Integration and test of the REXIS and recommendations for low-cost, high-risk spaceflight programs

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 115-118).NASA Risk Class D programs must meet their technical goals with limited resources. The Regolith X-Ray Imaging Spectrometer (REXIS) is a Class D student collaboration instrument flying on the NASA OSIRIS-REx mission. This thesis describes and analyzes the NASA management and systems engineering processes that were tailored for REXIS. Part of the Class D approach is to accept more risk to meet schedule and cost requirements. This added risk is carried into the Integration and Test (I&T) phase, and can manifest in an off-nominal sequence. The REXIS I&T phase is examined in detail to provide insight into the resource tradeoffs necessary to successfully deliver a Class D instrument. Each step of the I&T sequence is portrayed, including critical incidents that arose during this phase and how they were handled. The I&T process of the REXIS Radiation Cover Deployment System is described in detail, and recommendations are made to further reduce the risk on this critical system. Three key lessons from REXIS I&T are presented to help inform future low-cost, high-risk missions. First, challenges arise when inevitable changes occur between the Engineering and Flight Models. Secondly, procuring flight spare hardware for Class D missions is highly valuable. Finally, small co-located teams ease communication and lessen the burden of documentation, but can have limitations in expertise and flexibility during critical phases.by Laura C. Bayley.S.M