Historically, there has been very limited regulation in this area -- though from the very beginning of man's incursion into near earth space, attempts to at least coordinate knowledge about what and where things were located, were begun through the International Committee on Space Research (COSPAR) which is part of the non-governmental International Council of Scientific Unions.
Quite recently, the International Telecommunication Union (ITU), which is recognized to various degrees by different governments, has been recognized by many nations in coordinating the allocation of usable sites in geosynchronous orbit. The only area not so organized on a recognized basis by them is the slice covering the Americas. The ITU arm so responsible is the World Administrative Radio Conference (WARC). You can find a number of search-engine results containing minutes of their meetings, which occur every 2 or 3 years.
It's not that likely that satellites themselves will collide, though this has happened -- it's that the radio frequency bands available in the beamwidth of an antenna get quickly filled, and no more communications bandwidth is available to ground stations using these satellites. Since the only area of near earth space which presents the same "fixed" orientation of the satellites to the ground is geosynchronous orbit, this is the primary area that has a problem.
There *is* the problem of increasing density of satellites, mainly dead satellites, in near earth orbit. In particular, several upper stage booster rockets have exploded, creating not just one relic, but thousands -- it is conceivable that at some point a cascade of collisions could reduce much of low earth orbit space into a debris field and render this area useless to satellites. The primary launching governments have started practicing some degree of good stewardship in this area, making sure that booster rockets deorbit or at the very least vent fuel which could cause explosions after they've performed their function. Paint has also been a problem -- a 1/4" pockmark on a space shuttle windshield some years back was traced to a small fleck of paint from the upper stage of a NASA booster.
However, American hegemony in this area has led to a more or less "we set the rules" approach, especially in recent years. Nuclearization of near earth space, which was abandoned after several accidents in the 70's, culminating in the reentry and contamination of parts of Ontario in 1979 by a Russian spacecraft with onboard nuclear reactor, is now nearly set to resume. American military interests, in the guise of promoting "scientific research", would like to see development of high power space-qualified reactors. They claim these would be used in exploration missions to the outer solar system (such as a proposed mission to orbit several of the moons of the planet Jupiter), but it is generally believed that this is merely a cover for development of technology primarily intended to provide the capability to destroy other satellites in Earth orbit on command, should the perceived military need arise.
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