Shuttle with water dump. Copyright Clair Perry 
Source:  www.universetoday.com
This picture is from last week; September 9, 2009 to be exact, but I still  wanted to share it. I just got in touch with photographer Clair Perry from  Prince Edward Island, Canada to get his permission to post the image. No, this  is not a comet. Pictured is space shuttle Discovery executing a water dump. The shuttle  needed to get rid of excess waste water before landing the next day, and  jettisoned it overboard via the waste water dump line, creating a spectacular  visual effect as sunlight hit the spraying water. This dump occurred just as the  shuttle was flying over North America last week, and lots of people witnessed  this "toilet flush." Some reports indicated it was "pristine" water (the shuttle  fuel cells' by-product is water) and other reports said it was "waste water and  urine" (the  Bad Astronomer called it Constellation Urion). Whatever, it was pretty. NASA  said this was an unusually large dump, about 150 pounds (68 kg), because new  regulations say no shuttle water dumps can take place while docked to the ISS,  so as not to contaminate the outdoor experiments on the Kibo lab.  
See below for the spectacular entire image, which also includes the nearby  ISS creating a streak in the sky. Thanks to Clair Perry for sharing his images.
 
