Voyager program in the context of Enceladus (moon)

Music is the arrangement of sound to create some combination of form, harmony, melody, rhythm, or otherwise expressive content. Music is generally agreed to be a cultural universal that is present in all human societies. Definitions of music vary widely in substance and approach. While scholars agree that music is defined by a small number of specific elements, there is no consensus as to what these necessary elements are. Music is often characterized as a highly versatile medium for expressing human creativity. Diverse activities are involved in the creation of music, and are often divided into categories of composition, improvisation, and performance. Music may be performed using a wide variety of musical instruments, including the human voice. It can also be composed, sequenced, or otherwise produced to be indirectly played mechanically or electronically, such as via a music box, barrel organ, or digital audio workstation software on a computer.

Music often plays a key role in social events and religious ceremonies. The techniques of making music are often transmitted as part of a cultural tradition. Music is played in public and private contexts, highlighted at events such as festivals and concerts for various different types of ensembles. Music is used in the production of other media, such as in soundtracks to films, TV shows, operas, and video games.

Voyager 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 the interstellar space beyond the Sun's heliosphere. It was launched 16 days after its twin, Voyager 2. It communicates through the NASA Deep Space Network (DSN) to receive routine commands and to transmit data to Earth. Real-time distance and velocity data are provided by NASA and JPL. At a distance of 170.02 AU (25.4 billion km; 15.8 billion mi) as of November 2025, it is the most distant human-made object from Earth. Voyager 1 is also projected to reach a distance of one light day from Earth in November of 2026.

The probe made flybys of Jupiter, Saturn, and Saturn's largest moon, Titan. NASA had a choice of either conducting a Pluto or Titan flyby. Exploration of Titan took priority because it was known to have a substantial atmosphere. Voyager 1 studied the weather, magnetic fields, and rings of the two gas giants and was the first probe to provide detailed images of their moons.

Voyager 2 is a space probe launched by NASA on August 20, 1977, as a part of the Voyager program. It was launched on a trajectory towards the gas giants (Jupiter and Saturn) and enabled further encounters with the ice giants (Uranus and Neptune). The only spacecraft to have visited either of the ice giant planets, it was the third of five spacecraft to achieve Solar escape velocity, which allowed it to leave the Solar System. Launched 16 days before its twin Voyager 1, the primary mission of the spacecraft was to study the outer planets and its extended mission is to study interstellar space beyond the Sun's heliosphere.

Voyager 2 successfully fulfilled its primary mission of visiting the Jovian system in 1979, the Saturnian system in 1981, Uranian system in 1986, and the Neptunian system in 1989. The spacecraft is in its extended mission of studying the interstellar medium. It is at a distance of 141.55 AU (21.2 billion km; 13.2 billion mi) from Earth as of November 2025.

Enceladus is the sixth-largest moon of Saturn and the 18th largest in the Solar System. It is about 500 kilometres (310 miles) in diameter, about a tenth of that of Saturn's largest moon, Titan. It is covered by clean, freshly deposited snow hundreds of meters thick, making it one of the most reflective bodies of the Solar System. Consequently, its surface temperature at noon reaches only −198 °C (75.1 K; −324.4 °F), 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.

Enceladus was discovered on August 28, 1789, by William Herschel, but little was known about it until the two Voyager spacecrafts, Voyager 1 and Voyager 2, flew by Saturn in 1980 and 1981. In 2005, the spacecraft Cassini started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. In particular, Cassini discovered water-rich plumes venting from the south polar region. Cryovolcanoes near the south pole shoot geyser-like jets of water vapour, molecular hydrogen, other volatiles, and solid material, including sodium chloride crystals and ice particles, into space, totalling about 200 kilograms (440 pounds) per second. More than 100 geysers have been identified. Some of the water vapour falls back as snow, now several hundred metres thick; the rest escapes and supplies most of the material making up Saturn's E ring. According to NASA scientists, the plumes are similar in composition to comets. In 2014, NASA reported that Cassini had found evidence for a large south polar subsurface ocean of liquid water with a thickness of around 10 km (6 mi). The existence of Enceladus's subsurface ocean has since been mathematically modelled and replicated.

A nose cone is the conically shaped forwardmost section of a rocket, guided missile or aircraft, designed to modulate oncoming airflow behaviors and minimize aerodynamic drag. Nose cones are also designed for submerged watercraft such as submarines, submersibles and torpedoes, and in high-speed land vehicles such as rocket cars and velomobiles.

Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver (to make silver-gilt), by a chemical or electrochemical (electroplating) process. Plating refers to modern coating methods, such as the ones used in the electronics industry, whereas gilding is the decorative covering of an object with gold, which typically involve more traditional methods and much larger objects.

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 (e.g. orbit around the Sun) 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.

Gravity assistance can be used to accelerate a spacecraft, that is, to increase or decrease its speed or redirect its path. The "assist" is provided by the motion of the gravitating body as it pulls on the spacecraft. Any gain or loss of kinetic energy and linear momentum by a passing spacecraft is correspondingly lost or gained by the gravitational body, in accordance with Newton's Third Law. The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon, and it was used by interplanetary probes from Mariner 10 onward, including the two Voyager probes' notable flybys of Jupiter and Saturn.

Mariner 10 was an American robotic space probe launched by NASA on 3 November 1973, to fly by the planets Mercury and Venus. It was the first spacecraft to visit Mercury and the first to perform a flyby of multiple planets.

Mariner 10 was launched approximately two years after Mariner 9 and was the last spacecraft in the Mariner program. (Mariner 11 and Mariner 12 were allocated to the Voyager program and redesignated Voyager 1 and Voyager 2.)

The Titan IIIE or Titan 3E, also known as the Titan III-Centaur, was an American expendable launch system. Launched seven times between 1974 and 1977, it enabled several high-profile NASA missions, including the Voyager and Viking planetary probes and the joint West Germany-U.S. Helios spacecraft. All seven launches were conducted from Cape Canaveral Air Force Station Launch Complex 41 in Cape Canaveral, Florida.

The Jupiter radius or Jovian radius (plural Jupiter radii or Jovian radii; denoted as R_J or, less commonly, R_Jup) has a value of 71,492 km (44,423 mi), or of 11.2 Earth radii (R_🜨) (one Earth radius, 6378 km, equals 0.08921 R_J). The Jupiter radius is a unit of length used in astronomy to describe the radii of large planets (especially gas giants) and certain exoplanets. It is also used in describing certain stars, in particular brown dwarfs.

The general shape of the planet Jupiter has been directly measured from radio occultations of passing spacecraft, starting with the Pioneer and Voyager missions. This method gives an overall margin of error of about ±5 km. Estimates of the radius at one bar pressure are then determined through extrapolation. The planet Jupiter has the approximate shape of an oblate spheroid, which is mainly set by the rate of rotation. This gives a difference of about 10% between its polar and equatorial radii. The polar radius has been determined with an accuracy of ±10 km (as of 1987). Density fluctuations within the planet can create variations in the equatorial radius of up to 30 km. The winds in Jupiter's outer atmosphere can vary the radius by up to 4 km.

The Viking program consisted of a pair of identical American space probes, Viking 1 and Viking 2 both launched in 1975, and landed on Mars in 1976. The mission effort began in 1968 and was managed by the NASA Langley Research Center. Each spacecraft was composed of two main parts: an orbiter spacecraft which photographed the surface of Mars from orbit, and a lander which studied the planet from the surface. The orbiters also served as communication relays for the landers once they touched down.

The Viking program grew from NASA's earlier, even more ambitious, Voyager Mars program, which was not related to the successful Voyager deep space probes of the late 1970s. Viking 1 was launched on August 20, 1975, and the second craft, Viking 2, was launched on September 9, 1975, both riding atop Titan IIIE rockets with Centaur upper stages. Viking 1 entered Mars orbit on June 19, 1976, with Viking 2 following on August 7.

A starship, starcraft, or interstellar spacecraft is a theoretical spacecraft designed for traveling between planetary systems. The term is mostly found in science fiction. Reference to a "star-ship" are found as early as 1882 in Oahspe: A New Bible.

While NASA's Voyager and Pioneer probes have traveled into local interstellar space, the purpose of these uncrewed craft was specifically interplanetary, and they are not predicted to reach another star system; Voyager 1 probe and Gliese 445 will pass one another within 1.6 light years in about 40,000 years. Several preliminary designs for starships have been undertaken through exploratory engineering, using feasibility studies with modern technology or technology thought likely to be available in the near future.

The 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 successful planetary flyby, the planetary orbiter, and the first gravity assist maneuver. Of the 10 vehicles in the Mariner series, seven were successful, forming the starting point for many subsequent NASA/JPL space probe programs. The planned Mariner Jupiter-Saturn vehicles were adapted into the Voyager program, while the Viking program orbiters were enlarged versions of the Mariner 9 spacecraft. Later Mariner-based spacecraft include Galileo and Magellan, while the second-generation Mariner Mark II series evolved into the Cassini–Huygens probe.

Carolyn C. Porco (born March 6, 1953) is an American planetary scientist who explores the outer Solar System, beginning with her imaging work on the Voyager missions to Jupiter, Saturn, Uranus and Neptune in the 1980s. She led the imaging science team on the Cassini mission in orbit around Saturn. She is an expert on planetary rings and the Saturnian moon, Enceladus.

She has co-authored more than 110 scientific papers on subjects ranging from the spectroscopy of Uranus and Neptune, the interstellar medium, the photometry of planetary rings, satellite/ring interactions, computer simulations of planetary rings, the thermal balance of Triton's polar caps, heat flow in the interior of Jupiter, and a suite of results on the atmosphere, satellites, and rings of Saturn from the Cassini imaging experiment. In 2013, Cassini data confirmed a 1993 prediction by Porco and Mark Marley that acoustic oscillations within the body of Saturn are responsible for creating particular features in the rings of Saturn.