A recent discussion on the ISS has raised some questions in my mind about *Zvezda*:

http://space.stackexchange.com/questions/4525/can-the-us-part-of-iss-survive-independent-of-the-russian

What does *Zvezda* alone lack from being a capable space station? Are there any existing Russian modules or modules in development that could be attached to enable it to be a capable space station if it is not already? If Russia detached *Zvezda* from the ISS today, approximately how quickly could they have a functioning independent space station?