The head of Russia’s space agency Sunday said the US has rebuffed an offer from Moscow to jointly explore the moon, while announcing a separate contract with NASA for nearly one billion dollars for the International Space Station. Roskosmos chief Anatoly Perminov was quoted as saying by the Interfax news agency that Russia had proposed pooling resources to explore the moon. ‘We were ready to cooperate but for unknown reasons, the United States have said they will undertake this programme themselves,’ he said. The National Aeronautics and Space Administration (NASA) in December said it envisaged setting up a manned base, possibly on the moon’s south pole, by around 2020, powered by sunlight and perhaps hydrogen and oxygen, with astronauts cruising over the lunar surface in pressurized rovers. Perminov said Roskosmos had meanwhile signed with NASA a ‘contract for nearly one billion dollars’ — an unprecedented sum — to supply cargo shuttles between now and 2011 for the US segment of the International Space Station. The US-led ISS draws upon the scientific and technological resources of 16 nations: Canada, Japan, Russia, 11 nations of the European Space Agency and Brazil.