Four kilometers deep, and at the point of the Pacific Ocean furthest from any land, there is the place where space stations go to die. In that abyss, called by scientists “Point Nemo” in homage to the novel “20,000 leagues under the sea” by Jules Verne, NASA and other space agencies precipitate satellites that have become obsolete and that would endanger the safety of other objects in an increasingly crowded orbit.
From a technical point of view, this vast body of water has been defined as the “Inaccessibility Point of the Ocean”, because it is the most difficult and expensive to reach. Visiting the space cemetery to perhaps pick up some pieces among the tons of metal that survived the friction with the Earth’s atmosphere is practically impossible, except to acquire equipment similar to those that have taken some objects from the wreck of the Titanic.
In this cemetery, wrote the “Guardian”, the International Space Station will also finish, which still works very well, but is starting to show signs of age: some cracks have appeared on the walls and a good part of the equipment that is on board has now passed the expiration date. When it is pushed towards Earth for its last journey, an event not imminent but inevitable, the Station will burn in contact with the atmosphere most of its laboratories. But it’s the size of a football field, and many of its sturdiest structures will end up at Point Nemo Cemetery.
Anyone who has seen the film “Gravity” by Alfono Cuaròn, with Sandra Bullock and George Clooney, has an idea of how dangerous the impact of the debris of a satellite can be with a space station. When an object sent into orbit dies, however small it is it can become a danger to everyone else. At orbital speeds of 17-18,000 kilometers per hour, a bolt that has unscrewed, and even tiny spots of paint, can cause very serious damage and kill astronauts.
NASA is concerned about the amount of space junk around Earth. The overcrowding is such that it is feared that a collision could cause a chain reaction called Kessler’s syndrome, an event that deprives those who are trying to avoid it from sleep. The scenario hypothesized in 1978 by NASA consultant Donald J. Kessler considers probable a domino effect caused by the collision in orbit of two objects no more than a few tens of centimeters whose relative speeds reach 16 kilometers per second. The cloud of splinters thrown in random directions will cause new impacts, with a cascading reaction that will fill Earth’s lower orbit with garbage, making it uncrossable for centuries, perhaps millennia, to the launch of new spacecraft or new satellites.
It would be the end of our civilization, today based largely on the transmission of data through satellites, a return to the Middle Ages more abrupt than what global warming already seems to promise us. To prevent a disaster of this magnitude today anyone who launches something into orbit is forced to have a plan to dispose of it when it becomes space waste, and Point Nemo is a good address to ship it to.
Space agencies get rid of old satellites in many ways. Vehicles spinning in a high orbit can be launched into space with the last reserve of their fuel: they will come out of the Earth’s gravitational pull and become someone else’s problem or object of study, in this solar system or in a distant galaxy. The smaller satellites are instead pushed towards the Earth, where they burn completely in friction with the atmosphere. The problem is the larger ones, such as the Chinese Long March rocket, whose version Y1 was the most massive object to fall uncontrolled after the Soviet space station Salyut 7 in 1991 and the US Skylab in 1979.
So far it has gone well, no spacecraft has fallen on a city, no one has been hurt. But NASA and the European Space Agency believe more caution should be exercised: obsolete satellites can be better targeted for their last voyage and all sent to crash at Point Nemo. In 2001, the Russian Mir space station was directed towards Earth with precise coordinates: it is largely burned in the atmosphere, but 25 tons of metal are now in the Pacific Ocean cemetery.
The same will happen to the International Space Station, which has been in orbit since 1998, when Russia, the USA, Japan, Canada, Italy and several other countries decided to collaborate on a feat that seemed impossible at the time. It has hosted astronauts since 2000, and was expected to remain active for only 15 years. It is still in good shape, and has been allowed to operate until 2024, but the end is inevitably approaching. When the ISS is declared too old to serve again, it will be pushed towards the Earth from which all its components have departed, most of which will be destroyed in contact with the atmosphere. The rest will descend into the depths of the Pacific, where it will become the habitat of marine species so far from us that we don’t even know them. It has served to study the unknown and in a sense it will continue to do so, but it will no longer be able to tell us anything of what it will discover.