Technicians work on Telstar, the first TV satellite, before its - TopicsExpress


Technicians work on Telstar, the first TV satellite, before its launch by Thor Delta rocket on July 10, 1962. The number of objects in Earth orbit has increased steadily, by 200 per year on average. The objects here are an artist’s impression based on actual density data but are shown at an exaggerated size to make them visible at this scale. Iridium, which notes it “is the only satellite communications company that offers truly global voice and data communications coverage,” employs a network of 66 satellites that spin around the Earth a few hundred miles up. The company had an inauspicious start—it went bankrupt in 1999 soon after going public—and it’s still relatively small. Revenues last quarter were about $100 million, and it has about 705,000 subscribers. Like others in the high-end communications business, it has a symbiotic relationship with the defense establishment. But no company better represents the potential and awesome power of the subject I’ve chosen for the final installment of this series on our invisible modern wonders: communications satellites. Only satellites can truly move signals (and the products and services they contain) from anywhere to anywhere—to emerging markets, to the deserts and mountains, to ships at sea, or to cars stuck in traffic on I-95—with a great deal of precision. Pretty much every item launched into space in the first half of the 20th century fell back to Earth after it ran out of fuel or momentum. None managed to travel far enough to gain the magic balance between momentum and gravity that would keep it in orbit. Then, on Oct. 4, 1957, the Soviet Union launched Sputnik and helped ignite the space race. A few months later, the U.S. managed to launch its first satellite, the 30-pound Explorer 1 (thanks in part to the expertise of German rocket scientist Wernher von Braun). The original U.S. satellites were designed primarily to gather information and to transmit it back to Earth. Explorer 1 detected cosmic rays, for example, before stopping its transmissions in 1958. It would fall back to Earth in 1970. That was an impressive achievement. But satellites would truly become indispensable only when they developed the ability to receive data from Earth and then to beam it back with great efficiency—to become, as the Satellite Industry Association calls them, “cell towers in the sky.” That came in 1962, with the launch of Telstar 1, which the Canadian-based satellite company Telesat describes as “the world’s first active communications satellite.” Ranging around in low orbit—between 300 and 500 miles above the Earth for seven months, “its technology of receiving radio signals from the ground, and then amplifying and retransmitting them over a large portion of the earth’s surface, set the standard for all communications satellites that followed.” In many ways, Telstar 1 and its successors provided the template for our mobile and digital world—vastly expanding the range of communications and what could be communicated and delivered, from where, and to where. Over the coming decades, more satellites went up, generally backed by consortia of government agencies and telecommunications companies. And they grew more sophisticated. Satellites launched into geosynchronous orbit—more than 22,000 miles above the Earth—could cover a great deal of territory as they tracked the planet’s rotation. A system of three satellites in geosynchronous orbit can cover the world, whereas several dozen satellites in low Earth orbit would be required to do the same. The first users were telephone companies, who used satellite as an alternative to long-distance wires. Then, in the 1970s, HBO used a satellite to beam movies directly to subscribers’ homes. News and sports companies used satellites to provide live coverage. “By the 1990s, satellite communications would be the primary means of distributing TV programs around the world,” as Telesat notes. Of course, these efforts consisted mostly of delivering signals from a stationary point (a television truck, an HBO transmission center) through satellites to other stationary points back on Earth. The big commercial leap for satellites has come in the last 15 years, now that those recipients are increasingly mobile. Iridium helped lead the way with mobile phones. After it went bankrupt—as many pioneering telecommunication firms have done, dating back to the telegraph—Iridium was taken for pennies on the dollar and continued to operate. (The technological model, it turned out, worked better than the initial financial model.) Iridium developed a smart network—satellites that could receive signals from mobile phones anywhere on Earth, share data with one another, and then reach out to another moving target anywhere on Earth. As Air and Space magazine notes, “That capability makes the system the only one in the world that can connect absolutely anywhere to absolutely anywhere else.” Now Iridium is part of what has become a very large industry of satellite manufacturers, launchers, and operators. The sector had revenues of $189.5 billion in 2012, according to a 2013 report published by the Satellite Industry of America. More than 1,000 satellites are in the sky, owned and operated by major networks like Intelsat, Entelsat, and XTAR. About half are in low Earth orbit, and about 40 percent are in geosynchronous orbit, with a much smaller number of satellites in elliptical orbit or medium Earth orbit. It’s hard to grok how much the satellite industry influences your life until you take an inventory of the industries and services it enables. This hit me recently as I walked along the rooftops of Jerusalem’s Old City and noticed that virtually every roof—in virtually every quarter—had a satellite dish for telephone, Internet, or television service. Yes, television signals make it possible for people in Israel to watch live feeds of sporting events and awards ceremonies. But they also let restaurants in Buenos Aires accept payments on debit cards belonging to tourists from Madrid, and allow international relief agencies to coordinate the response to Ebola, or let Sirius radio subscribers play E Street Radio as they tool around rural Vermont. slate/articles/technology/the_back_end/2014/10/the_new_seven_wonders_defining_the_top_technological_marvels_of_the_contemporary.html#part_five
Posted on: Tue, 30 Dec 2014 11:42:58 +0000

Trending Topics

Recently Viewed Topics

© 2015