User:Agmarusiak/lunar sandbox

Moonquakes
Several categories of moonquakes were recorded. Hundreds of deep moonquakes were recorded along with 28 shallow events. The deeper quakes are caused by tidal forces with the Earth and tended to occur in clusters. The shallow events have tectonic origins. Although more rare than deep events, the shallow events were larger, with body wave magnitudes > 5.5 and stress drops exceeding 100 MPa. Other sources of seismic activity included meteorite impacts and artificial signals from lunar modules.

Structure of the Lunar Interior
One key finding was an improved understanding of the structure of the deep lunar interior, including the existence of a solid inner-core and sharp core-mantle boundary and a partial-melt layer at the base of the lunar mantle. The solid core has a radius of about 240 km and is surrounded by a much thinner liquid outer core with a thickness of about 90 km

Future plans
Due to the success of the Apollo seismometers, several space agencies including NASA have expressed interest in funding future seismic missions to the moon. NASA's Planetary Science Decadal Survey for 2012-2022 lists a lunar geophysical network as a recommended New Frontiers mission. The mission would be tasked with enhancing the knowledge of the lunar interior using several identical landers distributed over the lunar surface. A network of arrays would be able to better constrain lunar seismicity, especially on the far side of the Moon. In early 2018, NASA a new program called the Development and Advancement of Lunar Instrumentation (DALI). The goal of DALI is to fund potential instruments so that they reach a technology readiness level of 6, meaning the instruments could be proposed for flight opportunities as early as 2023 and would not require significant technology development. DALI looks to fund instruments that would support the Science Mission Directorate's Planetary Science Division, including the desired lunar geophysical network. The due-date for proposals was in the Spring of 2018, and selected proposals were not announced as of of September 2018.