NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

Apollo 15 Laser Altimeter

NSSDC ID: 1971-063A-05
Mission Name: Apollo 15 Command and Service Module (CSM)
Principal Investigator: Dr. William M. Kaula


The laser altimeter experiment obtained data on the altitude of the Command Service Module (CSM) above the lunar surface. These data, acquired with a 1-m resolution, were used to support mapping and panoramic camera photography, to provide altitude data for other orbital experiments, and to relate lunar topographical features for a better definition of lunar shape. The experiment measured slant range to the lunar surface (plus or minus 2 m). The range was measured parallel to the optical axis of the terrain camera. The laser altimeter was hard-mounted and aligned with the mapping camera subsystem mounted on the top shelf in the CSM scientific experiment module (SIM), sharing a SIM shelf-mounted optics protective cover with the mapping camera. The altimeter and camera system were deployed on a rail-type mechanism. The altimeter could operate in either of two modes. When the mapping camera was operated, the altimeter automatically emitted a laser pulse to correspond to a midframe ranging for each frame of film exposed by the metric camera. The altimeter also operated in a decoupled (from the metric camera) mode that allowed for independent ranging measurements (one every 20 sec) when the metric camera was not operating. Command module controls were provided to enable the crewman to activate or deactivate the altimeter. The altimeter operated normally until revolution 24, at which time it started to fail, became progressively worse, and failed completely by revolution 38.


Name Role Original Affiliation E-mail
Dr. William M. Kaula Principal Investigator University of California, Los Angeles  


  • Planetary Science: Geology and Geophysics
Questions or comments about this experiment can be directed to: Dr. David R. Williams.

Apollo Laser Altimeters

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