  A significant and growing portion of systematic error on a number of
fundamental parameters in astrophysics and cosmology is due to uncertainties
from absolute photometric and flux standards. A path toward achieving major
reduction in such uncertainties may be provided by satellite-mounted light
sources, resulting in improvement in the ability to precisely characterize
atmospheric extinction, and thus helping to usher in the coming generation of
precision results in astronomy. Using a campaign of observations of the 532 nm
pulsed laser aboard the CALIPSO satellite, collected using a portable network
of cameras and photodiodes, we obtain initial measurements of atmospheric
extinction, which can apparently be greatly improved by further data of this
type. For a future satellite-mounted precision light source, a high-altitude
balloon platform under development (together with colleagues) can provide
testing as well as observational data for calibration of atmospheric
uncertainties.
