Preventing Premature Death in the M&S Lifecycle: Lessons Learned from Resurrection and Modernization of a Space System Contamination Model

Models and simulations (M&S) are often developed to meet specific needs and unique requirements for a particular situation. Once the M&S is implemented for a specific case and questions are answered, the M&S may go dormant until a similar need arises again at a later time, perhaps months to years later. Possible modification of the M&S may be required, and issues may arise if the M&S is not well documented, captured, or available. This can severely limit the useful life of the M&S and hinder future development or enhancements. This situation occurred with an M&S tool that had been developed to determine the impact to space system performance due to the presence of molecular contaminant films accumulating on key spacecraft surfaces. The challenges and issues encountered when resurrecting, executing, and modernizing the tool will be presented as a case study. To stay ahead of tomorrows challenges, resources to create M&S tools must be utilized efficiently. Lessons learned from this case study will aid M&S developers and users in planning for proper maintenance, transfer, and capture of key M&S tools and knowledge to avoid increased cost, increased development time, and wasted resources for projects relying on M&S

Modular Open System Architecture for Reducing Contamination Risk in the Space and Missile Defense Supply Chain

To combat contamination of physical assets and provide reliable data to decision makers in the space and missile defense community, a modular open system architecture for creation of contamination models and standards is proposed. Predictive tools for quantifying the effects of contamination can be calibrated from NASA data of long-term orbiting assets. This data can then be extrapolated to missile defense predictive models. By utilizing a modular open system architecture, sensitive data can be de-coupled and protected while benefitting from open source data of calibrated models. This system architecture will include modules that will allow the designer to trade the effects of baseline performance against the lifecycle degradation due to contamination while modeling the lifecycle costs of alternative designs. In this way, each member of the supply chain becomes an informed and active participant in managing contamination risk early in the system lifecycle

Analysis of Observed Contamination Through SAGE III's First Year on Orbit

SAGE III is a payload on the International Space Station that conducts measurements of ozone and other atmospheric constituents through the use of a moderate resolution spectrometer with an operating wavelength range of 290 nm to 1550 nm. Because of the optically sensitive nature of the payload, a suite of eight Thermoelectric Quartz Crystal Microbalances (TQCMs) were included to monitor the operating environment. During the rst year of operation, the SAGE III TQCMs were instrumental in detecting several periods of higher contamination and localizing their sources. A clear window made from quartz crystal covers the instrument assembly's aperture. Under nominal operating conditions, this window is only open during science gathering activities. However, if the rates of contamination accumulation are detected to be above the background rate, the window will be kept closed during science gathering to protect the optically sensitive instrument mirror. An analysis of the signal transmissions through the window for the wavelengths of 290 nm to 1550 nm has been conducted to determine any possible degradation of the window and potential in uence on science data collected to date, and established a baseline for future analysis

Methodology to Evaluate Proposed Leading Indicators of Space System Performance Degradation Due to Contamination

Leading indicators can be utilized to monitor a system and detect if a risk is present or increasing over time during key development phases such as integration and test. However, no leading indicator is perfect, and each contains inherent holes that can miss signals of risk. While the Swiss cheese model is a well-known framework for conceptualizing the propagation of risks through holes in system defenses, research is lacking on characterizing these holes. There are many choices for leading indicators, and to select an appropriate indicator for a system, engineering managers need to know how well the indicator will detect a signal of risk and what it can miss. A methodology was developed to quantify holes in proposed leading indicator methods and determine the impact to system performance if the methods miss detecting the risk. The methodology was executed through a case study that empirically evaluated two different techniques for detecting and monitoring molecular contamination risk to space system hardware performance during systems integration: visual inspections and portable Raman spectroscopy. Performance model results showed the impact the presence of a contaminant film had on space system surfaces, and how each indicator method missing the detection of a film could impact the system. Results from the methodology provide an understanding of the limitations in the risk detection and monitoring techniques of leading indicators to aid engineering managers in effectively selecting, deploying, and improving these techniques

Blind to Chemistry: Molecular Contaminant Films We Could Be Missing During Visual Inspections and the Potential Impact to System Performance

Throughout the assembly, integration and test process, molecular contamination levels of space mission hardware are monitored to meet system performance requirements. Qualitatively, reflective surfaces and witness mirrors are continuously inspected for the visible presence of molecular contaminant films. Quantitatively, periodic reflectance measurements of witness mirrors indicate changes of mirror reflectivity over time due to the accumulation of molecular contaminant films. However, both methods only consider the presence of a contaminant film and not the molecular composition. Additionally, there is a risk that hardware may appear to be visibly clean even with a molecular contaminant film present on critical surfaces. To address these issues, experiments were performed to quantify the maximum molecular contaminant film that could be missed in visual inspections on witness mirrors with five different contaminants present. The corresponding changes in mirror reflectivity were modeled using the program STACK to determine the impact to space mission hardware performance. The results of this study not only show the criticality in considering the chemical make-up of molecular contaminant films on system performance, but also the need to recognize and understand the limitations of traditional visual inspection techniques on detecting molecular contaminant films

A New Era For Planetary Protection: The Probabilistic Approach

The primary aims of planetary protection are to ensure that: 1) scientific investigations of possible extra-terrestrial life forms, precursors, and remnants are not jeopardised during planetary space missions; 2) Earth is protected from the potential hazard posed by extra-terrestrial matter carried by spacecraft returning from an interplanetary mission. The concept of planetary protection has received increased attention over recent years due to the emergence of new spacefaring countries and the growing involvement of commercial actors. The international standards for planetary protection have been developed through consultation with the scientific community and the space agencies by the Committee on Space Research's Panel on Planetary Protection, which provides guidance for compliance with the Outer Space Treaty of 1967. To date, there are five categories of requirements, which are defined based on the mission's target, type, and scientific rationale. The categories outline the recommended measures to be applied to a mission. As the mission target increases in relevance to habitability and/or the origins of life, the stringency in hardware cleanliness requirements increases. Initial guidelines were guided by a probabilistic approach. This approach uses mathematical models to calculate the probability of the initial microbial contamination from a spacecraft contaminating a target body. Post-Viking, bioburden limits/ spore counts were introduced to the policy for target bodies like Mars, as it was concluded that Mars was less hospitable than initially believed. Yet, the probabilistic approach is still applied to Category III and IV (e.g., Europa Clipper) and Category V (e.g., Mars sample return) missions. This approach could benefit more complex missions where there is a need for a more advanced approach to planetary protection. For this to be reliable, further scientific knowledge is required, e.g., our understanding of cleanroom contaminants and the biocidal impact of the mission environment, and the mathematical models need to be constrained. Ongoing research by space agencies and the scientific community is working towards addressing these knowledge gaps. The COSPAR Panel on Planetary Protection will continue to review this approach as a plausible alternative to bioburden limits to enable the next generation of missions

The COSPAR Planetary Protection Policy for robotic missions to Mars: a review of current scientific knowledge and future perspectives

Planetary protection guidance for martian exploration has become a notable point of discussion over the last decade. This is due to increased scientific interest in the habitability of the red planet with updated techniques, missions becoming more attainable by smaller space agencies, and both the private sector and governments engaging in activities to facilitate commercial opportunities and human-crewed missions. The international standards for planetary protection have been developed through consultation with the scientific community and the space agencies by the Committee on Space Research's (COSPAR) Panel on Planetary Protection, which provides guidance for compliance with the Outer Space Treaty of 1967. In 2021, the Panel evaluated recent scientific data and literature regarding the planetary protection requirements for Mars and the implications of this on the guidelines. In this paper, we discuss the COSPAR Planetary Protection Policy for Mars, review the new scientific findings and discuss the next steps required to enable the next generation of robotic missions to Mars

The COSPAR Planetary Protection Requirements for Space Missions to Mars

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