Science Objectives of the Ganymede Laser Altimeter (GALA) for the JUICE Mission

• KIMURA Jun

  Department of Earth and Space Science, Osaka University

• HUSSMANN Hauke

  Institute of Planetary Research, DLR

• KAMATA Shunichi

  Creative Research Institution, Hokkaido University

• MATSUMOTO Koji

  RISE Project Office, National Astronomical Observatory of Japan

• OBERST Jürgen

  Institute of Planetary Research, DLR

• STEINBRÜGGE Gregor

  Institute of Planetary Research, DLR

• STARK Alexander

  Institute of Planetary Research, DLR

• GWINNER Klaus

  Institute of Planetary Research, DLR

• OSHIGAMI Shoko

  Center for Computational Astrophysics, National Astronomical Observatory of Japan

• NAMIKI Noriyuki

  RISE Project Office, National Astronomical Observatory of Japan

• LINGENAUBER Kay

  Institute of Planetary Research, DLR

• ENYA Keigo

  Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency

• KURAMOTO Kiyoshi

  Department of Cosmosciences, Hokkaido University

• SASAKI Sho

  Department of Earth and Space Science, Osaka University

Abstract

Laser altimetry is a powerful tool for addressing the major objectives of planetary physics and geodesy. Through measurements of distances between a spacecraft and the surface of the planetary bodies, it can be used to determine the global shape and radius: global, regional, and local topography: tidal deformation: and rotational states including physical librations. Laser altimeters have been applied in planetary explorations of the Moon, Mars, Mercury, and the asteroids Eros, and Itokawa. The JUpiter Icy Moons Explorer (JUICE), led by European Space Agency (ESA), has started development to explore the emergence of habitable worlds around gas giants. The Ganymede Laser Altimeter (GALA) will be the first laser altimeter for icy bodies, and will measure the shape and topography of the large icy moons of Jupiter, (globally for Ganymede, and using flyby ground-tracks for Europa and Callisto). Such information is crucial for understanding the formation of surface features and can tremendously improve our understanding of the icy tectonics. In addition, the GALA will infer the presence or absence of a subsurface ocean by measuring the tidal and rotational responses. Furthermore, it also improves the accuracy of gravity field measurements reflecting the interior structure, collaborating with the radio science experiment. In addition to range measurements, the signal strength and the waveform of the laser pulses reflected from the moon's surface contain information about surface reflectance at the laser wavelength and small scale roughness. Therefore we can infer the degrees of chemical and physical alterations, e.g., erosion, space weathering, compaction and deposition of exogenous materials, through GALA measurements without being affected by illumination conditions. JUICE spacecraft carries ten science payloads including GALA. They work closely together in a synergistic way with GALA being one of the key instruments for understanding the evolution of the icy satellites Ganymede, Europa, and Callisto.

Journal

• TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN

  TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 17 (2), 234-243, 2019

  THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

Keywords

• Icy Moon
• Habitability
• Tectonics
• Interior
• Spacecraft Exploration

Details

• CRID: 1390282763101316864
• NII Article ID: 130007607430
• DOI: 10.2322/tastj.17.234
• ISSN: 18840485
• Web Site: https://www.jstage.jst.go.jp/article/tastj/17/2/17_17.234/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed