NASA Photo ID: S65-23078
Date Taken: 03/23/65
In the white room atop the Gemini launch vehicle, Astronauts John W. Young (left) and Virgil I. Grissom prepare the enter the Gemini spacecraft. Astronaut Thomas P. Stafford, GT-3 backup pilot, along with spacecraft engineers and technicians look on.
Source: NASA photo in my possession