A Sterling woman, one of three employees accused of stealing at least $400,000 in parking fees from the Steven F. Udvar-Hazy Center in Chantilly, pleaded guilty Thursday in U.S. District Court.

Freweyni Mebrahtu, 45, faces a maximum penalty of 10 years in prison when she is sentenced on Jan. 18, 2013.

Mebrahtu was arrested on Aug. 4 by agents of the Smithsonian Office of Inspector General and FBI.

In a statement of facts filed with her plea agreement, Mebrahtu admitted that from March 2009 through July 2012, she was a full-time employee of Parking Management Inc. (“PMI”) who worked as a booth attendant at the Steven F. Udvar-Hazy Center parking lot. The Udvar-Hazy Center is the annex facility of the National Air and Space Museum and is home to the Space Shuttle Discovery and other historic aircraft.

PMI, under contract with the Smithsonian, has managed and operated the Udvar-Hazy Center’s 2,000-vehicle parking lot since March 2009.

In the statement of facts, Mebrahtu admitted that since at least October 2009, she has stolen the $15 entrance fee from thousands of museum visitors.

Mebrahtu admitted to stealing using two methods. First, she often reached under the counter in her attendant’s booth to unplug the electronic vehicle counter which was installed. Second, after a visitor paid the entrance fee, Mebrahtu would not hand the customer a serialized parking ticket to display in the car’s windshield as proof of purchase. By unplugging the vehicle counter and suppressing the number of tickets which were distributed, Mebrahtu was able to keep the entrance fees from all vehicles she had not reported as entering the parking lot.

Mebrahtu also admitted that she and other booth attendants discussed techniques for stealing parking revenues. Further, Mebrahtu admitted that she paid a portion of her stolen proceeds to the location manager at the lot.

The statement of facts states that Mebrahtu stole thousands of dollars each week from the Smithsonian, and the three-year loss to the Smithsonian attributable to Mebrahtu is at least $400,000. She is the second PMI attendant who worked at the parking lot to plead guilty to stealing from the Smithsonian.

Meseret Terefe, 36, of Silver Spring, Md., pleaded guilty to the same charge on Sept. 28. Genete Yigzu, 46, of Alexandria, is also charged in connection with the thefts.