University of Maryland
The Birth and Future of Lunar Laser Ranging
Over the past five decades, the Lunar Laser Ranging (LLR) program has daily measured the distance to the Moon with an accuracy that approaches a centimeter. This long data series has allowed the determination of the most accurate values of many parameters in lunar physics, astrophysics, cosmology, and tests of General Relativity. The history, technologies, and results of this LLR program will be described. However, the combination of the lunar librations and our design of the original retroreflector arrays results in a limit on the accuracy of the individual range measurements and a limit on the observational procedures of the Earth-based Lunar Laser Ranging Observatories (LLROs). The Next Generation Lunar Retroreflectors (NGLRs) are being developed for deployment on the Moon in the next few years. They will support the improvement the accuracy of an individual range measurement by almost a factor of 100 and will support the improvement the accuracy of the science results by factors of hundreds. The design, method and location of deployment, and schedule for the NGLRs will be discussed.