Figure 1. Phase I
experiment, with efforts to regenerate oxygen and provide CO2.G. Ron Chen, Ph.D., Associate Professor, UH; Jane Malin, Ph.D., JSC; Mike Dowell, Ph.D., Post-Doctoral Fellow, UH
The recent announcement of possible past life on Mars has increased interest in human exploration of the planet. These missions present tremendous challenges to NASA and the research organizations involved. These challenges include the extended time required for the space flight to Mars plus the limited opportunity for supplying the spacecraft and planetary base. In addition, there are restrictions on the volume, mass, energy, and crew labor for the life support systems.
Figure 1. Phase I
experiment, with efforts to regenerate oxygen and provide CO2.
Researchers for this project are working with Johnson Space Center's Intelligent Systems Branch personnel to develop artificial intelligence and advanced automation software technologies to monitor and control advanced life support systems. NASA's Advanced Life Support (ALS) project[1] is building a testbed to experiment with and verify life support systems to grow, harvest, and process plants for food, purify water for the crew and plants, and regenerate oxygen for the crew and carbon dioxide for the plants.[2] The current focus is on providing physico-chemical and biological regenerative approaches for a planetary base with a stronger emphasis on the biological approach.
The Advanced Life Support Project consists of a series of three tests with a crew of one to four human subjects for durations of 15 to 90 days within sealed chambers. The first test, Early Human Test Initiative Phase I, was completed in August, 1995. This test configuration, shown in Fig. 1, used one human subject and a wheat crop in a continuous 15-day test sealed in the Variable Pressure Growth Chamber (VPCG) located at NASA's Johnson Space Center. The wheat crop produced O2 used by the test subject while the test subject produced CO2 used by the plants.
Figure 2. Overview of 3 Tier Architecture
The Early Human Test Initiative Phase II, complete in August 1996, used four test subjects for a continuous 30-day test in the Life Support Systems Integration Facility (LSSIF). This three-story chamber, shown in Fig. 2, includes sleeping quarters on the top floor and a kitchen and exercise room on the ground floor. The Phase II test focused on water and air recycling systems using physicochemical methods as opposed to the biological methods used for air recycling in the Phase I test. For Phase II, the researchers assisted the Intelligent Systems Branch in developing a monitoring program to store and classify test data.
The project continues with the Early Human Test Initiative Phase III test scheduled to begin August, 1997. This test combines subsystems from Phase II with air revitalization and crop growth subsystems from Phase I. This test is for 90 days with four human subjects in the LSSIF chamber. The researchers are assisting the development of monitoring and control software for integrating the gas exchange between the two chambers. This task is considered the most important goal of the Phase III test.
Phase III experiment. Note the NASA-JSC LSSIF on the title page.
The project concludes with the Intelligent Systems Branch developing the intelligent monitoring and control systems for the Bioplex Test Facility. This group of chambers will be used for tests of 120 to 425 days with several crews of four humans and subsystems for air, water, and nutrient recycling in the Phase I test. For Phase II, researchers assisted the Intelligent Systems Branch in developing a monitoring program to store and classify test data. The Bioplex Test Facility is under construction and will be used for tests to begin in the year 2000.
The
Bioplex Test Facility.
A goal of the branch is to develop and maintain a high level of expertise in the areas of monitoring, command and control for advanced life support systems. The branch has a limited number of personnel and depends upon contractors to fill key positions. With few people on each project, reassigning individuals has a great impact. The challenge is maintaining core expertise with small teams when turnover occurs. The University of Houston research staff provides a valuable and stable source of expertise.
The goal of the present research project, under the support from both the ISSO at UH and the NASA-JSC, is to reduce the work load of the crew and ground support personnel in monitoring, controlling, planning, and fault detection. Previous research designed an expert system for fault detection for a subsystem of the water recovery system. This system combines fuzzy logic with the reasoning capabilities of an expert system to diagnoses faults in the urine treatment part of the water recovery system. This constitutes the main effort of this research team devoted to the project in 1995-1996.
References
1Donald L. Henninger. "Advanced Life Support Program Plan," Life Sciences
Division, Office of Life and Microgravity Sciences and Application, NASA, Washington, D.
C., Feb. 26, 1996
2G. Ron Chen, J. Li, and J. Dong. "A Fuzzy Expert System for Fault Management of
Water Supply and Recovery in the ALSS Project," Annual Report, NASA Johnson Space
Center, July 25, 1995.
Contents
ISSO -- Institute for Space Systems Operations
1995-1996 Annual Report
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