Original Date: 04/26/1999
Revision Date: 01/18/2007
Best Practice : X-Ray Calibration Facility
Marshall Space Flight Center’s (MSFC’s) X-Ray Calibration Facility (XRCF) is a world-class, one-of-a-kind operational site that was constructed in 1975. Over the years, it has gone through many changes to make it a highly flexible facility with a multi-disciplined workforce. As the largest x-ray, optical test site in the world, the XRCF (Figure 2-4) features a 2,000-square foot, class 10,000 area for unpacking and assembling hardware and a 6,000- square foot, class 2,000 vertical laminar flow clean room. The XRCF’s vacuum chamber is a 24-foot by 75-foot stainless steel compartment, capable of sustaining temperatures from -180°F to +180°F and vacuums to 10-7 Torr. The chamber can accommodate in-flight configurations of any payload to be launched from the space shuttle.
The facility’s x-ray system produces a nearly parallel beam that travels down a 1,700-foot long, stainless steel guide tube with gate valve isolation from the calibration chamber. The guide tube varies in diameter from three feet at the source of the beam to five feet at the chamber. Internal baffles prevent the scattering of the beam by eliminating rays that hit the sides of the tube. The x-ray source and the chamber are isolated from the surrounding building and the ground to remove any possible interference from seismic disturbances. The high vacuum levels of the chamber can be achieved in six hours, first by mechanical pumps (also isolated from the chamber and the ground) and then by cryogenic and turbo-molecular pumps. Additionally, MSFC can isolate the calibration chamber from the guide tube to perform thermal vacuum testing of space shuttle payloads, leak testing of space station modules, space simulation testing, and large space structure bake-outs.
The XRCF is strategically located near the Redstone Arsenal Airport, the Tennessee River, and major interstate highways. As a result, materials and components for testing can be easily delivered to the facility. All buildings within the XRCF maintain a controlled access and are connected by a secure local area network. Manning levels for normal operations is two to four employees per shift. MSFC’s ability to test and calibrate instruments prior to their launch is a significant benefit, thereby reducing unexpected and costly problems/failures before they occur in space.
Figure 2-4. X-Ray Calibration Facility
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