On 21 July 1969, during the first manned lunar mission, Apollo 11, the first retroreflector array was placed on the moon, enabling highly accurate measurements of the Earthmoon separation by means of laser ranging. Lunar laser ranging (LLR) turns the Earthmoon system into a laboratory for a broad range of investigations, including astronomy, lunar science, gravitational physics, geodesy, and geodynamics. Contributions from LLR include the three-orders-of-magnitude improvement in accuracy in the lunar ephemeris, a several-orders-of-magnitude improvement in the measurement of the variations in the moon's rotation, and the verification of the principle of equivalence for massive bodies with unprecedented accuracy. Lunar laser ranging analysis has provided measurements of the Earth's precession, the moon's tidal acceleration, and lunar rotational dissipation. These scientific results, current technological developments, and prospects for the future are discussed here.

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The International Laser Ranging Service (ILRS) through its permanent components (Tracking Stations, Operations Centers, Data Centers, Analysis Centers, Central Bureau, and Governing Board) distributes satellite and lunar laser ranging data and derived products to support global, multidisciplinary scientific research. The ILRS Data Centers and Central Bureau serve as the primary source for information, data, and products for this global user community. The ILRS website, https://ilrs.gsfc.nasa.gov, is a key tool for communication for the service, providing background information on the ILRS, its organization and operation, and detailed descriptions of ILRS components, data, and products. Links are provided to extensive information on the supported satellite missions and ILRS network stations including performance assessments and data quality evaluations. Furthermore, the website connects users to archives of laser ranging data and derived products available through the data centers. In this paper, we discuss the development of the ILRS infrastructure, its current status, website resources, description of laser ranging data and products, and plans for future enhancements.

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For over 40 years, NASA's global network of satellite laser ranging (SLR) stations has provided a significant percentage of the global orbital data used to define the International Terrestrial Reference Frame (ITRF). The current NASA legacy network is reaching its end-of-life and a new generation of systems must be ready to take its place. Scientific demands of sub-millimeter precision ranging and the ever-increasing number of tracking targets give aggressive performance requirements to this new generation of systems. Using lessons learned from the legacy systems and the successful development of a prototype station, a new network of SLR stations, called the Space Geodesy Satellite Laser Ranging (SGSLR) systems, is being developed. These will be the state-of-the-art SLR component of NASA's Space Geodesy Project (SGP). Each of SGSLR's nine subsystems has been designed to produce a robust, kilohertz laser ranging system with 24/7 operational capability and with minimal human intervention. SGSLR's data must support the aggressive goals of the Global Geodetic Observing System (GGOS), which are 1 millimeter (mm) position accuracy and 0.1 mm per year stability of the ITRF. This paper will describe the major requirements and accompanying design of the new SGSLR systems, how the systems will be tested, and the expected system performance.