The board for the National 9/11 Memorial Museum approved a plan Thursday to charge $24 for general admission when the museum opens sometime this year. Families of victims, however, will be able visit for free.

Joe Daniels, the memorial's president, said the ticket prices were necessary because the museum and memorial doesn't have federal funding to offset the cost of the annual $63 million operating budget.

"A general admission ticket of $24 will help fulfill our obligation to commemorate and preserve the history of 9/11. It will also enable educational programming that will teach the nature of and responsibility for the special freedoms we have," he said in a statement.

Daniels added there will be discounts for senior citizens, school groups and children. Free admission will be available during certain days of the week, according to the board.

The 9/11 Memorial, which has had more than 11.5 million visitors since opening in 2011, will remain free to the public, according to the board.

The board will continue to seek additional funding from the government, according to

The museum, which will contain artifacts, exhibitions and first-person recollections on audio and video related to the 9/11 attacks, is expected to open this spring. As of Thursday, the board did not give an exact date, however, they planned a news conference for Friday to update the public on the museum's progress.