Mariner 1 in JPL's Spacecraft Assembly Facility
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ Dec. 23, 2019
JPL's Spacecraft Assembly Facility looks more like a hangar in this photo of two engineers standing with Mariner 1 on May 2, 1962. However, the gowning procedures were far less rigorous than they are today. Mariner 1 was destroyed during its attempted launch to Venus.