The Seismometer to Investigate Ice and Ocean Structure
When
Where
Daniella DellaGiustina
Lead Scientist, OSIRIS-REx Image Processing Senior Staff Scientist
Lunar and Planetary Laboratory
A global sub-surface ocean at Europa is likely and provides the first of three key requirements for life – liquid water. The possibility of life forming in this sub-surface ocean relies in part on transfer of oxidants from the irradiated ice surface to the sheltered ocean below. This transfer depends on the thickness of the ice shell: a thick, stagnant crust would likely halt the development of indigenous life. The determination of Europa’s crustal thickness is an important exobiological issue and one of the controversial topics of planetary science. Seismology can determine Europa’s interior structure to directly implicate habitability. Indeed, the 2016 Europa Lander Science Definition Team Study [JPL D-97667, 2016] recognized the utility of seismic measurements and their unique availability on a landed-mission. Accordingly, the Geophysical Sounding System (GSS) is a threshold payload element for the upcoming Europa Lander. The University of Arizona's Seismometer to Investigate Ice and Ocean Structure (SIIOS) program is developing an instrument capable of achieving the GSS instrument objectives outlined in the 2016 SDT Study. SIIOS is a broadband optical seismic sensor based on an existing Silicon Audio Inc. device, which is being redesigned for deployment on a landed mission to Europa. Here, we present the results of an analog study conducted with the SIIOS instrument on a subglacial lake beneath the Greenland ice sheet.