The SISTINE-3 sounding rocket payload: calibration and in-flight performance

Abstract

The Suborbital Imaging Spectrograph for Transition-region Irradiance from Nearby Exoplanet host stars (SISTINE) is a rocket-borne imaging spectrograph designed to probe a broad region of the far-ultraviolet (FUV; 976-1272, 1300-1565 Å) emission of nearby stars. The instrument is composed of an f /14 Cassegrain telescope feeding a 2.1x magnifying spectrograph with a blazed, holographically ruled diffraction grating and a powered fold mirror. The telescope optics employ enhanced-lithium fluoride overcoated Al, with the secondary mirror providing the first flight test of hot-deoposition LiF coatings employing an ALD deposited aluminum trifluoride (Al + LiF + AlF3) capping layer. Spectra are captured on a large-format microchannel plate detector consisting of two 110 x 40 mm segments. The third flight of SISTINE was successfully executed on July 6th, 2022, from Arnhem Space Center (ASC), Northern Territory, Australia. SISTINE-3 successfully obtained FUV spectra of α Centauri A and B, fully resolving the binary pair with a 7” separation on sky. The spectra contain a suite of FUV emission lines crucial for reconstructing the high-energy stellar radiation incident onto planets orbiting solar-mass stars. We present the pre-flight calibration at the University of Colorado Boulder, including predicted performance, effective area, and resolving power; the integration and assembly performed at NASA Wallops Flight Facility (WFF) and ASC; and preliminary science results from the in-flight data.