MOSCOW, October 4. /TASS/. Russia is unable to use one of the docking ports of the ISS to its full extent due to cracks in the transitional chamber of the Zvezda module, the general designer of Russia's Energia corporation, associate member of the Russian Academy of Sciences Vladimir Solovyov said on Monday.

"The transitional chamber's loss of airtightness is often mentioned these days. We are very fortunate the cracks are at the end. We shut down that compartment, thus losing one docking port, which narrows our opportunities somewhat. The crack is very insignificant, though," Solovyov told a conference entitled Scientific Space of the 21st Century: Challenges, Solutions, Breakthroughs at the RAS Space Research Institute in Moscow on Monday.

He warned that 80% of the Russian segment's equipment was past its service life.

"Sometimes there occur - not fires, of course - but serious emissions of smoke. Any equipment past its expiration date is prone to failure," he stressed.

The American segment, Solovyov said, still has in its logbook as many as 250 yet-to-be met requests concerning serious systems, such as structures and solar cell panels.

"In what respect are they fundamentally different from us? They have far more opportunities and far greater resources. They can order a large list of reserve equipment and replace all this stuff very quickly," Solovyov said.

Currently, spacecraft dock with the Rassvet and Nauka modules. The nodal module Prichal is due to arrive at the ISS in November.