Mechanism of a gravimeter. A quartz spring (1) is housed in a partially evacuated chamber (2) which protects it from pressure changes. Levelling screws (3)keep the meter vertical and the movement of the spring is indicated by the position of the pointer (4) on a scale observed through an eyepiece (5).

A gravimeter is an instrument for detecting small variations in the gravitational field of Earth or other body, frequently used in mineral and oil prospecting, and in planetary exploration. Variations in the gravitational force on a mass suspended from a spring cause it to stretch or be deflected in a way which is then measured. See also accelerometer.


Vibrating String Accelerometer
The Vibrating String Accelerometer (VSA) at the heart of the Apollo Traverse Gravimeter Experiment.