Projects at Early Stages

A Comprehensive New Software Tool with a Monte Carlo Code Tuned to Simulate the Environment in Space

Our environment is constantly being traversed by what is known by the umbrella term of "radiation." In general, it includes individual charged particles which span the spectrum in energy from those that are unable to penetrate the skin to those which in some cases are capable of penetrating miles of rock. It also includes the highest energy photons, which we term gamma rays, and even their lower energy cousins, the x-rays. Even neutral particles such as neutrons and neutrinos fit under this umbrella term. At the surface of the Earth we sit in an environment that includes, at some level all, of these constituents. For example, the average person's body is traversed by approximately 100 relativistic muons per second, and neutrons and gamma rays bombard our bodies from the decay of various radioactive nuclides in our immediate environment that we ingest. In space, beyond the Earth's atmosphere, the radiation environment is significantly more intense. There are contributions from the so-called Galactic Cosmic Rays (GCR) which diffuse throughout our galaxy and impinge upon us after auguring their way first through the fringes of the Sun's effects and then through the Earth's magnetic field.

The Need to Model the Radiation Environment in Space
The ACCESS experiment is being designed to study the composition of the GCR flux in the very high energy region around 100 TeV per nucleon. The Sun itself contributes a constant stream of lower energy particles along with occasional outbursts in the form of directional flares which can be so intense as to be lethal, even to astronauts inside a typical spacecraft. The Earth's magnetic field provides a shield of sorts from the lower energy incident charged particles, and, at the same time, a source of radiation when it acts to funnel charged particle into the intense regions of trapped particles known as the radiation belts. Finally, there is an albedo of particles coming upward from the Earth itself. In part, this is a result of the interactions of the GCRs with the atmosphere, but even some contribution comes from sources at or near the surface. One should also mention the potential for sources that will come from within the spacecraft material and components themselves. All of these represent sources that require accurate modeling for a variety of planning purposes, some scientific and others dosimetry-related.

Categorizing and Measuring Sources
We can and have made great strides in categorizing and measuring the nature and composition of each of these sources as they exist in the native environments. However, it is the nature of these particles that they interact in very complex and transformative ways as they traverse matter. This is the primary subject of study in the field of elementary particle physics. While the enormous number of experiments done in the history of that field is staggering, attempts have been made to provide succinct mathematical models that include the transport for all of these kinds of particles traversing all forms of material. Given the probabilistic nature of the interactions, individual events are best modeled through the use of stochastic processes based on pseudo-random number generators whose expectation values coincide with the physics observable that we intend to model. Such simulations are termed Monte Carlo calculations.

Methodology
It is possible in principle to attempt to solve for the total statistical average results using analytic mathematical techniques. This has been the path chosen by the NASA/Langley group. Certainly, when the same physics is included, the results give the same global statistical results. In practice, however, such calculations are difficult to apply to anything more than the most simplistic bulk geometries, and present versions of the NASA/Langley code, for example, do not include the breadth of physics available in the Monte Carlo code we are planning to use. While such an approach has been very useful in predicting crew exposures in the past, it would be far less applicable than a Monte Carlo simulation to an experiment such as ACCESS. Clearly, the method of choice in elementary particle physics has been to use Monte Carlo codes to generate large samples of events based upon physics models and then to propagate the produced particles through realistic geometric models, using measured or modeled interaction probabilities. The results are summed to obtain global statistical estimates of the value of parameters of interest such as the total energy deposited in some particular volume. The project we are attempting to initiate with NASA is the development of a comprehensive new software tool that includes a Monte Carlo code tuned to simulate the environment in space.

Project Status
High level meetings have been held with JSC management and a collaboration has been established between the PI and counterparts at NASA JSC, Texas Tech University and at CERN, in Geneva, Switzerland. Funding from ISSO is being used to support one post-doctoral fellow to initiate the actual effort while attempting to get NASA funding in place by the end of the 1998 calendar year. It is anticipated that the eventual project will reach a level of up to four supported post-doctoral fellows, two at the University of Houston and two funded through Texas Tech University. The collaboration will include several senior scientists at NASA JSC and at CERN, as well. The initial effort is foreseen to take between two and three years with a continuation beyond that to provide evolving support for the code once it enters widespread use. The primary thrust of the funding effort is being directed at support for the ACCESS experiment. That experiment is in phase II planning and is base-lined for flight on the ISS beginning in 2004-5 and continuing for a period of three years. An alternative funding source within NASA also being explored is the prospect for support from the medical teams to provide the code to provide prediction of neutron fluxes on all present and future spacecraft.

Papers, Presentations, and Proposals
The PI presented a summary of the project to Dr. Bonnie Dunbar at NASA JSC on July 20, 1998. A supplemental proposal addressed to the Regional Universities Grant program proposal, submitted in 1997, was also submitted at that time. In addition, several internal NASA proposals that were directed toward obtaining funding for this project have been generated by our NASA-JSC collaborators. NASA JSC has expressed considerable interest in leveraging their funds with support from the State of Texas for post-doctoral fellows and students to work on this type of project. Such efforts are being coordinated with ISSO director, Dr. David Criswell. An invited paper was presented at the meeting, Predictions and Measurements of Secondary Neutrons in Space, at the Center for Advance Space Studies on Sept 28-30, 1998. An invited talk was given at JSC and another at the University of Houston on September 4, 1998, describing the proposed project by one of our CERN collaborators, Dr. Federico Carminati. Another pair of talks describing this project was presented on September 21, 1998 by Dr. Rene Brun, also of CERN.

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An Automated Support Process for Decision Making

University of Houston personnel scheduled several meetings with personnel at the Johnson Space Center directed to the Space Operations Management Office (SOMO) of JSC. Presentations culminated in a formal proposal to continue on-going research and development of analytical methods to optimize multiple criterion methods for mutually exclusive criteria and, further, for interactive or inter-dependent criteria in the planning and design of complex systems. UH has proposed to help SOMO plan the transition of NASA communication and tracking functions in support of missions to Mars. Mr. Charles Willow, a doctoral student in the Department of Industrial Engineering, assisted in the preparation of a 97-page monograph entitled "Multiple Criterion Computational Methods in Design." This treatise developed the logic for combining multiple criteria into a single figure of merit to evaluate alternative plans (systems) on a common cardinal scale. It employed probability theory in unconventional ways to achieve results. We believe that this method is unique in its application and, perhaps, significantly ahead of the state-of-the-art. Eight classes of mathematical models were developed to handle these methods exhaustively. These eight were divided into two classes. The first included cases with mutually exclusive criteria while the second class, yet to be submitted, will include the more complex interactive or inter-dependent criterion models. Both classes are described and explained in the monograph cited above. The submittal was enhanced by an article that Mr. Willow had completed entitled "A Stochastic Method for Mutually Exclusive Criteria in Systems Engineering Design," which he has submitted for publication. A sequel to the article has also been submitted to reviewers entitled "A Stochastic Approach to Designing Systems with Interactive Criteria." While awaiting commentaries from referees, Mr. Willow is developing his dissertation entitled "Multiple Criterion Function Methods in Design with Varying Relative Weights." Part of this dissertation will deal with modeling the support of missions to and about Mars. To publicize these methods, a technical paper was submitted to the archival journal of the International Council on Systems Engineering as part of a two-phase plan. An additional technical paper is being developed entitled "Integrating Logistics into the System Life Cycle." This document will describe the activities necessary to effectively integrate major supporting activities into the Life Cycle phases in order to emerge with an effective system.

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Astrobiology Initiative

NASA recently embarked on a significant new direction with the establishment of an Astrobiology Program. NASA defines astrobiology as the scientific study of the origin, distribution and future of life in the Universe. Typical questions to be explored include (1) How did life begin? (2) What are the key properties of habitable worlds? (3) Do other habitable worlds exist? (4) How has the Earth changed as a result of interaction between the biosphere and the environment on a geological time scale? (5) How will terrestrial life adapt and evolve in extraterrestrial environments? (6) How have physical factors such as gravity and radiation influenced our genetic history? Given such far-reaching questions, it is clear that the range of potentially relevant science disciplines is vast and clearly includes significant components of astronomy, chemistry, biochemistry, geosciences, and biology. NASA's astrobiology initiative is a broad science effort that includes basic research, technology development and flight missions. Recently, a virtual Astrobiology Institute managed by Ames Research Center was created and a cadre of 11 member institutions chosen with first year funding of $9 million and projected funding for year two of $20 million with future increases in subsequent years. Johnson Space Center (JSC) is included among the 11 initial members of the consortium. This is likely a prelude to significant involvement of JSC in the eventual analysis of samples from Mars.

The increasing funding for astrobiology at NASA in general and the emerging involvement of JSC in this kind of activity, represents a new opportunity for researchers at the University of Houston and throughout Texas. There is already active origin of life research at UH and given the broad scope of the astrobiology initiative, it is clear that many additional scientists may be able to participate. We, therefore, are organizing an astrobiology initiative under the auspices of the Institute of Space Systems Operations (ISSO). The immediate goal of this initiative will be to develop a strong focus group for astrobiology in the Houston area. To this end, a significant effort will be made to identify astrobiology researchers at UH and Rice and possibly nearby institutions; e.g., Texas A & M and University of Texas at Austin. It will be of especially high priority to establish a strong interaction with the new astrobiology group at the Johnson Space Center As part of this initiative, we expect to establish a seminar program and participate in organizing an astrobiology symposium at one or more appropriate local meetings; e.g., the annual bioengineering conference.

A second aspect of the initiative is a new research direction-understanding the origin and evolution of biochemical pathways. Recently, it has become technologically possible to sequence all the DNA in a given organism. Approximately 20 of these complete genome sequences are now available. Many more will be forthcoming in the next few years. In the majority of cases, it is possible to identify particular genes in newly sequenced organisms by comparison with genes whose products have been characterized in other organisms. Thus, it is typically possible to determine which biochemical pathways or versions of a particular pathway are present in a newly sequenced organism. Thus, genome data allow one to establish most of the likely biochemistry of a new organism. These data can also be readily correlated with previously sequenced organisms and placed in the context of known evolutionary relationships. When viewed from this perspective, the data set allows one to address many classic problems relating to the origin and early evolution of life on Earth. In particular, we expect to use whole genome data to identify the earliest biochemical reactions, the relative age of various pathways, and the mechanisms by which pathways have emerged. Tasks of this type require the integration of knowledge from diverse sources and will rely heavily on the emerging tools of bioinformatics.

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ISSO -- Institute for Space Systems Operations
1997-1998 Annual Report