IXPE

IXPE (for Imaging X-ray Polarimetry Explorer) is a NASA Small Explorer Program (SMEX) space X-ray observatory launched in December 2021, intended for 5 years of observation (with a 2-year primary mission), specifically to observe polarization of X-ray sources, such as active galactic nuclei (AGNs) and magnetars. IXPE has three identical X-ray telescopes, the three to provide redundancy as well as collection area. The sensors are a type of proportional counter (gas ionized by the incident X-rays, producing photoelectrons) with an array of electron sensors allowing the direction of the electrons to be recorded, which reveals information on the photon's polarization.

In 2024 a 20-month extension of IXPE operation, through September 2025 was announced; I haven't found specific news regarding funding and operation since then, but it apparently remains in operation in 1/2026, but has been mentioned as a target for reduced funding in announcements about proposed USA budgets.