By Andrei NAZARENKO, Dr. Sc. (Tech.), Program Study Center, Russian Academy of Sciences Available statistics tell us that an annual average of about 100 man-made space objects have been orbited by various countries over the last 30 years. Combined with the bits and pieces left from all sorts of misfirings and explosions during launchings and from various assembly and disassembly operations in orbit, a total of 600 to 700 pieces of junk enter near-Earth space each year. Russian and American experts have catalogued over the aforesaid period close upon 22,000 man-made objects, ranging from 10 to 30 cm in size. According to their count some 14,500 such objects have burned down in dense lower atmosphere, but the remaining 7,500 of these objects are still hurtling over our heads. And only 5 percent of them is really useful equipment and all the rest is nothing but junk. To make the picture even grimmer, experts tell us that the rate of junk accumulation in space is twice as high as the rate of its "self- purification". And most of the junk is orbiting the Earth at altitudes from 600 to 1,600 km - the two "belts" wherein most of the man- made satellites are operating. Experts laid special emphasis on the excessive pollution of the geostationary orbit wherein more than 1,000 objects of different kind are concentrated. Used-up space probes can come as close as 10 km one to the other and this imposes limitations on the uses of the geostationary orbit. The first to sound the alarm were NASA experts in the United States where a special study group was set up in 1981 from representatives of various agencies concerned. These studies were joined by the European Space Agency some ten years ago. And as for Russia, the problem has not escaped the attention of its experts who mainly come from Moscow State University, the Institute of Space Studies of the Russian Academy, the Central Research Institute of Engineering, the Central Research Institute of the Ministry of Defense, the V ... Читать далее