Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about nine times that of Earth. It has an eighth the average density of Earth, but is over 95 times more massive. Even though Saturn is almost as big as Jupiter, Saturn has less than a third the mass of Jupiter. Saturn orbits the Sun at a distance of 9.59 AU (1,434 million km), with an orbital period of 29.45 years.
Titan is the largest moon of Saturn and the second-largest in the Solar System. It is the only moon known to have an atmosphere denser than the Earth's and is the only known object in space—other than Earth—on which there is clear evidence that stable bodies of liquid exist. Titan is one of seven gravitationally rounded moons of Saturn and the second-most distant among them. Frequently described as a planet-like moon, Titan is 50% larger in diameter than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's Ganymede and is larger than Mercury; yet Titan is only 40% as massive as Mercury, because Mercury is mainly iron and rock while much of Titan is ice, which is less dense.
Cassini–Huygens, commonly called Cassini, was a space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class robotic spacecraft comprised both NASA's Cassini space probe and ESA's Huygens lander, which landed on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit, where it stayed from 2004 to 2017. The two craft took their names from the astronomers Giovanni Cassini and Christiaan Huygens.
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense.
Huygens was an atmospheric entry robotic space probe that landed successfully on Saturn's moon Titan in 2005. Built and operated by the European Space Agency (ESA), launched by NASA, it was part of the Cassini–Huygens mission and became the first spacecraft to land on Titan and the farthest landing from Earth a spacecraft has ever made. The probe was named after the 17th-century Dutch astronomer Christiaan Huygens, who discovered Titan in 1655.
Enceladus is the sixth-largest moon of Saturn and the 19th-largest in the Solar System. It is about 500 kilometers in diameter, about a tenth of that of Saturn's largest moon, Titan. It 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 reaches only −198 °C, far colder than a light-absorbing body would be. Despite its small size, Enceladus has a wide variety of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrain.
This article provides a timeline of the Cassini–Huygens mission. Cassini was a collaboration between the United States' NASA, the European Space Agency ("ESA"), and the Italian Space Agency ("ASI") to send a probe to study the Saturnian system, including the planet, its rings, and its natural satellites. The Flagship-class uncrewed robotic spacecraft comprised both NASA's Cassini probe, and ESA's Huygens lander which was designed to land on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit. The craft were named after astronomers Giovanni Cassini and Christiaan Huygens.
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns.
The exploration of Saturn has been solely performed by crewless probes. Three missions were flybys, which formed an extended foundation of knowledge about the system. The Cassini–Huygens spacecraft, launched in 1997, was in orbit from 2004 to 2017.
Lakes of liquid ethane and methane exist on the surface of Titan, Saturn's largest moon. This was confirmed by the Cassini–Huygens space probe, as had been suspected since the 1980s. The large bodies of liquid are known as maria (seas) and the small ones as lacūs (lakes).
The climate of Titan, the largest moon of Saturn, is similar in many respects to that of Earth, despite having a far lower surface temperature. Its thick atmosphere, methane rain, and possible cryovolcanism create an analogue, though with different materials, to the climatic changes undergone by Earth during the far shorter year of Earth.
Ligeia Mare is a lake in the north polar region of Titan, the planet Saturn's largest moon. It is the second largest body of liquid on the surface of Titan, after Kraken Mare. Larger than Lake Superior on Earth, it is mostly composed of liquid methane, with unknown but lesser components of dissolved nitrogen and ethane, as well as other organic compounds. It is located at 78° N, 249° W, and has been fully imaged by the Cassini spacecraft. Measuring roughly 420 km (260 mi) by 350 km (217 mi) across, it has a surface area of about 126,000 km2, and a shoreline over 2,000 km (1,240 mi) in length. The lake may be hydrologically connected to the larger Kraken Mare. Its namesake is Ligeia, one of the sirens in Greek mythology.
Titan Mare Explorer (TiME) is a proposed design for a lander for Saturn's moon Titan. TiME is a relatively low-cost, outer-planet mission designed to measure the organic constituents on Titan and would have performed the first nautical exploration of an extraterrestrial sea, analyze its nature and, possibly, observe its shoreline. As a Discovery-class mission it was designed to be cost-capped at US$425 million, not counting launch vehicle funding. It was proposed to NASA in 2009 by Proxemy Research as a scout-like pioneering mission, originally as part of NASA's Discovery Program. The TiME mission design reached the finalist stage during that Discovery mission selection, but was not selected, and despite attempts in the U.S. Senate failed to get earmark funding in 2013. A related Titan Submarine has also been proposed.
The Cassini space probe was deliberately disposed of via a controlled fall into Saturn's atmosphere on September 15, 2017, ending its nearly two-decade-long mission. This method was chosen to prevent biological contamination of any of the moons of Saturn now thought to offer potentially habitable environments. Factors that influenced the mission end method included the amount of rocket fuel left, the health of the spacecraft, and funding for operations on Earth.
Journey to Enceladus and Titan (JET) is an astrobiology mission concept to assess the habitability potential of Enceladus and Titan, moons of Saturn.
A flyby is a spaceflight operation in which a spacecraft passes in proximity to another body, usually a target of its space exploration mission and/or a source of a gravity assist to impel it towards another target. Spacecraft which are specifically designed for this purpose are known as flyby spacecraft, although the term has also been used in regard to asteroid flybys of Earth for example. Important parameters are the time and distance of closest approach.
Vid Flumina is a river of liquid methane and ethane on Saturn's moon Titan. It is more than 400 km (249 mi) long and flows into Titan's second largest hydrocarbon sea, Ligeia Mare. The surface of Titan is mostly water ice, so Vid Flumina is a river of methane and ethane flowing across and cutting canyons into ice as though it were bedrock. NASA scientists think that it likely has rapids, whirlpools and falls, just like rivers on Earth.
The following outline is provided as an overview of and topical guide to Saturn:
Oceanus is a NASA/JPL orbiter mission concept proposed in 2017 for the New Frontiers mission #4, but it was not selected for development. If selected at some future opportunity, Oceanus would travel to Saturn's moon Titan to assess its habitability. Studying Titan would help understand the early Earth and exoplanets which orbit other stars. The mission is named after Oceanus, the Greek god of oceans.
Titan Submarine is a proposed NASA submarine probe that will visit Saturn’s largest moon Titan, and will plausibly explore either Kraken Mare or Ligeia Mare, two of Titan’s largest lakes. The concept was proposed by Steven Oleson, Ralph Lorenz, and Micheal Paul, technical experts at NASA’s Glenn Research Center in Ohio.
