ocr: The Passive Seismic Experiment uses extremely sensitive seismometers to m ure lunar surface vibrations, free OSC tions, and tidal variations in surface Three long-period seismometers are mo ed orthogonally to measure wave mot with periods between V and 250 seco while the short-period seismometer m - - - - . - ho ures and vertical 20 motions seconds. with The periods electronics betv A housed in the ALSEP central station. thermal shroud isolates the sensor ar patch of ground 5 feet in diameter the temperature extremes of the lunar and night. Lunar Surface Magnefometers, operating at three ALSEP ...
