Les nanosatellites

Pages: 12 (2961 mots) Publié le: 13 avril 2011
Citizen Satellites (Article Scientific American)

EVER SINCE SPUTNIK KICKED OFF THE AGE OF SPACE SATELLITES more than fifty years ago, big institutions have dominated the skies. Almost all the many thousands of satellites that have taken their place in Earth orbit were theresult of huge projects funded by governments and corporations. For decades each generation of satellites has been more complicated and expensive than its predecessor, taken longer to design, and required an infrastructure of expensive launch facilities, global monitoring stations, mission specialists and research centers. In recent years, however, improvements in electronics, solar power and othertechnologies have made it possible to shrink satellites dramatically. A new type of satellite, called CubeSat, drastically simplifies and standardizes the design of small spacecraft and brings costs down to less than $100,000 to develop, launch and operate a single satellite--a tiny fraction of the typical mission budget of NASA or the European Space Agency. A CubeSat is about the size of a BeanieBaby box--appropriate, given that until recently, most scientists regarded CubeSats as little more than toys. The idea behind CubeSats is to give satellite developers standard specifications for size and weight and then combine many satellites--each made by a different group of scientists, graduate students, engineers--into a single rocket payload, usually piggybacking on other, more expensivemissions that have a bit of room to share. The high expense of the rocket launch thus gets spread out over all the participants, keeping costs low. And the CubeSat design standards allow participants to share design features and know-how and buy components off the shelf. Since the CubeSat concept was introduced, scientists from the U.S., Asia, Europe and Latin America have successfully launched atleast two dozen CubeSats, which have performed everything from biomedical research in microgravity to studies of the upper atmosphere. CubeSats' low cost, rapid development times and global user community, combined with their value as teaching tools, have made them increasingly popular. University teams--often consisting largely of college and grad students-have sprouted around the world. CubeSatsare also enabling small countries, start-up companies and even high school teams to develop their own space programs. Soon launch costs may come down to about $10,000--low enough for space amateurs to follow suit. We think that CubeSats could do for space what the Apple II did for computing 30 years ago: spark an economic and technological revolution by placing a well-known but formerlyinaccessible technology in the hands of just about everyone. LAUNCHING AN IDEA SMALL SATELLITES, weighing a few kilograms, have been around since the beginning of the Space Age; Sputnik 1 itself weighed just over 80 kilograms. But as rockets became more powerful, satellites grew larger and more complex, to the point where a typical communications or research satellite weighs several tons. Meanwhile"microsatellites"--spacecraft weighing between 10 and 100 kilograms--were pushed to the margins of space science but never disappeared completely. For example, atmospheric scientists sent

them up to explore the thermosphere, the layer of the atmosphere that extends from about 80 kilometers to about 600 kilometers above Earth's surface, and scores of OSCAR (for Orbiting Satellite Carrying AmateurRadio) communications satellites have been helping ham radio enthusiasts connect since the early 1960s. But the potential of small satellites really began to grow in the 1980s, thanks to electronic miniaturization and the development of precision manufacturing techniques and microelectro-mechanical systems, such as the tiny accelerometers now common in devices from iPhones to air bags. By the late...
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