Laser Ranging Support
The objective of the Lunar Reconnaissance Orbiter (LRO) Laser Ranging (LR) system is to enable the spacecraft to achieve its precision orbit determination requirement. The LR will make one-way range measurements via laser pulse time-of-flight from Earth to LRO, and will determine the position of the spacecraft at a sub-meter level with respect to Earth and the center of mass of the Moon. Ranging will occur whenever LRO is visible in the line of sight from participating Earth ground tracking stations.
The LR consists of two primary components. The flight system, mounted on the LRO high gain antenna, consists of a receiver telescope that captures the uplinked laser signal, and a fiber optic cable that routes the signal to the Lunar Orbiter Laser Altimeter (LOLA) instrument on LRO. The LOLA instrument receiver electronics record the time of the laser signal based on an ultrastable crystal oscillator, and provide the information to the onboard LRO data system for storage and/or transmittal to the ground through the spacecraft radio frequency link.
The LR ground system consists of a pointable laser device at a satellite laser ranging station that times and transmits the laser pulse, a data reception and distribution facility, and the LOLA Science Operations Center. Positioning by the LR will enable the determination of a three-dimensional geodetic grid for the Moon based on the precise seleno-location of ground spots from LOLA.
+ Go to the Laser Ranging Web Site