WASHINGTON (AFP) - Some prominent American astronomers are boycotting a Nasa meeting next month on exoplanets due to a ban on attendance by Chinese scientists, experts told AFP on Tuesday.
The restriction is based on a law passed in 2011 and signed by President Barack Obama that prevents Nasa funds from being used to collaborate with China or host Chinese visitors at US space agency facilities.
Among those leading the boycott are Dr Debra Fischer, an astronomy professor at Yale University and Dr Geoff Marcy, an astronomy professor at the University of California, Berkeley.
"In good conscience, I cannot attend a meeting that discriminates in this way. The meeting is about planets located trillions of miles away, with no national security implications," Dr Marcy wrote in an e-mail to the organisers.
While the law that bans Nasa cooperation with the Chinese has been on the books for two years, Nasa administrator Charles Bolden told lawmakers in March that he was implementing additional security measures following a potential security breach by a Chinese national working for a contractor at a Nasa facility in Virginia.
"The person in question no longer works at Langley," Mr Bolden said at a hearing on March 20 before the House subcommittee that oversees funding for Nasa.
"I have ordered a complete review of the access which foreign nationals from designated countries are granted at Nasa facilities," Mr Bolden told lawmakers.
"I have ordered a moratorium on granting any new access to Nasa facilities to individuals from specific designated countries, specifically China, Burma, Eritrea, Iran, North Korea, Saudi Arabia, Sudan and Uzbekistan." Dr Pascale Ehrenfreund, a space policy expert at George Washington University, said tensions between the United States and China in scientific matters have persisted for years.
"Also at the International Astronautical Congress at the end of September in Beijing, China, US participation was scarce," she told AFP.
"I wonder why the conference was planned on Ames soil and not just outside the fence of Ames, like often done in the past," she added.
The Second Kepler Science Conference is scheduled for November 4-8 at Nasa Ames Research Centre in Mountain View, California.
Co-chair Alan Boss of the Carnegie Institution in Washington did not immediately respond to an AFP request for comment.