Plans for the US and China to collaborate on a space project have been put in doubt by the row over whether American satellite firms aided Beijing's missile programme. Both sides had been hoping to announce during next month's mainland visit by President Bill Clinton a joint project between Beijing and America's NASA to monitor climate changes from space. Also in jeopardy is a longstanding White House plan to relax all restrictions on satellite launch co-operation with the mainland if Beijing agrees to introduce further controls on its missile technology exports. With the House of Representatives having voted last week to block satellite co-operation with China - and having set up a special investigative committee into the cash-for-technology allegations - both proposals may be judged too politically explosive by Mr Clinton's aides. The administration is working behind the scenes with Congress to try to deflate the controversy, including the release of documents detailing its internal discussions over the granting of the most recent licence to US company Loral to take part in a launch in China. Loral chief executive Bernard Schwartz - whose large donations to the Democrats have also come under intense scrutiny - mounted a public relations campaign at the weekend to deny gaining any special favours from the White House. But the NASA project, which would involve working with Chinese officials and scientists to monitor pollution and other ecological phenomena, could fall foul of the same concern on Capitol Hill. Despite safeguards which Washington would insist on, the administration fears the deal could open it up to suggestions from Congress members that China would steal American spy satellite expertise. White House officials are still considering dropping some unrelated sanctions which were imposed in 1989 by recommencing aid to American firms doing business in China. Beijing, trying to fend off a rising tide of criticism, urged the US Congress to help improve bilateral ties ahead of Mr Clinton's visit and dismissed domestic calls for the American President to cancel his visit. Chinese Foreign Ministry spokesman Zhu Bangzao said: 'President Clinton's state visit to China and the common interests of China and the United States have won the broad support of the people of the two countries.'