Planetary Protection Assessment of Radioisotope Thermoelectric Generator (RTG)-Powered Landed Missions to Ocean Worlds: Application to Enceladus

被引：4

作者：

Neveu, Marc ^{[1
,2
]}

Coker, Robert F. ^{[3
]}

Lorenz, Ralph D. ^{[3
]}

MacKenzie, Shannon M. ^{[3
]}

Lunine, Jonathan, I ^{[4
]}

Davila, Alfonso F. ^{[5
]}

机构：

[1] Univ Maryland, Dept Astron, 4296 Stadium Dr, College Pk, MD 20742 USA

[2] NASA, Goddard Space Flight Ctr, Planetary Environm Lab, Greenbelt, MD USA

[3] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA

[4] Cornell Univ, Dept Astron, Ithaca, NY 14853 USA

[5] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA

来源：

ASTROBIOLOGY | 2022年 / 22卷 / 09期

关键词：

Planetary protection; Radioisotope thermoelectric generator; Enceladus; Ocean worlds; THERMAL-CONDUCTIVITY; OPTICAL NAVIGATION; SOLAR-SYSTEM; ICE; PLUME; WATER; HEAT; SUBSURFACE; EVOLUTION; ORIGIN;

D O I：

10.1089/ast.2020.2432

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Landed missions to icy worlds with a subsurface liquid water ocean must meet planetary protection requirements and ensure a sufficiently small likelihood of any microorganism-bearing part of the landed element reaching the ocean. A higher bound on this likelihood is set by the potential for radioisotope thermoelectric generator (RTG) power sources, the hottest possible landed element, to melt through the ice shell and reach the ocean. In this study, we quantify this potential as a function of three key parameters: surface temperature, ice shell thickness (i.e., heat flux through the shell), and thickness of a porous (insulating) snow or regolith cover. Although the model we describe can be applied to any ocean world, we present results in the context of a landed mission concept to the south polar terrain of Saturn's moon Enceladus. In this particular context, we discuss planetary protection considerations for landing site selection. The likelihood of forward microbial contamination of Enceladus' ocean by an RTG-powered landed mission can be made sufficiently low to not undermine compliance with the planetary protection policy.

引用

页码：1047 / 1060

页数：14