L2-SSM-SEIS ESSENTIAL ENVIRONMENTAL Level 2 · hardware

Seismometer Network

Broadband Seismometer Array Subsystem

Distributed network of broadband and short-period seismometers detecting moonquakes, meteorite impacts, and artificial vibrations across the Ark site.

Purpose

Provide comprehensive seismic monitoring of the Ark environment to characterize ground motion, detect potentially damaging seismic events, and supply data for structural response analysis.

Context

Lunar seismicity differs fundamentally from Earth: deep moonquakes originate at 700-1100 km depth from tidal stresses, shallow moonquakes are rare but powerful, thermal moonquakes occur at the terminator, and meteorite impacts produce seismic signals. This network must detect all types to protect the Ark.

Principles

▸Broadband seismometry covering 0.001-50 Hz frequency range for all moonquake types
▸Three-component sensing (vertical + two horizontal) at each station
▸Array configuration enabling source localization through triangulation
▸Ultra-low noise floor required due to absence of oceanic and atmospheric noise on Moon

Typical implementations

▸CNES/IPGP SEIS-type very broadband seismometers (InSight heritage)
▸Apollo Lunar Surface Experiment Package (ALSEP) passive seismic experiment legacy
▸Molecular electronic transfer (MET) seismometers for high sensitivity
▸MEMS accelerometers for strong-motion recording close to structure
▸Geophones for short-period, high-frequency detection

Lunar considerations

▸Extreme thermal cycling requires oven-controlled or deep-buried sensor installations
▸Lunar seismic Q factor is very high causing prolonged signal ringing (scattering in regolith)
▸No atmospheric noise floor enables detection of extremely small events
▸Vacuum environment eliminates convection-based thermal noise but complicates thermal management
▸Regolith coupling requires careful installation technique (burial or pier mounting)
▸200+ deep moonquake nests identified from Apollo data can inform monitoring strategy

Specifications

Functional

primary function	Detect and characterize all seismic events in the vicinity of the Lunar Ark
inputs	Ground motion (velocity and acceleration), Calibration signals from internal calibration coils, Timing signals from master clock
outputs	Continuous seismic waveform data (three components per station), Event detection triggers, Ground motion parameters (PGA, PGV, spectral acceleration)
frequency range hz	0.001-50
sensitivity m per s2	1e-10
dynamic range db	180
number of stations	8
sample rate hz	100
timing accuracy ms	1

Physical

mass kg	120
dimensions	Each station: 30cm diameter x 25cm height; array spans 500m radius
materials	Titanium housings, Fused silica suspension elements, Mu-metal magnetic shielding, Radiation-hardened electronics, Thermal insulation (MLI blankets)
installation depth m	1.0
burial in regolith	True
thermal stabilization	passive burial plus active oven control

Operational

power consumption w	40
thermal range c	-173, 127
lifetime years	100
mtbf hours	600000

Interfaces

Provides

→Data Processing & AnalysisContinuous seismic waveform dataessential
Three-component broadband seismic data from all stations at 100 sps
→Structural Health MonitoringGround motion input for structural responseessential
Free-field ground motion data for comparison with structural response measurements

Requires

←Power Generation SystemElectrical powercritical
40W continuous power distributed to 8 stations via buried cabling
←Data Processing & AnalysisData acquisition and timingessential
Digitization, timestamping, and data collection from sensor array