A summary of the 1983 Integrated Flywheel Technology Workshop

The use of flywheels to perform the functions of attitude control and/or energy storage on a variety of space missions was studied. Integrated Flywheel Technology was discussed. The four primary objectives are: (1) determine the potential of flywheels for energy storage system applications and for combined energy storage and attitude control concepts; (2) assess the state of the art (SOA) in integrated flywheel technology through a review of government sponsored programs; (3) identify those technology areas which are in critical need of development to meet projected space mission requirements; (4) scope a program for the coordinated development of the required technology

An Assessment of Integrated Flywheel System Technology

The current state of the technology in flywheel storage systems and ancillary components, the technology in light of future requirements, and technology development needs to rectify these shortfalls were identified. Technology efforts conducted in Europe and in the United States were reviewed. Results of developments in composite material rotors, magnetic suspension systems, motor/generators and electronics, and system dynamics and control were presented. The technology issues for the various disciplines and technology enhancement scenarios are discussed. A summary of the workshop, and conclusions and recommendations are presented

Description and simulation of an integrated power and attitude control system concept for space-vehicle application

An Integrated Power and Attitude Control System (IPACS) concept with potential application to a broad class of space missions is discussed. A description is given of the basic concept of combining the onboard energy storage and attitude control functions by storing energy in spinning flywheels which are used to provide control torques. A shuttle-launched Research and Applications Module (RAM) A303B solar-observatory mission having stringent pointing requirements (1.0 arc second) is selected to investigate possible interactions between energy storage and attitude control. A simulation of this spacecraft involving actual laboratory-model control-system hardware is presented. Simulation results are discussed which indicate that the IPACS concept, even in a failure-mode configuration, can readily meet the RAM A303B pointing requirements

Determination of ASPS performance for large payloads in the shuttle orbiter disturbance environment

A high fidelity simulation of the annular suspension and pointing system (ASPS), its payload, and the shuttle orbiter was used to define the worst case orientations of the ASPS and its payload for the various vehicle disturbances, and to determine the performance capability of the ASPS under these conditions. The most demanding and largest proposed payload, the Solar Optical Telescope was selected for study. It was found that, in all cases, the ASPS more than satisfied the payload's requirements. It is concluded that, to satisfy facility class payload requirements, the ASPS or a shuttle orbiter free-drift mode (control system off) should be utilized

Integrated Flywheel Technology, 1983

Topics of discussion included: technology assessment of the integrated flywheel systems, potential of system concepts, identification of critical areas needing development and, to scope and define an appropriate program for coordinated activity

Real-time digital-computer-hardware simulation of a spacecraft with control-moment-gyroscope stabilization

Computer simulation of Apollo Telescope Mount to evaluate performance of control moment gyroscope system used for stabilizatio

Synoptic-scale controls on the δ18O in precipitation across Beringia

Oxygen isotope records of precipitation (δ18Oprecip) from Beringia are thought to reflect synoptic-scale circulation changes associated with the Aleutian Low. To delineate the spatial pattern of δ18Oprecip associated with the two dominant modes of Aleutian Low circulation, we combine modern δ18Oprecip and deuterium excess data with climate reanalysis and back-trajectory modelling. Aleutian Low strength and position are revealed to systematically affect regional moisture source and δ18Oprecip; whereby a strengthened Aleutian Low causes lower (higher) δ18Oprecip in western (eastern) Beringia. We compare a new 100-year-long δ18O record from the Aleutian Islands with the North Pacific Index, the primary indicator of Aleutian Low strength, and find a significant positive relationship (r = 0.43, p < 0.02, n = 28) that tracks late 20th century change. This study demonstrates synoptic-scale circulation controls on our isotope record, and provides a coherent framework for interpreting existing and emerging paleo-isotope data from the region

An evaluation of the TRIPS computer system

The TRIPS system employs a new instruction set architecture (ISA) called Explicit Data Graph Execution (EDGE) that renegotiates the boundary between hardware and software to expose and exploit concurrency. EDGE ISAs use a block-atomic execution model in which blocks are composed of dataflow instructions. The goal of the TRIPS design is to mine concurrency for high performance while tolerating emerging technology scaling challenges, such as increasing wire delays and power consumption. This paper evaluates how well TRIPS meets this goal through a detailed ISA and performance analysis. We compare performance, using cycles counts, to commercial processors. On SPEC CPU2000, the Intel Core 2 outperforms compiled TRIPS code in most cases, although TRIPS matches a Pentium 4. On simple benchmarks, compiled TRIPS code outperforms the Core 2 by 10% and hand-optimized TRIPS code outperforms it by factor of 3. Compared to conventional ISAs, the block-atomic model provides a larger instruction window, increases concurrency at a cost of more instructions executed, and replaces register and memory accesses with more efficient direct instruction-to-instruction communication. Our analysis suggests ISA, microarchitecture, and compiler enhancements for addressing weaknesses in TRIPS and indicates that EDGE architectures have the potential to exploit greater concurrency in future technologies

Adverse Events Post Smallpox-Vaccination: Insights from Tail Scarification Infection in Mice with Vaccinia virus

Adverse events upon smallpox vaccination with fully-replicative strains of Vaccinia virus (VACV) comprise an array of clinical manifestations that occur primarily in immunocompromised patients leading to significant host morbidity/mortality. The expansion of immune-suppressed populations and the possible release of Variola virus as a bioterrorist act have given rise to concerns over vaccination complications should more widespread vaccination be reinitiated. Our goal was to evaluate the components of the host immune system that are sufficient to prevent morbidity/mortality in a murine model of tail scarification, which mimics immunological and clinical features of smallpox vaccination in humans. Infection of C57BL/6 wild-type mice led to a strictly localized infection, with complete viral clearance by day 28 p.i. On the other hand, infection of T and B-cell deficient mice (Rag1−/−) produced a severe disease, with uncontrolled viral replication at the inoculation site and dissemination to internal organs. Infection of B-cell deficient animals (µMT) produced no mortality. However, viral clearance in µMT animals was delayed compared to WT animals, with detectable viral titers in tail and internal organs late in infection. Treatment of Rag1−/− with rabbit hyperimmune anti-vaccinia serum had a subtle effect on the morbidity/mortality of this strain, but it was effective in reduce viral titers in ovaries. Finally, NUDE athymic mice showed a similar outcome of infection as Rag1−/−, and passive transfer of WT T cells to Rag1−/− animals proved fully effective in preventing morbidity/mortality. These results strongly suggest that both T and B cells are important in the immune response to primary VACV infection in mice, and that T-cells are required to control the infection at the inoculation site and providing help for B-cells to produce antibodies, which help to prevent viral dissemination. These insights might prove helpful to better identify individuals with higher risk of complications after infection with poxvirus