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301.
Douglas A. Vakoch 《Acta Astronautica》2011,68(3-4):512-519
With recently growing interest in the Active Search for Extraterrestrial Intelligence (SETI), in which humankind would send intentional signals to extraterrestrial civilizations, there have been increased concerns about appropriate policy, as well as the role of space law and ethics in guiding such activities. Implicit in these discussions are notions of responsibility and capability that affect judgments about whether humans or other civilizations should initiate transmissions. Existing protocols that guide SETI research address transmissions from Earth, but there is debate over whether these guidelines should inform de novo transmissions as well. Relevant responsibilities to address include (1) looking out for the interests of humankind as a whole, (2) being truthful in interstellar messages, and (3) benefiting extraterrestrial civilizations. Our capabilities as a species and a civilization affect how well we can fulfill responsibilities, as seen when we consider whether we will be able to reach consensus about message contents (and whether that would be desirable), and whether we have the capacity to decode messages from beings that rely on different sensory modalities. The interplay of these responsibilities and capabilities suggests that humankind should place increased emphasis on Active SETI. 相似文献
302.
Structural health management technologies for inflatable/deployable structures: Integrating sensing and self-healing 总被引:1,自引:0,他引:1
Erik J. Brandon Max Vozoff Elizabeth A. Kolawa George F. Studor Frankel Lyons Michael W. Keller Brett Beiermann Scott R. White Nancy R. Sottos Mark A. Curry David L. Banks Robert Brocato Lisong Zhou Soyoun Jung Thomas N. Jackson Kevin Champaigne 《Acta Astronautica》2011,68(7-8):883-903
Inflatable/deployable structures are under consideration as habitats for future Lunar surface science operations. The use of non-traditional structural materials combined with the need to maintain a safe working environment for extended periods in a harsh environment has led to the consideration of an integrated structural health management system for future habitats, to ensure their integrity. This article describes recent efforts to develop prototype sensing technologies and new self-healing materials that address the unique requirements of habitats comprised mainly of soft goods. A new approach to detecting impact damage is discussed, using addressable flexible capacitive sensing elements and thin film electronics in a matrixed array. Also, the use of passive wireless sensor tags for distributed sensing is discussed, wherein the need for on-board power through batteries or hardwired interconnects is eliminated. Finally, the development of a novel, microencapuslated self-healing elastomer with applications for inflatable/deployable habitats is reviewed. 相似文献
303.
Jean A. Kéchichian 《Acta Astronautica》2011,68(11-12):1914-1930
An efficient self-contained trajectory optimization software is generated by making use of de Pontécoulant's analytic lunar theory removing the need for an outside third body ephemeris program to compute the lunar and solar position vectors at each integration step. The accelerations being further resolved along the rotating Euler–Hill frame after expansion to third order in the spacecraft radial distance, the adjoint differential equations are derived in a direct manner complementing the generation of the dynamic system of equations for full compatibility. Because the variation of parameters equations are cast in terms of the nonsingular equinoctial elements with the perturbation accelerations resolved in their analytic form along the rotating axes, the adjoint equations are also derived in the same manner providing a highly efficient and accurate system of equations for rapid computations in conjunction with Aerospace Corporation's NLP2 nonlinear programming codes to search for the initial values of the multipliers that steer the spacecraft towards its target orbit in minimum time. Numerical simulations show that the solutions obtained by the analysis developed in this paper are essentially identical to the more indirect approach based on the use of inertial accelerations obtained from a separate ephemeris generator and subsequent conversions to the thrust frame and equinoctial system. 相似文献
304.
We describe the results of determining the mass of the International Space Station using the data of MAMS accelerometer taken during correction of the station orbit on August 20, 2004. The correction was made by approach and attitude control engines (ACE) of the Progress transporting spacecraft. The engines were preliminary calibrated in an autonomous flight using the onboard device for measuring apparent velocity increment. The method of calibration is described and its results are presented. The error in station mass determination is about 1%. The same data of MAMS and similar data obtained during the orbit correction on August 26, 2004 were used for the analysis of high-frequency vibrations of the station mainframe caused by operation of the ACE of Progress. Natural frequencies of the ACE are determined. They lie in the frequency band 0.024–0.11 Hz. ACE operation is demonstrated to result in a substantial increase of microaccelerations onboard the station in the frequency range 0–1 Hz. The frequencies are indicated at which disturbances increase by more than an order of magnitude. The study described was carried out as a part of the Tensor technological experiment. 相似文献
305.
On going flights of Foton satellites allow to carry out research in the following domains: effect of space flight and outer space factors such as microgravity, artificial gravity and space radiation on physical processes and biological organisms. Experts from many Russian and foreign scientific institutions participated in the research. Over a period of time from 1973 to 1997 there were launched 11 BION satellites designed by the Central Specialized Design Bureau for carrying out fundamental and applied research in the field of space biology, medicine, radio physics and radiobiology with participation of specialists from the foreign countries.The goal of the present investigation was in developing a numerical simulator aimed at determining gas concentration and temperature fields established inside the scientific module of the spacecraft “Bion-M” and to perform optimization studies, which could meet strong requirements for air quality and temperature range allowable for operation of different biological experiments. 相似文献
306.
The results of reconstruction of uncontrolled attitude motion of the Foton M-2 satellite using measurements with the accelerometer TAS-3 are presented. The attitude motion of this satellite has been previously
determined by the measurement data of the Earth’s magnetic field and the angular velocity. The TAS-3 data for this purpose
are used for the first time. These data contain a well-pronounced additional component which made impossible their direct
employment for the reconstruction of the attitude motion and whose origin was unknown several years ago. Later it has become
known that the additional component is caused by the influence of the Earth’s magnetic field. The disclosure of this fact
allowed us to take into account a necessary correction in processing of TAS-3 data and to use them for the reconstruction
of the attitude motion of Foton M-2. Here, a modified method of processing TAS-3 data is described, as well as results of its testing and employing. The testing
consisted in the direct comparison of the motion reconstructed by the new method with the motion constructed by the magnetic
measurements. The new method allowed us to find the actual motion of Foton M-2 in the period June 9, 2005–June 14, 2005, when no magnetic measurements were carried out. 相似文献
307.
O. Koudelka G. Egger B. Josseck N. Deschamp C. Cordell Grant D. Foisy R. Zee W. Weiss R. Kuschnig A. Scholtz W. Keim 《Acta Astronautica》2009,64(11-12):1144-1149
A nanosatellite to investigate the brightness oscillations of massive luminous stars by differential photometry is currently developed by a Canadian/Austrian team within the BRITE (Bright Target Explorer) project. The first Austrian satellite funded by the Austrian Space Program, called TUGSAT-1/BRITE-Austria, builds on the space heritage of the most successful Canadian CanX-2 and MOST missions. The satellite makes use of recent advances in miniaturized attitude determination and control systems. Precision three-axis stabilization by small reaction wheels and a star tracker provides the necessary accuracy for the photometer telescope to the arcminute level. This will provide to the astronomers photometric data of the most massive stars with unprecedented precision; data which cannot be obtained from the ground due to limitations imposed by the terrestrial atmosphere.The paper describes the spacecraft characteristics and the ground infrastructure being established in support of the BRITE mission which will consist of a constellation of up to four nearly identical satellites allowing to carry out long-term observation of stars (magnitude +3.5) not only with respect to brightness variations, but also in different spectrum ranges. 相似文献
308.
R.M. Baevsky I.I. Funtova A. Diedrich A.G. Chernikova J. Drescher V.M. Baranov J. Tank 《Acta Astronautica》2009,65(7-8):930-932
Investigations of blood pressure, heart rate (HR), and heart rate variability (HRV) during long term space flights on board the “ISS” have shown characteristic changes of autonomic cardiovascular control. Therefore, alterations of the autonomic nervous system occurring during spaceflight may be responsible for in- and post-flight disturbances. The device “Pneumocard” was developed to further investigate autonomic cardiovascular and respiratory function aboard the ISS. The hard-software diagnostic complex “Pneumocard” was used during in-flight experiment aboard ISS for autonomic function testing. ECG, photoplethysmography, respiration, transthoracic bioimpedance and seismocardiography were assessed in one male cosmonaut (flight lengths six month). Recordings were made prior to the flight, late during flight, and post-flight during spontaneous respiration and controlled respiration at different rates.HR remained stable during flight. The values were comparable to supine measurements on earth. Respiratory frequency and blood pressure decreased during flight. Post flight HR and BP values increased compared to in-flight data exceeding pre-flight values. Cardiac time intervals did not change dramatically during flight. Pulse wave transit time decreased during flight. The maximum of the first time derivative of the impedance cardiogram, which is highly correlated with stroke volume was not reduced in-flight.Our results demonstrate that autonomic function testing aboard the ISS using “Pneumocard” is feasible and generates data of good quality. Despite the decrease in BP, pulse wave transit time was found reduced in space as shown earlier. However, cardiac output did not decrease profoundly in the investigated cosmonaut.Autonomic testing during space flight detects individual changes in cardiovascular control and may add important information to standard medical control. The recent plans to support a flight to Mars, makes these kinds of observations all the more relevant and compelling. 相似文献
309.
India has established a ‘critical mass’ in terms of EO infrastructure for disaster management. Starting from IRS 1A in 1980s to the most recent CARTOSAT-2, India's EO series of satellites are moving away from the generic to thematic constellations. The series of RESOURCESAT, CARTOSAT, OCEANSAT and forthcoming Radar Imaging Satellite (RISAT) satellites exemplifies the thematic characters of the EO missions. These thematic constellations, characterized with multi-platform, multi-resolution and multi-parameter EO missions, are important assets for disaster reduction. In the more specific term, these constellations in conjunction with contemporary EO missions address the critical observational gaps in terms of capturing the catastrophic events, phenomena or their attributes on real/near real time basis with appropriate spatial and temporal attributes.Using conjunctively the data primarily emanating these thematic constellations and all weather radar data from aerial platform and also from RADARSAT as gap-fillers has been a part of India's EO strategy for disaster management. The infrastructure has been addressing the observational needs in disaster management. The high resolution imaging better than one-meter spatial resolution and also Digital Elevation Models (DEM) emanating from Cartosat series are providing valuable inputs to characterize geo-physical terrain vulnerability. Radar Imaging Satellite, with all weather capability missions, is being configured for disaster management. At present, the current Indian EO satellites cover the whole world every 40 h (with different resolutions and swaths), and the efforts are towards making it better than 24 h. The efforts are on to configure RESOURCESAT 3 with wider swath of 740 km with 23 m spatial resolution and also to have AWiFS type of capability at geo-platform to improve the observational frequencies for disaster monitoring.India's EO infrastructure has responded comprehensively to all the natural disasters the country has faced in the recent times. As a member of International Charter on Space and Major Disasters, India has also been instrumental in promoting the related UN initiatives viz., RESAP of UN ESCAP, SPIDER of UN OOSA, Sentinel Asia of JAXA initiative and also of GEOSS initiative. The paper intends to illustrate India's EO strategy for disaster reduction. 相似文献
310.
Spatial structure of the magnetosheath of the Earth was studied under the conditions when no sharp (more than 40° during 5 min) changes in the interplanetary magnetic field direction were observed. On the basis of 24 flights of the Interball-1 satellite through the magnetosheath, it is found that three regions differing from each other by parameters of the field and plasma can be observed in the magnetosheath under the above-indicated conditions. These regions also differ from the solar wind region before front of the Earth’s magnetospheric bow shock. Empirical distributions of parameters were studied in each region. Taking into account the influence of the interplanetary magnetic field direction on the processes in the magnetosheath, the cases of quasi-perpendicular and quasi-parallel shock waves were considered separately. The study showed that the distribution of parameters in the selected regions (in the solar wind before front of the bow shock, in the magnetosheath behind the bow shock (post-shock), in the region of the magnetosheath with minimal fluctuations in the field, and in the inner magnetosheath) differ from each other at any interplanetary magnetic field direction. 相似文献