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301.
Marco B. Quadrelli Paul Backes W. Keats Wilkie Lou Giersch Ubaldo Quijano Jason Keim Daniel Scharf Rudranarayan Mukherjee S. Case Bradford Michael McKee 《Acta Astronautica》2011,68(7-8):947-973
This paper summarizes the modeling, simulation, and testing work related to the development of technology to investigate the potential that shape memory actuation has to provide mechanically simple and affordable solutions for delivering assets to a surface and for sample capture and possible return to Earth. We investigate the structural dynamics and controllability aspects of an adaptive beam carrying an end-effector which, by changing material equilibrium phases, is able to actively decouple the end-effector dynamics from the spacecraft dynamics during the surface contact phase. Asset delivery and sample capture and return are at the heart of several emerging potential missions to small bodies, such as asteroids and comets, and to the surface of large bodies, such as Titan. 相似文献
302.
303.
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
304.
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
305.
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
306.
307.
Korea’s space development program was created almost 40 years behind those of the advanced countries but it has nevertheless made remarkable progress. Korean space development has been focused on technology catch-up, where commercialization and growth of industrial competitiveness are important rationales. However, the program has several problems, including: lack of a space equipment manufacturing industry, total system companies in the space manufacturing industry and communication between industry and researchers, and much concentration of projects and initiatives in the Korean Aerospace Research Institute (KARI). This study analyzes the problem by comparing space agencies and programs in Korea and other countries, particularly Japan and the USA. It is shown that the role of a national laboratory is critical in space industry development and argued that KARI should make greater efforts to promote the Korean space industry by encouraging technology transfer, sharing equipment and communication between companies. For successful space development, the main organization – usually the national research institute – should change its role from a research-only laboratory to manager and supporter of space development and industry. Such a move would invigorate Korea’s space industry and allow it to catch up with countries with a similar environment. 相似文献
308.
Abrevaya XC Paulino-Lima IG Galante D Rodrigues F Mauas PJ Cortón E Lage Cde A 《Astrobiology》2011,11(10):1034-1040
The haloarchaea Natrialba magadii and Haloferax volcanii, as well as the radiation-resistant bacterium Deinococcus radiodurans, were exposed to vacuum UV (VUV) radiation at the Brazilian Synchrotron Light Laboratory. Cell monolayers (containing 10(5) to 10(6) cells per sample) were prepared over polycarbonate filters and irradiated under high vacuum (10(-5) Pa) with polychromatic synchrotron radiation. N. magadii was remarkably resistant to high vacuum with a survival fraction of (3.77±0.76)×10(-2), which was larger than that of D. radiodurans (1.13±0.23)×10(-2). The survival fraction of the haloarchaea H. volcanii, of (3.60±1.80)×10(-4), was much smaller. Radiation resistance profiles were similar between the haloarchaea and D. radiodurans for fluences up to 150?J m(-2). For fluences larger than 150?J m(-2), there was a significant decrease in the survival of haloarchaea, and in particular H. volcanii did not survive. Survival for D. radiodurans was 1% after exposure to the higher VUV fluence (1350?J m(-2)), while N. magadii had a survival lower than 0.1%. Such survival fractions are discussed regarding the possibility of interplanetary transfer of viable microorganisms and the possible existence of microbial life in extraterrestrial salty environments such as the planet Mars and Jupiter's moon Europa. This is the first work to report survival of haloarchaea under simulated interplanetary conditions. 相似文献
309.
Albi E Ambesi-Impiombato FS Peverini M Damaskopoulou E Fontanini E Lazzarini R Curcio F Perrella G 《Astrobiology》2011,11(1):57-64
The aim of this work was to analyze the possible alteration of thyrotropin (TSH) receptors in microgravity, which could explain the absence of thyroid cell proliferation in the space environment. Several forms of the TSH receptor are localized on the plasma membrane associated with caveolae and lipid rafts. The TSH regulates the fluidity of the cell membrane and the presence of its receptors in microdomains that are rich in sphingomyelin and cholesterol. TSH also stimulates cyclic adenosine monophosphate (cAMP) accumulation and cell proliferation. Reported here are the results of an experiment in which the FRTL-5 thyroid cell line was exposed to microgravity during the Texus-44 mission (launched February 7, 2008, from Kiruna, Sweden). When the parabolic flight brought the sounding rocket to an altitude of 264?km, the culture media were injected with or without TSH in the different samples, and weightlessness prevailed on board for 6 minutes and 19 seconds. Control experiments were performed, in parallel, in an onboard 1g centrifuge and on the ground in Kiruna laboratory. Cell morphology and function were analyzed. Results show that in microgravity conditions the cells do not respond to TSH treatment and present an irregular shape with condensed chromatin, a modification of the cell membrane with shedding of the TSH receptor in the culture medium, and an increase of sphingomyelin-synthase and Bax proteins. It is possible that real microgravity induces a rearrangement of specific sections of the cell membrane, which act as platforms for molecular receptors, thus influencing thyroid cell function in astronauts during space missions. 相似文献
310.
Periodic episodes of increased sunspot activity (solar electromagnetic storms) occur with 10-11 and 5-6 year periodicities and may be associated with measurable biological events. We investigated whether this sunspot periodicity characterized the incidence of Pap smear-determined cervical epithelial histopathologies and human physiologic functions. From January 1983 through December 2003, monthly averages were obtained for solar flux and sunspot numbers; six infectious, premalignant and malignant changes in the cervical epithelium from 1,182,421 consecutive, serially independent, screening Pap smears (59°9″N, 4°29″E); and six human physiologic functions of a healthy man (oral temperature, pulse, systolic and diastolic blood pressure, respiration, and peak expiratory flow), which were measured ~5 times daily during ~34,500 self-measurement sessions (44°56″N, 93°8″W). After determining that sunspot numbers and solar flux, which were not annually rhythmic, occurred with a prominent 10-year and a less-prominent 5.75-year periodicity during this 21-year study span, each biological data set was analyzed with the same curve-fitting procedures. All six annually rhythmic Pap smear-detected infectious, premalignant and malignant cervical epithelial pathologies showed strong 10-year and weaker 5.75-year cycles, as did all six self-measured, annually rhythmic, physiologic functions. The phases (maxima) for the six histopathologic findings and five of six physiologic measurements were very near, or within, the first two quarters following the 10-year solar maxima. These findings add to the growing evidence that solar magnetic storm periodicities are mirrored by cyclic phase-locked rhythms of similar period length or lengths in human physiology and pathophysiology. 相似文献