In space water would likely sublimate instead of melting to liquid form. Of course, it would depend on the circumstances.
That's kind of my initial thoughts on the OP's question, along with satellites (moons) and planets further out than our own......and, of course, those gigantic alien spaceships sitting on the dark side of those planets waiting to terrify the human race ( I know that the first things I need to do after travelling for ever to get to a vacation destination are to mutilate livestock and subject the resident mobile-home dwellers to a rectal probe...stands to reason that vastly more intelligent spacefaring cultures would want to do likewise).I thought that too. But then I thought about comets.