WASHINGTON, D.C. ? Congressional leaders Thursday asked NASA to guarantee scientific openness at the agency following accusations that a public affairs officer changed or filtered information on global warming and the big bang.

Rep. Sherwood Boehlert, chairman of the House Science Committee, said that while space administrator Michael Griffin had responded admirably to the allegations, “NASA still has a lot of work to do to ensure openness.”

“We need free and open inquiry, an agency that recognizes that the greatest exploration takes place inside the human mind,” Boehlert, R-N.Y., said during a hearing on NASA’s $16.8 billion budget request.

NASA public affairs officer George Deutsch, a political appointee, resigned last week after he was accused of trying to limit reporters’ access to a noted NASA climate scientist and insisting that a Web designer insert the word “theory” with any mention of the big bang. Deutsch has denied censoring scientists or inserting religion into NASA literature.