The National Capital Planning Commission has approved preliminary site and building plans for the Vietnam Veterans Memorial visitor center that is planned for the Mall.

The approval, issued Thursday, was another step toward the construction of the $85 million underground facility on a 5.2 acre site just west of the Vietnam Veterans Memorial and north of the Lincoln Memorial.

Twelve years in the making, the Education Center at the Wall is the creation of Jan C. Scruggs, president of the Vietnam Veterans Memorial Fund. The fund built Washington’s famous Vietnam Wall, which bears the names more than 58,000 people killed in the war.

The fund said it anticipates final commission approval this fall and a groundbreaking in November.

The center is to feature an interactive history of the Vietnam era and a display of some of the thousands of mementos left at the Wall. It will also show a changing montage of photos of those whose names are on the Wall and those who have been killed in Iraq and Afghanistan.

Such pictures can still be submitted via the Internet to the Vietnam Veterans Memorial Fund.

“This is the fantastic forward momentum that we need to complete the mission and break ground in 2012,” Scruggs said.