An extended-source grating spectrograph for suborbital rockets and small satellites

The rise of high-throughput X-ray reflection gratings has enabled new instrument concepts in soft-X-ray spectroscopy. Coupling modern, highly efficient gratings with an optical design that enables a large field of view (FOV) allows for spectrographs that can achieve higher-resolution observations of extended sources and the X-ray background. The Rockets for Extended-source X-ray Spectroscopy (tREXS) are a series of suborbital rocket payloads that apply this concept, utilizing modern reflection gratings fabricated with electron-beam lithography, passive, mechanical beam-shaping modules to achieve a large FOV, and an extended focal-plane array of X-ray CMOS detectors. We present here the design of the tREXS instrument, and discuss ways that the instrument concept can be adapted to other formats, including SmallSats, that can enable longer observations and more complete sky coverage.