The members of the Aerospace Safety Advisory Panel and two staff members of the panel sent letters of resignation to NASA administrator Sean O'Keefe.
Glen Mahone, a NASA spokesman, said that the ASAP chairman, Shirley McCarty, said in a cover letter to O'Keefe that the resignations "will give you and the Congress the freedom to revitalize the panel and reshape its charter and mission."
O'Keefe, in accepting the resignations, said that the Columbia accident investigation showed that "a wide range of oversight functions should be strengthened within the agency.
"We need to take this opportunity to explore how the original concept for an Aerospace Safety Advisory Panel needs to evolve to best meet the future needs of the agency," he said.
The ASAP was established after the 1967 Apollo 1 fire which took the lives of three astronauts. That was the first major accident in the American space program. Members include space engineers, scientists, former aerospace industry executives and military officers.
In the wake of the Columbia accident, which killed seven astronauts on Feb. 1, the safety panel was criticized by members of Congress as being ineffective.
The Columbia Accident Investigation Board said in its report that the ASAP lacked influence. Members of the Senate Appropriations Committee said the ASAP failed to spot potential danger signs in the operation of the space shuttle and that NASA should reconstitute the panel.
McCarty told The New York Times that the panel felt "a very big sense of frustration."
McCarty, an aerospace consultant, told the paper after the accident, her group advocated installing a crew escape mechanism on the shuttle. The panel also recommended reorganizing the space agency so the safety officer for a flight would be more independent, and would not report to officials responsible for flight operations. NASA was not receptive, she said.
"One wants to get out of the way when you're in the way," she said.
Mahone said NASA already has started the process "to revise the panel's charge based on congressional reaction to the findings of the CAIB."
He said NASA "will review the original 1967 charge (that established the safety panel) and its amendments."