It might be the most powerful that can be used now, but it is not the most powerful ever ;) http://en.wikipedia.org/wiki/Energia http://en.wikipedia.org/wiki/E

It might be the most powerful that can be used now, but it is not the most powerful ever ;) http://en.wikipedia.org/wiki/Energia http://en.wikipedia.org/wiki/Energia could lift up to 100 tons to LEO in the tested configuration and up to 200 tons in Hercules configuration (which never tested though).