image credit: U.S. Navy; larger image

US Satellite Shoot-down

This photo shows the U.S. Navy SM-3 missile, the type that shot down a U.S. spy satellite on 20 February 2008.  Click on the world map, courtesy of the Washington Post, to see the track of this satellite's debris after it was hit--to learn more, see Spy Satellite's Downing Shows a New U.S. Weapon Capability.  The SM-3 struck the satellite at an altitude of 240 km (150 mi); for comparison, earlier this year China shot down its own weather satellite at an altitude of 870 km (540 mi). From Physics Research for 1 March 2008 shows the debris field from the Chinese satellite.

(This feature was revised on 15 March 2008.)

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J-Track Satellite Tracking

Visit J-Track Satellite Tracking to explore satellite orbits.  You can see tracks on a world map or in space around Earth, and you can also see the positions of the satellites in space.  Don't miss J-Track 3D--it lets you see the satellites orbiting around Earth, and you can zoom in or out and also tilt the view. When you zoom out and tilt, you'll see an interesting ring of satellites.

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Reprinted with permission from "Back Scatter," Physics Today, March 2007, page 100. Analysis and images, generated with the STK software package, courtesy of CSSI.  Object sizes magnified for visibility. larger version

Space Debris

Before October 4, 1957, when Sputnik was launched, space above Earth was pristine. But now...take a look at the image above (larger version). The green dots show satellites in low Earth orbit in January, 2007. The red dots show debris pieces bigger than 5 cm across from China's 11 January 2007 demolition of its weather satellite in an anti-satellite missile test. To learn more, visit the Wikipedia site Space Debris.

(This feature was updated on July 28, 2011.)

Skylab Debris Hits Australian Desert; No Harm Reported

Visit Skylab Debris Hits Australian Desert; No Harm Reported for the New York Times' 1979 article on Skylab's fiery return to Earth over the Indian Ocean, with some debris falling on Australia. For a retrospective, also from the Times, see Remembering Skylab, the Space Station's Frugal Great-Uncle. Click to see largest piece of Skylab to reach Earth, now on display at the U.S. Space and Rocket Center.