147 Fastener Capture Plate Technology to Contain On-Orbit Debris 

Kevin Eisenhower * 

   Abstract   The Fastener Capture Plate technology was developed to  solve the problem of capturing loose hardware  and small fasteners, items that were not originally  intended to be disengaged in microgravity, thus  preventing them from becoming space debris. This  technology was incorporated into astronaut tools  designed and successfully used on NASA’s Hubble  Space Telescope Serv icing Mission #4. The  technology’s ultimate benefit is that it allows a very time-efficient method for disengaging fasteners and  removing hardware while minimizing the chances of losing parts or generating debris. The technology aims to simplify the manual labor required of the oper ator. It does so by optimizing visibility and access to  the work site and minimizing the operator's need to  be concerned with debris while performing the  operations. It has a range of unique features that were developed to minimize task time, as well as  maximize the ease and confidence of the astrona ut operator. This paper describes the technology and  the astronaut tools developed specifically for a complicated on-orbit repair, and it includes photographs of the hardware being used in outer space.   Introduction 

Background of Problem

Confronted with the unique challenge of fixing a failed electronics board inside the Hubble Space  Telescope (HST), NASA got the job done thanks to astronauts equipped with ne w tools and technologies.  Servicing Mission #4 (SM4) occurred in May of 2009 and was a complete success. The failed electronics  board was inside one of HST’s many  instruments, the Space Telescope Imaging Spectrograph (STIS).  Accessing the board meant getting behind an aluminum Front Panel that was held in place with 111 fasteners, ranging from #4 countersunk to #4 a nd #8 socket head caps screws, with many having  washers. It also meant worksite preparation by removi ng parts such as a handrail that blocked access to  the Front Panel. To make things even more challenging, during the late stages of mission planning another instrument, the Advanced Camera for Surveys (ACS), had an electrical failure requiring four more electronics boards be removed.  Replacing entire inst ruments was not an option in this case, so  NASA set off to replace just the failed  electronics boards. This meant performing on-orbit surgery, but if any one of those fasteners had come free inside the telescope it could have been very detrimental to the telescope’s functionality.  Technologies, tools, and techniques had to be developed to avoid such a situation and ensure the mission would be successful.  Problem Solution – Tools

Four tool designs were developed and fabricated for HST SM4, each incorporating the same general fastener capture technology but for distinctly differ ent work sites. These t ools are the STIS Fastener  Capture Plate (Figure 1), the ACS Fastener Capture Plate (Figure 2), the Handrail Removal Tool (Figure 3), and the Clamp Removal Tool (Figure 4).                                                       * Alliant Techsystems, Beltsville, MD  

Proceedings of the 40th Aerospace Mechanisms Symposium, NASA Kennedy Space Center, May 12-14, 2010  NASA/CP-2010-216272