China and the United States are unlikely to partner on large space projects any time soon, but co-operation is already under way on smaller endeavours deeply rooted in science. In a visit to Beijing, Nasa administrator Charles Bolden met Bai Chunli, president of the Chinese Academy of Sciences on Wednesday. They "exchanged frank opinions on pragmatic co-operation in relevant fields in the future", according to a statement by the academy. The administrator of the American space agency was visiting China to take part in the International Astronautical Congress (IAC), which was held in Beijing last week. The academy is the largest scientific body run by the government and it is deeply involved in sensitive research projects, such as space programmes. It was Bolden's second official trip to China and he avoided revealing who he met in Beijing. In 2010, he led a small delegation to China and visited some of the country's largest space facilities, such as the Jiuquan Satellite Launch Centre. But the trip drew criticism from some US lawmakers who worried that China would steal US space technology for military use. In 2011, Congress banned the use of federal funds in that year's fiscal spending bill for any collaboration between Nasa and China. Bai expressed gratitude for US help on China's space programmes. Nasa, for instance, provided "enormous help" with the construction of satellite ground stations for remote sensing, he was quoted by the statement as saying. Bai said the two sides were co-operating on space geodesy, which dealt with the three-dimensional measurement of the earth. The co-operation had been going on for years and has produced encouraging results. China hoped the collaboration could continue. In an effort to show China's commitment to working together, Bai shared with Bolten some of the mainland's most advanced space projects the academy had been developing, including the world's first quantum communication satellite, and he hoped China and the US would strengthen co-operation in these fields. Bolden said Nasa was "highly serious" about working with the Chinese. He wished for more co-operation in fields such as space-to-earth observation. Representatives with several academy institutes, such as National Space Centre and Shanghai Astronomical Observation Centre, had attended the event. Neither Nasa nor the agency responded to the Post's inquiries about the meeting. It was also unknown whether Bolden had met other Chinese authorities. He said in Tokyo two weeks ago that the primary purpose of his visit was to attend the International Astronautical Congress, the largest annual gathering of space scientists. A geodesist with the school of astronautics at Beihang University said yesterday the statement had not changed his pessimism over co-operation between China and the US in space, even on science. The co-operation on geodesy had been shallow and it would remain so as long as China and the US remained politically hostile to each other, he said, declining to be named due to the sensitivity of the issue. "We can't talk about space science without satellites, and we can't talk about satellites without military-related technology," he said. "So both sides seem to have a lot of secrets to keep, and that makes co-operation difficult, if not impossible. "That's just the narrow mindset of politicians. As scientists, we want to share everything. Co-operation between the two largest economies in the world will only benefit the entire human race."