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Deborah Scherrer Morris Cohen Todd Hoeksema Umran Inan Ray Mitchell Philip Scherrer 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
The International Heliophysical Year (IHY) aims to advance our understanding of the fundamental processes that govern the Sun, Earth, and heliosphere. The IHY Education and Outreach Program is dedicated to inspiring the next generation of space and Earth scientists as well as spreading the knowledge, beauty, and relevance of our solar system to the people of the world. In our Space Weather Monitor project we deploy a global network of sensors to high schools and universities to provide quantitative diagnostics of solar-induced ionospheric disturbances, thunderstorm intensity, and magnetospheric activity. We bring real scientific instruments and data in a cost-effective way to students throughout the world. Instruments meet the objectives of being sensitive enough to produce research-quality data, yet inexpensive enough for placement in high schools and universities. The instruments and data have been shown to be appropriate to, and usable by, high school age and early university students. Data contributed to the Stanford data center is openly shared and partnerships between groups in different nations develop naturally. Students and teachers have direct access to scientific expertise. 相似文献
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Mark A. Skinner Ray W. Russell Tom Kelecy Steve Gregory Richard J. Rudy Daryl L. Kim Kirk Crawford 《Acta Astronautica》2014
There exists a population of defunct satellites in the geo-stationary arc that potentially pose a hazard to current and future operational satellites. These drifting, non-station-kept objects have a variety of ages and sizes, and many are trapped in libration orbits around the Earth?s two gravitational potential wells (the non-spherical nature of the Earth gives rise to two geo-potential wells or “stable points” that affect objects in geostationary and geosynchronous orbits), whereas others were boosted to higher altitudes into so-called “graveyard” orbits. 相似文献
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The following report presents the main conclusions of the sixth and seventh EOPOLE workshops, held in Hydra, Greece, 3–4 May and Leiden, the Netherlands, 3–5 July 2000, respectively. The objectives of the first workshop were to evaluate different approaches to pricing policy and to assess how new developments in Earth observation and information technology are having an impact on Earth observation data pricing policy. Those of the second were to assess the constraints that legal frameworks impose on Earth observation and to explore ways in which they can be used to its advantage. 相似文献
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Ray A. Williamson 《Space Policy》1992,8(4):295-305
The US space programme continues to face difficulties in restructuring to meet existing political and fiscal conditions, in part because the basic structure and focus of the programme derive from the tensions of the Cold War. This paper argues that the world's new, more complicated political and economic conditions present a challenge for US policy makers that can be met with a renewed focus on the pursuit of science and the public good, within the context of international economic competition and political and scientific cooperation. 相似文献
57.
Xavier Collilieux Zuheir Altamimi David Coulot Tonie van Dam Jim Ray 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The International Terrestrial Reference Frame (ITRF), as a realization of the International Terrestrial Reference System (ITRS), is represented by a set of station positions and linear velocities. They are intended to be used as regularized coordinates to which some corrections should be added to access instantaneous coordinates. The latest ITRS realization is the ITRF2005, which has integrated time series of station positions to form long-term solutions for the four space geodetic techniques. Currently, a purely linear model is used to parameterize station displacements in the estimation process, plus occasional discontinuities in case of earthquakes or equipment changes. However the input data have been derived without applying surface loading models and so surface loading effects are supposed to be embedded in the coordinates as measured quantities. We evaluate the effect of applying a posteriori loading corrections, which include the effect of atmospheric, non-tidal ocean, and continental water loading, to time series of positions estimated from Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), and Global Positioning System (GPS) data. We notice that they reduce about 50% or more of the annual signals in the translation and scale parameter time series of the SLR and VLBI techniques, except in SLR Z translation. In general, the estimated secular frame definition is negligibly affected and estimated positions and velocities are not significantly modified for stations that have accumulated a large number of observations. A multi-technique combination of such derived frames allows concluding that, for some cases, loading model corrections might degrade co-located station coordinates almost as much as they benefit them. However, most significant improvement of the estimated secular coordinates is observed for stations with less than 100 estimated positions as demonstrated with a multi-technique combination. 相似文献