ewan douglas (@douglase.bsky.social)

Pioneering far UV emission mapping of the circumgalactic medium with Aspera—motivation, mission status, and lessons learned Aspera is a far ultraviolet (FUV) SmallSat mission in the NASA Astrophysics Pioneers Program with the science objectives surrounding detection and mapping of the warm-hot circumgalactic medium in emission for the first time in nearby galaxies. Aspera comprises a pair of identical long-slit FUV spectrographs optimized to detect faint extended source emission at ∼103 nm. The operations phase of the mission will include a commissioning phase, a primary science phase, and a closeout phase. Placed in a Sun-synchronous 500 to 600 km orbit, Aspera will operate in detection, mapping, and calibration modes during the primary science phase to achieve the mission’s science objectives. We note that minor damage outside of the clear aperture of the off-axis parabola mirrors was discovered during the application of high reflectance FUV coatings. It was determined that this damage was likely due to a cold welding effect when the Al optic holder came in contact with the contact point regions of the optic during the enhanced lithium fluoride coating process. These features do not affect the performance of the optic, nor do they pose any structural risk, and they can be avoided for future projects through material selection. The payload critical design is complete, and assembly of the payload began as of summer 2024. https://www.spiedigitallibrary.org/journals/Journal-of-Astronomical-Telescopes-Instruments-and-Systems/volume-11/issue-04/042216/Pioneering-far-UV-emission-mapping-of-the-circumgalactic-medium-with/10.1117/1.JATIS.11.4.042216.full