Description:

Michael Donley is the team leader at WP-AFRL concerned with the behavior of coatings and surface chemistry in the space environment. Some of his concerns are the durability and thermal management characteristics of current and future flight systems. Our focus on "materials for the future" (i.e., light-weight polymeric & carbon containing materials in combination with thin metallic coatings) resonates with his efforts.

Specific goals of the AFRL / WUD 2 Thermal Control Coating (TCC) In House Research Group are to: (1) gain an understanding of currently used TCC's performance and degradation mechanisms; and (2) develop TCC's with improved space stable properties (i.e. longevity, better end-of-life performance, absorptance, emittance, electrical conductivity). His group has developed the AFRL / MLBT Space Combined Effects Primary Test & Research (SCEPTRE) facility to gain an understanding of how currently used and newly formulated TCC's perform in the geosynchronous and, in the near future, in the LEO environment.

Our MURI Center will complement his effort, bringing new expertise and techniques to add further leverage to his SCEPTRE data, and thereby effectively enlarging the interdisciplinary team which is already knowledgeable in spacecraft thermal management research issues. The WP Formulations Lab is also interested in improved conductivity coatings, again commensurate with our interests. It is clear that our MURI team will be a superb complement to this effort; very strong research ties and mutual visits are envisioned with this WP group.


Dr. Arthur H. Edwards

Description:

Dr. Edwards is a theoretician at AFRL whose expertise encompasses the following areas: theory of defects in electronics materials including oxides; electronic structure of solids and interfaces; quantum chemical methods for solids; electrically and optically induced phase transitions in chalcogenides; and theory of chemical reactions at interfaces and surfaces. Dr. Edwards would like very much to work with the MURI team on such issues as oxidation of Si, Al, and C, as well as diffusion of oxygen through the oxides of these materials. In addition, Dr. Edwards could lend expertise to the interaction of protons and ions with these oxides. The interaction between the MURI team and Dr. Edwards will likely be through a post-doc who would spend part time working with Dr. Edwards and performing calculations relevant to space effects on metal and semiconductor oxides. (It is anticipated that these calculations would relate directly to experiments being conducted in the lab of a MURI team member.)


Dr. Rainer Dressler

Description:

Rainer Dressler is team leader of the "Chemical Processes in the Space Environment" task of the Space Vehicles Directorate at Hanscom AFB, Massachusetts. His task investigates hyperthermal ion-neutral processes associated with non-equilibrium plasmas such as those associated with low-Earth orbiting spacecraft, electric propulsion thrusters, meteors, reentry plasmas, and future hypersonic vehicle SCRAM jet engines. Rainer's team will apply the Hyperthermal Ion Beam Facility at AFRL to elucidate the fundamental dynamics of targeted gas-phase ion-molecule reaction processes. In conjunction with parallel theoretical efforts by MURI members, this work will provide a basis for understanding the ion-space-material surface scattering studies conducted in Dennis Jacob's group.


Dr. Ed Murad

Description:

Ed Murad is the technical advisor of the Space Weather Center of Excellence (VSBX) of the Space Vehicles Directorate at AFRL. The Space Weather Center of Excellence advances the Space Science and Technology Base of the AF to assure reliability and survivability of C³ and surveillance systems operating throughout the space environment. He has studied surface reactions related to the space shuttle glow phenomenon and meteors passing through the ionosphere. He has told us that spacecraft drag is an important yet unresolved issue in the calculation of satellite lifetimes in low earth orbit - better models to describe momentum transfer (drag) in gas/surface collisions are needed. Given our experimental and theoretical expertise, Ed has expressed considerable interest in partnering with our MURI.


Dr. Shawn Phillips

Description:

Dr. Shawn Phillips is the project leader of the Polymer Working Group (AFRL/PRSM, Edwards AFB). Over the last 1.5 years, Phillips and his coworkers have been synthesizing hybrid organic/inorganic polymers, termed POSS (Polyhedral Oligomeric Silsesquioxane), as candidate materials for space applications. In collaboration with researchers at U. of Florida and Wright Patterson, Phillips has begun testing the relative stability of these compounds in simulated LEO and GEO environments. Early results indicate that the polymer rapidly forms a passivating SiO2 layer that self-anneals in the presence of VUV radiation. Following this treatment, the compounds show resistance to degradation when bombarded with 3 eV O-atoms.

It is important that these O-atom tests be extended to higher kinetic energies and that POSS compounds be studied under bombardment by ions & electrons. The diverse backgrounds and capabilities of our MURI team can be brought to bear on this problem. Mechanistic studies will be undertaken to determine the resistance and to what degree the passivation layer forms. Theoretical modeling of the interaction of POSS polymers with the LEO environment may help in the rational design of more materials with enhanced resistance. Dr. Phillips is enthusiastic about working with our MURI. He will synthesize novel polymeric materials with unique physical properties. We will help him identify the mechanistic pathways by which his POSS materials evolve under O, O⁺, e^-, and hv attack.


Bruce Banks

Description:

Bruce Banks is a world-recognized leader in the selection, testing, and qualification of materials for use in space. He leads a group that deals with all aspects of space environmental effects. He understands all the hazards of the various space environments, and has been involved in the qualification of most new materials for use in low Earth orbit over the past 20 years. He leads a group that has significant expertise in the testing of materials, in both laboratory and space environments, for durability to atomic oxygen, UV/VUV light, and the combination of the two.

Mr. Banks is enthusiastic about sharing information with our MURI team. Mr. Banks's ongoing work will complement the MURI effort perfectly, as it tends to focus on practical materials issues relevant to spacecraft. His expertise will make him a valuable consultant who will help bridge the gap between fundamental studies and real-world problems. In addition to his role as a consultant to the MURI effort, Mr. Banks is eager to test in his laboratory any new materials developed in our MURI.


Billy Kauffman

Description:

Mr. Billy Kauffman is the manager of the NASA Space Environmental Effects (SEE) Program, which is the current embodiment of what was once the Long Duration Exposure Facility (LDEF) project. The SEE program funds technology development activities and acts as a clearinghouse for all information pertaining to space environmental effects. This program provides advocacy for environmental definition models, life certification methodology, databases, design guidelines, test standards, flight opportunities, and national test facilities. The mission of the NASA SEE program makes it the ideal conduit for the dissemination of new information produced by this MURI.

The SEE program will advocate for and coordinate interactions between the MURI team and space environmental effects researchers at NASA Marshall Space Flight Center. These researchers have a host of environmental testing capabilities that are used to service various NASA missions and would like to use the fundamental knowledge gained from the MURI effort to guide them in the improvement of their testing methodologies. They are particularly interested in combined environment effects on contaminant deposition, combined atomic oxygen and ultraviolet environmental effects, and modeling materials ageing phenomena for very long duration missions in space. The Marshall researchers would be happy to test new materials in their facilities and to assist the MURI team in identifying space flight opportunities for these materials. It is anticipated that information transfer with SEE Program personnel would involve occasional visits of MURI team member (faculty, student, or post-doc) to Marshall Space Flight Center, as well as visits to MURI institutions by Marshall staff.

Description:

Dr. Pippin has been working in the area of space environmental effects for 15 years at Boeing, and he has been involved in the organization of 8 materials flight experiments. His primary interest is in the long-term performance of materials in the space environment. Dr. Pippin's current job duties include support to the International Space Station, the Space-Based Laser, and other advanced projects. Dr. Pippin will consult with the MURI team on materials issues of interest to Boeing projects and will help ensure that the MURI research effort addresses problems of critical relevance to space-based operations. In addition to his role as a consultant, Dr. Pippin will (1) help the MURI team identify flight opportunities for new materials, (2) utilize the laboratories of MURI team members for ground-based testing of Boeing-relevant materials, and (3) coordinate a research and development project that can be done by an undergraduate or graduate student at a Boeing facility.

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