NASA experts have signed a protocol with Russia on radiation safety for space flights despite the new set of US sanctions against Moscow, the director of Moscow State University's Institute of Nuclear Physics said Thursday.

"Despite the sanctions, specialists from NASA are currently in Moscow. We are signing a joint Russia-US protocol on radiation safety during flights to the moon and Mars," Mikhail Panasyuk said.

"We feel the desire of our US scientific partners to approach us on this position," Panasyuk said.

The United States and the European Union have introduced sanctions against Russia in response to its reintegration of Crimea and stance on Ukraine.

NASA earlier said it had to freeze cooperation with Russian space researchers following Washington's sanctions against Russia over Ukraine, prompting Russian Deputy Prime Minister Dmitry Rogozin to suggest Americans would now have to "get their astronauts to the ISS [International Space Station] using a trampoline."

Later, Rogozin announced Moscow was not planning to use the International Space Station after 2020 and would instead re-focus its funding on more promising new space projects. In response, NASA Administrator Charles Bolden vowed the US and Russia would continue to cooperate on space missions and keep each other informed.