Much of the Michoud Assembly Facility's NASA history was focused on construction and production of NASA's External Tank (ET).
Silicon Valley is an area that located on the San Francisco, California, peninsula, radiates outward from Stanford University. It is contained by the San Francisco Bay on the east, the Santa Cruz Mountains on the west, and the Coast Range to the southeast.
Silicon Valley is geographically based too, and its center of gravity has shifted from Santa Clara County and the Valley proper, where the great first and second generation tech companies started, up through Palo Alto and Menlo Park in San Mateo County, and more recently, towards San Francisco proper.