An Assload of Debris

The fantastic photo is by Victor Minghir.

FY-1 Charlie is now more than five hundred pieces of tracked debris (International Launch Designators 1999-025E – 1999-025WS). As a result, Leo Barhorst notes
on the SeeSat Listserv, the Space Track catalogue has reached 30,000 objects five months sooner than he anticipated.

As NORAD continues to add debris fragments to the catalogue, David Wright and Wang Ting’s initial calculation of about 800 pieces of debris larger than 10 cm is looking pretty accurate.* (For more, you can read Wang Ting’s paper, “The Consequences of Using Kinetic Energy Anti-Satellite Weapons,” The INESAP Bulletin 26, August 2006, pp 60-63.)

Recall that Wright and Wang also estimated more than 40,000 fragments with size between 1 and 10 cm—too small to track but plenty big enough to wipe out another satellite or the International Space Station.

TS Kelso has an cool animation of the first 33 pieces debris on his site, with a startling reminder of the small, but real, threat the debris fragments from China’s ASAT test poses to the International Space Station. (Alan Boyle writes up the animation on his MSNBC Cosmic Log.)

I should note that the risk for any individual satellite from untracked debris remains small, but the cumulative risk from the debris population to objects in orbit is enough to be worrisome, particularly if China continues destructive ASAT testing, or other countries follow suit.

* Late Update: David Wright adds a little more bad news in the comments:

Our original numbers for the amount of debris used a mass for the FY-1C that was somewhat too small. Using what appears to be the correct mass (954 kg) increases the expected number of debris to roughly 1,000 with a size of 10 cm or greater, 50,000 with a size of 1 cm or greater, and 2.6 million greater than 1 mm.

For more on debris, see: Mehrholz et al, “Detecting, Tracking and Imaging Space Debris,” ESA Bulletin 109, February 2002, pp.128-134.