What happens when the lights are turned out in the enormous cleanroom that currently houses NASA's James Webb Space Telescope? The technicians who are inspecting the telescope and its expansive golden mirrors look like ghostly wraiths in this image as they conduct a "lights out inspection" in the Spacecraft Systems Development and Integration Facility (SSDIF) at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The cleanroom lights were turned off to inspect the telescope after it experienced vibration and acoustic testing. The contamination control engineer used a bright flashlight and special ultraviolet flashlights to inspect for contamination because it's easier to find in the dark.
NASA photographer Chris Gunn says, "The people have a ghostly appearance because it's a long exposure." He left the camera's shutter open for a longer than normal time so the movement of the technicians appear as a blur. He also used a special light "painting" technique to light up the primary mirror.
The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. It is being assembled in a Class 10,000 cleanroom at NASA's Goddard Space Flight Center. Webb is an international project led by NASA with its partners, ESA (European Space Agency), and the Canadian Space Agency.