BigPic: What Is This 'Vital Equipment' On The International Space Station?

Come on, guys, guess! It'll be fun! International Space Station astronaut Chris Hadfield just tweeted this photo of... some sort of tank or something on board the International Space Station. This vital equipment is used in both the US and Russian sections of the Space Station. Do you recognize what it is? twitter.com/Cmdr_Hadfield/...-- Chris Hadfield (@Cmdr_Hadfield) January 2, 2013 Hmm. Some very important space technology, no doubt. But what could it be? Well, we got the answer pretty soon a...