NASA is trying to resolve an international spat over banning Chinese scientists from a planetary conference but efforts are being hampered by the US government shutdown, a meeting organizer said Wednesday.
Some leading US astronomers have vowed to boycott the conference next month at a US space agency facility in California because six Chinese scientists were told they could not attend.
Beijing's foreign ministry has also described the move as discriminatory, and said academic meetings should remain free of politics.
Organizers of the Second Kepler Science Conference on November 4-8 said they were acting based on a March 2013 order for a moratorium to visits to NASA facilities by citizens of several nations including China.
The basis for the ban was called into question on Tuesday by Congressman Frank Wolf, who authored related legislation in 2011 that he said restricted space cooperation with the Chinese government and Chinese companies but not individuals.
The moratorium and other additional security measures were issued earlier this year by NASA administrator Charles Bolden following a potential security breach at a NASA facility in Virginia by a Chinese citizen, and should have been lifted by now, Wolf said.
Several attempts by AFP to reach NASA spokespeople have gone unanswered.
"The NASA folks are not legally able to read their e-mails. This is the major reason the brouhaha continues, in my opinion," said conference co-organizer Alan Boss of the Carnegie Institution for Science, in an email to AFP.
The US government shutdown, in place since October 1 over Republican opposition to President Barack Obama's health care reform, has sent 97 percent of the space agency home without pay along with hundreds of thousands of federal workers across the country.
"Representative Wolf's statement has caught the attention of NASA officials, who are working now to see if the problem can be solved," Boss told AFP.
"This is all happening in real time, though with the furlough still in place, this effort is an uncertain one," he added.
"I believe this problem would have been solved were it not for the federal shutdown preventing communication with NASA."
Boss and other members of the organizing committee said in a statement Tuesday "we find the consequences of this law deplorable and strongly object to banning our Chinese colleagues, or colleagues from any nation."
Had they been aware of the restrictions on holding the meeting at NASA's Ames facility and inviting Chinese scientists, they would have pursued an alternate venue, he added.
"The policies that led to this exclusion have had a negative impact on open scientific inquiry. We feel very strongly that it is wrong to exclude scientists, on the basis of nationality, from a meeting that welcomes free and open exchange of scientific ideas."
One of the leading astronomers who vowed to boycott, Debra Fischer of Yale University, told AFP that one of her post-doctoral students was among those whose application was denied.
However, he has so far declined to speak to reporters.
"This has not been his fight. Indeed, that was the point. He would never complain or feel that it would be proper to speak out," Fischer told AFP in an email.
"So, I took this issue on -- both on his behalf, and for other scientists who were excluded."