![[Left]: A concept raytrace showing the IFS, with just the FUV channels shown. The NUV channels take the zero-order from each FUV grating and reflect it towards the IFS fold mirror (on either side) into a similar format NUV IFS (see Haughton et al., 2026 for a depiction of the INFUSE design that this IFS is based on13). The IFS assembly is forward (out of the page) from the MOS at the focal plane, with the IFS fold mirror canted slightly to move the slicer, gratings, and detectors over 0.7 meters from the MOS optical path. [Right]: The slicer-based IFS operates by reflecting portions of the image plane to different gratings, which then focus a spectrogram to a unique portion of the detector. In essence, each reflective slice operates like a long-slit spectrograph, with the slicer geometry separating the multi-slit spectrograph to avoid spectral confusion.-- astro-ph.IM](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/An-Ultraviolet.png?fit=1200%2C528&ssl=1)
[astro-ph.IM] The Habitable Worlds Observatory (HWO) is NASA’s next-generation astrophysics platform, delivering transformative capability in the search for life and study of the origins of the universe.
Amongst the instruments under consideration for HWO is a multi-purpose ultraviolet spectrograph and imager that provides a deep toolbox for some of the most pressing science investigations of the next several decades.
In this paper, we present a basic draft model of a potential UVI, including a multi-object spectrograph, far ultraviolet imager, high resolution spectrograph, and integral-field spectrograph.
The draft designs for these channels of the UV instrument serve as a basis for a general discussion of the instrument architecture and design challenges, while also identifying potential trades, enhancements, and other considerations that the HWO project will need to address as it moves into the formulation phase.
A flow chart depiction of the major elements of our baseline UVI. Certain mechanisms, such as focus adjusters, are not shown. The MOS and Imager presented in §3 share many common elements, including a focal plane, while the HRS is split into two completely independent channels for different bandpasses. The pros and cons, as well as potential enhancing trades, are presented in §4. This basic design is intended primarily to show in a straightforward manner an average performing UVI concept that is feasible within the constraints of the EAC2 model. — astro-ph.IM
We conclude with a presentation of several scientific simulations that have helped guide the capabilities of the draft design. This paper is intended to serve as a summary of UV instrument modes, technology, and potential design ahead of planned instrument studies in the late 2020’s, and then Phase A in the early 2030’s.
Brian Fleming, Kevin France, Dmitry Vorobiev, Jeanette Donber, Eric Frater, Thomas Delker, Vicki Herde
Comments: 41 pages, 19 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2610.12974 [astro-ph.IM] (or arXiv:2610.12974v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2610.12974
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Submission history
From: Brian Fleming
[v1] Fri, 9 Oct 2026 04:14:38 UTC (12,404 KB)
https://arxiv.org/abs/2610.12974
Astrobiology, Astronomy, exoplanet,
