COFS 3: Multibody dynamics and control technology

COFS 3 is the third project within the Control of Flexible Structures (COFS) program. It deals with developing multibody dynamics and control technology for large space structures. It differs from COFS 1 and 2 in two respects. First, it addresses a more complex class of structure, and second it is basically a scale model ground test and analysis program while COFS 1 and 2 feature Shuttle flight experiments. The specific technology thrusts within COFS 3 are model sensitivities, test methods, analysis validation, systems identification, and vibration suppression. The COFS 3 project will develop the methods for using dynamically scaled models and analysis to predict the structural dynamics of large space structures. The project uses the space station as a focus because it is typical of the structures of interest and provides the first opportunity to obtain full-scale on-orbit dynamics data

Paper Session II-B - National Launch System Launch Operations

The National Launch System (NLS) is the nation\u27s next generation family of launch vehicles, and is being jointly developed by NASA and the Air Force. The three vehicle classes, capable of placing 20Klb, SOKlb, and SOKlb into low earth orbit (LEO), will initially be launched between 2001 and 2004 from Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). This paper describes the launch operations concepts currently envisioned for the NLS vehicles. Ground processing timelines, facilities, core stage processing options, launch support manpower estimates (as compared to the Space Shuttle), and new technologies will also be discussed. Launch processing costs will also be discussed as they relate to the total cost per flight of the existing Shuttle program

Paper Session II-B - Personal Launch System -Launch Site Processing Perspective

The Personnel Launch System (PLS) Is currently planned to supplement the Space Shuttle in the year 2000 by transporting eight passengers and two crewmembers to and from Space Station Freedom (SSF). Alternate PLS missions include satellite servicing and on-orbit rescue. The importance of the PLS assured access to space role is supported by recommendation No. 11 of the Augustine Committee\u27s Report of the Advisory Committee on the Future of the U.S. Space Program, which states: That NASA initiate design effort so that manned activity in the Space Station could be supported in the absence of the Space Shuttle. Crew recovery capability must be available immediately, and provision made for the relatively rapid introduction of a two-way personnel transport module on a selected expendable launch vehicle.** Winged high-lift and biconic medium-lift PLS spacecraft configurations are being studied in conjunction with several potential launch vehicles. At Kennedy Space Center (KSC), these spacecraft and booster concepts are being evaluated to determine processing requirements and attendant impacts on the ongoing Space Transportation System (STS) launch environment and infrastructure. From these launch site studies, design recommendations are being developed. One of the primary goals in the PLS study is to design a vehicle that is easy to maintain and turnaround for launch, particularly in view of the proposed 30-year life cycle. Current KSC studies and recommendations are therefore critical in developing operationally efficient spacecraft and launch vehicle designs that minimize launch site impacts

Creating Processes Associated with Providing Government Goods and Services Under the Commercial Space Launch Act at Kennedy Space Center

Kennedy Space Center (KSC) has decided to write its agreements under the Commercial Space Launch Act (CSLA) authority to cover a broad range of categories of support that KSC could provide to our commercial partner. Our strategy was to go through the onerous process of getting the agreement in place once and allow added specificity and final cost estimates to be documented on a separate Task Order Request (TOR). This paper is written from the implementing engineering team's perspective. It describes how we developed the processes associated with getting Government support to our emerging commercial partners, such as SpaceX and reports on our success to date

COFS 3 multibody dynamics and control technology

One of the results from the model definition study showed that the maximum scale factor for a replica model is .25. This is dictated by the fixed dimensions of the Large Spacecraft Lab. Replica scaling laws were applied to simplified theoretical models of joints and the joint/tube/joint system. The practical interpretation of the results for the specific Space Station configuration under study yielded a number of conclusions which are briefly discussed. Detailed suspension analyses were conducted to evaluate the ability of the suspended scale model to emulate the dynamic behavior of the free-free Space Station. The results indicated only a slight preference for smaller scales. A candidate erectable Space Station joint was fabricated at full scale, 1/4 scale and 1/3 scale in order to assess the comparability of the scaled joints to the full scale behavior. Another important question discussed is how well the inherent damping characteristics of the scaled joints compare to those of the full scale joint. The preliminary definition study yielded three separate scale factor recommendations for the scale model

Joint Density-Functional Theory of the Electrode-Electrolyte Interface: Application to Fixed Electrode Potentials, Interfacial Capacitances, and Potentials of Zero Charge

This work explores the use of joint density-functional theory, a new form of density-functional theory for the ab initio description of electronic systems in thermodynamic equilibrium with a liquid environment, to describe electrochemical systems. After reviewing the physics of the underlying fundamental electrochemical concepts, we identify the mapping between commonly measured electrochemical observables and microscopically computable quantities within an, in principle, exact theoretical framework. We then introduce a simple, computationally efficient approximate functional which we find to be quite successful in capturing a priori basic electrochemical phenomena, including the capacitive Stern and diffusive Gouy-Chapman regions in the electrochemical double layer, quantitative values for interfacial capacitance, and electrochemical potentials of zero charge for a series of metals. We explore surface charging with applied potential and are able to place our ab initio results directly on the scale associated with the Standard Hydrogen Electrode (SHE). Finally, we provide explicit details for implementation within standard density-functional theory software packages at negligible computational cost over standard calculations carried out within vacuum environments.Comment: 18 pages, 5 figures. Initially presented at APS March Meeting 2010. Accepted for publication in Physical Review B on Jul. 27, 201