A failed Russian probe designed to travel to a moon of Mars but stuck in Earth orbit will come crashing down within hours, the Russian space agency said today.

Russia has laid out its ambition to gain an edge in the space race by building a nuclear-powered spaceship.

Japanese space agency officials insist they have not yet lost Hope. But the fate of the country’s first interplanetary explorer - a Mars probe dubbed Nozomi, which means hope - is growing doubtful.