Development of an autonomous video rendezous and docking system

Video control systems using three flashing lights and two other types of docking aids were evaluated through computer simulation and other approaches. The three light system performed much better than the others. Its accuracy is affected little by tumbling of the target spacecraft, and in the simulations it was able to cope with attitude rates up to 20,000 degrees per hour about the docking axis. Its performance with rotation about other axes is determined primarily by the state estimation and goal setting portions of the control system, not by measurement accuracy. A suitable control system, and a computer program that can serve as the basis for the physical simulation are discussed

Experimental and simulation study results for video landmark acquisition and tracking technology

A synopsis of related Earth observation technology is provided and includes surface-feature tracking, generic feature classification and landmark identification, and navigation by multicolor correlation. With the advent of the Space Shuttle era, the NASA role takes on new significance in that one can now conceive of dedicated Earth resources missions. Space Shuttle also provides a unique test bed for evaluating advanced sensor technology like that described in this report. As a result of this type of rationale, the FILE OSTA-1 Shuttle experiment, which grew out of the Video Landmark Acquisition and Tracking (VILAT) activity, was developed and is described in this report along with the relevant tradeoffs. In addition, a synopsis of FILE computer simulation activity is included. This synopsis relates to future required capabilities such as landmark registration, reacquisition, and tracking

Multi-Mission Suitability of the NASA Ames Modular Common Bus

The obvious advantages of small spacecraft - their lower cost structure and the rapid development schedule - have enabled a large number of missions in the past. However, most of these missions have been focused on Earth observation from low Earth orbits. In 2006, the Small Spacecraft Division at the NASA Ames Research Center began the development of the Modular Common Bus, a spacecraft capable of delivering scientifically and technically useful payloads to a variety of destinations within 0.1 AU around the Earth. The core technologies used in the Common Bus design are a composite structure with body-mounted solar cells, an integrated avionics unit, and a high performance bipropellant propulsion system. Due to its modular approach, the Common Bus can be adapted to fit specific mission needs while still using a standardized and qualified set of components. Additionally a number of low cost launch vehicles are supported, resulting in overall mission costs of around $150M including the launch vehicle but excluding the science payloads. This significant reduction in cost and the shorter development time would enable NASA to conduct more frequent exploration missions within its budget and timeframe constraints, compared to the status quo. In this paper the suitability of the Common Spacecraft Bus for four different exploration scenarios is analyzed. These scenarios include a lunar orbiter, a lunar lander, a mission to a Sun-Earth Libration Point, and a rendezvous mission to a Near Earth Object. For each scenario, a preliminary design reference mission is developed and key design parameters for the spacecraft are determined

Study and simulation results for video landmark acquisition and tracking technology (Vilat-2)

The results of several investigations and hardware developments which supported new technology for Earth feature recognition and classification are described. Data analysis techniques and procedures were developed for processing the Feature Identification and Location Experiment (FILE) data. This experiment was flown in November 1981, on the second Shuttle flight and a second instrument, designed for aircraft flights, was flown over the United States in 1981. Ground tests were performed to provide the basis for designing a more advanced version (four spectral bands) of the FILE which would be capable of classifying clouds and snow (and possibly ice) as distinct features, in addition to the features classified in the Shuttle experiment (two spectral bands). The Shuttle instrument classifies water, bare land, vegetation, and clouds/snow/ice (grouped)

Eosinophilia in patients infected with the human immunodeficiency virus

The prevalence and significance of peripheral blood eosinophilia in patients infected with the human immunodeficiency virus (HIV) were evaluated. Fifteen of 119 consecutive patients had absolute eosinophil counts of > 450/mm3. During a mean follow-up period of 419 days eosinophilia could be identified as secondary to a parasitic infection in only one patient. Correlation with disease stage showed a higher rate of advanced disease in patients with absolute eosinophilia. In a multivariate regression analysis, only low CD4+ cell counts, not the CDC disease stage or the use of antiretroviral therapy or primary prophylaxis, contributed significantly to the prevalence of eosinophilia. It is concluded that expen-sive laboratory investigations in asymptomatic patients with advanced-stage HIV disease are neither necessary nor cost effectiv

Associations Between Hearing Performance and Physiological Measures - An Overview and Outlook

The current paper summarises the research investigating associations between physiological data and hearing performance. An overview of state-of-the-art research and literature is given as well as promising directions for associations between physiological data and data regarding hearing loss and hearing performance. The physiological parameters included in this paper are: electrodermal activity, heart rate variability, blood pressure, blood oxygenation and respiratory rate. Furthermore, the environmental and behavioural measurements of physical activity and body mass index, alcohol consumption and smoking have been included. So far, only electrodermal activity and heart rate variability are physiological signals simultaneously associated with hearing loss or hearing performance. Initial findings suggest blood pressure and respiratory rate to be the most promising physiological measures that relate to hearing loss and hearing performance