2024ApJ...971..171M

The Rockets for Extended-source X-ray Spectroscopy (tREXS) are a series of suborbital rocket payloads designed to collect spectral emission from extended astronomical sources of soft X-rays. The tREXS spectrograph uses mechanical beam-shaping modules and reflection gratings to passively focus and then disperse incident X-rays to an array of Teledyne/e2v CIS 113 CMOS X-ray sensors. Designed to achieve a moderate spectral resolution, R ⪆ 50, from ≈15 to 40 Å over a large field of view (>10 deg²), the tREXS instrument is sensitive to line emission from key ion species over the soft-X-ray band. Here we present the complete end-to-end design of the tREXS spectrograph and discuss its significance and expected performance, using simulated observations of the Cygnus Loop supernova remnant and an enhanced region in the soft X-ray background.