US is asking for a prolongation of the International Space Station program through to 2024 since the American segment of the station cannot exist autonomously, Russian Deputy Prime Minister Dmitry Rogozin told Vesti’24 news channel on Friday. "The US does not have an opportunity to separate its segment from the ISS so that it would continue flying," he said. "The Americans don’t have an analog of our engine RD-180." "They don’t have engines as perfect, simple and inexpensive as this one," Rogozin said in a comment on the statements by US politicians Washington might stop these purchases. "They still have to buy the products manufactured in the USSR in the 1970’s or in the Russian Federation in the 1990’s since their characteristics surpass the best US samples of today."