May 20 (UPI) -- NASA's chief of human spaceflight has resigned ahead of a launch that will send astronauts into space from U.S. soil for the first time in a decade.
Doug Loverro resigned on Monday and told The Washington Post his departure has to do with NASA's Artemis project, which aims to return astronauts to the moon.
"It had nothing to do with commercial crew," he said. "It had to do with moving fast on Artemis, and I don't want to characterize it in any more detail than that."
Loverro's resignation came as a surprise to many, especially its timing. Astronauts Bob Behnken and Doug Hurley are scheduled to take a SpaceX Falcon 9 rocket into space May 27 on a test flight from the Kennedy Space Center.
Former astronaut Ken Bowersox will replace Loverro as associate administrator of the agency's Human Exploration and Operations Mission Directorate, on an interim basis.
NASA said it is proceeding as scheduled with next week's launch, which will be its first to send astronauts into space since the end of the Space Shuttle program in 2011.
Behnken and Hurley were scheduled to arrive Wednesday at the Kennedy Space Center in Florida.