The Ganymede laser altimeter (GALA): key objectives, instrument design, and performance
| Autor: | Miguel Herranz de la Revilla, Thomas Gerber, Jose M. Castro-Marin, Hiroshi Araki, Horst-Georg Lötzke, Hirotomo Noda, Alexander Stark, Noriyuki Namiki, Kazuyuki Touhara, Shoko Oshigami, Luisa Lara, Keigo Enya, Christian Hüttig, Ko Ishibashi, Ignacio Martinez-Navajas, Nicolas Thomas, Simone Del Togno, Pascal Thabaut, Christian Althaus, Kerstin Rösner, Jürgen Oberst, Alexander Lichopoj, Masanori Kobayashi, Belinda Wendler, Henri Eisenmenger, H. Hussmann, Juan Pablo Rodríguez García, Reinald Kallenbach, Sebastian Villamil, Jun Kimura, Konrad Willner, Thomas Behnke, K. Lingenauber, Gregor Steinbrügge, J. Rodrigo, Harald Michaelis, Kai Wickhusen, Fabian Lüdicke, Jaime Jiménez-Ortega |
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| Přispěvatelé: | German Centre for Air and Space Travel, Ministerio de Economía y Competitividad (España), European Commission |
| Rok vydání: | 2019 |
| Předmět: |
Solar System
010504 meteorology & atmospheric sciences Aerospace Engineering 01 natural sciences law.invention law Performance model Ganymede 0103 physical sciences Surface roughness Satellites of Jupiter Altimeter JUICE mission 010303 astronomy & astrophysics 0105 earth and related environmental sciences 520 Astronomy Laser Altimetry GALA Icy moon Geodesy Laser Avalanche photodiode 620 Engineering Instrument design Wavelength Space and Planetary Science Satellite Geology |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | The Ganymede Laser Altimeter (GALA) is one of the ten scientific instruments selected for the Jupiter Icy Moons Explorer (JUICE) mission currently implemented under responsibility of the European Space Agency (ESA). JUICE is scheduled for launch in mid 2022; arrival at Jupiter will be by end of 2029 with the nominal science mission—including close flybys at Ganymede, Europa, and Callisto and a Ganymede orbit phase—ending by mid 2033. GALA’s main objective is to obtain topographic data of the icy satellites of Jupiter: Europa, Ganymede, and Callisto. By measuring the diurnal tidal deformation of Ganymede, which crucially depends on the decoupling of the surface ice layer from the deep interior by a liquid water ocean, GALA will obtain evidence for (or against) a subsurface ocean in a 500 km orbit around the satellite and will provide constraints on Ganymede’s ice shell thickness. In combination with other instruments, it will characterize the morphology of surface units on Ganymede, Europa, and Callisto providing not only topography but also surface roughness and albedo (at 1064 nm) measurements. GALA is a single-beam laser altimeter operating with up to 50 Hz (nominal 30 Hz) shot frequency at a wavelength of 1064 nm and pulse lengths of 5.5 ± 2.5 ns using a Nd:YAG laser. The return pulse is detected by an Avalanche Photo Diode (APD) with 100 MHz bandwidth and is digitized at a sampling rate of 200 MHz providing range measurements with a subsample resolution of 0.1 m and surface roughness measurements from pulse-shape analysis on the scale of the footprint size of about 50 m at 500 km altitude. The instrument is developed in collaboration of institutes and industry from Germany, Japan, Switzerland, and Spain. © 2019, CEAS. Financial support was provided under grant 50 QJ 1401 on behalf of the DLR Space Administration by the German Bundesministerium fur Wirtschaft und Energie. This research has been supported by the Spanish Ministerio de Economia y Competitividad under Contract ESP 2016-76076-R. |
| Databáze: | OpenAIRE |
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