Search Results

The possibility and consequences of a fire on board a spacecraft and the subsequent effects of the resultant toxic gases and smoke on the crew, equipment and mission is an ever-present hazard for the National Aeronautics and Space Administration (NASA). The necessity to remove these contaminants in the presence of high levels of humidity and carbon dioxide has prompted the development of a new prototype atmospheric filter (smoke eater) that can scrub acid gases, basic gases, and carbon monoxide from a spacecraft atmosphere in a post-fire event to a concentration below one half the Spacecraft Maximum Allowable Concentration (SMAC) levels. TDA Research, Inc. (TDA) is developing an advanced smoke eater to remove combustion byproducts. The material makeup of the smoke eater will also be applicable to spacecraft evacuation masks and the shipboard atmospheric revitalization system.

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.

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 current Extravehicular Mobility Unit (EMU) system provides thermal control using a sublimator to reject both the heat produced by the astronaut's metabolic activity as well as the heat produced by the Portable Life Support Unit (PLSS). This sublimator vents up to eight pounds of water each Extravehicular Activity (EVA). If this load could be radiated to space, the amount of water that would need to be sublimated could be greatly reduced. There is enough surface area on the EMU that almost all of the heat can be rejected by radiation. Radiators, however, reject heat at a relatively constant rate, while the astronaut generates heat at a variable rate. To accommodate this variable heat load, NASA is developing a new freeze tolerant radiator where the tubes can selectively freeze to “turn down” the radiator and adjust to the heat rejection requirement. This radiator design significantly reduces the amount of expendable water needed for the sublimator.

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.

Incineration is a promising method for converting biomass and human waste into CO2 and H2O during extended planetary exploration. During incineration, however, small amounts of NOx and SO2 are produced and must be removed. TDA Research, Inc. (TDA) has developed a safe and effective process to remove NOx and SO2 from waste incinerator product gas streams. In our process, NO is oxidized into NO2 with high selectivity. The NO2 is then removed by wet scrubbing with a weak base to form an innocuous water solution of nitrates and nitrites. SO2 will be removed by a packed bed containing a basic sorbent developed at TDA. As part of an SBIR Phase II project, TDA is to design and construct a pilot-scale effluent cleaning system to be coupled with an existing waste incinerator at NASA Ames Research Center. The effluent from this incinerator may contain fly ash, SO2, unburned hydrocarbons, CO, and NOx.

Incineration is a promising method for converting biomass and human waste into CO2 and H2O during extended planetary exploration. During incineration, small amounts NOX and SO2 are produced and must be removed. TDA has developed a NOX control process that is safe and effective and does not require addition of NH3, which is commonly used in selective catalytic reduction of NOx. In our process, NO is catalytically oxidized to NO2 which is then removed by wet scrubbing with a weak base to form an innocuous water solution of nitrates and nitrites. We plan to integrate our catalytic NO oxidation process into a complete gas cleaning system that will remove NOX, SO2, particulate material, CO and unburned organic compounds.