Browsing by Author "Moffatt, Sam"

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Astro GardenTM Aeroponic Plant Growth System Design Evolution
(49th International Conference on Environmental Systems, 2019-07-07) Moffatt, Sam; Morrow, Robert; Wetzel, John
By providing dietary nutrients as well as unburdening physiochemical life support equipment, Hybrid Life Support Systems (HLSS) can be an attractive option for longer duration space exploration such as Mars transit missions. State of the art microgravity plant nutrient delivery utilizes a physical media in which the plant roots grow (e.g., clay-based arcillite). This added media increases mass to orbit necessary for growing plants in space – limiting the appeal of large-scale plant growth systems in terms of Equivalent System Mass (ESM) when considering long duration mission architectures. Plants grown hydroponically or aeroponically represent a logistically favorable alternative for space-based plant growth systems, as nutrients are delivered without the added mass of a soil-like media. However, by removing the media material, controlling the water delivery and recovery in a microgravity environment presents a challenge. Astro Garden is being developed to provide a large-scale space-based aeroponic plant growth system, leveraging modifications of current designs meant to operate within a gravitational environment. This paper examines: the challenges surrounding aeroponics/hydroponics in microgravity, what techniques have been attempted thus far, to what varying degrees of success, and how they can be adapted to the Astro Garden design for future flight systems.
Design & Testing of a Catalytic Oxidizer for Cleaning of Hazardous Compounds in the Trash Compaction & Processing System (TCPS) Effluent Gas
(2024 International Conference on Environmnetal Systems, 2024-07-21) Klopotic, Joe; Shakouri, Nate ; Petrie, Zachary ; Coleman, Brynne; Wetzel, John ; Moffatt, Sam ;
The Trash Compaction & Processing System (TCPS) being developed for long duration space missions compresses, safens, and dries crew-generated standard trash, recovers and recycles water, and manages gaseous effluent produced during trash processing. As the trash is processed at elevated temperatures, it emits gaseous effluent containing Volatile Organic Compounds (VOCs) and other complex gaseous contaminants which evolve from the trash load. To conserve valuable resources during flight these gases are managed and recycled to reduce consumable losses. A Catalytic Oxidizer (CatOx) was developed by Sierra Space to treat this contaminated gas and render it safe for reintroduction into the cabin environment. VOCs are catalytically decomposed at high temperatures using a specially synthesized proprietary catalyst. Resulting gas outflows can be safely released into the cabin atmosphere, or through other downstream systems. The TCPS CatOx is functional at diverse pressure ranges and can be readily adopted for other trace contaminant control applications in spaceflight. Testing using representative contaminants was conducted to characterize and quantify the performance of the CatOx in support of the TCPS flight hardware development, with discussion of performance measures including destruction efficiency, thermal performance, and suitability for integration with other life-support systems.
ECLSS Architecture and Breakeven Analysis for Mission-Flexible LIFE™ Habitat
(51st International Conference on Environmental Systems, 7/10/2022) Marandola, Elizabeth; Moffatt, Sam; Kelsey, Laura
Loop closure for Environmental Control and Life Support Systems (ECLSS) has long been a goal for extended duration crewed missions. Journeys to destinations beyond Low Earth Orbit can take days, months, or years. As the distance from the Earth increases so does the need for efficient life support systems and effective allocations for consumables. Different mission durations have different ideal ECLSS configurations. System mass, crew size, consumables mass, and technology readiness level all factor into designing a suitable ECLSS. Sierra Space's Large Integrated Flexible Environment (LIFE™) habitat is suited to a wide range of low Earth and deep space missions. The flexibility of LIFE necessitates an evolvable and adaptable ECLSS design. To encompass a wide range of potential LIFE missions, ECLSS selections were made for three mission durations: 30 days, 180 days, and 1100 days. A literature survey was completed for each major environmental control and life support subsystem to determine the current state of the art, up and coming technologies, expected operational lifetime, and support services needed. Armed with the information gathered, the team evaluated each subsystem technology against mission needs, logistical limitations, and crew size and made selection recommendations for each mission configuration. This paper summarizes the considered options, resulting integrated systems, and necessary consumables for each of the three mission durations.
Flexible Motor Controller Architecture for Spacecraft Applications
(2024 International Conference on Environmnetal Systems, 2024-07-21) Myers, Connor; Wallace, Russell; Cowgill, Bradley; Rorabeck, Casey; Tarver, Elias; Carney, David; Moffatt, Sam; Bourget, Mike; Heindl, George
Brushless DC (BLDC) motors are ubiquitous to spacecraft operation. BLDC Motors provide the driving force for many different components within ECLSS and TCS such as: valves, fans, blowers, pumps, and rotary separators. Specific to valve operation, several considerations come into play when developing a control system for a BLDC motor. Position sensing/indication, mass, power, volume, cost, radiation susceptibility, and maintainability are among primary design driving factors for developing a BLDC motor controller. Looking at the potential needs for valve control and design, a common product was developed to balance the design driving factors towards the end goal of cost reduction and simplifying on-orbit logistics and maintenance for future spacecraft. The flexible design supports a wide array of valve functions and can be maintained/removed without exposing the internal fluid to the spacecraft environment. The microcontroller-based design provides a simplified and abstracted serial data interface to the flight computer, enables low level hardware and software fault detection, allows modularity for adding additional application specific sensors and features without impacting vehicle avionics, simplifies channelization and wire harness to vehicle avionics, and allows for in field software updates. The design supports different part grades from automotive to grade 1 to optimize for the application. Additionally, key internal components have been tested to support the radiation and vibration environment encompassing many potential valve applications.
In situ Manufacturing derived from Bioregenerative Life Support Systems
(51st International Conference on Environmental Systems, 7/10/2022) Morrow, Robert; Wetzel, John; Moffatt, Sam
In situ resources from planetary sources can be used in conjunction with a bioregenerative life support system to produce excess biomass which along with miscellaneous waste streams can be used as a feedstock for manufacturing numerous items necessary to support and expand a planetary habitation. Materials that can be fabricated include: structural materials like beams, joists, wall studs, structural cables, and wall and floor panels, doors; furniture items such as tables, chairs, cabinets, beds, and shelves; geotextiles, fabrics for clothing, cushions and bedding; numerous specialty items like filters, plastics, thermal and sound insulation; and useful biochemicals like lubricants, detergents, alcohol, protective coatings, and adhesives. These feedstock materials can also be used in several manufacturing technologies such as compression forming, extrusion, and 3D additive manufacturing. One example is straw fiberboard, which is formed by fiberization and compression, with or without binding agents, and is used commercially as a renewable construction resource. More exotic materials that are produced through synthetic biology techniques, using genetically modified plants to produce materials that could not otherwise be produced in a remote setting, can be processed through biorefining (extraction, separation and purification) techniques before being processed by standard manufacturing techniques. Required processes for using biomass feedstocks can be evolved from information derived from similar processes now or previously used commercially, or that have been developed in the laboratory. A biomanufacturing system could provide a tool to reduce costs of maintaining and expanding a planetary outpost by eliminating the need to transport from Earth either finished items or the raw materials needed to fabricate those items on site. It also provides the means and flexibility to respond to sudden, unanticipated needs including repair or replacement of damaged items, and supports NASA�s philosophy for long duration planetary bases to �make what you need where you need it.�.