Taking Out The Trash
Although space is a very big place, bigger than we can imagine, it is getting increasingly crowded, at least when it comes down to space travel. The Earth is surrounded by millions of pieces coming from man-made debris, which represent a potential hazard for other functioning objects in Earth’s Orbit. Beginning in 1957 with the launch of the Soviet satellite Sputnik, the era of space travel began. Although Sputnik spent only three months in orbit before it returned to Earth, it became a catalyst for a series of launches we still remember and which still inspire us. But, along with the spacecrafts that represented pivotal achievements, the Earth’s orbit was also filled with large chunks of debris from those spacecrafts.
“Backdropped by Earth’s horizon and the blackness of space, an unpiloted Progress 14 supply vehicle departs from the International Space Station at 2:05 a.m. EDT on July 30, 2004, carrying its load of trash and unneeded equipment to be deorbited and burned up in Earth’s atmosphere.”
As we speak, there are many inactive satellites, upper stages of launch vehicles, separation debris, frozen cloud of water and bits of paint floating above our heads. When those pieces crash into one another, it creates even more debris, which remains floating in the orbit. It is estimated that over 21,000 pieces of space junk larger than 10 centimeters and half a millions pieces between 1 cm and 10 cm are circling the planet, and that number continues to grow every day. Also, there are millions of chunks that are smaller than 1cm. In low Earth-orbit, objects travel at speeds of about 7 kilometers per second. For example, at that speed, a tiny bit of paint makes the same impact as a 550 pound object traveling at 100 kilometers per hour. Before you say that there’s nothing to be damaged in space, remember the sensitive equipment we have up there, especially things like solar panels, pressurized items, glass cockpits on spacecrafts and so on.
At the beginning, the main source of the junk were objects that fell apart or exploded by accident. However, more than fifty years later, the situation is a bit different. In 2007, the intentional destruction of the Chinese weather satellite Fengyun-1C, which was a part of anti-satellite missile test, created an entire field of debris after it was completed. Also, two years later, a non-operational Russian satellite collided with an active American Iridium satellite, creating even more debris in the process.
Even the size of the chunks is so small, the U.S. and Russian military are capable of tracking most of the junk, as object about 10 centimeters and larger are visible via radars or using an optical telescope. Launch missions also include a part where a predicted post-lunch orbit is monitored in order the avoid as much damage as possible. Also, if an a spacecraft such as the Space Shuttle or the International Space Station is about to collide with a large object, it can change its orbit in order to avoid the crash.
Bits of the debris are constantly falling from the sky, one piece per day on average, though most of it burns up before it reaches the ground. In recent years, various space organizations have worked to reduce the amount of trash added to Earth’s orbit by implementing better designs.