Space Debris Growth Slideshow -

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					Historical Growth of
   Space Debris


       Global Security Program
     Union of Concerned Scientists
            The Growth of Space Debris
The United States tracks active satellites as well as large
   pieces of space debris. It keeps a list of those objects in
   a debris catalog.


The following NASA graph shows the growth of the number
   of objects in the catalog from the beginning of the space
   age in 1957.


Today, only 5-6% of those objects are active satellites—the
   rest are debris.


 (Source: http://orbitaldebris.jsc.nasa.gov/newsletter/pdfs/ODQNv13i2.pdf )
             The Growth of Space Debris

The top line of the graph shows the total number of objects in
   the catalog. This total consists of various types of objects,
   which are shown in the lines at the bottom of the graph:
•   Fragmentation debris are debris created by the breakup of rocket
    bodies or satellites due to explosions or collisions in orbit.

•   Spacecraft refers to satellites in orbit. Only about one quarter of these
    are active (900); the rest are no longer functional and are considered
    to be debris.

•   Mission-related debris are orbiting objects that are created in the
    normal operation of a space mission, such as releasing a satellite.

•   Rocket bodies are upper stages of launch vehicles, which remain in
    orbit because their speed is similar to the satellites they place in orbit.
Historical Growth of Space Debris Through 2006



                    Debris from
                           Total objects
                    Chinese ASAT test




                              Components of Total
Historical Growth of Space Debris Through 2006



 This graph shows that the total number of objects grew
 steadily and showed a roughly linear increase from 1960
 through the mid-1990s (red line on next slide).




 During this period, space was sparsely populated, and
 few people thought about space debris or worried about
 its increase.
Historical Growth of Space Debris Through 2006


                         Debris growth
                    Debris fromline
                         trend
                    Chinese ASAT test
Historical Growth of Space Debris Through 2006



 In the 1990s, the United States led an international effort
 to get space-faring countries to take space debris
 seriously and find ways to slow the production of space
 debris.




 This effort seems to have helped, since the blue line on
 the next slide shows that the growth of debris slowed
 considerably over the decade 1996-2006.
Historical Growth of Space Debris Through 2006


                           Trend for
                           from
                    Debris 1996-2006
                    Chinese ASAT test
Historical Growth of Space Debris Through 2009


Several events in 2007-2009 created a very large
amount of new debris.


In January 2009, China destroyed a defunct weather
satellite in the test of an anti-satellite device. More than
2,500 pieces of debris have been cataloged from this
fragmentation.


This debris moved the total back up onto the pre-1995
growth trend. This single event eliminated the gains of
debris mitigation over the previous decade.
Historical Growth of Space Debris Through 2009


                         Debris from
                         Chinese
                    Debris from
                         ASAT test
                    Chinese ASAT test
Historical Growth of Space Debris Through 2009

Two other recent events further increased the amount of
debris, although they have not been fully cataloged.


In February 2007, a Russian rocket stage—the Briz-M—
exploded in orbit, due to residual propellant. This event
could lead to 1,000 additional pieces of cataloged
debris.


In February 2009, a defunct Russian satellite collided
with an active Iridium satellite. This collision could result
in more than 2,000 pieces of cataloged debris.
Historical Growth of Space Debris Through 2009

                        With Briz-M and
                        collision debris
                    Debris from
                    Chinese ASAT test
Historical Growth of Space Debris Through 2009

These slides show that the fragmentation of large-mass
objects in space, including satellites and rocket bodies,
can create very large amounts of debris.


This underlines the importance of having the international
community:
   -prevent the intentional destruction of satellites at high
   altitude
   -rigorously follow guidelines to minimize the risk of
   collisions and explosions in orbit

				
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