A major headache is any kind of space debris that is in orbit around the Earth around satellites
When this year, the European environmental satellite Cryosat-2 made its usual discreet ride over our heads, some 700 kilometers from Earth’s surface, suddenly the ESA’s auditors realized they had a serious problem : a fragment, one of the many space “garbage” up there, was threateningly directed towards the cost of a satellite of 140 million euros, which monitors the ice of our planet. Just at the last minute, the ESA engineers who recorded both the satellite and the scrambled trajectories instructed the Cryosat-2 propellers to be activated to climb a little higher.
About 50 minutes later, the space wreck passed from the previous point of the satellite at a speed of 4.1 kilometers per second … It took a few more days with maneuvers to return Cryosat-2 to its original orbit. This incident is characteristic of how much spacecraft that have been orbiting the Earth along with the satellites have grown into a major headache. Increasingly, ground controllers, who have to be in constant alert, are instructing satellites to change positions to avoid a fatal conflict.
However, this is not always easy or desirable, because such a change of location and route consumes time and valuable fuel that the satellite needs for its work. The most recent known incident occurred on August 23, 2018, when just four months after it was in orbit, another European Earth Observation Satellite, Sentinel-3B, was forced to change track to avoid a dangerous fragment.
At least 400 new satellites in 2017 In 2017, private companies, armies, public agencies, and even amateurs from different countries have traded more than 400 new satellites, at least four times more than the average annual period of 2000-2010. A sign that space is becoming increasingly busy as more and more businesses and countries are deploying space-based applications and technologies for peaceful, spying or war use. Last year, over 1,800 small and large objects in orbit (scattered or not) came to be added to the sky.
The number of satellites is expected to increase significantly over the next few years, as several companies (Boeing, One-Web, Space X, etc.) are planning to ship hundreds to thousands of new telecoms and other satellites. At the same time, states are bringing in more and more known or secret military satellites. Accidents are inevitable. In 2009, an American telecommunications satellite Iridium dropped off the Russian telecommunication satellite Cosmos-2251, creating thousands of new space fragments. They have been circling since then and threaten other satellites in a low orbit, a zone reaching up to 2,000 kilometers (the average track reaches up to 35,000 kilometers where the geostationary trajectory begins).
Another incident occurred in 2007 (these two were the worst in history in terms of “garbage”) when – as part of a military test – a Chinese rocket destroyed a Chinese satellite. In these two incidents in 2007 and 2009 and in the thousands of fragments that scattered in space unchecked, about half of the at least 20 maneuvering satellites are due to make ESA time to avoid some new collision, as Holger Krag said, head of the Space Fragmentation Office of the European Space Agency in Darmstadt, Germany.
From October 4, 1957, when the first artificial satellite was launched, the Soviet Sputnik, and so the space era began, the number of satellites steadily increased, reaching about 2,000 in 1970 and 7,500 in 2000.
Today, around the Earth, there are thousands of large and small objects, made by human hand: from whole or inactive satellites to rockets, solar panels, old satellites, and so on. About 95% of all orbiting objects are “zombies,” meaning dead satellites or their tracks.
According to NASA, there are more than 500,000 “garbage” of different sizes, from entire satellites and missile fragments to screws and nuts. According to ESA, there are at least 29,000 objects larger than ten centimeters, 750,000 with a size of one to ten centimeters, and over 170 million fragments of one millimeter to one centimeter.
Several space agencies and operators are looking for solutions to the problem. Several teams of engineers and scientists are already working to improve the methods of calculating the satellites and fragments in the first place, having created a large database with all the information on everything flying over there. In this context, information is gathered and estimates are made for the properties (shape, size, composition, etc.) of the slightest known spaceframe.
As the 2009 accident showed, a conflict is enough to produce thousands of extra ‘trash’ and that would be a nightmare. “If we continue this way, we will reach a point without return,” said Karolina Froheh, an astronomy specialist at Indiana University of Perny, to Nature.
Each year the US military issues 21 averages of possible conflicts in space, a figure expected to increase dramatically in the coming years. In part this will happen because the US Air Force will operate a new powerful radar that can detect objects less than ten centimeters in space, the current limit.
The International Commission on Coordination of Space Fractures has issued guidelines to companies, organizations and states to reduce the risks by either discharging the “outgoing” satellites’ fuels (to reduce the risk of an explosion) or lowering them to lower trajectory to burn in the Earth’s atmosphere. To date, however, only half satellites have responded to these requests.
Needle in a haystack
At 15,900, the relatively large and detectable objects are counted in a low orbit (up to 2,000 km), in 2,931 in geostationary orbit (about 35,000 km) and in 1,488 in other intermediate orbits. Their total mass, according to the ESA, is more than 8,135 tons, larger than the Aével in Paris metal tower. “If we knew exactly where everything is, we would have almost no problem,” said Marlon Sorgue, a space aerospace expert in the aerospace corporation, Aerospace Corporation.
In theory, there is plenty of space in space for all satellites and for all “trash”, as long as one knows exactly where everything is, so it can take preventive measures in time. This field of science is called “space motion management” and recalls the corresponding problems with cars on the streets or on airplanes in the skies.
But while air traffic controllers know the positions of all aircraft with a precision of one meter, unfortunately not all space fragments are detectable, and for many of those known, there is not as much precision in the assessment of the track their. There is not even a single international catalog containing all known ‘rubbish’. Not rarely eg. American and Russian elements differ for the trajectory of a fragment, and no one else knows what the most accurate estimate is.
On the other hand, there is no lack of secrecy. The largest public database for fragments is the US, but almost certainly the US is hiding data on their secret satellites. But the Russian government is doing so. Some private companies have their own databases, but they are not freely accessible.
So-called “space environmentalists,” who want to be free and safe for all, speak of a “common tragedy”, as individuals and states “pollute” space, a common precious resource for mankind. They are under pressure, especially in the US, and President Trab shows already willing to transfer from the military to a civilian civil service (perhaps the Department of Commerce) the responsibility for monitoring and public recording of space fragments.
The RemoveDEBRIS net
But how can one pick up a space wreck? Among the solutions that have been proposed, they are nets to catch them like fish, magnet in orbit to stick on them the broken fragments, as well as laser beams that will destroy them or they will still send them further into space.
The RemoveDEBRIS satellite arrived at the International Space Station in April and from there it was launched in June. A few days ago, the RemoveDEBRIS (something between a fisherman, a bucket and a garbageier of space!) Stretched a net to catch another Cubesat microwave satellite bread loaf, which unfolded a balloon of one meter in diameter. The RemoveDEBRIS wrapped his net around the balloon and pulled it close to him. At the beginning of 2019 something more advanced is planned, as RemoveDEBRIS will launch another “paraglider”, a space harpoon
If the cost of a 15 million euro mission proves to be successful, such nets and hooves will be used in the future to collect stray space fragments and crawl down into the atmosphere where they will burn themselves by friction.