NASA announced today that Navy Capt. Lisa Nowak's assignment in the space agency's astronaut corps will end Thursday. It is believed to be the first time NASA has taken the step of severing ties with an astronaut from the military, said a spokeswoman for the space agency. She will be sent to a naval air base in Corpus Christi, Texas, and is expected to report there for duty on March 21, said a Navy spokeswoman. Nowak will join a staff that trains naval aviators. "She's on active duty with the Navy," said Cmdr. Lydia Robertson. As for Nowak's ongoing criminal proceedings, Robertson called it a "civilian matter" and would not speculate on any military actions "that would come under her new commander."Nowak, who was arrested last month in Orlando on charges she attempted to kidnap a romantic rival, remains an active duty naval officer. She has been "on detail" to NASA as an astronaut since her selection in 1996. NASA requested an end to the relationship because "the agency lacks the administrative means to deal appropriately with the criminal charges pending," a NASA press release said. Nowak is not subject to administrative action by NASA because she is a naval officer on assignment and not a space agency civil servant.