Innovative Approaches to Future Outer Planet Exploration -- Destination: Ganymede
References: R. T. Pappalardo, K. K. Khurana, and W. B. Moore
As outlined in NASA's February 18, 2009 announcement, the Europa Jupiter System Mission (EJSM) is a system-level investigation of the Jovian system that has been selected to illuminate the larger question of how potentially habitable planetary systems form and evolve.
With an estimated cost to NASA of $2.7 Billion (FY07) The EJSM will consist of two separate vehicles, one provided by NASA and the other by ESA, which will each launch (separately) in 2020 and arrive at the Jupiter system in late 2025 and early 2026.
Both the NASA-built Jupiter Europa Orbiter (JEO), and the ESA-built Jupiter Ganymede Orbiter (JGO) would utilize chemical propulsion. Venus and Earth gravity assists would speed each spacecraft onward for arrival at Jupiter only 6 years later.
JGO is the ESA element of the EJSM. JGO will be built to accommodate the moderate radiation environment outside of Europa orbit. It would consist of a solar powered orbiter with 10 science instruments designed for remote sensing of Jupiter and the outer Galilean satellites including extensive mapping of Ganymede.
Prior to Ganymede arrival, JGO will intensely investigate Callisto from a resonant orbit, and make extensive observations of the Jupiter system to complement those of JEO. JGO's instruments will study dynamic phenomena such as Io's volcanoes and Jupiter's atmosphere. In addition, the orbiters will map Jupiter's massive magnetosphere and study how it interacts with its moons. The orbiters will also characterize any liquid water oceans, which are believed to exist beneath the ice shells of Europa and Ganymede.
Ganymede, the largest moon in the solar system, is the only moon known to have its own internally generated magnetic field and is suspected to have a deep undersurface water ocean. Since its discovery in 1995, scientists have sought to understand the causes and implications of the magnetic field.
Ganymede is also important as a logical destination for a detailed investigation around the gas giant Jupiter because of its diverse geological features, and its radiation environment is less harsh than that of Europa.
A study of Ganymede will contain broad science goals of surface, magnetosphere, interior, and atmosphere--and overarching themes of water and organics-- all of which tie to NASA's outer planet exploration objectives.
Implications
Gaining insight into the composition and volatile inventory of Jupiter and its moons will shed light on how planets and satellites accrete and evolve. Hence, a system-level investigation of the Jovian system will illuminate the question of how planetary systems form and evolve.
Significance to Solar System Exploration
Gaining insight into the composition and volatile inventory of Jupiter and its moons will shed light on how planets and satellites accrete and evolve. Hence, a system-level investigation of the Jovian system will illuminate the question of how planetary systems form and evolve.
Written by Samantha Harvey
For more information about NASA Science Highlights and information on publication, please contact Samantha Harvey, Samantha.K.Harvey@jpl.nasa.gov.
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