Europa mission update: Beyond payload selection

Bayer, Todd; Buffington, Brent; Castet, Jean‐François; Jackson, Maddalena; Lee, Gene; Lewis, Kari; Kastner, Jason; Schimmels, Kathy; Kirby, Karen

doi:10.1109/aero.2017.7943832

Cited by 18 publications

(6 citation statements)

References 7 publications

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“…Future and planned space missions such as OSIRIS‐REx (Lauretta et al, ), Hayabusa‐2 (Kawaguchi et al, ), Psyche (Elkins‐Tanton et al, ; Lord et al, ), Lucy (Levison & Lucy Science Team, ), Europa Clipper (e.g., Bayer et al, ), and Jupiter Icy Moons Explorer (Grasset et al, ) would determine the shape and gravity fields of a wide range of new bodies. The results presented here are to be verified with the shape and gravity models from these future space missions.…”

Section: Discussionmentioning

confidence: 99%

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

2018

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When a spacecraft visits a new planetary body, it is useful to know the properties of its shape and gravity field. This knowledge helps predict the magnitude of the perturbations in the motion of the spacecraft due to nonsphericity of a body's gravity field as well as planning for an observational campaign. It has been known for the terrestrial planets that the power spectrum of the gravity field follows a power law, also known as the Kaula rule (Kaula, 1963, https://doi.org/10.1029Rapp, 1989 Rapp, , https://doi.org/10.1111 Rapp, /j.1365 Rapp, -246X.1989. A similar rule was derived for topography (Vening Meinesz, 1951). The goal of this study is to generalize the power law dependence of the gravity and topography spectra for solid surface solar system bodies across a wide range of body sizes. Traditionally, it is assumed that the gravity and topography power spectra of planets scale as g −2 , where g is the surface gravity. This gravity scaling also works for the minor bodies to first order. However, we find that a better fit can be achieved using a more general scaling based on the body's radius and mean density. We outline a procedure on how to use this general scaling for topography to provide an a priori estimate for the gravity power spectrum. We show that for irregularly shaped bodies the gravity power spectrum is no longer a power law even if their topography spectrum is a power law. Such a generalization would be useful for observation planning in the future space missions to the minor bodies for which little is known. Plain Language SummaryWe used the available models of shape and gravity field of the solar system bodies. We study how the amplitude of the mountains and valleys in gravity and topography depends on their size. Mountains on Mars are greater than on the Earth and yet larger on asteroid Vesta compared relative to the body's size. The same is true for gravity: Relative variations in gravity are larger on smaller bodies. We quantify this dependence and develop a method to predict the variations in gravity and topography depending on the body's size and density.

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Section: Discussionmentioning

confidence: 99%

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

2018

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“…Subsurface radar sounding of ocean world ice shells by the Europa Clipper REASON and JUICE RIME instruments might therefore find variations in thickness and electrical properties associated with fossil reservoirs. For example, the REASON very high frequency band will use 60 MHz signals to identify reflective contrasts (Bayer et al 2017) at scales relevant to the size of the reservoirs and resulting brine deposits described here.…”

Section: Ice Shell Characterization By Upcoming Missionsmentioning

confidence: 99%

Salt Distribution from Freezing Intrusions in Ice Shells on Ocean Worlds: Application to Europa

Naseem,

Neveu,

Howell

et al. 2023

Planet. Sci. J.

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Several icy moons and dwarf planets appear to have hosted subsurface liquid water. Liquid water intruding upwards into the icy outer shells of these worlds freezes, forming ice and (from ocean solutes) non-ice solids. Here, we model concentrated aqueous solutions below 273 K to simulate the compositional evolution of freezing spherical intrusions. Starting solutions are based on five previously reported compositional end members for Europa’s ocean. For moderate-pH end members dominated by chloride, sulfate, and/or carbonate, the solids formed include Ca-, Mg-, and Na-sulfates and -carbonates, as well as Na- and K-chlorides. For silica-rich, high-pH end members, abundant amorphous silica forms with, potentially, similarly abundant NaOH and KOH. We further develop a new numerical model to compute the spatial distribution of the formed solids and residual brine as freezing progresses. If non-ice solids settle to the bottom, their deposits tend to have stacked hourglass shapes, widening each time the crystallization temperature of a new solid is reached. We discuss the applicability of this model to vertical fractures and global freezing of a subsurface ocean. These results inform (i) how compositional heterogeneities may affect the thermophysical properties of ice shells, which in turn influence convective and cryovolcanic transport, (ii) the compatibility of brine pockets with physicochemical conditions suitable for microbial life, and (iii) possible measurements of compositional heterogeneities within ice shells by spacecraft such as NASA’s Europa Clipper and ESA’s JUICE missions. The methodology developed here is applicable to other ice-covered ocean worlds.

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“…al. [96] demonstrated that MTJs are even resilient to radiation that is 100× greater than what is observed on particularly harsh inter-planetary travel [11,156]. Therefore, MTJs represent leading candidates for space applications [39,67].…”

Section: Radiationmentioning

confidence: 99%

Energy-efficient and Reliable Inference in Nonvolatile Memory under Extreme Operating Conditions

Resch

Khatamifard

Chowdhury

et al. 2022

ACM Trans. Embed. Comput. Syst.

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Beyond edge devices can operate outside the reach of the power grid and without batteries. Such devices can be deployed in large numbers in regions which are difficult to access. Using machine learning, these devices can solve complex problems and relay valuable information back to a host. Many such devices deployed in low earth orbit can even be used as nano-satellites. Due to the harsh and unpredictable nature of the environment, these devices must be highly energy efficient, be capable of operating intermittently over a wide temperature range, and be tolerant of radiation. Here, we propose a non-volatile processing-in-memory (PIM) architecture which is extremely energy efficient, supports minimal overhead checkpointing for intermittent computing, can operate in a wide range of temperatures, and has a natural resilience to radiation.

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Europa mission update: Beyond payload selection

Cited by 18 publications

References 7 publications

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

Power Laws of Topography and Gravity Spectra of the Solar System Bodies

Salt Distribution from Freezing Intrusions in Ice Shells on Ocean Worlds: Application to Europa

Energy-efficient and Reliable Inference in Nonvolatile Memory under Extreme Operating Conditions

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