Mapping the Moon: Simulating LOLA in the Classroom Introduction to LIDAR Mapping with LOLA. National Aeronautics and Space Administration

National Aeronautics and Space Administration 2 What is a satellite? Is it just a spacecraft? What do all satellites have in common? What do all those instruments do? And what kind of data is collected? They all have to do what?

National Aeronautics and Space Administration 3 Examples of measurement quantities? Distance Volume Time Velocity/speed

National Aeronautics and Space Administration 4 How are they all related? RADAR (Radio Detection and Ranging) i.e. Our friendly neighborhood policeperson SONAR (Sound Navigation and Ranging) i.e. Bathymetry of ocean floor LIDAR (Light Detection and Ranging) i.e. LOLA (Lunar Orbiter Laser Altimeter)

National Aeronautics and Space Administration 5 How does LOLA work? Laser pulses bounce off the surface. The time taken by the light to travel to the surface and back is measured. LOLA is capable of timing pulses with a precision of 0.6 nanoseconds, corresponding to a distance error of no more than 10 cm.

National Aeronautics and Space Administration 6 How do we “see” the topography? Signals that LOLA receives will be transferred to create a topographic map. But how is that actually constructed? One swath equals one cross-sectional slice of the surface. Multiple parallel scans can yield a contour representation

National Aeronautics and Space Administration 7 ABCDE ■ ■ ■

National Aeronautics and Space Administration 8 For each “satellite orbit” the motion detector is moved once across the surface The frame is then moved 5 cm, and the process is repeated until the entire surface has been scanned If Lunar Land is 150 cm x 150 cm, how many scans will be required to complete the map? If the “orbit” lasts for 15 seconds, what should the sampling rate be to collect 30 data points per orbit? Mapping with the Ultra-Sound Motion detector

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