Reference Model Payload for Ice Giant Entry Probe Missions
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Reference Model Payload for Ice Giant Entry Probe Missions D.H. Atkinson1
· O. Mousis2 · T.R. Spilker3 · F. Ferri4
Received: 18 February 2020 / Accepted: 25 September 2020 © Springer Nature B.V. 2020
Abstract Descent probes afford the opportunity to make essential atmospheric measurements that are beyond the reach of remote sensing, including the atmospheric abundances of noble gases and key isotopes, and the structure of the atmosphere beneath the cloud tops. Measurements are defined as Tier 1, representing threshold science required to justify the probe mission, and Tier 2 representing valuable science that significantly complement and enhance the threshold measurements, but of themselves are not sufficient to justify the mission. Tier 1 measurements comprise atmospheric noble gas abundances including helium, key noble gas isotope ratios, and the thermal structure of the atmosphere. Instrumentation required to achieve the Tier 1 measurements include a mass spectrometer, a helium abundance detector, and an atmospheric structure instrument comprising both sensors for pressure, temperature, and atmospheric acoustic properties (speed of sound). Tier 1 science can be achieved with a probe making measurements near one to several bars. Tier 2 science includes measurements of key isotopic ratios, the abundances of atmospheric condensables and disequilibrium species, atmospheric dynamics, the net radiative flux transfer profile of the atmosphere, and the location, composition, properties, and structure of the clouds. To achieve all the Tier 2 science objectives requires a probe descending through at least ten bars carrying the full Tier 1 suite of instruments as well as a nephelometer, net flux radiometer, and an ultrastable oscillator to enable Doppler wind tracking of the probe throughout descent. Keywords Uranus · Neptune · Atmospheric probes · Planetary probe instrumentation · In situ measurements In Situ Exploration of the Ice Giants: Science and Technology Edited by Olivier J. Mousis and David H. Atkinson
B D.H. Atkinson
[email protected]
1
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA, 91109, USA
2
Aix Marseille Univ., CNRS, CNES, LAM, Marseille, France
3
Independent Consultant, Monrovia, CA, USA
4
Universit a degli Studi di Padova, CISAS, Padova, Italy
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D.H. Atkinson et al.
1 Introduction, Background, and Context Containing most of the mass and angular momentum in the solar planetary system, the giant planets (Jupiter, Saturn, Uranus, and Neptune) have played a significant role in the large-scale evolution and current structure of the solar system, including the location and characteristics of the terrestrial planets (Gomes et al. 2005). The giant planets may well have affected volatile delivery to all the inner planets including Earth (Chambers 2001; Chambers and Wetherill 2001). An understanding of giant planet formation and evolution is necessary to discern the origin and evolution of the entire solar system, includi
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