Istituto di Fisica dello Spazio Interplanetario V. Iafolla, E. Fiorenza, C. Lefevre, S. Nozzoli, R. Peron, M. Persichini, A. Reale, F. Santoli Istituto di Fisica dello Spazio Interplanetario (IFSI/INAF), Roma, Italy ISA on the Moon: an instrument proposal for the ILN (International Lunar Network) ISA on the Moon: an instrument proposal for the ILN (International Lunar Network) EGU General Assembly 2009 Vienna, Austria, 19 – 24 April 2009

Istituto di Fisica dello Spazio Interplanetario Renewed interest for the Moon Nearest body outside Earth Solar System history Outpost for Solar System settlement Quiet place Fundamental physics Photo Apollo 11

Istituto di Fisica dello Spazio Interplanetario Lunar Laser Ranging Three retroreflectors arrays were carried on The Moon by Apollo missions and two by Soviet missions Probably the most important scientific contribution from Apollo missions! Selenodesy Lunar rotation General relativity

Istituto di Fisica dello Spazio Interplanetario Constraints on formation, evolution and present state of the Moon come from: Surface composition Magnetic field Gravitational field Selenoseismology Moon history Picture NASA Picture ESA

Istituto di Fisica dello Spazio Interplanetario ISA: the accelerometer ISA sensing element ISA pick-up

Istituto di Fisica dello Spazio Interplanetario ISA: the accelerometer

Istituto di Fisica dello Spazio Interplanetario ISA: the accelerometer Geostar Gradiometer GReAT BepiColombo

Istituto di Fisica dello Spazio Interplanetario The mission MAGIA MAGIAMissione Altimetrica Gravimetrica Geochimica lunAre MAGIA (Missione Altimetrica Gravimetrica Geochimica lunAre) is a Moon exploration mission proposal (funded by Agenzia Spaziale Italiana) Scientific objectives internal structure gravityfigureDetailed study of the internal structure of the Moon through its gravity and figure polar and subpolar regions morphologymineralogyStudy of the polar and subpolar regions in terms of their morphology and mineralogy lunar exosphere and radioactive environmentStudy of the lunar exosphere and radioactive environment gravitational redshiftImproved measure of the gravitational redshift measurements from a circumlunar platform position of the seleno- centerDetermination of the position of the seleno- center ISA contributio n

Istituto di Fisica dello Spazio Interplanetario ISA-S: the seismometer acts as a seismometer without any changes The accelerometer, placed on ground, is directly sensitive to seismic disturbances, and therefore acts as a seismometer without any changes The three sensing elements are arranged with their centers of mass along the same axis (the local vertical) tiltmeters gravimeter local vertical

Istituto di Fisica dello Spazio Interplanetario Solid tide of Earth Teleseismic (free oscillation of Earth) Seismic Noise Seismic measurements

Istituto di Fisica dello Spazio Interplanetario ParameterValueRemarks Measurement Accuracy10 -9 m/s 2 Accuracy required for the acceleration measurements ISA-S intrinsic random noise S 0 (f) = m/s 2 /Hz 1/2 Level of the total random noise in the ISA measurements process Frequency Range10 -5 – 1 Hz The max resolution is obtained inside the frequency band, but ISA-S can works quite well also at frequency out of the indicated band, increasing the bit rate and taking into account the mechanical transfer function Dynamic range10 6 Set by the acquisition system and converter Frequency readout interval1 s The required data rate is 1 sample/s for the three acceleration components and the three sensing temperatures Resonance frequency3.5 HzFrequency of the mechanical oscillator Quality factor Q10Quality factor of the oscillator Thermal stability x,y m/s 2 /°CISA-S thermal stability for the two tiltmetric components Thermal stability z m/s 2 /°CISA-S thermal stability for the gravimetric component Mass, total5.5 kgISA-S Total mass Dimension300 x 300 x 300 mm Electronic power dissipation 6 WISA-S Total power dissipation Data rate (nominal)15 kbit/s Capability of ISA-S/ Capability to recover the local vertical autonomously, in order to operate with two of its elements like tiltmeters and one like gravimeter ISA-S: the seismometer

Istituto di Fisica dello Spazio Interplanetario Requirements Science Goal Understand the current seismic state of the Moon, and determine the internal structure of the Moon. 2) Detection of new aggregate states of matter (e.g., strange quark nuggets) Network Requirement Multiple, simultaneously operating sites about the Moon are required to interpret seismic events 2) Multiple, simultaneously operating sites about the Moon are required to interpret seismic events. Science Rationale Seismic waves from lunar tectonic events can be used to determine the structure and composition of the crust, mantle and core. 2) The existence of strange quark nuggets is an important prediction which could also provide a candidate for Dark Matter. Measurement Requirements Measure lunar seismicity using broad-band seismometry at multiple, geographically dispersed, locations. 2) Measure lunar seismic events using broad-band seismometry at no fewer than 5 geographically dispersed locations. SeismometryNew fundamental physics ILN Core Instrument Working group

Istituto di Fisica dello Spazio Interplanetario Requirements Mission Requirements At least 4 sites simultaneously operating for 6 years. Inter-station timing accuracy: 5ms. Instrument attached to ground and vibrationally isolated from the spacecraft. 2) Detection of strange quark nuggets via epilinear seismic source identification requires at least 5 sites simultaneously operating for as many years as possible. Instrument Requirements Three axis Very Broad Band (VBB) seismometers with: Dynamic Range >24 bits; High Frequency Cutoff about 20 Hz. Sensitivity [ Hz] 10-11m/s [0.1-1 Hz] 2x 10-11m/s [1-20Hz] 10-9m/s. Thermal stability +/_ 5deg with need to thermal blanket ground within 1m if surface deployed. Altitude knowledge. Same. Mass, Power, Thermal Mass 6 kg: Power 2 W(peak), and 1 W(cont.), and 0.2 W (low power). May need additional power for instrument heating. Same.Data 100 Mbits per Earth day; no down link drivers. Same. ILN Core Instrument Working group SeismometryNew fundamental physics

Istituto di Fisica dello Spazio Interplanetario Site selection Barbara Cohen (SDT Co-chair), The International Lunar Network (ILN) and the US Anchor Nodes mission, Update to the LEAG/ILWEG/SRR, 10/30/08 Strong science desire for farside placement. Due to dependency upon communications satellite, SDT also identified suitable nearside sites. Node 1 must be placed antipodal to a moonquake epicenter known by the Apollo network: -5°S, 75°W is only nearside site Node 2 must be placed within ~30° of the same epicenter, so could also be nearside 2: 30°N, 75°E Nodes 3 and 4 should form a triangle with western node, preferably on the farside Site selection criteria will also involve desires from engineering for DV and comm

Istituto di Fisica dello Spazio Interplanetario Thermal issues More than 200 °C range during lunar day 10 4 m/s 2 for the most sensitive (gravimetric) component Need for an adequate thermal control system!

Istituto di Fisica dello Spazio Interplanetario Passive Seismic Experiment Passive Seismic Experiment on Apollo 16 T. A. Sullivan, Catalog of Apollo Experiment Operations, NASA Reference Publication 1317 ISA thermal control system performance Thermal issues