FOB Vibration Testing

Vibration tests (“shake tests”) on the Fixed Optical Bench (FOB) (manufactured by the Nippi co. Ltd.) have begun in the ISAS vibration test room. In the picture, the inside of the vibration test room is seen from the hallway of the second floor. The scaffold for the operations has been erected, and the FOB has been placed into the middle. The rectangular box on the right-hand side of the upper platform is a model of the HXT-1 telescope. From now, a sunshade and the sunshade base (Nippi co. Ltd.) will be installed, in order to block sunlight from entering the teescope. The silver-colored cylinder on the left-hand side is the sunshade base for the second hard X-ray telescope (HXT-2). The black cover in the picture is the sunshade. Inserted in the middle is a model of the HXT-2 telescope.

The soft X-ray telescope (SXT-S) model is installed in the middle of the black sunshade base on the mirror support (a 90 cm tower needed to provide the necessary focal distance). The black sunshade is also installed. A model for the second soft X-ray telescope, the SXT-I, has already been installed and it is located behind the SXT-S mirror support. Each of the various models are exact replicas of the actual flight instruments, and the vibrations they will experience replicate the level of vibrations the FOB will experience during launch. Accelerometers have been placed at various positions of the FOB for the test. The bundles of red cables in the picture are connected with accelerometers. It is expected that a maximum acceleration of 12 G will be experienced.

After the test, it will be verified whether or not anything has broken. On December 23, late into the evening laser tracker was used to measure the alignments. On December 27 and 28, the FOB will be vibrated along the X-axis. Tests will continue in this manner into the new year. Once the new year has started, the alignments will be measured along the Y- and Z-axes. At each step, along the side panel the alignment must be within 0.5 mm of the design values in order to have “passed” the test. Let us hope the FOB can endure the tests!

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