The European Space Agency (ESA) is currently working with NASA to develop a major Mars exploration project.
However, the ESA but has no immediate plans to collaborate with Russia, a nation which is also developing nuclear-powered spacecraft technology for a long journey to the red planet.
Nuclear technology offers more power in less space, which makes it particularly attractive for long missions.
Russia and the United States have been developing nuclear technology for decades, but placed new emphasis on the concept in recent years.
The Russian government allotted 430 million rubles ($14.4 million USD) in 2010 to the cause.
Alongside the Russians, the ESA is working with NASA on a project known as ExoMars (Exobiology in Mars), a similar but separate initiative to build nuclear-powered spaceships.
Although all of the above-mentioned entities are researching nuclear power for spacecraft, a spokesman for the Russian Federal Space Agency Roscosmos reiterated there was no collaborative agreement between the three agencies.
Roscosmos director Anatoly Perminov said the development of Megawatt-class nuclear space power systems (MCNSPS) would help Russia maintain a competitive edge in the space race for exploration of the moon and Mars.
The Russians are hoping to complete the nuclear engine design by 2012 at an estimated cost of 17 billion rubles ($600 million USD).
Still, it should be noted that ESA head Jean-Jacques Dorden recently confirmed the agency would "consider" using Russian experience and technology in its own nuclear-powered spacecraft developments.
(Via Ria Novosti)