Complex sentence: The Russian Federal Space Agency (Roscosmos) was officially invited to the launch on March 21 by the North Korean Embassy to Russia but Roscosmos's spokeman said Russia refused to dispatch its experts to the launch because it violated a UN Security Council resolution.
Split into simpler sentences: The Russian Federal Space Agency (Roscosmos) was officially invited to the launch. On 21 March by the North Korean Embassy to Russia but Roscosmos's spokeman said Russia refused to dispatch its experts to the launch because it violated the UN Security Council resolution.