Accelerometer Triad
MEMS + Quartz Accelerometer Triad
The MEMS and quartz accelerometer triad is a three-axis instrument that measures specific force for lunar inertial navigation and seismic monitoring. Weighing 1 kilogram and drawing 3 watts, the unit pairs primary microelectromechanical proof masses with high-precision quartz pendulums to achieve a bias stability below 10 micro-g. Operating in the unshielded lunar radiation environment requires radiation-tolerant application-specific integrated circuits to sustain a 25-year operational lifetime. Calibrated against the Moon’s gravity reference, the instrument maintains the sensitivity necessary to detect moonquakes while providing continuous reference data for surface navigation.
Triad of MEMS + quartz pendulum accelerometers measuring specific force for inertial navigation and seismic monitoring.
Purpose
Triad of MEMS + quartz pendulum accelerometers measuring specific force for inertial navigation and seismic monitoring.
Context
Child of L2-NAV-IMU within the Lunar Ark system
Principles
- ▸MEMS accelerometers for primary inertial
- ▸Quartz pendulum for high-precision backup
- ▸Bias stability <10 ug
- ▸Calibrated against lunar gravity reference
- ▸Doubles as seismic sensor (couples to L1-SSM)
Typical implementations
- ▸Honeywell QA-2000 quartz accelerometer (heritage)
- ▸Sercel AC-2 accelerometer
- ▸Analog Devices MEMS accelerometers
- ▸Apollo Lunar Surface Experiments seismometer
Lunar considerations
- ▸Long-life MEMS with periodic calibration
- ▸Sensitive enough to detect moonquakes (Apollo legacy)
- ▸Rad-tolerant ASIC electronics
Specifications
Functional
| primary function | Triad of MEMS + quartz pendulum accelerometers measuring specific force for inertial navigation and seismic monitoring. |
| bias stability ug | 10 |
| axes | 3 |
Physical
| mass kg | 1 |
| materials | MEMS proof masses, Quartz pendulums, Rad-hard ASIC |
| vacuum compatibility | True |
Operational
| power consumption w | 3 |
| thermal range c | -40, 70 |
| lifetime years | 25 |
| mtbf hours | 200000 |
Interfaces
Provides
- Specific force triad
- Seismic sensor signal
Requires
- Sensor electronics (~3 W)
Cite this entry
Lunar Ark Codex. "Accelerometer Triad" (L3-NAV-IMU-ACCEL). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-NAV-IMU-ACCEL
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.