Europa Clipper planetary protection probabilistic risk assessment summary

McCoy, Kelli; DiNicola, Michael; Everline, Chester J.; Burgoyne, Hayden; Reinholtz, Kirk; Clement, Brian

doi:10.1016/j.pss.2020.105139

Cited by 13 publications

(16 citation statements)

References 14 publications

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“…The number of grid elements of the ocean world's surface with a microorganism delivered by the spacecraft can be conservatively bounded through impact and debris modeling (McCoy et al 2020). The speed at which the spacecraft contacts the ocean world, as well as the shallowness of the contact angle relative to the surface (sometimes referred to in terms of "obliquity"), and ice properties (most notably, ice porosity) have been shown to be important drivers in these analyses (McCoy et al 2020). The speed and angle at which the spacecraft contacts the ocean world, as well as location and time of the spacecraft's initial contact, are typically provided by way of Monte Carlo simulation of the spacecraft trajectory and orbital dynamics (e.g., Arrieta et al 2016).…”

Section: Ormentioning

confidence: 99%

“…The event that one or more microorganisms launched with the spacecraft survive to come in contact with the subsurface is denoted by S. Biological analysis of microorganism mortality, potentially lethal environmental conditions to which the spacecraft is exposed, and microbial abundance inform the probability calculation in this part of the model (McCoy et al 2020).…”

Section: Ormentioning

confidence: 99%

“…Here we elaborate on the geologic basis for the resurfacing model summarized in McCoy et al (2020) but also make mathematically rigorous the modeling of the resurfacing rate and its connection to the observed average surface age of an ocean world. A Poisson process model is developed to assess the probability of resurfacing in a contaminated region within timescales relevant to planetary protection, treating the resurfacing process as discrete spatial events that occur over time, informed by a range of resurfacing rates based on the average observed age of the surface.…”

Section: Introductionmentioning

confidence: 99%

“…InMcCoy et al (2020), 20 Myr is used as the worst-case value of the surface age, with 65 Myr used as the current best estimate in order to capture the uncertainty in the surface age, as agreed to by the NASA Office of Planetary Protection. Further discussion can be found in Section 3.3.…”

mentioning

confidence: 99%

“…SeeMcCoy et al (2020) for further discussion as to how Europa Clipper demonstrated compliance with planetary protection requirements.…”

mentioning

confidence: 99%

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Resurfacing: An Approach to Planetary Protection for Geologically Active Ocean Worlds

DiNicola¹,

Howell²,

McCoy³

et al. 2022

Planet. Sci. J.

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The putative and potential ocean worlds of our solar system span the asteroid belt to the Kuiper Belt, containing within their icy shells past or present global saltwater oceans. Among these worlds, those bearing signs of present-day geologic activity are key targets in the search for past or extant life in the solar system. As the icy surfaces of these bodies are modified by geologic processes, landforms are erased and replaced through what is called “resurfacing.” To avoid contaminating sites for robotic spacecraft exploration, planetary protection requirements obligate missions to these ocean worlds to demonstrate a less than 10−4 probability of introducing a viable terrestrial microorganism into a liquid water body. To constrain the probability of subsurface contamination, we investigate the interaction with geologic resurfacing on an active ocean world. Through the example of Europa, we show how the surface age can be used to constrain the resurfacing rate, a critical parameter to estimate the probability that nonsterile spacecraft material present on the surface is geologically incorporated into the subsurface, and extend this example to mission scenarios at Ganymede and Enceladus. This approach was critical to demonstrating compliance with planetary protection requirements for the Europa Clipper mission, reducing its probability of contamination by two to five orders of magnitude. We also show how a Europa lander mission might be brought close to complying with planetary protection requirements, that a Ganymede impactor could easily comply, and that the situation of Enceladus, while more complex, can greatly benefit from this approach.

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Section: Ormentioning

confidence: 99%

Section: Ormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

“…SeeMcCoy et al (2020) for further discussion as to how Europa Clipper demonstrated compliance with planetary protection requirements.…”

mentioning

confidence: 99%

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Resurfacing: An Approach to Planetary Protection for Geologically Active Ocean Worlds

DiNicola¹,

Howell²,

McCoy³

et al. 2022

Planet. Sci. J.

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Ocean Worlds: Interior Processes and Physical Environments

Howell

Leonard

2023

Handbook of Space Resources

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Science Overview of the Europa Clipper Mission

Pappalardo,

Buratti,

Korth

et al. 2024

Space Sci Rev

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The goal of NASA’s Europa Clipper mission is to assess the habitability of Jupiter’s moon Europa. After entering Jupiter orbit in 2030, the flight system will collect science data while flying past Europa 49 times at typical closest approach distances of 25–100 km. The mission’s objectives are to investigate Europa’s interior (ice shell and ocean), composition, and geology; the mission will also search for and characterize any current activity including possible plumes. The science objectives will be accomplished with a payload consisting of remote sensing and in-situ instruments. Remote sensing investigations cover the ultraviolet, visible, near infrared, and thermal infrared wavelength ranges of the electromagnetic spectrum, as well as an ice-penetrating radar. In-situ investigations measure the magnetic field, dust grains, neutral gas, and plasma surrounding Europa. Gravity science will be achieved using the telecommunication system, and a radiation monitoring engineering subsystem will provide complementary science data. The flight system is designed to enable all science instruments to operate and gather data simultaneously. Mission planning and operations are guided by scientific requirements and observation strategies, while appropriate updates to the plan will be made tactically as the instruments and Europa are characterized and discoveries emerge. Following collection and validation, all science data will be archived in NASA’s Planetary Data System. Communication, data sharing, and publication policies promote visibility, collaboration, and mutual interdependence across the full Europa Clipper science team, to best achieve the interdisciplinary science necessary to understand Europa.

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Europa Clipper planetary protection probabilistic risk assessment summary

Cited by 13 publications

References 14 publications

Resurfacing: An Approach to Planetary Protection for Geologically Active Ocean Worlds

Resurfacing: An Approach to Planetary Protection for Geologically Active Ocean Worlds

Ocean Worlds: Interior Processes and Physical Environments

Science Overview of the Europa Clipper Mission

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