HOUSTON — Arizona Congresswoman Gabrielle Giffords will undergo surgery today to replace a piece of her skull removed by doctors after she was shot in January.

The surgery was confirmed to The Associated Press by a person familiar with Giffords’ care. The person spoke on condition of anonymity because the information has not officially been released.

Giffords had a piece of her skull removed shortly after the shooting to allow room for brain swelling, and has been wearing a helmet adorned with an Arizona state flag. Doctors said earlier this year they expected to reattach the skull in May.

The surgery comes just days after Giffords returned from Florida where she watched her astronaut husband rocket into space. Mark Kelly is Endeavour’s commander.

Giffords, a three-term Democratic congresswoman, has recovered enough from the shooting to twice fly from Houston to Florida for launch attempts. When Endeavour’s five Americans and one Italian got off the ground on Monday, she watched in private from a wheelchair on the roof of the launch control center and remarked, “good stuff, good stuff,” according to her staff.

While some patients don’t have this surgery until after they are released from the hospital, Giffords’ operation indicates she is recovering according to schedule.

The next step will be to release her from the hospital.

Then she will continue speech, occupational and physical therapy at an outpatient clinic.