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| Titel |
Science of the Joint ESA-NASA Europa Jupiter System Mission (EJSM) |
| VerfasserIn |
Michel Blanc, Ron Greeley |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250043459
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| Zusammenfassung |
| The Europa Jupiter System Mission (EJSM), an international joint mission under study by NASA and ESA, has the overarching theme to investigate the emergence of habitable worlds around gas giants. Jupiter’s diverse Galilean satellites—three of which are believed to harbor internal oceans—are the key to understanding the habitability of icy worlds. To this end, the reference mission architecture consists of the NASA-led Jupiter Europa Orbiter (JEO) and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO will execute a coordinated exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. JEO and JGO carry sets of complementary instruments, to monitor dynamic phenomena (such as Io’s volcanoes and Jupiter’s atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede.
Encompassed within the overall mission theme are two science goals, (1) Determine whether the Jupiter System harbors habitable worlds and (2) Characterize the processes within the Jupiter System. The science objectives addressed by the first goal are to: i) characterize and determine the extent of subsurface oceans and their relations to the deeper interior, ii) characterize the ice shells and any subsurface water, including the heterogeneity of the ice, and the nature of surface-ice-ocean exchange; iii) characterize the deep internal structure, differentiation history, and (for Ganymede) the intrinsic magnetic field; iv) compare the exospheres, plasma environments, and magnetospheric interactions; v) determine global surface composition and chemistry, especially as related to habitability; vi) understand the formation of surface features, including sites of recent or current activity, and identify and characterize candidate sites for future in situ exploration. The science objectives for addressed by the second goal are to: i) understand the Jovian satellite system, especially as context for Europa and Ganymede; ii) evaluate the structure and dynamics of the Jovian atmosphere; iii) characterize processes of the Jovian magnetodisk/magnetosphere; iv) determine the interactions occurring in the Jovian system; and v) constrain models for the origin of the Jupiter system.
Both spacecraft launch separately in 2020 and use a Venus-Earth-Earth Gravity Assist (VEEGA) trajectory to reach Jupiter in 2026. After orbit insertion, each would perform a multi-year tour of the Jovian system. The tours would include i) multiple flybys of Io, Europa, Ganymede, and Callisto, ii) continuous magnetospheric monitoring, and iii) regular monitoring of Io and Jupiter’s atmosphere and Jupiter’s ring system. JEO’s Europa orbital phase would start on a circular 200 km altitude around Europa at 90°-100° inclination for about one month before transferring to a 100 km orbit. JGO’s Ganymede orbital phase would start on an elliptical orbit 200 x 10000 km at 86° inclination for about 2-3 months and later transfer to a 200 km circular orbit. JEO would eventually impact Europa and JGO Ganymede, bringing the joint mission to a close.
Operation of two spacecraft in the Jupiter system provides the unparalleled opportunity to address the high-priority questions posed by the NASA Decadal Survey and ESA Cosmic Vision for exploration of the outer solar system. The EJSM mission concept represents a conservative and robust design approach to successfully answering these high-priority questions and making a major step forward in understanding the emergence of habitable worlds around gas giants. |
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