"I don't think I need to elaborate on how a waste-collection system is much more comfortable than the diapers that astronauts aboard the [U.S. spacecraft] Orion will have to use," Vladimir Pirozhkov of the Moscow Institute of Steel and Alloys told RIA Novosti.
The institute is involved in the development of the Russian ship intended for voyages to the International Space Station and to the moon.
"Besides, the Russian segment of the International Space Station has a limited number of toilets, which means a spacecraft with an extra 'space toilet' will come in handy," he said Friday.
A prototype of the proposed Russian spaceship was unveiled last week at an airshow in Moscow.
The first unmanned test launch of the new spacecraft is scheduled for late 2017 or 2018, Pirozhkov said, and a manned flight is expected by 2020.
The Orion spacecraft, being developed by NASA and the European Space Agency to take as many as four people on missions to the ISS, Mars or near-Earth asteroids, is set for an unmanned test flight in 2014 and manned flights after 2020.