Testing The James Webb Space Telescope Pathfinder

Image Credit: NASA/Chris Gunn

Image Credit: NASA/Chris Gunn

September 29, 2016 – In this photograph taken on September 1, 2016, the James Webb Space Telescope (JWST) Pathfinder structure has been configured for the Thermal Pathfinder Test at NASA Johnson Space Center’s giant thermal vacuum chamber, called Chamber A. The Pathfinder is a test version of the structure that supports the telescope. This is where end-to-end testing of the actual telescope will occur in 2017.

The dummy Aft Optical System (AOS) is visible in the center of the primary mirror segments. The AOS is the upright piece at the center of the primary mirror – it contains the telescope’s tertiary and fine steering mirrors.

Among the mirror segments seen here are one gold-coated flight-spare beryllium segment (just in front of the AOS), one uncoated beryllium engineering unit segment, and ten gold-coated aluminum thermal simulator segments.

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. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency.

Colorado’s Ball Aerospace & Technologies Corp. is responsible for the eighteen primary mirrors that make up the James Webb Space Telescope. Once on orbit, the 18 hexagonal segments will work together as one 21.3-foot (6.5-meter) primary mirror, the largest mirror ever flown in space and the first to deploy in space. Ball Aerospace is also responsible for developing the secondary mirror, tertiary mirror and fine-steering mirror.

The Near Infrared Camera (NIRCam) instrument for the James Webb Space Telescope (JWST) is being developed by Lockheed Martin, under contract with the University of Arizona. NIRCam is the primary science camera on JWST, and also functions as the sensor that is used to align the observatory’s primary mirror.