1. Historical Growth of Space Debris Global Security Program Union of Concerned Scientists

2. 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 )http://orbitaldebris.jsc.nasa.gov/newsletter/pdfs/ODQNv13i2.pdf

3. 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.

4. Historical Growth of Space Debris Through 2006 Debris from Chinese ASAT test Total objects Components of Total

5. 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.

6. Historical Growth of Space Debris Through 2006 Debris from Chinese ASAT test Debris growth trend line

7. 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.

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

9. 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.

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

11. 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.

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

13. 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