Journey to Enceladus and Titan (JET) is an

astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that invest ...

mission concept to assess the habitability potential of

Enceladus Enceladus 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 refle ...

and

Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...

moons of Saturn The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan, which is larger than the planet Mercury. Saturn has 83 moons with confirmed orbits that are not embedded in its rings—of ...

. The JET orbiter concept was proposed in 2011 by the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, La Cañada Flintridge, California ...

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...

's Discovery Program for its 13th mission, but it was not selected as a semi-finalist; Lucy was selected on January 4, 2017.

Concept

is a small icy moon, seemingly similar in chemical makeup to

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...

s, with jets or

geyser A geyser (, ) is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only i ...

s of water erupting from its surface that might be connected to active

hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspo ...

s at its subsurface water ocean floor, where the moon's ocean meets the underlying rock, a prime habitat for

life Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from that which does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energy ...

. The geysers could provide easy access for sampling the moon's subsurface ocean, and if there is microbial life in it, ice particles from the sea could contain the evidence astrobiologists need to identify them. An

organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or is the product ...

-rich world,

has a

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...

cycle comparable in atmospheric and geological processes to Earth's water cycle. Enceladus geysers June 2009

The JET orbiter mission concept was proposed in 2011 by the

to NASA's Discovery Program Mission #13. During the orbiter's one-year mission, it would perform high-resolution mass spectroscopy mapping that would determine what processes have shaped and are shaping the moons, and it would permit assessment of the habitability potential of Enceladus and Titan. In order to meet the $450 million cost cap, the orbiter would carry only two instruments. It would orbit

Saturn 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 and a half times that of Earth. It has only one-eighth the average density of Earth; h ...

and make a total of 16 flybys of Enceladus and Titan, the closest ones at 900 km from Titan's surface. In June 2015 NASA announced a list of five finalists for the current competition, but the ''Journey to Enceladus and Titan'' proposal was not selected. Lucy was selected on January 4, 2017 and is planned to launch in October 2021.

Objectives

The three goals of the mission are to determine the processes that have shaped and are shaping Enceladus and Titan, to assess their astrobiological potential, and to investigate their formation and evolution. At Enceladus, the mission will determine composition and flux of material in the plume, and will produce temperature maps of the faults, tectonics and interior dynamics. At Titan, it will characterize of the organic molecules in the upper atmosphere at different altitudes (> 900 km) and latitudes, and will produce high-resolution images for detailed study of features forming at different time-scales.

Launch and trajectory

If using an Atlas V rocket, JET would reach Saturn in 8.5 years using a Venus–Earth–Earth

gravity assist In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the p ...

trajectory.

Payload

The orbiter payload consists of two instruments: *Infrared camera: 'Titan Imaging and Geology, Enceladus Reconnaissance' (TIGER) – This high-heritage

thermographic camera Infrared thermography (IRT), thermal video and/or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared ...

exploits infrared wavelengths to image through Titan's thick atmosphere and would image the heat of Enceladus's fractures known as ' tiger stripes', permitting a detailed thermal modeling. It would provide 10× better imaging resolution of Titan's surface than ''Cassini'', yielding 50 m/pix images of 15% of Titan's surface. *

Mass spectrometer Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is us ...

: 'Spectrometer for Titan and Enceladus Astrobiology Mission' (STEAM) – It would characterize elements and molecules, including complex

organic molecules In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The s ...

with 100× higher resolution, and 1000× better sensitivity than '' Cassini''. STEAM is the ''

Rosetta Rosetta or Rashid (; ar, رشيد ' ; french: Rosette ; cop, ϯⲣⲁϣⲓⲧ ''ti-Rashit'', Ancient Greek: Βολβιτίνη ''Bolbitinē'') is a port city of the Nile Delta, east of Alexandria, in Egypt's Beheira governorate. The R ...

'' flight-spare.

References

{{DEFAULTSORT:Journey to Enceladus and Titan Discovery program proposals Enceladus Missions to Saturn Proposed NASA space probes Proposed astrobiology space missions

Concept

Objectives

Launch and trajectory

Payload

See also

References