Satellite attitude motion models for capture and retrieval investigations

The primary purpose of this research is to provide mathematical models which may be used in the investigation of various aspects of the remote capture and retrieval of uncontrolled satellites. Emphasis has been placed on analytical models; however, to verify analytical solutions, numerical integration must be used. Also, for satellites of certain types, numerical integration may be the only practical or perhaps the only possible method of solution. First, to provide a basis for analytical and numerical work, uncontrolled satellites were categorized using criteria based on: (1) orbital motions, (2) external angular momenta, (3) internal angular momenta, (4) physical characteristics, and (5) the stability of their equilibrium states. Several analytical solutions for the attitude motions of satellite models were compiled, checked, corrected in some minor respects and their short-term prediction capabilities were investigated. Single-rigid-body, dual-spin and multi-rotor configurations are treated. To verify the analytical models and to see how the true motion of a satellite which is acted upon by environmental torques differs from its corresponding torque-free motion, a numerical simulation code was developed. This code contains a relatively general satellite model and models for gravity-gradient and aerodynamic torques. The spacecraft physical model for the code and the equations of motion are given. The two environmental torque models are described

Aerodynamic flight control to increase payload capability of future launch vehicles

The development of new launch vehicles will require that designers use innovative approaches to achieve greater performance in terms of pay load capability. The objective of the work performed under this delivery order was to provide technical assistance to the Contract Officer's Technical Representative (COTR) in the development of ideas and concepts for increasing the payload capability of launch vehicles by incorporating aerodynamic controls. Although aerodynamic controls, such as moveable fins, are currently used on relatively small missiles, the evolution of large launch vehicles has been moving away from aerodynamic control. The COTR reasoned that a closer investigation of the use of aerodynamic controls on large vehicles was warranted

Simulation of spacecraft attitude dynamics using TREETOPS and model-specific computer Codes

The simulation of spacecraft attitude dynamics and control using the generic, multi-body code called TREETOPS and other codes written especially to simulate particular systems is discussed. Differences in the methods used to derive equations of motion--Kane's method for TREETOPS and the Lagrangian and Newton-Euler methods, respectively, for the other two codes--are considered. Simulation results from the TREETOPS code are compared with those from the other two codes for two example systems. One system is a chain of rigid bodies; the other consists of two rigid bodies attached to a flexible base body. Since the computer codes were developed independently, consistent results serve as a verification of the correctness of all the programs. Differences in the results are discussed. Results for the two-rigid-body, one-flexible-body system are useful also as information on multi-body, flexible, pointing payload dynamics

The control of gullies

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Aerodynamic flight control to increase payload capability of future launch vehicles

In this report, we provide some examples of French, Russian, Chinese, and Japanese launch vehicles that have utilized fins in their designs. Next, the aerodynamic design of the fins is considered in Section 3. Some comments on basic static stability and control theory are followed by a brief description of an aerodynamic characteristics prediction code that was used to estimate the characteristics of a modified NLS 1.5 Stage vehicle. Alternative fin designs are proposed and some estimated aerodynamic characteristics presented and discussed. Also included in Section 3 is a discussion of possible methods of enhancement of the aerodynamic efficiency of fins, such as vortex generators and jet flaps. We consider the construction of fins for launch vehicles in Section 4 and offer an assessment of the state-of-the-art in the use of composites for aerodynamic control surfaces on high speed vehicles. We also comment on the use of smart materials for launch vehicle fins. The dynamic stability and control of a launch vehicle that utilizes both thrust vector control (engine nozzle gimballing) and movable fins is the subject addressed in Section 5. We give a short derivation of equations of motion for a launch vehicle moving in a vertical plane above a spherical earth, discuss the use of a gravity-turn nominal trajectory, and give the form of the period equations linearized about such a nominal. We then consider feedback control of vehicle attitude using both engine gimballing and fin deflection. Conclusions are stated and recommendations made in Section 6. An appendix contains aerodynamic data in tabular and graphical formats

Phase I/II Archaeological Testing on Fleet Street (18AP111), Cornhill Street (18AP112), and 26 Market Space (18AP109), for the Proposed Fleet and Cornhill Streets Reconstruction Project, Annapolis, Maryland, 2008

From 3/31/08 to 5/30/08 staff from the Department of Anthropology, University of Maryland, College Park (UMCP), Archaeology in Annapolis Project, conducted archaeological testing on city-owned public right-of-ways at 26 Market Space (18AP109), on Fleet Street (18AP111), and on Cornhill Street (18AP112) prior to the upcoming undergrounding and replacement of city-owned utilities along and beneath these streets. In addition, from 06/02/08 to 06/20/08, undergraduate and graduate students enrolled in the University of Maryland, Field School in Urban Archaeology conducted further testing of city-owned public right-of-ways on Cornhill Street (18AP112). This Phase II investigation has been conducted at the request of the City of Annapolis, Department of Public Works (DPW) as part of the Fleet and Cornhill Streets Reconstruction Project. The project area comprises the streetscapes of what is referred to as the Fleet-Cornhill neighborhood. Eleven test units were used to evaluate archaeological integrity and significance of these sites and to evaluate the potential effects of planned construction on archaeological resources. Background research shows that the Fleet Street neighborhood was initially developed in the late 17th and early 18th century. Throughout the later 18th, 19th and 20th centuries the area became known as an ethnically diverse working class neighborhood in the heart of the city. Historical residents of the project area have included in the early 20th century native people of European, African descent, and a community of Russian Ashkenazi Jews in the early 20th century. Previous archaeological investigations found evidence of intact archaeological resources within the project area dating from the 18th to 20th centuries. In addition to providing evidence of patterns of Annapolis’ historical urbanization, several features excavated in the course of this project have shed light on the development of public space within this working class neighborhood. These features include a corduroy or log road dating to the first quarter of the 18th century; what is believed to be a Yoruba ritual bundle dating to the first quarter of the 18th century; and a series of city improvements (i.e. curbs, sidewalks, and a public well) dating from the 18th through 20th centuries. A high degree of archaeological integrity at all three sites has the potential to add considerable knowledge concerning both Annapolis city development, and an ethnically diverse working class community. All three sites are eligible for inclusion in the National Register of Historic Places under Criterion D. Because of the integrity and uniqueness of the archaeological record within the project area, it is recommended that further archaeological research be done. Included within this recommendation is the need to process flotation and macrobotanical samples recovered in the fiel

Why build a silo, and how?

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Phase II Archaeological Testing on Wye Greenhouse (18TA314), Talbot County, Maryland, 2008

From October 27, 2008 to November 24, 2008 staff from the Department of Anthropology, University of Maryland, College Park (UMCP), Archaeology in Annapolis Project, conducted archaeological testing on the Wye House Greenhouse (18TA314), Talbot County, Maryland. This Phase II investigation has been conducted at the request of the Greenhouse’s current owner, Mrs. Mary Tilghman, prior to planned Greenhouse foundation stabilization efforts. The project area for this Phase II archaeological investigation comprises the immediate exterior perimeter of the Wye Greenhouse foundation. Seven test units were excavated in the course of this project to evaluate archaeological integrity and to evaluate the potential effects of planned stabilization efforts on archaeological resources. In addition to questions of archaeological integrity, research questions guiding this project focused on the architectural development of the Wye Greenhouse as well as its social use, both by members of the Lloyd family and the plantation’s enslaved African-American inhabitants. Background historical research and oral histories differ concerning the Greenhouse’s initial date of construction. Historical research suggests a construction date of the c. 1770s, while oral histories suggest an initial date of construction of c. 1740s. Archaeological testing has shown that the Greenhouse underwent two major developmental phases—with the main block of the Greenhouse having been constructed in the 1770s and the East and West Wings and hypocaust system added in the mid 1780s. In addition to providing evidence of the Greenhouse’s structural change, levels and features excavated in the course of this project have shed light on the social use of the Wye Greenhouse throughout the 18th and 19th centuries. Artifact deposits analyzed in this report detail the Lloyd family’s use of the Greenhouse as both a social space and as a symbol of 18th century opulence. Artifact analyses also shed light on the use of the Greenhouse’s north shed as a slave quarter from the 1790s through the 1840s. Testing in the course of this project has concluded that there is a high degree of archaeological integrity within the project’s area of potential effect. In addition, testing has determined that intact archaeological resources have the distinct potential to add a considerable depth of historical knowledge concerning the Greenhouse’s structural change and social use throughout the 18th and 19th centuries. Archaeological evidence detailed in this report should be read as supporting evidence for the Greenhouse’s inclusion on the National Register of Historic Places

Combining Metabolic Engineering and Electrocatalysis: Application to the Production of Polyamides from Sugar

Biorefineries aim to convert biomass to a spectrum of products ranging from biofuels to specialty chemicals. To achieve economically sustainable conversion it is crucial to streamline the catalytic and downstream processing steps. Here we report a route that integrates bio- and chemical catalysis to convert glucose into bio-based unsaturated nylon 6,6. An engineered strain of Saccharomyces cerevisiae, with the highest reported muconic acid titer of 559.5 mg L-1 in yeast, was used as the initial biocatalyst to convert glucose into muconic acid. Without any separation, muconic acid was further electrocatalytically hydrogenated to 3-hexenedioic acid with 94% yield, despite the presence of all the biogenic impurities. Bio-based unsaturated nylon 6,6 (unsaturated polyamide 6,6) was finally obtained by polymerization of 3-hexenedioic acid with hexamethylenediamine, demonstrating the integrated design of bio-based polyamides from glucose

Occupant Dynamics in Rollover Crashes: Influence of Roof Deformation and Seat Belt Performance on Probable Spinal Column Injury

Motor vehicle crashes are the leading cause of death in the United States for people ages 3–33, and rollover crashes have a higher fatality rate than any other crash mode. At the request and under the sponsorship of Ford Motor Company, Autoliv conducted a series of dynamic rollover tests on Ford Explorer sport utility vehicles (SUV) during 1998 and 1999. Data from those tests were made available to the public and were analyzed in this study to investigate the magnitude of and the temporal relationship between roof deformation, lap–shoulder seat belt loads, and restrained anthropometric test dummy (ATD) neck loads