66 th International Astronautical Congress, Jerusalem, Israel. Copyright ©2015 by the International Astronautical Federation. All rights reserved. IAC-15,C2,5,3,x29660 Page 1 of 11 IAC-15,C2,5,3,x29660 STRUCTURAL HEALTH MONITORING DURING SUBORBITAL SPACE FLIGHT Andrei Zagrai 1 , 1 New Mexico Institute of Mining and Technology, USA, azagrai@nmt.edu Nickolas Demidovich 2 , Benjamin Cooper 1 , Jon Schlavin 1 , Chris White 1 , and Seth S. Kessler 3 , Joseph Macgillivray 1 , Samuel Chesebrough 1 , Erik Magnuson 1 , Lloyd Puckett 1 , Karen Tena 1 , Jaclene Gutierrez 1 , Blaine Trujillo 1 , David Siler 1 , Tiffany Gonzales 1 1 New Mexico Institute of Mining and Technology, 801 Leroy Pl., 124 Weir Hall, Socorro, NM 87801, USA. 2 US Federal Aviation administration (FAA), 3 Metis Design Corporation, 205 Portland St, Boston, MA 02114, USA Structural Health Monitoring (SHM) has potential to revolutionize assessment and qualification of space vehicles. This technology is seen as important element in improving safety of space travel and reducing spacecraft operation costs. It is envisioned that structural health monitoring will provide near real-time information on structural integrity and report potentially abnormal behaviour to astronauts or support personnel. In this capacity, SHM system is viewed as an integral part of spaceflight information system and flight recorder. A concept of spacecraft SHM system was implemented in a payload designed by New Mexico Institute of Mining and Technology and flown on NASA Flight Opportunity commercial suborbital spaceflight. The aim of the test was to investigate performance of state-of-the-art SHM technologies in launch, accent, space, and decent environments as well as survivability at landing. Two SHM approaches were considered: wireless strain and temperature sensing and active/passive embedded ultrasonic, which included elastic wave propagation studies, electro-mechanical impedance diagnostics, and acoustic emission monitoring. Wireless strain and temperature measurements, which university conducted in collaboration with Microstrain Corporation, allowed for collecting data at two locations inside payload and for investigating prospects of wireless sensing during commercial spaceflight. Interference with other payloads and vehicle’s command/control/communication were considered and the test has demonstrated utility of on-board wireless sensing. The university cooperated with Metis Design Corporation on active and passive embedded ultrasonic experiments. Active ultrasonic testing provided data on variation of structural sound speed during the flight and confirmed noticeable difference for in-space and on-the ground conditions. Additional active ultrasonic experiments have demonstrated potential for in-flight detection of structural cracks and loose bolted joints. Acoustic emission activity was measured in the passive embedded ultrasonic experiment, which indicated possibility for sensing structural events. Collected structural health data indicates feasibility of SHM during suborbital flight and highlights importance of acquiring environmental parameters that could influence diagnostic decisions. I. INTRODUCTION Structural health monitoring (SHM) is aimed at providing near real-time information of structural integrity and reporting potentially abnormal behaviour. Space system SHM is unique and notably deviates from typical aircraft SHM applications because of its multi- functionality at various stages of the mission 1 . Research 2 has shown SHM utility in pre-launch diagnostics and qualification of the spacecraft. It may be used to monitor spacecraft structure during launch and provide benefits of in-orbit monitoring. Finally, it may record data on structural performance and potential damage during atmospheric re-entry of the spacecraft. This last application is critical for understanding of structural breakup during re-entry or re-certification of the landed spacecraft for the next mission. Until recently, attention of the space community to SHM has been limited. The most likely reason for such an inattention is economics of space operation affecting opportunities (and needs) for non-destructive evaluation (NDE) during spaceflight. Previous work on pre-launch qualification 3 , monitoring of thermal protection system and assessment of satellite bolted joints has influenced broader acceptance of SHM as an integral part of new generation of spacecrafts. Aiming to improve safety and reliability of commercial spacecrafts, SHM mission was extended from almost exclusively pre-launch diagnosis to structural condition monitoring during all stages of space flight. A significant step forward in addressing safety concerns was development of a flight information recorder, aka “black box”. Initial configuration for such a recorder has been developed and tested by the Aerospace Corporation 4 . In the conducted tests 5 , REBR has recorded accelerations, internal pressure and heat shield temperatures. However, to improve understanding of the break-up process or re-certification of reusable parts, it is important to record information on structural