The long-term goal of this activity is to demonstrate the feasibility of a laser sounder instrument capable of measuring the surface-pressure field for the entire air column from satellite-to-ground with global coverage. The earth's surface pressure is a vital component of a variety of important scientific measurements, which are being undertaken at Goddard. Accurate knowledge of the surface pressure can enable calibration of 2-D measurements of CO2 content in the atmosphere and greatly improve the fidelity of surface water redistribution measurements from time-varying gravity fields. It is also important in weather prediction and atmospheric modeling.