Exploration of Life Support and Particulate Matter Removal (Filtration)
Research Associate: Jonathan Barr
Principal Investigator: Juan Agui
Background on Particulate Matter Removal
The mitigation of lunar dust is one of the primary challenges to future manned missions to the moon. With NASA’s renewed emphasis on returning to the moon through the Constellation program, lunar spacecraft and life support systems must be designed to withstand the harsh effects of the Moon’s environment. Lunar dust poses a two faceted problem; it can have long-term effects on the crew’s health, and can reduce the nominal performance of sensitive equipment and instrumentation. Some of these health effects were observed on the Apollo missions, as lunar dust caused respiratory and ocular irritation in several astronauts. Additionally, properties of the lunar dust affect the sensitivity and durability of spacecraft equipment. The dust can reduce the efficiency and strain spacecraft instrumentation. Given these challenges, effective ingress infiltration barriers and particulate removal technologies geared toward the filtration of lunar dust will be of the upmost importance.
Particulate filtration will most likely serve as a primary means of removing particles from the circulating air in the habitat cabin for lunar surface exploratory missions. Filters will remove both internally generated dust and intruding lunar dust from the spacecraft. The filtration systems needed to support future missions will need to handle the load of lunar dust particles. The devices or systems need to provide longer service life to maintain an acceptable level of air cleanliness must be efficient, robust, and low-maintenance.
In support of developing these necessary filtration systems, a new test facility has been designed and constructed to investigate filtration and gas-phase separation technologies. This facility will be used to test the efficiency and practicality of filtering lunar dust under similar constraints to those found in the lunar landing vehicle and spacecraft cabin. The facility has been designed to test filters in a replicated spacecraft environment using lunar simulant dust particles as the challenge aerosol. The pressure inside the facility can be reduced under a vacuum pump, and the temperature and relative humidity controls can also be controlled.
Primary Roles of the Research Associate
Working under Dr. Juan Aqui, my work this summer will cover four primary aspects; a flow characterization of the lunar dust filtration testing facility, an analysis and optimization of the particle delivery system in the facility, performance tests of various filters and filter systems, and a design for a new filtration system.
Some preliminary work has been conducted to analyze the flow in the facility, although additional testing is needed to further analyze the facility’s performance. Some initial velocity profiles have already been constructed and the facilities’ vacuum pressure sustainability has already been assessed. Further analysis of the velocity profile and characterization of the vortex flow will be conducted using higher resolution transducers. Also, I will be conducting tests on the facility to mitigate any possible leaking and improve the facility’s ability to hold a vacuum. These tasks will be conducted before most of the testing with particulate to optimize the current configuration and provide a greater understanding of the airflow.
Before the test facility was constructed, a prototype facility was built. In the prototype, an auger system was used to disperse the particulate. This auger system was tested in two configurations, horizontally and vertically. The vertical configuration was determined to be better suited for our purpose because it delivered a higher concentration of particles. However, the vertical dispersion technique had more variability in the particle delivery concentration at higher rotational rates. My work this summer will involve testing various corrective measures to reduce the variability of the dust concentration. Such measures may include experimenting with various rotational rates and particle delivery angles. I will also be studying the effects of various rotational rates to determine the optimum rate for filter testing.
The third facet of my work will involve conducting performance tests on various filters. Preliminary testing has already begun using a HEPA and an ASHRAE filter. These two filters will be used as the standard for which to compare future testing on different filter types and configurations. The filtration technologies I will be testing will be evaluated on improved efficiency, high load capacity, low energy consumption, a low mass and volume, and the ability to be regenerated. Regenerating filters could be either self-cleaning or could be used for very long durations.
The final aspect of my work will be to provide a preliminary design concept of the filtration system needed to carry out lunar missions. I will be performing literature and market research of state of the art filtration systems that can be applied to space exploration. These suggestions can be used by NASA to determine the optimal application of filter technology.
Secondary Roles of the Research Associate
There are several other subprojects I will also be carrying out this summer in addition to the principal tasks. Often these subprojects are in support of, or complementary to the three primary goals. Thus far, I have been assigned three second tier tasks; assembling a new extended flexible fume exhaust arm from previous parts, familiarizing myself with the PMS Las X-II particle counter, and crafting a logo for the Exploration of Life Support Project. Thus far, I have already begun work with the PMS Las X-II system, working under Marit Meyer, a GSRP student. I have conducted two tests thus far with the machine on standardized polystyrene particles. I have also already begun work on the micro-fume hood. Currently, I am in contact with a representative of Car-Mon Inc. to order the missing pieces of the hood’s extension arm. As time progresses, more of these auxiliary projects will be added to this list. The side projects are often necessary to carry out the primary research with the facility.
The development of effective and efficient filtration systems is vitally important for the upcoming manned missions to the moon. With my work this summer, I hope to further advance NASA’s understanding of the possible filtration systems that could be employed in lunar missions. I hope I can contribute to NASA’s already broad base of scientific knowledge by applying my previous research experience, and course work as an aerospace engineering student. With any luck, my work can be used to improve the current filter technology and the quality of life of astronauts on lunar missions.