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P. J. Shelus, R. L. Ricklefs (University of Texas Center for Space Research), J. R. Wiant, J. G. Ries (University of Texas McDonald Observatory)
The lunar and artificial satellite laser ranging network, part of the International Laser Ranging Service, monitors a large number of targets. Many scientific disciplines are investigated using these data. These include the realization and maintenance of the International Terrestrial Reference Frame; the 3-dimensional deformation of the solid Earth; Earth orientation; variations in the topography and volume of the liquid Earth, including ocean circulation, mean sea level, ice sheet thickness, and wave heights; tidally generated variations in atmospheric mass distribution; calibration of microwave tracking techniques; picosecond global time transfer; determination of the dynamic equinox, the obliquity of the ecliptic, the precession constant and theories of nutation; gravitational and general relativistic studies, including Einstein's Equivalence Principle, the Robertson-Walker b parameter and time rate of change of the gravitational constant; lunar physics, including the dissipation of rotational energy, shape of the core-mantle boundary (Love Number k2), and free librations and their stimulating mechanisms; Solar System ties to the International Celestial Reference Frame.
With shrinking resources, we must not only assess specific data requirements for each target, but also maximize the efficiency of the observing network. Several factors must be considered. First, not only does a result depend critically upon the quality and quantity of the data, it also depends upon the data distribution. Second, as technology improves, the cost of obtaining data can increase. Both require that scientific endeavor pay close attention to the manner in which the data is gathered. We examine the evolution of the laser network, using data analysis requirements and efficient network scheduling to maximize the scientific return. This requires an understanding of the observing equipment, as well as the scientific principles being studied. Queue scheduling and worth functions become important.
This work is funded by: NSF AST-0204127, NASA NAG5-10195, NAS5-01096, NAG5-11464.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.