The SpaceX Dragon approaches the International Space Station in May. Image by NASA.

The SpaceX Dragon approaches the International Space Station in May. Image by NASA.

Soot pours off a very different type of rocket—in this case, a toy. Black carbon (the main ingredient of soot) is formed from the incomplete combustion of fuel. Image by Flickr user jurvetson.
Virgin Galactic's hanger for SpaceShip Two, located in Mojave, CA, is LEED certified.