Abstract: A method and apparatus for reconfiguring a satellite based on its position relative to one or more reference points on the Earth's surface. The method and apparatus use dot products defining relative locations of the satellite and predefined regions on the Earth's surface to determine when the satellite is within the predefined region. When the dot product comparison indicates that the satellite is located within the predefined region, a computer on-board the satellite executes a stored command set to reconfigure the satellite's communications protocol for the predefined region in which the satellite is located.

Abstract: A battery charge control method which relies upon the relationship between the battery state of charge and the charge efficiency. The battery charging efficiency is estimated by computing the amount of charge received by the battery as a function of input charge. Thermodynamic calculations are used to obtain an estimate of battery charge levels over a wide range of temperatures, and two stage filtering is used to obtain a useful slope from noisy charge level signals to determine charging efficiency and ultimately control the charge rate. The method is especially useful for recharging nickel-hydrogen batteries used aboard spacecraft. The battery charge in such a battery is estimated by computing the number of moles of hydrogen gas in a cell. The input charge is the integral of the charge current. Thus, the charge efficiency is proportional to the rate of change of the number of moles of gas with respect to the input charge.

Abstract: An improved method and apparatus for regenerating aqueous desiccants for use in an air conditioning system are disclosed. The disclosed method and apparatus utilizes a gas-fired desiccant boiler and a combined desiccant regenerator/interchange heat exchaner. The combined regenerator/heat exchanger utilizes steam produced from the boiler to provide heat for partial regeneration. The desiccant boiler has a liquid/vapor separator chamber and thermosyphon recirculation to reduce scale and corrosion of the boiler.