Since the late 1950s humans have launched thousands of objects into space Some of them like these Japanese craft shown in an artist’s rendering entering the atmosphere over South Australia are designed to return to Earth Others will drift in space until gravity and other forces pull them down 1 ZOMBIES IN SPACE If we don’t change the way we operate in space all this results in an exponentially increasing amount of debris until all objects are reduced to a cloud of orbiting fragments that are capable of destroying any spacecraft that attempts to operate anywhere within that cloud Donald Kessler astrophysicist 2014 On February 10 2009 high above Earth two satellites slammed into each other Both satellites were traveling at nearly 17,000 miles 27,350 kilometers per hour when they crashed One of the satellites US communications satellite Iridium 33 had been going about its business As it orbited Earth 490 miles 790 km above the ground it relayed signals from one cell phone to another With no warning another satellite came barreling out of the dark Cosmos 2251 a Russian communications satellite had been launched into space in 1993 and had stopped operating two 6
years later Unlike operational satellites Cosmos was no longer under the control of people on Earth It was orbiting on its own circling Earth the same way Earth and the other planets circle the sun Drifting off its original course Cosmos sped into Iridium s path High above Siberia part of northern Russia the two spacecraft slammed into each other smashing each other to smithereens The two spacecraft broke apart into more than twenty-one hundred shards of metal glass plastic and paint which blasted out from the collision in every direction Satellites operated by Iridium Communications in Virginia relay signals from one cell phone on Earth to another In 2009 a Russian zombie satellite a satellite that is no longer functioning or controlled by people on Earth smashed into an Iridium satellite The two spacecraft broke apart into hundreds of pieces of metal plastic glass and paint Many Iridium customers lost phone service after the crash Most of this material is still orbiting Earth And each piece from fingernail-sized chips of paint to chunks of metal as big as a human head has the potential to strike and damage other spacecraft Eventually through orbital decay objects orbiting Earth will slow down and drop into the atmosphere the layer of gases surrounding the planet Most of these objects will burn up and disintegrate high in the air but some pieces of debris could hit the ground possibly hurting people animals or buildings FROM SATELLITES TO SPACE JUNK Since the late 1950s humans have launched more than sixty-six hundred satellites into space Some of these craft are as small as shoe boxes Others are as big as school buses Rockets carry them into space and then release them into orbit Each satellite is designed to do a specific job Some satellites 7
take images of Earth the moon and other objects in space Others study weather and atmospheric conditions on Earth Communications satellites relay TV telephone and radio signals from one location to another Some nations use satellites to gather military intelligence such as the location of ships and weapons depots in foreign countries Commanded by people on the ground satellites are equipped with computers cameras sensors and other instruments Rocket fuel batteries and solar panels provide them with the power they need to carry out their jobs and to travel through space Of the sixty-six hundred satellites launched into space since the late 1950s about one thousand are still functioning doing the jobs they were designed for About three thousand of these satellites stopped operating at some point and eventually fell back to Earth pulled down by orbital decay Of this group most completely burned up when they reentered Earth’s atmosphere But in a few cases debris from falling satellites has hit the ground although so far it hasn’t caused any serious damage on Earth The remaining twenty-six hundred nonoperational satellites are called zombies Like Cosmos 2251 they are out of fuel and out of communication with Earth But they will continue to orbit the planet until orbital decay pulls them down The higher they are in orbit the longer they will remain in space The zombies are so numerous that they endanger new functional satellites and other spacecraft Scientists use the term space junk to describe any human-made debris in space from the tiniest pieces of metal to intact but nonoperational satellites Zombie satellites are the largest pieces of space junk Other large pieces include the upper sections of the rockets used to launch spacecraft into orbit Smaller pieces of space junk include a glove that floated 8 SPACE JUNK
That Burning Feeling When objects rub against one another a natural force called friction slows When objects rub against one another a natural force called friction slows them down Friction also creates heat When rockets boost satellites into them down Friction also creates heat When rockets boost satellites into orbit and when satellites fall out of orbit and reenter Earth’s atmosphere orbit and when satellites fall out of orbit and reenter Earth’s atmosphere they rub against the air The friction that results makes the satellites extremely hot sometimes causing them to burst into flames The same thing happens when asteroids and meteors chunks of metal and rock that fly through space hit Earth’s atmosphere Spacecraft that carry Sailors from the USS Anchorage retrieved the National Aeronautics and Space Administration’s Orion spacecraft top right following its splashdown in the Pacific Ocean in December 2014 after a two-orbit test flight The sailors maneuvered Orion into a chamber at the bottom of the ship which took the vehicle back to shore for reuse Orion is used to carry astronauts into space and back astronauts must be specially designed so that they don’t get too hot when they exit and reenter Earth’s atmosphere Engineers outfit these vehicles with heat-reflecting tiles insulation and Engineers outfit these vehicles with heat-reflecting tiles insulation and other equipment to keep them cool during exit and reentry Sometimes the other equipment to keep them cool during exit and reentry Sometimes the tiles and other materials fall off during spaceflight further adding to space tiles and other materials fall off during spaceflight further adding to space junk Some spacecraft reentering the atmosphere are aimed to land in the junk Some spacecraft reentering the atmosphere are aimed to land in the ocean which further cools them when they reach the surface of Earth ocean which further cools them when they reach the surface of Earth away from astronaut Ed White in 1965 when he became the first American to walk in space a tool kit that slipped from US astronaut Heidemarie Stefanyshyn-Piper’s hand during a 2007 space walk and the thousands of pieces of debris from the Cosmos and Iridium crash Without a powerful telescope you can’t see zombie satellites or any other space junk But using high-tech equipment scientists can detect and monitor space junk as it orbits By 2011 scientists had identified twenty thousand pieces of junk in space and they expect this figure to triple by 2030 But those Zombies in Space 9
