In the last fifty-five years, the space surrounding the Earth has gone from being almost devoid of junk to being clogged with man-made items that threaten launches, active satellites, and the International Space Station (ISS). According to NASA, more than 21,000 particles the size of a softball were being tracked in 2013, with an estimated 500,000 bits the size of a marble believed to exist. Over 100 million much smaller things, as little as a speck of paint, are impossible to detect or track. Around 1,100 active satellites make up around 6% of all Earth-orbiting objects; the remainder is garbage. Humans have been exploring space for as long as we can remember, leading to irreparable consequences. Thousands of dead satellites orbit our globe, along with bits of debris from all the rockets we have fired throughout the years. This could become a problem in the future.
WHAT IS SPACE DEBRIS OR SPACE JUNK
Any piece of machinery or debris left by humans in space is known as space junk or space debris. It can refer to large objects like failed or abandoned satellites left in orbit after the mission ends or tiny items such as fragments of debris or paint flecks that have fallen from a rocket. There is also some human-made junk even on the Moon. Debris can also be produced by a space explosion or when countries conduct missile tests to destroy their satellites. Aside from Russia, China, the US, and India have all shot down satellites, resulting in space debris. Due to the high speeds at which space junk orbits the globe - roughly 15,700 miles per hour (25,265 kilometers per hour) in low Earth orbit - it might inflict considerable damage to a satellite or spacecraft in the event of a collision. With the deployment of more satellites from firms like Elon Musk's Starlink and OneWeb satellite constellations, space debris in the vicinity of Earth will undoubtedly increase. According to NASA, In 1996, debris from a French rocket that had exploded a decade earlier struck and destroyed a French satellite. A derelict Russian spacecraft collided with and destroyed a functional US Iridium commercial satellite on February 10, 2009. More than 2,300 pieces of massive, trackable debris and many smaller pieces of debris were added to the inventory of space junk as a result of the collision. China's anti-satellite test in 2007, which used a missile to destroy an old weather satellite, added about 3,500 pieces of massive, trackable debris to the debris problem, as well as many smaller pieces.
CONSEQUENCES OF SPACE JUNK
The proliferation of orbital debris causes concerns in space as well as on Earth. If the projected route of a tracked debris object intersects with the path of a rocket launch, the launch may be delayed. A three-minute delay in the launch of an Indian rocket carrying satellites for four foreign countries in late June 2014 was one such incident. Maneuverable satellites can be relocated to escape orbital debris. In the year 2010, more than 100 similar moves were documented. For example, debris tracking revealed in April 2012 that a defunct Russian satellite and NASA's Fermi Gamma-Ray Telescope will cross paths within 30 milliseconds of each other. The thrusters aboard Fermi were used for one second, and the debris missed Fermi by 9.7 kilometers (6 mi). Fermi was out of commission for one hour due to the avoidance maneuver.
The Joint Space Operations Center (JSpOC) at Vandenberg Air Force Base keeps track of over 800 maneuverable satellites and compares their routes to orbital debris collected by the Space Surveillance Network. When the JSpOC detects a possible collision, they alert NASA, who then notifies the satellite owners. A total of twenty-nine satellite collision avoidance maneuvers were undertaken or aided by NASA in 2013. NASA tracked objects that could collide with a space shuttle from 1988 to 2011. They looked for items whose routes would lead them into a maneuver box enclosing the shuttle that was 2km x 5km x 2km (1.25 mi x 3 mi x 1.25 km). If a collision was foreseen, the shuttle would maneuver to avoid it unless it would interfere with "either major payload or mission objectives." Nine cataloged objects entered the maneuver box of a space shuttle between September 1988 and February 1997. In just four of those instances did the shuttle perform a collision avoidance maneuver; in the other five, the maneuver would have interfered with its mission. The first of these maneuvers, carried out in September 1991, avoided colliding with a spent upper stage rocket body from the Soviet Cosmos 955 satellite launch in 1977.
The International Space Station, too, has had to avoid space junk. The station's livable compartments are protected from debris up to 1 cm (0.4 in. ), but smaller particles can harm other parts of the station, such as the solar panels. In July 2014, space debris tore a 30 cm (12 in.) long rip in a radiator panel's cover sheet. The ISS has performed nineteen collision avoidance maneuvers since 1999. In March and April 2014, two such movements were performed within three weeks to escape debris from two distinct spacecraft. The ISS avoided debris from the Cosmos 2251 satellite on October 27, 2014. The crew aboard the ISS took refuge in the associated Soyuz crew transportation vessel on three previous occasions when the approach of space debris was discovered too late to undertake an avoidance maneuver. Despite these safeguards, numerous components of the ISS have been damaged, including thermal radiators, solar panels, and a window.
On the Ground
Space debris that falls out of orbit burns up in the atmosphere, but larger fragments can reach the earth intact or in chunks. Every week, on average, one uncontrolled re-entry of a spacecraft or rocket body weighing around 2,000 kg (4,400 lbs) happens. 10–40% of their mass reaches the ground in these cases. Because water covers 70% of the Earth's surface, the majority of the trash ends up in the oceans. Several huge pieces, however, have landed on land. The unplanned re-entry of the US space station Skylab in July 1979 was one famous incident. As it streaked through the atmosphere, the 76,000 kg (84 tonnes) object disintegrated. As the fragments approached the earth, residents in two locations in southwestern Australia heard sonic booms. Debris was strewn across 200 km (125 mi) by 1,000 km (620 mi) area, and more than 500 pieces weighing a total of 20,000 kg (22 tons) were found in the Australian Outback. Due to the increasing potential of collision with and damage to functional satellites, the building of space junk poses a particularly catastrophic threat to humanity's future in space exploration. It may potentially have negative consequences for the Earth's ecosystem.
CONTROLLING SPACE DEBRIS
The plethora of methods being developed to control space trash can sound more science fiction than reality. The electrodynamic tether is an electronic space whip that runs six football fields long and is being tested by JAXA, Japan's space agency (EDT). The roughly 2,300-foot-long electric cable is capped by a 44-pound weight. It's designed to push trash out of orbit and burn up in Earth's atmosphere after it's deployed. That is by no means the only choice. To safely pare down the expanding debris cloud, other concepts include huge magnets, harpoons, and nets. Many countries are approaching the problem from the other side of the equation, ensuring that any future man-made orbiters dispatched to soar beyond Earth's surface have a proper end-of-life plan in place to restrict the expanding cloud of garbage that engulfs our home planet. The United Nations has requested that all firms de-orbit their satellites within 25 years of their mission's completion. However, because satellites can (and do) fail, this is difficult to enforce. Several companies throughout the world have devised unique strategies to address this issue. Dead satellites are removed from orbit and dragged back into the atmosphere, where they will burn up. Using a harpoon to capture a satellite, catching it in a big net, using magnets to capture it, or even using lasers to heat the satellite and increase its atmospheric drag, causing it to fall out of orbit are all possibilities.