Uranus and Neptune missions: A study in advance of the next Planetary Science Decadal Survey

Hofstadter, Mark; Simon-Miller, A. A.; Atreya, S. K.; Banfield, D.; Fortney, Jonathan J.; Hayes, Alexander G.; Hedman, Matthew M.; Hospodarsky, G. B.; Mandt, K.; Masters, A.; Showalter, M. R.; Soderlund, K. M.; Turrini, D.; Turtle, E. P.; Reh, Kim; Elliott, John; Arora, Nitin; Petropoulos, Anastassios E.

doi:10.1016/j.pss.2019.06.004

Cited by 68 publications

(66 citation statements)

References 26 publications

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“…These processes couple different vertical regions of the atmosphere, and must be understood to infer properties of the deeper atmosphere and cloud decks (see Figure 5). It is not known in detail how the energy inputs to the atmosphere interact to create the planetaryscale patterns seen on these ice giants (Hofstadter et al, 2017). Knowledge of net vertical energy fluxes would supply critical information to improve our understanding of atmospheric dynamics.…”

Section: Scientific Impetusmentioning

confidence: 99%

Scientific rationale for Uranus and Neptune in situ explorations

Mousis

Atkinson

Cavalié

et al. 2018

Planetary and Space Science

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The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H 2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a highpriority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes : i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission.

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Section: Scientific Impetusmentioning

confidence: 99%

Scientific rationale for Uranus and Neptune in situ explorations

Mousis

Atkinson

Cavalié

et al. 2018

Planetary and Space Science

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“…This is severely unconstrained-even by planetary science standards-and leaves both Uranus and Neptune's origin and the evolution of the outer solar system open to rampant speculation. This uncertainty is one of the major motivations for a new ice giant mission [27][28][29][30]. In this review, we take an alternative approach by considering if atmospheric observations can provide further insight into internal structure.…”

Section: Introductionmentioning

confidence: 99%

Neptune and Uranus: ice or rock giants?

Teanby

Irwin

Moses

et al. 2020

Phil. Trans. R. Soc. A.

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Existing observations of Uranus and Neptune’s fundamental physical properties can be fitted with a wide range of interior models. A key parameter in these models is the bulk rock:ice ratio and models broadly fall into ice-dominated (ice giant) and rock-dominated (rock giant) categories. Here we consider how observations of Neptune’s atmospheric temperature and composition (H 2 , He, D/H, CO, CH 4 , H 2 O and CS) can provide further constraints. The tropospheric CO profile in particular is highly diagnostic of interior ice content, but is also controversial, with deep values ranging from zero to 0.5 parts per million. Most existing CO profiles imply extreme O/H enrichments of >250 times solar composition, thus favouring an ice giant. However, such high O/H enrichment is not consistent with D/H observations for a fully mixed and equilibrated Neptune. CO and D/H measurements can be reconciled if there is incomplete interior mixing (ice giant) or if tropospheric CO has a solely external source and only exists in the upper troposphere (rock giant). An interior with more rock than ice is also more compatible with likely outer solar system ice sources. We primarily consider Neptune, but similar arguments apply to Uranus, which has comparable C/H and D/H enrichment, but no observed tropospheric CO. While both ice- and rock-dominated models are viable, we suggest a rock giant provides a more consistent match to available atmospheric observations. This article is part of a discussion meeting issue ‘Future exploration of ice giant systems’.

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“…This is likely more a reflection of particle physics laboratories which tend to incorporate older machines into the support infrastructure of the new generation which may not be possible with other types of LSRI. This horizon scanning process also seems to look much further into the future than current policy of 30 and ten years respectively (Baker, 2016;Burrows, 2017;ESFRI, 2018;Hofstadter et al, 2019). This potentially represents an opportunity for policymakers to capture these 'bottom-up' community practices by commissioning a 'generational survey' upon completing an LSRI.…”

Section: Discussionmentioning

confidence: 99%

“…Funders and policymakers may also wish to capture the 'bottom up' community assessments that occur once an LSRI has been completed. Current policy usually assesses community needs within a two-, five-, or ten-year timeframe (Baker, 2016;ESFRI, 2018;Hofstadter et al, 2019), whereas the community uses a timeframe as long as 30 years. It may therefore be desirable to introduce a new 'generational survey' upon completing an LSRI project to incorporate the community's very long-term needs into research strategy.…”

Section: Discussionmentioning

confidence: 99%

Tailoring Leadership to the Phase-Specific Needs of Large Scale Research Infrastructures

Eggleton

2020

SSRN Journal

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'Large Scale Research Infrastructures' (LSRIs), a subcategory of megaprojects which incorporate a characteristic of a high or 'super high' level of technological uncertainty, are often undertaken as cooperative projects with long lead times by one or more national governments. A lack of research into the effect of the LSRI project's lifecycle on the research organisation is apparent, particularly when scientists and engineers exercise freedom to organise the project directly. Two case studies used senior leadership selection as proxy for the LSRI project lifecycle using a contingency theory framework. These were the Tevatron (Fermi National Accelerator Laboratory, USA) and the Large Hadron Collider at the European Organisation for Nuclear Research (CERN). This LSRI lifecycle is mapped onto lifecycles used in theory and in policy. Previous research did not detect that these projects become institutionalised, so influencing the selection of new research organisation senior leadership according to its needs at that stage of its lifecycle. This represents something of a novelty as most contingency theory work is theoretical with few attempts to use it as a conceptual framework for empirical evidence. The findings indicate a second new understanding, that while the literature characterises a leadership style transition from democratic to authoritarian as the project progresses, LSRIs exhibit a reverse transformation, probably as a product of the characteristically high level of organisational technical competence. The construction of LSRIs maps better onto the traditional project lifecycle and the National Science Foundation's large facility lifecycle than onto other lifecycles. There is a policy opportunity to commission a 'generational survey' upon the completion of an LSRI, to understand the characteristics of the 'next big machine'. The author would like to thank the CERN Archives Service (Geneva, Switzerland) for granting access to restricted sections of the CERN Archives, and also the Fermilab History and Archives Project (Batavia, IL, USA) for access to the Fermilab Archives, and both for assisting with the creation of interviewee pools. This version of the paper benefitted from the advice and comments of the SPRU Working Papers Series (SWPS) Editors and Reviewers including Katherine Lovell. The original research could not have been possible without the advice and support of my PhD supervisors: Ben Martin, the late Puay Tang, and Martin Meyer. Thanks also to my PhD viva examiners, Josh Siepel and Andy Davies, for their valuable comments and advice. This research was supported by a Graduate Teaching Assistant (GTA) grant from the University of Sussex.

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Uranus and Neptune missions: A study in advance of the next Planetary Science Decadal Survey

Cited by 68 publications

References 26 publications

Scientific rationale for Uranus and Neptune in situ explorations

Scientific rationale for Uranus and Neptune in situ explorations

Neptune and Uranus: ice or rock giants?

Tailoring Leadership to the Phase-Specific Needs of Large Scale Research Infrastructures

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