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In February 2004 NASA released “The Vision for Space Exploration.” The important goals outlined in this document include extending human presence in the solar system culminating in the exploration of Mars. Unprocessed waste poses a biological hazard to crew health and morale. The waste processing methods currently under consideration include incineration, microbial oxidation, pyrolysis and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this project is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. In the Phase I project, TDA Research, Inc. demonstrated the potential of a low temperature oxidation process using ozone. In the current Phase II project, TDA and NASA Ames Research Center are developing a pilot scale low temperature ozone oxidation system.

The objective of this SBIR Phase I project was to identify catalysts that are active for ammonia conversion and are also selective for nitrogen and water. Our approach to the problem was centered on the development of a bifunctional catalyst, which could separate adsorbed oxygen and nitrogen atoms, thereby reducing NOx formation. The results of our project demonstrated that our approach was successful. We prepared a group of catalysts and tested them for ammonia oxidation activity. We identified a catalyst formulation that was active for ammonia oxidation at low temperatures in the presence of water and produced very little NOx. We used kinetic data to generate a rate model that predicts 100% ammonia conversion in the full-scale system at a temperature 50°C lower than the current design.

Incineration is a promising method for converting biomass and human waste into CO2 and H2O during extended planetary exploration. However, incineration produces small amounts of NOX and SO2 in the effluent, which must be removed. TDA Research has developed a safe and effective process to remove NOX and SO2 from waste incinerator product gas streams. In our process, NO is catalytically oxidized to NO2, using a low temperature oxidation catalyst developed at TDA. Wet scrubbers then remove the NO2, with most of the NO2 converted into an aqueous solution that can be used as a plant nutrient. A packed bed containing a basic sorbent, also developed at TDA, removes SO2 from the effluent. As part of an SBIR Phase II project, TDA designed and constructed a pilot scale effluent cleaning system, which will be used with the incinerator at NASA Ames Research Center.

A safe, effective means to control solid waste is a critical need on long-term space missions. With current waste models, 1300 kg of waste occupying a volume 20 m3 will be generated in a 180-day mission to Mars. Unprocessed waste poses a biological hazard to crew health and morale. The waste processing methods currently under consideration include incineration, microbial oxidation, pyrolysis and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this project was to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. In this Small Business Innovative Research (SBIR) Phase I project, TDA Research Inc. (TDA) conducted tests to measure the rates of oxidation using ozone with five model waste components.

The Trace Contaminant Control System (TCCS) removes most hazardous contaminants from the space station atmosphere using a carbon bed, but some must be destroyed in a high temperature catalytic oxidizer. While the oxidizer is protected from catalyst poisons by the carbon bed, if contaminant loads are greater than anticipated, the catalyst may be exposed to a variety of poisons. Thus, we studied the effect of halocarbons, sulfides and nitrogen compounds on the catalytic activity and the products produced. We found that even if poisoning occurs, the catalyst will recover, and will not produce toxic partial oxidation products.

As manned spacecraft travel farther from Earth, the cost of delivering the payloads to space increases dramatically. For example the cost of delivering a payload to low Earth orbit currently is about $10,000/lb. On the other hand the cost of delivering a payload to Mars may be up to 40 times greater and therefore missions to deep space place a strong emphasis on reducing launch weight and eliminating resupply requirements. The Vapor Phase Catalytic Ammonia Removal (VPCAR) system, which is being developed to purify water, is an example of this focus. In addition to having a lower launch weight than the Water Recycle System (WRS) currently used on the International Space Station, it also has no resupply requirements. A key step in the VPCAR system is the catalytic oxidation of ammonia and volatile hydrocarbons to benign compounds such as carbon dioxide, water, and nitrogen. Currently platinum-based commercial oxidation catalysts are being used for these reactions.

In February 2004 NASA released “The Vision for Space Exploration.” The goals outlined in this document include extending the human presence in the solar system, culminating in the exploration of Mars. A key requirement for this effort is to identify a safe and effective method to process waste. Methods currently under consideration include incineration, microbial oxidation, pyrolysis, drying, and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this work is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. Previously, TDA Research, Inc. demonstrated the potential of a low temperature dry oxidation process using ozone in a small laboratory reactor.