![]() ![]() ![]() If this likelihood is less than 10 –4 over a period of 10 3 years, then no bio-load reduction measures are required for planetary protectionīeyond clean-room assembly. If a lander is employed, the likelihood of the spacecraft interacting with a habitable region must be evaluated, and for all missions the probability of the lander crashing or otherwise interacting with a region where surface-subsurface transport is possible must be assessed. Consideration must be given to whether the mission employs a lander and/or an orbiter and whether a flyby attempt will be made of the given planetary body. The right-hand portion of Figure C.1 considers the nature of the mission itself (e.g., flyby, orbiter, lander) as relevant to determining planetary protection requirements for missions to potentially habitable planetary bodies. If the planetary body does possess these four essential attributes for habitability by terrestrial life, or if this information remains undetermined at the time of the mission, then the planetary body is deemed to be potentially habitable. If the planetary body does not possess one or more of these attributes, then it is judged as uninhabitable by terrestrial life and, although assembly of spacecraft intended for these bodies should be performed in a clean room, no bioload reduction is required for planetary protection. Four criteria are used to judge the habitability of the planetary body and specifically question whether the planetary body is known to possess liquid water, the key elements considered essential for terrestrial life, environments known to be compatible with known extreme conditions of terrestrial life, and accessible sources of chemical energy. The left-hand portion of Figure C.1 represents the decision of whether the planetary body of interest should be considered to be potentially habitable. This bimodal determination process (that is, the determination of the fragility of the process, design, target) and the determination of the potential for damage initiation are consistent with the general process of risk determination used across a variety of applications. The event sequence diagram presented in Figure C.1 is included to provide mission planners with the functional equivalent of the decision-making framework in Chapter 2, but in a more familiar format.įigure C.1 indicates the process to be applied for the two determinations necessary, the first of which is related to potential habitability of the icy body target (that is, its “fragility” against bio-propagation), and the second related to the type of mission proposed so as to address the potential for “initiating” a bio-contamination of a potentially habitable icy body. Indeed, engineers tend to visualize decision networks as event sequence diagrams. The committee’s preferred depiction (see Figure 2.2) may not be the one most familiar to all relevant scientific and technical communities. The decision-making framework can be visualized in a number of different ways. The binary decision-making framework outlined in Chapter 2 provides an alternative to probabilistic estimates of contamination constrained by the uncertain and/or unknowable factors included in the Coleman-Sagan equation. You can right click on a diagram to save it as SVG, PNG or JPG files to your local disk.Īlso, you can right click on a diagram to copy it in your clipboard.Event Sequence Diagram for the Determination of Planetary Protection Measures for Missions to Icy Bodies :root %% in the first line of mermaid diagram to config mermaid details like below: For example, add following CSS in Custom CSS, and you will get: You could change CSS variable -sequence-theme to set theme for sequence diagrams, supported value are simple (default) and hand. This feature uses js-sequence, which turns the following code block into a rendered diagram: ```sequenceįor more details, please see this syntax explanation. Therefore, we still recommend you to insert an image of these diagrams instead of write them in Markdown directly. Besides, you should also notice that diagrams is not supported by standard Markdown, CommonMark or GFM. ![]() When exporting as HTML, PDF, epub, docx, those rendered diagrams will also be included, but diagrams features are not supported when exporting markdown into other file formats in current version. Typora supports some Markdown extensions for diagrams, to use this feature, first please enable Diagrams in Preferences Panel → Markdown section. ![]()
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