The Near Laser Rangefinder (NLR) was a laser altimeter that measured the distance from the 
 spacecraft to the asteroid surface by sending out a short burst of laser light and then 
 recording the time required for the signal to return from the asteroid. It used a                     
 chromium-doped neodymium/yttrium-aluminum-garnet (Cr-Nd-YAG) solid-state laser and a compact 
 reflecting telescope. It sent a small portion of each emitted laser pulse through an optical        
 fiber of known length and into the receiver, providing a continuous in-flight calibration of 
 the timing circuit.  The ranging data were used to construct a global shape model and a        
 global topographic map of Eros with horizontal resolution of about 300 m. The NLR also 
 measured detailed topographic profiles of surface features on Eros with a best spatial              
 resolution of under 5 m. These topographic profiles enhanced and complemented the study of 
 surface morphology from imaging.