Related Research Articles
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 investigates the deterministic conditions and contingent events with which life arises, distributes, and evolves in the universe. It considers the question of whether extraterrestrial life exists, and if it does, how humans can detect it.
Enceladus is the sixth-largest moon of Saturn. It is about 500 kilometers 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 −198 °C, 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 terrains.
A biosignature is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attributes of life include its complex physical or chemical structures and its use of free energy and the production of biomass and wastes. A biosignature can provide evidence for living organisms outside the Earth and can be directly or indirectly detected by searching for their unique byproducts.
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.
Jonathan I. Lunine is an American planetary scientist and physicist. Lunine teaches at Cornell University, where he is the David C. Duncan Professor in the Physical Sciences and Chair of the Department of Astronomy. Having published more than 380 research papers, Lunine is at the forefront of research into planet formation, evolution, and habitability. His work includes analysis of brown dwarfs, gas giants, and planetary satellites. Within the Solar System, bodies with potential organic chemistry and prebiotic conditions, particularly Saturn's moon Titan, have been the focus of Lunine's research.
The habitability of natural satellites is a measure of their potential to sustain life in favorable circumstances. Habitable environments do not necessarily harbor life. Natural satellite habitability is a new area that is significant to astrobiology for various reasons, the most important of which being that natural satellites are expected to outnumber planets by a large margin, and it is projected that habitability parameters will be comparable to those of planets. There are, nevertheless, significant environmental variables that affect moons as prospective alien life locations. The strongest candidates for natural satellite habitability are currently icy satellites such as those of Jupiter and Saturn—Europa and Enceladus respectively, although if life exists in either place, it would probably be confined to subsurface habitats. Historically, life on Earth was thought to be strictly a surface phenomenon, but recent studies have shown that up to half of Earth's biomass could live below the surface. Europa and Enceladus exist outside the circumstellar habitable zone which has historically defined the limits of life within the Solar System as the zone in which water can exist as liquid at the surface. In the Solar System's habitable zone, there are only three natural satellites—the Moon, and Mars's moons Phobos and Deimos —none of which sustain an atmosphere or water in liquid form. Tidal forces are likely to play as significant a role providing heat as stellar radiation in the potential habitability of natural satellites.
Planetary oceanography also called exo-oceanography is the study of oceans on planets and moons other than Earth. Unlike other planetary sciences like astrobiology, astrochemistry and planetary geology, it only began after the discovery of underground oceans in Saturn's moon Titan and Jupiter's moon Europa. This field remains speculative until further missions reach the oceans beneath the rock or ice layer of the moons. There are many theories about oceans or even ocean worlds of celestial bodies in the Solar System, from oceans made of diamond in Neptune to a gigantic ocean of liquid hydrogen that may exist underneath Jupiter's surface.
Enceladus Life Finder (ELF) is a proposed astrobiology mission concept for a NASA spacecraft intended to assess the habitability of the internal aquatic ocean of Enceladus, which is Saturn's sixth-largest moon and seemingly similar in chemical makeup to comets. The spaceprobe would orbit Saturn and fly through Enceladus's geyser-like plumes multiple times. It would be powered by energy supplied from solar panels on the spacecraft.
Journey to Enceladus and Titan (JET) is an astrobiology mission concept to assess the habitability potential of Enceladus and Titan, moons of Saturn.
Life Investigation For Enceladus (LIFE) was a proposed astrobiology mission concept that would capture icy particles from Saturn's moon Enceladus and return them to Earth, where they could be studied in detail for signs of life such as biomolecules.
Enceladus Explorer (EnEx) is a planned interplanetary orbiter and lander mission equipped with a subsurface maneuverable ice melting probe suitable to assess the existence of life on Saturn's moon Enceladus.
THEO is a feasibility study for a New Frontiers class orbiter mission to Enceladus that would directly sample its south pole water plumes in order to study its internal habitability and to search for biosignatures. Specifically, it would take advantage of the direct sampling opportunities of a subsurface ocean.
Explorer of Enceladus and Titan (E2T) is a space mission concept that would investigate the evolution and habitability of the Saturnian satellites Enceladus and Titan and is proposed by the European Space Agency in collaboration with NASA.
Enceladus Life Signatures and Habitability (ELSAH) is an astrobiology concept mission proposed in 2017 to NASA's New Frontiers program to send a spacecraft to Enceladus to search for biosignatures and assess its habitability. The Principal Investigator is Christopher P. McKay, an astrobiologist at NASA Ames Research Center, and the managing NASA center is Goddard Space Flight Center. No details of the mission have been made public, but observers speculate that it would be a plume-sampling orbiter mission.
The Ocean Worlds Exploration Program (OWEP) is a NASA program to explore ocean worlds in the outer Solar System that could possess subsurface oceans to assess their habitability and to seek biosignatures of simple extraterrestrial life.
The MAss SPectrometer for Planetary EXploration (MASPEX) is a mass spectrometer capable of high-resolution and high-sensitivity that allows the determination of a wide variety of chemical compounds in complex mixtures. This instrument will fly on board the planned Europa Clipper orbiter to explore Jupiter's moon Europa. This astrobiology mission will analyse the composition of Europa's surface while in orbit, and will directly assess its internal ocean habitability by flying through Europa's tenuous atmosphere.
The SUrface Dust Analyser (SUDA) is a time-of-flight mass spectrometer of reflectron-type that employs impact ionization and is optimised for a high mass resolution. The instrument was selected in May 2015 to fly on board the Europa Clipper mission, that is planned for 2025 to Jupiter's moon Europa.
The Cosmic Dust Analyzer (CDA) on the Cassini mission is a large-area multi-sensor dust instrument that includes a chemical dust analyzer, a highly reliable impact ionization detector, and two high rate polarized polyvinylidene fluoride (PVDF) detectors. During 6 years en route to Saturn the CDA analysed the interplanetary dust cloud, the stream of interstellar dust, and Jupiter dust streams. During 13 years in orbit around Saturn the CDA studied the E ring, dust in the plumes of Enceladus, and dust in Saturn's environment.
Ever since the beginning of the space age satellites and space probes performed space dust measurements. The goal was, initially, to quantify the hazard of meteoroid impacts onto space vehicles. Samples returned to Earth by the Apollo astronauts demonstrated that the lunar surface is peppered by microcraters generated by high speed impacts of cosmic dust particles. Their analysis provided a measurement of the flux of interplanetary dust particles. The later goal of dust measurements was the exploration of the dust environments throughout interplanetary space, within planetary systems, and, today, it is to analyze planetary bodies from which dust particles originate. The development of instrument swent from simple and small but noisy microphone detectors, over large and reliable multi-coincidence dust detectors to sophisticated dust analyzers that determine the composition of individual dust particles.
References
- 1 2 3 Enceladus Icy Jet Analyzer (ENIJA) : Search for life with a high resolution TOF-MS for in situ characterization of high dust density regions. (PDF) R. Srama, F. Postberg, H. Henke), T. Klopfer, Y. Li, J. Simolka, S. Bugiel, S. Kempf, J. Hillier, N. Khawaja, M. Trieloff, B. Abel, G. Moragas-Klostermeyer, H. Strack, J. Schmidt, R. Soja, Z. Sternovsky, T. Spohn. EPSC Abstracts, Vol. 10, EPSC2015-769, European Planetary Science Congress 2015.
- ↑ Lunine, Jonathan I.; Waite, Jr., Jack Hunter; Postberg, Frank; Spilker, Linda J. (2015). Enceladus Life Finder: The search for life in a habitable moon (PDF). 46th Lunar and Planetary Science Conference (2015). Houston (TX): Lunar and Planetary Institute.
- ↑ Lunine, Jonathan I. "Searching for Life in the Saturn System: Enceladus Life Finder" (PDF). ELF Team. Lunar And Planetary Institute. Retrieved 2015-04-07.
- ↑ Explorer of Enceladus and Titan - Home page.
| Geography |
|  | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Exploration |
| |||||||||||||
| Other | ||||||||||||||
