By Lynne Schaufenbil
Title: REXIS (REgolith X-ray Imaging Spectrometer) – a Student Instrument on OSIRIS-REx: The Short Story
The Regolith X-ray Imaging Spectrometer (REXIS) is the student collaboration experiment launched aboard NASA's OSIRIS-REx asteroid sample return mission. It is a collaboration between MIT Aero/Astro, MIT EAPS, MIT Kavli Institute, Lincoln Laboratory and the Harvard College Observatory. REXIS complements the scientific investigations of other OSIRIS-REx instruments by determining the relative abundances of key elements present on the asteroid's surface by measuring the X-ray fluorescence spectrum (stimulated by the natural solar X-ray flux) over the range of energies 0.5 to 7 keV. REXIS consists of two components: a main imaging spectrometer with a coded aperture mask and a separate solar X-ray monitor to account for the Sun's variability. In addition to element abundance ratios (relative to Si) pinpointing the asteroid's most likely meteorite association, REXIS also maps elemental abundance variability across the asteroid's surface using the asteroid's rotation as well as the spacecraft's orbital motion. Image reconstruction at the highest resolution is facilitated by the coded aperture mask. Through this operation, REXIS aimed to be the first application of X-ray coded aperture imaging to planetary surface mapping, making this student-built instrument a pathfinder toward future planetary exploration. More than 80 students at the undergraduate and graduate levels have been involved with the REXIS project, with the hands-on experience translating to a dozen Master's and Ph.D. theses and other student publications. In this talk, I will give an overview of how REXIS went from a short proposal in 2011 to a fully qualified flight instrument that was integrated to the OSIRIS-REx spacecraft in December 2015. I will also discuss the in-flight calibrations that REXIS conducted along and report on REXIS observations of the asteroid Bennu.
Rebecca Masterson is a Principal Research Scientist at MIT and Director of the MIT Space Systems Laboratory. She holds affiliations with both the Department of Aeronautics and Astronautics and the MIT Kavli Institute, and has over 20 years of experience in spacecraft design and development that includes structural design, control structure interactions, system engineering, program management, and integration and test. Masterson was Co-PI and Instrument Manager for the Regolith X-Ray Imaging Spectrometer (REXIS), the student instrument onboard the OSIRIS-REx asteroid sample return mission. She was the Integration and Test Lead for the Transiting Exoplanet Survey Satellite (TESS), and is currently managing a ground-based instrument for the Magellan telescope (LLAMAS), a pair of LEO CubeSats (AERO VISTA) and an X-ray polarimetry experiment on a sounding rocket (REDSoX). Masterson has mentored over 50 students, graduate and undergraduate and teaches the Aerospace senior capstone class, a graduate satellite engineering class, and MATLAB for aerospace engineers.
Please contact Lynne_Schaufenbil@uml.edu if you plan on attending. Thank you!