A mission template for exploration and damage mitigation of potential hazard of Near Earth Asteroids

The Apophis Exploratory and Mitigation Platform (AEMP) concept was developed as a prototype mission to explore and potentially deflect the Near Earth Asteroid (NEA) 99942 Apophis. Deflection of the asteroid from the potential 2036 impact will be achieved using a gravity tractor technique, while a permanent deflection, eliminating future threats, will be imparted using a novel albedo manipulation technique. This mission will serve as an archetypal template for future missions to small NEAs and could be adapted to mitigate the threat of collision with other potential Earth-crossing objects.     

Near-real time monitoring of the TEC fluctuations over the northern hemisphere using GNSS permanent networks

Since the early 1990s, global positioning system measurements have been used to study of the state and rapid changes of the Total Electron Content in the ionosphere. Currently, the increasing number of permanent stations makes it possible to generate maps of the irregularities in the ionosphere for specified regions with sub-daily resolution. The main goal of this work was to apply global navigation satellite system observations to obtain information about ionospheric variability around the North Geomagnetic Pole. In order to detect the ionospheric disturbances, 30-s observation data was used. The Rate of Total Electron Content Index was applied as a measure of the variability in the ionosphere. The first analyses were executed using more than 100 permanent stations. The results show two kinds of products: 2-hour maps in spherical geomagnetic coordinates and daily maps presenting the occurrence of the strong Total Electron Content fluctuations as a magnetic local time function, for the most disturbed days of April 2010. Apart from the main product of the algorithm, the Rate of Total Electron Content time series for individual satellite tracks was presented. The results demonstrated very good sensitivity of the obtained maps, which can detect even quite weak disturbances. The presented algorithm developed at the Geodynamic Research Laboratory of the University of Warmia and Mazury, in cooperation with Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation, will be applied in the near future to create near-real time service of the conditions in the ionosphere based on the Global Navigation Satellite Systems observations.     

The conundrum of software estimation models

There are many sophisticated models and methods for estimating the size, cost, and schedule of software projects. However, the ability to accurately estimate software cost, size, or schedule is still dubious. In general, the predictive accuracy of models for estimating software development cost and schedule has not been shown to be better than “within 25 percent of actual cost or schedule, about one half of the time”, especially for Department of Defense software efforts. The same is true for software size estimating models and methods, although there are some studies that have shown superior results. For software support (or maintenance) cost estimation, no model has been demonstrated to be accurate. This paper presents a summary of efforts performed to date which demonstrate the accuracy (or lack thereof) of software models. The results of several studies in the areas of software development cost and schedule estimation, size estimation, and support cost estimation are presented to show what these models can and cannot do. Some ideas for improvement are also presented, including the results of some studies which may lead to a resolution of the accuracy conundrum which currently exists     

Stochastic battery discharge in portable communication devices

The objective of this work is to explore ways in which performance of battery systems can be enhanced through the use of energy-efficient battery management techniques. The phenomenon of charge recovery that takes place under pulsed discharge conditions is identified as a mechanism that can be exploited to enhance the capacity of a cell in a portable communication device. The bursty nature of many data traffic sources suggests that data transmissions in communication devices may provide natural opportunities for charge recovery. We model the data source as a stochastic process and let the cell discharge be driven by such a process. We use a model of a dual lithium ion insertion cell to identify the improvement to cell capacity that results from the stochastic discharge. The insight from this study leads us to propose discharge shaping techniques that tradeoff energy efficiency with delay in the required current supply     

Embedded information system re-engineering

Currently fielded embedded information systems face readiness challenges imposed by evolving missions and extended service lifespans. The ability to overcome these challenges is constrained by such factors as shrinking budgets, limited computational capacity and diminished manufacturing sources effects that impact both hardware and software options. Wholesale redevelopment is often cost prohibitive, particularly since large portions of embedded applications continue to fulfil mission requirements. Solutions must preserve prior investments while providing efficient pathways for continued technology refresh. A technology solution for affordable modernization of legacy system software is being development. The Embedded Information System Re-engineering (EISR) project is developing an automation-assisted JOVIAL-to-C re-engineering capability that permits simultaneous modernization of both the structure and source language of legacy embedded applications. Engineers will be able to apply the proven labor-saving visualization and analysis features of modern CASE tools to legacy JOVIAL applications. EISR will thus allow the DoD to recapture previous investments in proven legacy algorithms and mission capabilities while permitting the full exploitation of COTS economies of scale. This paper describes in brief the goals and objectives of the EISR project, and provides the current status of the EISR capability.     

Markets and Models for Large-Scale Courseware Development

Computer-aided instruction (CAI) has not achieved widespread use, even though experimental results have been promising, because of a complex of technical, economic, and social factors. The problems these factors produce might be overcome if a major ?market success? could be achieved with CAI systems. One potentially high-volume market, having probably a lower resistance to profound innovation than other sectors of education, is the junior college. To achieve a market success which would catalyze public and private investment to sustain the growth and dissemination of CAI requires technical solutions in the areas of hardware, software, and courseware. Courseware is a term designating the applications programs for CAI systems and associated textual, audio-visual, and other materials of instruction. Two different approaches to the production of courseware and their underlying philosophies are discussed and contrasted. The extent to which these different models of courseware design and development might lead toward the goal of mass dissemination is highlighted.     

An analysis of temperature fields in rotating fluid

A possible variant presented for solving the equation of motion of a rotating flow is more general with respect to the variants known in the literature. On the basis of the simultaneous solution of the equations of motion and energy, the temperature fields are determined under changes of the rotation nature.     

Some regularities in the relationship of limb coronal mass ejections with eruptive prominences and post-eruptive arcades

A positive correlation is shown to exist between the angular sizes (in the sky plane) of eruptive prominences and/or post-eruptive arcades and coronal mass ejections (CMEs) associated with them. New regularities are found that characterize the relationship between the latitude of eruptive prominences (post-eruptive arcades) and the latitude position of CMEs associated with them in the field of view of a coronagraph. An interpretation of these regularities is given.     

Fiber-optic gyros and quartz accelerometers for motion control

In article the opportunity of use strapdown inertial navigation system (SINS) on the base of fiber-optic gyroscopes and quartz accelerometers corrected from star sensors and satellite navigation equipment (SNE) for perspective interplanetary spacecrafts motion control on phases of interplanetary trajectory insertion, trajectory correction, and braking during transition to Mars orbit is investigated. Results of onboard control complex accuracy characteristics estimation are presented at the given dynamic spacecraft scheme which is taking into account the liquid oscillations in tanks and structure elements elasticity. At modelling the errors of measuring devices installation, errors of SINS initial alignment and instrumental errors of SINS sensitive elements, variation of control engines parameters were taken into account. The structure of the developed complex of imitation modelling of interplanetary spacecraft controlled motion is resulted. Estimations of active flight legs realization accuracy were received by a method of statistical modelling of spacecraft controlled motion