Lunar Laser Ranging Instrument (LLRI – ISRO)
The Lunar Laser Ranging Instrument determined the height of surface topography by sending pulses of infrared laser light towards the lunar surface and detecting the reflected portion of that light. It operated continuously, collecting 10 measurements per second on both the day and night sides of the Moon.
LLRI's altimetry, combined with imagery from the Terrain Mapping Camera, contributed to a three-dimensional atlas of the Moon and to studies of the lunar gravitational field.
The instrument was developed by the Laboratory for Electro-Optics Systems (LEOS) of ISRO, Bangalore, and was successfully activated on 16 November 2008.