The Johnson Space Center's director of engineering said Monday that NASA has removed him from the management team for the space shuttle flight scheduled for Saturday after he expressed support for workers who questioned preparations for the flight.

Charles Camarda, 54, a former shuttle astronaut and veteran aerospace engineer, said in an e-mail to colleagues that his removal from involvement in the scheduled launch of Discovery, on which he flew last year, was against his will. The e-mail was distributed to others, including reporters.

"I refused to abandon my position on the (mission management team) and asked that if I would not be allowed to work this mission that I would have to be fired from my position and I was," he wrote.