The first external tank, the Main Propulsion Test Article, rolled off the assembly line on September 9, 1977.
This section of barrel panel was cut from a developmental space shuttle external tank to be presented by the tank's prime contractor Martin Marietta to Mr. and Mrs. Roland B. Holland. Its "T" stiffeners were milled from a solid 10-inch thick aluminum billet. The 154-foot-long external tank holds over 530,000 gallons of liquid hydrogen and liquid oxygen.