NASA said today it had seen no signs of instability in astronaut Lisa M. Nowak before she was arrested on charges she tried to murder a woman she thought was her rival for a shuttle pilot's affections.

The space agency also said it was reviewing its psychological screening process for astronauts to see if there were any lessons it could learn from the case.

In a joint news conference held with officials at the Johnson Space Center in Houston and at NASA headquarters in Washington, NASA authorities said Nowak, 43, had been removed from flight status and placed on 30-day leave. They refused to discuss details of her psychological or medical condition, saying such information was protected by privacy laws.

Nowak, a NASA astronaut and Navy captain from Rockville, was charged yesterday with the attempted murder in Orlando of Air Force Capt. Colleen Shipman. Nowak, one of 46 women to fly in a space shuttle, is the first active astronaut to be arrested on a felony charge.

Orlando police say Nowak, dressed in a dark wig, glasses and a hooded trench coat, stalked Shipman, 30, at an airport parking lot early Monday. Unable to gain Shipman's confidence, police said, Nowak sprayed her with pepper spray through Shipman's partially open car window before the car sped away.

According to the charging document, police say Nowak intended to confront Shipman about her relationship with Navy Cmdr. William A. Oefelein, 41, an astronaut who like Nowak is based at the Johnson Space Center.

Nowak, who is married with a teenage son and twin daughters, has been charged with attempted first-degree murder, attempted kidnapping and other lesser offenses.

Deputy NASA Administrator Shana Dale said Nowak's performance on last July's shuttle trip on the Discovery, her first -- and probably last -- trip into space, was "excellent." She said the fact that Nowak had been removed from flight status "makes no statement whatsoever on the state of her mental health."

Robert Cabana, deputy director of the Johnson Space Center and a fellow NASA astronaut, said NASA saw "no indication of concern with Lisa." He said that part of NASA's review of the incident will include examining whether "there was anything we missed along the way."

Cabana said that although fellow astronauts were "shocked and concerned" about the incident, they needed to "not be distracted by what's going on."

"We have humans in space right now," he said. "We need to stay focused on it to be sure we do it right."

Asked if the incident marked the end of Nowak's stellar career, NASA officials would not comment.

Cabana said NASA had not yet been contacted by law enforcement authorities for any information on the case.

"We have frozen computers and e-mails should they be required," Cabana said. "It's something we would do in this situation."

Authorities said Oefelein was on "leave in Florida" at the time of the incident and that he remained on leave. He was still on active flight status, they said.