Search Results

Mathematical modeling of the Ni-H2 cell based on the fundamental electrochemical processes is necessary for accurately simulating the battery behavior on Space Station Freedom. Accurate predictions are incorporated as part of the development of the Space Station Electric Power System simulation. This simulation will be used to develop and test control algorithms which will maximize the available power in the most efficient way. This is a deviation from the approach used on smaller satellite power systems which are designed with substantial margin. Hence, the use of an empirical battery model is not feasible due to its low fidelity. This paper covers the electrochemical theory related to the Ni-H2 cells, and the analysis of experimental data used to develop relations between the cell state of charge and certain cell properties. Theoretical results are compared against well-documented experimental data.

Tests using the Thermogravimetric Analysis (TGA) techniques showed this approach to be a relatively simple and rapid method for assessing the affinity of trace contaminants for a solid amine, CO2 sorbent. Regenerative CO2 sorbents are applicable to many space systems air revitalization applications for removal of CO2. Sorbents may be chemically non-specific as regards reversible adsorption-desorption, chemicals other than CO2 can be regeneratively removed from spacecraft air. These other chemicals, present in trace amounts, may also interfere with the primary CO2 removal function. TGA test procedures were developed to determine adsorption-desorption behavior of trace contaminants on a regenerative solid amine sorbent: Hamilton Standard, material - C (HS-C).

The Space Shuttle Orbiter Atmospheric Revitalization Pressure Control System (ARPCS) and the Fuel Cell System (FCS) use a hot wire anemometer type of gas mass flow sensor for flow measurement. In the ARPCS oxygen and nitrogen mass flows are measured and in the FCS oxygen and hydrogen mass flows are measured. The existing flow sensors suffer from certain accuracy limitations and potential failure modes. A new type of commercially developed solid state micro-machined silicon gas mass flow sensor developed by Honeywell was adapted to allow the technology to be assessed for the application. A demonstration test program has been conducted to evaluate the performance characteristics of the new sensor for space system applications and environments. The testing was sponsored by the National Aeronautics and Space Administration (NASA) at the Johnson Space Center (JSC).