Scientific exploration of space is dramatically changing as a result of increasing participation by commercial and private space industries. Missions utilizing SmallSats and CubeSats for exploration are proliferating, and crewed missions to the Moon and Mars are anticipated in the near future. In 2020, NASA will release revisions to policy documents governing planetary protection to reflect the new multi-stakeholder community. These policy documents establish the foundation for practices to control forward contamination during exploration of extraterrestrial solar system bodies and to prevent backward contamination of the Earth/Moon system when extraterrestrial samples are returned to Earth for study. This paper will inform contamination control and planetary protection practitioners about these policy changes, which will clarify planetary protection standards and streamline implementation and verification processes throughout mission life cycles.
The Stratospheric Aerosol and Gas Experiment III (SAGE III) is an external payload on the International Space Station (ISS) that measures vertical profiles 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 utilizing the method of occultation. Because of the contamination sensitivity [particularly to silicate contamination] of the payload, a suite of eight Thermoelectric Quartz Crystal Microbalances (TQCMs) were included to monitor the operating environment. During the first year of operation, the SAGE III/ISS TQCMs were instrumental in detecting several periods of relatively high contamination and identifying the sources. A transparent window made of quartz crystal covers the instrument assembly's aperture. The contamination window may open during science acquisition under nominal operating conditions. However, if the contamination sensors measure mass adsorption rates significantly elevated above the background level, the window may be commanded to remain closed during science to protect the contamination sensitive scan mirror and telescope. An analysis of the spectral transmission through the window for the wavelength range of 290 nm to 1550 nm has been conducted to determine any possible degradation of the window transmission and potential effects on science data collected to date, and establish a baseline for future analysis.
Contamination control engineers provide critical plans to monitor, mitigate, and reduce the impact of molecular and particulate contamination on spacecraft systems. Witness monitoring programs are dependable methods that utilize strategically placed witness samples on space flight hardware to monitor particulate and molecular contaminants during the assembly, integration, and test (AI&T) phases. Traditionally, optical characterization of these witness plates is the tool to determine the presence of molecular films on space flight hardware in the AI&T environment. Once a visual inspection or optical measurement identifies the presence of a contaminant, analysts collect tape lifts and wipe samples from the witness plate for analysis in an analytical lab with a potential contaminant identified within 24 hours. To speed up this process and reduce the impact to project schedule and cost the use of a non-invasive and in situ method for optical witness plate program with portable Raman spectroscopy to detect molecular contamination on spacecraft was explored.
KEYWORDS: Raman spectroscopy, Contamination, Space operations, Spectrometers, Chemical analysis, Luminescence, Silicon, Aluminum, System integration, Polymers
Contamination control engineers are constantly challenged by time-consuming processes during the system assembly, integration and test phase for spacecraft. Hardware components, subassemblies, and integrated systems must be visually inspected throughout the process, and any signs of contamination found are usually analyzed by processes that can take days to complete. Portable Raman spectroscopy is a promising technology for spacecraft integration, where it may be possible to probe hardware or witness surfaces and identify contaminants throughout the assembly, integration and test phase. This study explored detection of five common spacecraft contaminants with portable Raman spectroscopy: silicone, hydrocarbon, fluorocarbon, ester, and a glycol polymer. It was found portable Raman spectroscopy can provide a quick-look capability which can be followed by more detailed contaminant quantification analysis techniques. In this way, portable Raman spectroscopy can aid contamination control engineers in providing actionable information to projects earlier in the assembly, integration and test phase of the project lifecycle.
Conference Committee Involvement (2)
Space Systems Contamination: Prediction, Control, and Performance 2022
23 August 2022 | San Diego, California, United States
Systems Contamination: Prediction, Control, and Performance 2020
24 August 2020 | Online Only, California, United States
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