The preliminary alignment for the Far Ultraviolet Spectrograph (FUV) instrument using visible wavelength light has been completed at Lockheed Martin. The next phase of testing will see the instrument ship to Belgium to complete the alignment in the FUV in a specialized vacuum chamber.
The FUV ICON instrument has an articulating field of view. In order to accommodate this, special machinery is required to rotate the instrument during alignment, testing and calibration while inside the vacuum chamber. Centre Spatial de Liege (CSL) in Belgium will provide this unique ultraviolet vacuum facility.
The design for the FUV instrument is such that the optical system can be focused using visible light and a visible grating, as well as FUV light and grating. This is preferable, since alignment using UV must be performed in a vacuum chamber, which makes it more challenging to conduct the alignment.
Over the past four weeks, the SSL team has been traveling to Lockheed Martin where the instruments’ mirrors were carefully adjusted to achieve best focus and optimum spectral performance at visible wavelengths. The visible wavelengths chosen were suitably scaled to simulate performance at the FUV operating wavelength.
The next phase of testing will see the optics package ship to Centre Spatial de Liege (CSL) in Belgium. After verifying the visible alignments were maintained, and no shifts happened during transport, the UV grating and the two UV cameras will be installed and UV alignment will begin.