ISSO Mini-Grants

International Space Station Alpha Electrical, Electronic, and Electromechanical Parts Database Development

John C. Watson, Ph.D., Assistant Professor, UH; Christopher C. Jones, Research Assistant, UH

This project aims to develop a prototype Electrical, Electronic, and Electromechanical (EEE) parts database for the International Space Station Alpha (ISSA) EEE Parts Control Board (PCB). The project consists of identifying the EEE parts data requirements, creating a relational database structure for storing EEE parts, creating data loading programs for receiving parts lists, and providing multi-user database access to NASA employees and support contractors while maintaining a secure database environment.

EEE parts data are configured under three main categories: (1) Parts list data, (2) Parts test data, and (3) Parts approval status data. The Parts list data section includes all as-designed and as-built EEE parts required to assemble ISSA. Parts test data include EEE stress analysis and radiation test data. The Parts approval status data section includes the qualification status for parts under consideration for approval or disapproval. Since the qualification of each individual part affects the certification of an entire assembly, the EEE parts database must be able to reference data at various levels down to the component level.

Creation of a relational database structure for storing EEE parts proved to be the most challenging aspect of the project. Since it was necessary to capture data down to the component level, it was difficult selecting an appropriate key for each table in the database. For example, two 1000pF 100V 1 percent ceramic capacitors have the same part number (2354911) because they are the same type of part. In order to capture data down to the component level, one needs a separate record for each. But, if one were to use the part number as the key, the key would repeat itself if that part were to occur more than once in the space station. It became evident that since the component level identifier (part number) cannot be used to distinguish components of the same type, each individual component in ISSA must be identified by a series of data fields such as part number, next higher assembly (NHA) number, and reference designator. The partial listing of data categories shown in Fig. 1 was selected to serve as composite keys in the EEE parts database.

A prototype EEE parts database was created using Microsoft Access. Data loader programs required for importing parts data from product groups, government, and international partners were developed using Visual Basic for Applications functions implemented within Microsoft Access macros. The macros mapped each column of a submitted parts data file to the appropriate database field. Macros were created to accommodate varying formats for the parts list.

The final phase of the project was to provide multiple users simultaneous access to the EEE parts database. Access was accomplished by instructing NASA personnel how to use the multi-user features of the database. NASA personnel were instructed how to place the database on a shared folder on their personal computer. Security groups and profiles were created for each new EEE parts database user. This step involved setting table and object level security for each security group and user. The final step was to setup each user's computer and instruct users how to login to the database.

The development of a EEE parts database for ISSA posed many business process and technical challenges. From the business perspective, there was the challenge of determining the types of data needed. From the technical side, there were the challenges of how to store parts data in a relational database, how to accommodate the non-standard type and formats of data received, and how to allow multiple users simultaneous access to the database while maintaining database security.

William R. Widger, Ph.D., Associate Professor, UH; Fadhi Abdi, Ph.D. Candidate, UH; Kirt Martin, Ph.D. Candidate, UH; Jane Siefert, Ph.D. Candidate, UH

One of the primary incentives for exploring space is to understand the origin and distribution of life in the Universe. NASA's charter reflects this objective and has for many years maintained the only National research program focused on this discipline officially termed "exobiology." The Exobiology Program encompasses studies ranging from the source and distribution of the biogenic-elements to studies on the origin of life and the history of early life on the Earth.

The best established physical evidence of early life forms on the Earth are the stromatolites which date to 3 billion years ago or earlier. These stromatolites are thought to be, in large part, the result of the activity of cyanobacteria. Recent microfossil evidence supports this view. Molecular evidence based on ribosomal RNA sequences does not place the cyanobacteria among the earliest branchings of life but rather shows them emerging somewhat later as one of approximately twelve distinct phyla of the Domain Bacteria. Regardless of the precise time of arrival of the cyanobacteria, they are of special interest to the study of early life because they were key factors in two important developments. At an early stage, they were almost certainly the first organisms to produce free oxygen with the consequent eventual development of the modern atmosphere. Later, the cyanobacteria played a key role in the emergence of land plants by serving as endosymbionts which eventually evolved to be chloroplasts.

Cyanobacteria are the single most important group of extant organisms in terms of relating the geological and molecular approaches to the study of extant organisms.

Methodology
Synechococcus PCC 7002 was chosen for detailed genomic characterization because earlier work had established the construction of a genomic map of large NotI and SalI fragments and a cosmid library of random partially digested Sau3AI genomic DNA ligated into Supercos cosmid vector (Stratagene). Furthermore, a set of 95 overlapping cosmids that span almost the entire genome had been identified. In order to obtain extensive comparative information, the following sequence sampling strategy is being used. Each mapped cosmid is digested with EcoRI. Approximately 400-600 bases of sequence are determined from each end of each fragment using an ABI-automated DNA sequencing system. The mapped cosmids contain a total of approximately 800 EcoRI fragments. Since these fragments are of modest size (2-6 KB) and because cyanobacteria bacterial genes are about 1 KB each with very small spacer regions, this strategy allows us to rapidly obtain partial sequence information from approximately 70 percent of the genes in any region. Equivalent genes in other organisms are identified by searches of public sequence databases. Genes of special interest can be readily sequenced in their entirety. Studies of gene content and gene arrangement can proceed directly from the raw data.

60 sequencing reactions
Since initiating this approach in May of 1996, a total of 60 sequencing reactions have been run, yielding 24,000 nucleotides of useful sequence. Computer software has been implemented to facilitate the direct importation of sequence data into the analysis environment from the sequencing laboratory. A preliminary Internet World Wide Web site has been established to make information about the genome readily available to others, and data analysis has begun.

A number of important genes, Table 1, as well as several previously unknown putative proteins (ORFs) have been positively identified. Efforts are now underway to improve the rate at which the identified proteins can be aligned with their equivalents in other organisms, a fundamental first step in data analysis. As alignments are established, it will be possible to begin looking for exogenous DNA, establishing codon usage patterns, and conducting studies of local and eventually overall evolutionary rate in the cyanobacterial genome.

Table 1. Newly Identified genes and previously unkown putative proteins (ORF's).

Richard C. Willson, Ph.D., Associate Professor, UH; Narinder Singh, Graduate Student, UH

Improved methods are sought for the detection of microbial pathogens in the spacecraft environment. Standard ground-based technologies are too bulky and labor-intensive, yet monitoring of the microbial environment is an increasingly important issue in manned spaceflight. Actual and suspected microbial contamination and infection have several times delayed missions, impaired equipment functioning, and reduced crew efficiency during missions. Along with Dr. Duane Pierson of NASA-JSC and Prof. George Fox of UH, we are investigating the use of modern DNA probe technology for monitoring of space craft microbial populations.

DNA probes have revolutionized the diagnosis of difficult-to-culture pathogenic microorganisms, and their use is expected to improve the speed, accuracy, and weight and labor requirements of space craft microbial monitoring. As a complement to work on "DNA chip" probe diagnostics conducted under a UH/JSC post-doctoral fellowship and a NASA headquarters grant on this topic, we are investigating the important and difficult practical problem of preparing samples for DNA probe analysis under spacecraft conditions. The majority of bacterial assays of interest involve detection of ribosomal 5S RNA species, present in the cell at about 10,000 copies per cell. We are currently investigating the tolerance of the DNA chip assay for contaminating cell constituents, but it is clear that some degree of pre-concentration and possibly pre-purification of the 5S RNA target molecules will be required for almost any probe-based assay.

RNA is relatively difficult to separate from several other potentially-troublesome cell constituents, including lipid membrane fragments, proteins, and DNA. The standard techniques are not applicable as they involve toxic and/or carcinogenic materials such as phenol or ethidium bromide, or require a gravitational field. One promising method is adsorptive separation such as the widely-used plasmid "mini-prep" kits produced by Qiagen et al. These kits, however, are based on ion-exchange chromatography which is poorly suited for selective isolation of RNA from other negatively-charged molecules. We are developing RNA-selective ligand chromatographic methods, focusing on boronate-based ligands which can form a cyclic ester with vicinal cis-diols, the presence of which distinguishes RNA from DNA.

We have extensively explored the variables which influence the efficiency of RNA adsorption on agarose-immobilized aminophenylboronic acid. We have found that pH is a less important variable than implied by the literature and that operation at low temperatures can make a two-fold improvement in adsorption affinity. Most important, however we have found that selection of the right ionic environment can radically increase the affinity with which RNA molecules are captured by this adsorbent. The improved operating conditions appear not to be discussed in any previous literature, and we have prepared a patent disclosure on this technique.

Larry C.Witte, Ph.D., Professor, UH

Gas-liquid mixtures occur in a number of situations relevant to on-going and planned space operations. Some examples are the incidental boiling of cryogenic fluids, evaporative heating/cooling systems and power generation systems. In these situations, knowledge of the phase distribution is important for the design of piping systems, separators, and other associated units. The prediction of heat transfer characteristics is of particular importance, since the design of such systems for space operations is inherently limited by size constraints.

A number of studies have been performed to identify the flow regimes that occur under reduced-gravity conditions and develop criteria for inter-regime transitions.[1,2,3,4] Three distinct regimes have been identified at reduced gravity: bubbly, slug, and annular, with transitions of bubbly-slug and slug-annular. Annular flow, where the liquid flows as a thin film along the tube wall and as droplets in a gas/vapor core, occurs over the widest range of gas and liquid flow rates. The largest frictional pressure gradients and heat transfer coefficients occur in annular flow, further increasing the need for good predictive methods.

Two-phase flows in space systems will involve a number of configurations like heat exchangers, flow headers, valves, elbows, tees, and other hardware. In some cases, our understanding of flow through such components is not complete even in Earth-normal gravity. A long range goal is the development of experimental techniques for investigating such flows, concentrating on pressure drop, and where applicable, heat transfer.

During this study, correlation of heat transfer data for straight tubes obtained aboard NASA's KC-135 in October, 1994 was completed. We found that the heat transfer data for annular flow in microgravity could be correlated by an equation of the form

Nu = 0.03Re0.6Pr1/3 [Prw/Pr]1/4,

where Nu is a dimensionless heat transfer coefficient, the Re number represents the influence of coolant velocity, and Pr, a scaling number representing the effectiveness of the coolant to accept heat. The subscript w represents the value at the tube wall. Figure 1 shows the correlation compared to our experimental data. Further details of the results for slug flow heat transfer and pressure drop can be found in Fore et al.[5,6]

A heated section has been developed to be flown aboard NASA's aircraft. Its design has been modified to allow for shorter transient start-up times so that heat transfer experiments can be done in a quasi-steady state during parabolic aircraft flights where only about 20 seconds of microgravity are available. It consists of a copper tube with a wall thickness of 0.65 mm wrapped with nickel resistance heaters. The wall temperature profile will be measured by RTDs cemented to the tube o.d. Specially designed pressure probes and film thickness probes are included. The region near the entrance to the tube will be more heavily instrumented so that information regarding the development of velocity and temperature layers can be obtained.

Design is also underway of an experimental rig for various tube diameters. This design will require modification of the test sections; such modifications must also be integrated into the flow rig that flies aboard NASA aircraft.

References
1A. E. Dukler, J. A. Fabre, J. B. McQuillen, and R. Vernon. "Gas-Liquid Flow at Microgravity Conditions: Flow Patterns and their Transitions," Int'l J. Multiphase Flow 14 (1988): 389-400.
2L. Zhao and K. S. Rezkallah. "Gas-Liquid Flow Patterns at Microgravity Conditions," Int'l J. Multiphase Flow 19 (1993): 751-63.
3W. S. Bousman and A. E. Dukler. "Ground Based Studies of Gas-Liquid Flows in Microgravity Using Lear Jet Trajectories," 32nd Aerospace Sciences Meeting and Exhibit, Reno, NV, 1994.
4W. S. Bousman, J. B. McQuillen, and L. C. Witte. "Gas-Liquid Flow Patterns in Microgravity: Effects of Tube Diameters, Liquid Viscosity and Surface Tension," Int'l J. Multiphase Flow (1995). (In press.)
5L. B. Fore, L. C. Witte, and J. B. McQuillen. "Heat Transfer to Annular Gas-Liquid Mixtures at Reduced Gravity," J. Thermophysics and Heat Transfer (1996). (In press.)
6L. B. Fore, L. C. Witte, and J. B. McQuillen. "Thermal Hydraulics of Two-Phase Slug Flow under Reduced Gravity," Int'l J. Multiphase Flow (1996). (In press.)

Joan N. Maier, Director; Assistant Professor of Education, UHCL

Twenty-two K-12 teachers, representing 12 private and public school districts in Texas participated in the Geography Institute for Teachers: Global and Environmental Geography with Space Age Technology. The 22 teachers, selected from a pool of applicants, received 115 space shuttle photographs and slides along with hundreds of dollars worth of other classroom curricular materials. Three university professors, three NASA Earth Observation scientists, and two National Geographic Society Teacher Consultants (NGSTC) constituted an interdisciplinary team of instructors.

The Institute was conducted for a total of three weeks during the summer of 1996 at the University of Houston Clear Lake. The first two weeks included content lectures connected directly to the 115 specific space shuttle photographs, basic training in interpreting those space shuttle photographs, and hands-on practice in problem-solving instructional strategies. Teachers also participated in a physical, environmental, and cultural geography field trip to Galveston Island that demonstrated instructional strategies designed to integrate geographic field work techniques, geographic content knowledge, and space shuttle photography.

During the third week, the teachers individually consulted with the Institute's team of instructors to complete the development of a total of 66 different problem-solving lessons and 66 different classroom activities that utilized space shuttle photographs to teach environmental problems and other related topics. Some teachers developed interdisciplinary lessons and utilized multimedia technology. Each teacher was required to demonstrate to class members one of the problem-solving lessons and one activity. The lessons and activities were evaluated by the Institute's Director and consultants from National Geographic Society.

All twenty-two teachers expressed plans to utilize their developed curricular materials and the space shuttle photographs in their classroom instruction. Seventeen of the 22 teachers indicated that they planned to design and implement approximately 28 in-service workshops to district, local, state, or national professional meetings based on environmental curricula and space shuttle photographs acquired at the Institute. As an example, four of these teachers presented their demonstration lessons at the Texas Alliance for Geographic Education Conference on September 14, 1996.

The success of the Geography Institute for Teachers will continue to be evaluate for effectiveness through follow-up surveys and telephone interviews with participating teachers. The Institute had received exceptionally high ratings by these teachers. The teachers expressed renewed enthusiasm and commitment to "passing the torch" to the next generation of dedicated citizens who will search for solutions to global and environmental geography problems. If these results are indicative of what is in store for each of these teachers' classes, the goals of the Institute will have been realized.

ISSO * 1995-1996 * Annual Report