PARIS (CNES PR) — CNES and the Institut de physique du globe de Paris (Université Paris Cité/IPGP/CNRS) have been selected to integrate a seismometer on NASA’s next lunar mission. As part of the CLPS (Commercial Lunar Payload Services) program, NASA has just selected the Draper company to send the lander that will carry this instrument and land on the Moon in May 2025.
The FSS project (Farside Seismic Suite) aims to deposit an autonomous instrument allowing to carry out seismic measurements on the far side of the Moon. The FSS instrument was proposed by the JPL (Jet Propulsion Laboratory, USA) to NASA on the occasion of the PRISM (Payloads and Research Investigations on the Surface of the Moon) call for tenders of the CLPS (Commercial Lunar Payload Services) and it was selected in 2021.
The first seismometer on the Moon since the Apollo missions (1972-1977), this instrument will have to measure earthquakes on the surface of the Moon, measure seismic attenuation in the deep lunar mantle, determine the thickness of the crust and its stratification and measure lunar micro-seismic noise thought to be associated with meteorite micro-impacts.
While the lander’s mission will be 14 Earth days, FSS will operate autonomously for 4 months at a landing site located in the Schrödinger crater on the far side of the Moon, near the South Pole.
FSS is a 40 kg cube equipped with its own modules for energy management, telecommunications and thermal regulation. At the heart of FSS are placed two types of seismometers, one of which is a French supply, as shown below. In order to preserve the energy accumulated in the batteries of FSS thanks to its solar panels, the instrument will not transmit data during the lunar night. On the other hand, during the lunar day, it will dialogue with an orbiter as soon as it is in visibility of this one. It is this orbiter that will act as a relay between the ground stations and FSS.
CNES and IPGP (Université Paris Cité/IPGP/CNRS) participate in FSS with JPL and will deliver one of the sensors for the spare model of the SEIS instrument (InSight 2018 mission), in particular a VBB (Very Broad Band), developed by Sodern as part of the SEIS project. With the company EREMS, the IPGP was able to improve by a factor of 3 the sensitivity of the displacement sensor of the VBB, which will thus be able to detect a displacement of the ground of the order of a picometer (10-12 m) at a period of one second. . With the support of the Astroparticle and Cosmology laboratory (CNRS/Université Paris Cité) and ISAE-Supaéro, they will also participate in the development and integration of a VBB accommodation box, called SeismoBox, funded by JPL.
Finally, the French team will play an important role in operations. JPL will receive telemetry and send all commands to FSS. CNES will analyze the data and prepare the orders for the two seismometers on board FSS (the VBB and the SPs), in the same way as it does for SEIS on InSight. The IPGP will be responsible for the scientific exploitation of the VBB and the analysis of lunar seismicity, and its data center will document and disseminate the data to the scientific community.
Gabriel Pont, FSS project manager at CNES and Philippe Lognonné, scientific manager of the seismometer at IPGP have already collaborated on the SEIS/InSight mission. With their team, they are proud to be on this lunar mission. “This is once again an opportunity, through collaboration with JPL, one of our privileged partners, to show French excellence in the field of scientific instrumentation, and in particular seismology. The use of spare equipment from the SEIS program makes it possible to carry out this collaboration while optimizing budgets,” Gabriel Pont likes to say. “With FSS and the return of seismology to the Moon, we will better understand the deep structure of our satellite and how it has evolved since its formation just over 4 years ago.
