet's rotation. Because of its retrograde orbit and composition similar to Pluto, Triton is thought to have been a dwarf planet, captured from the Kuiper belt.
AstrobiologyAstrobiology is a scientific field within the life and environmental sciences that studies the origins, early evolution, distribution, and future of life in the universe by investigating its deterministic conditions and contingent events. As a discipline, astrobiology is founded on the premise that life may exist beyond Earth. Research in astrobiology comprises three main areas: the study of habitable environments in the Solar System and beyond, the search for planetary biosignatures of past or present extraterrestrial life, and the study of the origin and early evolution of life on Earth.
Voyager programThe Voyager program is an American scientific program that employs two robotic interstellar probes, Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable alignment of the two gas giants Jupiter and Saturn and the ice giants, Uranus and Neptune, to fly near them while collecting data for transmission back to Earth. After launch the decision was made to send Voyager 2 near Uranus and Neptune to collect data for transmission back to Earth.
Europa (moon)Europa jʊˈroʊpə, or Jupiter II, is the smallest of the four Galilean moons orbiting Jupiter, and the sixth-closest to the planet of all the 95 known moons of Jupiter. It is also the sixth-largest moon in the Solar System. Europa was discovered independently by Simon Marius and Galileo Galilei and was named (by Marius) after Europa, the Phoenician mother of King Minos of Crete and lover of Zeus (the Greek equivalent of the Roman god Jupiter). Slightly smaller than Earth's Moon, Europa is made of silicate rock and has a water-ice crust and probably an iron–nickel core.
Voyager 1Voyager 1 is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin Voyager 2, Voyager 1 has been operating for 5 September 1977 12:56:00 as of . It communicates through NASA's Deep Space Network to receive routine commands and to transmit data to Earth. Real-time distance and velocity data is provided by NASA and JPL. At a distance of from Earth , it is the most distant human-made object from Earth.
