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AFR, Inc. is developing a multifunctional Carbon material that, in addition to excellent radiation shielding characteristics, is appropriate for certain energy storage applications. As an excellent Hydrogen gas sorbent, it increases the usable storage capacity of a gas cylinder by ∼25% at 3500 PSI and by ∼150% at 500 PSI. Our ongoing NASA Langley funded study shows that when a sorbent-filled tank is charged with hydrogen, it provides shielding superior to polyethylene against most types of ionizing particles. Even as hydrogen is consumed, the carbon and tank ensure that significant radiation shielding capability is maintained. In addition to storing hydrogen, the carbon material also displays considerable strength. In this paper, we explore some of its mechanical properties that show this material is very versatile and highly multifunctional.

Pyrolysis is a very versatile waste processing technology which can be tailored to produce a variety of solid, liquid and/or gaseous products. The pyrolysis processing of pure and mixed solid waste streams has been under investigation for several decades for terrestrial use and a few commercial units have been built for niche applications. The use of pyrolysis as a key step in solid waste processing in space has been under consideration by NASA for several years. A large component of the solid waste is from biomass sources (e.g., paper, food waste, human waste). A methodology has been developed to characterize a large number of biomass materials using a standard pyrolysis experiment in combination with a neural network model in order to classify the data. Such a methodology can be helpful in the design and operation of pyrolysis reactors for spacecraft applications.

Activated carbons have a unique capability of strongly absorbing a great variety of species, ranging from SO2 and NOx, to trace organics, mercury, and other heavy metals. Activated carbons can also be used for gas storage and gas separations, including systems of practical interest to NASA (e.g., CO2/N2/O2), and even for the purification of liquids. No single activated carbon is suitable for all applications, but appreciable control over sorbent properties can be exercised in the process of carbon preparation. Since activated carbons can be produced from a wide range of organic materials, including waste streams, the preparation of activated carbons on board spacecraft should involve a limited amount of additional resources, help manage on-board waste, and reduce the weight of materials to be launched from earth. The feasibility of producing waste-derived activated carbons suitable for SO2 and NO control was the subject of the current study.

Pyrolysis processing is one of several options for solid waste resource recovery in space. It has the advantage of being relatively simple and adaptable to a wide variety of feedstocks and it can produce several usable products from typical waste streams. The objective of this study is to produce a prototype mixed solid waste pyrolyzer for spacecraft applications. A two-stage reactor system was developed which can process about 1 kg of waste per cycle. The reactor includes a pyrolysis chamber where the waste is heated to temperatures above 600°C for primary pyrolysis. The volatile products (liquids, gases) are transported by a N2 purge gas to a second chamber which contains a catalyst bed for cracking the tars at temperatures of about 1000 °C −1100 °C. The tars are cracked into carbon and additional gases. Most of the carbon is subsequently gasified by oxygenated volatiles (CO2, H2O) from the first stage.

Pyrolysis processing is one of several options for solid waste resource recovery in space. It has the advantage of being relatively simple and adaptable to a wide variety of feedstocks and it can produce several usable products from typical waste streams. The overall objective of this study was to produce a prototype mixed solid waste pyrolyzer for spacecraft applications. A two-stage reactor system was developed which can process a maximum of about 0.5 kg of waste per cycle. The reactor includes a pyrolysis chamber where the waste is heated to temperatures above 600 °C for primary pyrolysis. The volatile products (liquids, gases) are transported by a N2 purge gas to a second chamber which contains a catalyst bed for cracking the tars at temperatures of about 1000-1100 °C. The tars are cracked into carbon and additional gases. Most of the deposited carbon is subsequently gasified by oxygenated volatiles (CO2, H2O) from the first stage.

AFR, Inc. is developing a multifunctional Carbon material that, in addition to excellent radiation shielding characteristics, is appropriate for certain energy storage applications. As an excellent Hydrogen gas sorbent, it increases the usable storage capacity of a gas cylinder by ∼25% at 3500 PSI and by ∼150% at 500 PSI. Our ongoing NASA Langley funded study shows that when a sorbent-filled tank is charged with hydrogen, it provides shielding superior to polyethylene against most types of ionizing particles. Even as hydrogen is consumed, the carbon and tank ensure that significant radiation shielding capability is maintained. Vastly improved radiation shielding is a clear requirement for a potential manned mission to Mars or a long-duration base on the surface of the Moon. However, current shielding technologies are predicated upon systems dedicated solely to the task of shielding.

The NASA objective of expanding the human experience into the far reaches of space will require the development of regenerable life support systems. On-board carbon dioxide (CO2) removal units play a key role in such systems ensuring high quality cabin air for crew members. Similar but more compact units are needed for extravehicular activities (space suit). The use of monolithic (e.g., honeycomb-shaped) rather than granular sorbents has the potential to result in a CO2-removal system that possesses substantial weight, size, and power-requirement advantages over current systems (improved CO2 adsorption and lower pressure drop). The subject of this study was the use and manufacture of lightweight, porous carbon monoliths with controlled pore characteristics that will serve as support for the sorbent material (e.g., liquid amines). The objective was to demonstrate the technical feasibility of the above approach.

Pyrolysis processing of solid waste in space will inevitably lead to carbon formation as a primary pyrolysis product. The amount of carbon depends on the composition of the starting materials and the pyrolysis conditions (temperature, heating rate, residence time, pressure). Many paper and plastic materials produce almost no carbon residue upon pyrolysis, while most plant biomass materials or human wastes will yield up to 20-40 weight percent on a dry, as-received basis. In cases where carbon production is significant, it can be stored for later use to produce CO2 for plant growth. Alternatively it can be partly gasified by an oxidizing gas (e.g., CO2, H2O, O2) in order to produce activated carbon. Activated carbons have a unique capability of strongly absorbing a great variety of species, ranging from SO2 and NOx, trace organics, mercury, and other heavy metals.