A planetary protection engineer at NASA's Jet Propulsion Laboratory prepares samples for analysis on March 20, 2024. The samples, swabbed from the surfaces of the agency's Europa Clipper spacecraft during its construction, were collected to help monitor the mission's adherence to strict standards for biological cleanliness. Created in keeping with the international 1967 Outer Space Treaty, the mission's planetary protection protocols are designed to minimize the chance that microbes brought from Earth could compromise future scientific investigations at its target destination: Jupiter's icy moon Europa. Europa Clipper's three main science objectives are to determine the thickness of the moon's icy shell and its interactions with the ocean below, to investigate its composition, and to characterize its geology. The mission's detailed exploration of Europa will help scientists better understand the astrobiological potential for habitable worlds beyond our planet. https://photojournal.jpl.nasa.gov/catalog/PIA26441