Following the collision in February 2009 of an Iridium satellite and a non-functioning Russian satellite, NASA published an image which illustrates the number of man-made products that must be tracked.

The U.S. Space Surveillance Network tracks all debris larger than 10 centimeters. In 2009, this amounted to approximately 19,000 objects. Orbital debris or "space junk" however is not a new phenomenon.

The nations of the world have long sought to establish effective means to identify and track objects in space. One step in that journey was the 1976 Convention on Registration of Objects Launched into Outer Space, also known as the Registration Convention.

This process began back in December 1973, when the United Nations General Assembly tasked the Committee on the Peaceful Uses of Outer Space to "make provision for registration by launching states of space objects launched into outer space with a view, inter alia, to providing States with additional means and procedures in the identification of space objects."

Almost one year later, on Nov. 12, 1974, the convention was opened to the General Assembly for signature and ratification. The United States became a signatory on Jan. 24, 1975. The convention was ratified by the U.S. Congress and went into effect on Sept. 15, 1976.

Under this agreement, the secretary general of the United Nations maintains a register on information on each item in space. The registry includes the name of the launching state or states which means the nation from whose territory the space object is launched and also the nation for whom the object is launched.

Each object shall have an appropriate designator or registration number. Each nation also needs to provide the date and location of the launch and the general function of the space object.

Most important however, is the requirement to provide basic orbital parameters: Nodal period (the time between two successive northbound crossings of the equator -- usually in minutes); Inclination (inclination of the orbit - polar orbit is 90? and equatorial orbit is 0?); Apogee (the highest altitude above the Earth's surface - in kilometers); and Perigee; (lowest altitude above the Earth's surface - in kilometers).

Finally, states should update the register "to the greatest extent feasible and as soon as practicable" to reflect the current condition and/or location of their specified space objects.