Characterization of Optical Fiber Cables for Space Flight

Characterization of Optical Fiber Cables for Space Flight New Proposal Total $ Funding for FY02: Technology Type: Newly Available (COTS) Emerging/Advanced Continuing NEPP Work Project Area: Proposing Centers: (Estimated Center Participation, %$): Collaborators: Point of Contact: Parts Packaging Radiation NASA GSFC & GRC 64 % GSFC % MSFC 36 % GRC % JSC % LaRC Other % JPL W.L Gore, Lucent SFT, USCONEC Melanie N. Ott, NASA Goddard Space Flight Center 301-286-0127 melanie.ott@gsfc.nasa.gov Dr. Margaret Tuma, NASA Glenn Research Center 216 433-8665 margaret.l.tuma@lerc.nasa.gov Harry C. Shaw, NASA Goddard Space Flight Center 301-286-6616 harry.c.shaw@gsfc.nasa.gov Investigator(s): Melanie Ott, Sigma Research and Engineering/ NASA GSFC Dr. Margaret Tuma, NASA GRC Harry C. Shaw, NASA GSFC Objective(s):     The continuation of characterization studies on COTS cable assemblies and high reliability cable assemblies for space flight use. To provide infusion of new technologies as they become available to space flight missions by identifying available designs and evaluating candidates for usage in a wide variety of space flight environments. To provide lessons learned on the proper usage of optical fiber cables in space flight environments. To provide through characterization testing a family of candidates for a variety of space flight environments. Task Description: This task proposes the continuation of characterization studies on COTS cable assemblies and high reliability cable assemblies for space flight use. New technologies are being developed each year, so to make sure that projects have the widest variety of products to chose from, we need to be able to characterize the cables which are emerging on the market. This task will identify newly available designs and will evaluate the best candidates for avionics and flight use. This requires testing of several different cables each year in a variety of environments including thermal, mechanical, vibration, and radiation. The results of these tests, and comparisons to cables currently in use by NASA will be provided. Feedback will also be given to the manufacturers regarding improvements that can be implemented to enhance the reliability of their products. Task Approach to Meeting NEPP Objectives: This program provides information to projects on usage of optical fiber cables in space flight environments as well as which candidates are most suitable for a variety of environments. NASA enterprises benefit from our ability to validate new fiber optic cables. The information gained by prior work in this area have enabled NASA centers to benefit from the lessons learned through this program both from our engineers and from the vendors themselves. Over the past several years programs including: GLAS, EO-1, and MAP and ISS have directly benefited from this work by having the test data and report already available on commercially available cables such that these projects did not have to conduct the research themselves. They have made use of our publications from our website to guide them in the selection of space flight optical fiber cable assemblies and their usage. Our work helps the vendors understand the issues faced by NASA fiber users and how they can modify their products to meet NASA mission requirements. We have had great successes working with Spectran and W.L. Gore and must continue to do so with the increasing number of suppliers of this type of component. The data provided to NASA and the manufacturers through this task have usefulness in the avionics, commercial, military and flight hardware sectors that include Codes S, Y, M and R. Technical Background: Through this program we have collected information regarding how to test for known failure and degradation modes of optical fiber cable assemblies for usage in space flight environments. Based on this information we are able to characterize a cable, for a given environment to bring out these known failure mechanisms. We are building on our previous work by using our test methods for evaluation of upcoming technologies in the prototype stage as well as commercially available cables that have not yet been used or tested for space flight environments. The tests we use to characterize a cable include: thermal cycling, low temperature testing (when necessary), post fabrication strength testing of the optical fiber, radiation testing at cold temperature for germanium doped fiber, radiation testing during thermal changes for commercially available fiber, and vibration of cables when terminated. The information this program provides has become an integral part of current space flight project specifications and designs. We continue to make this information available through NEPP reports as well as technical publications. We will continue to provide useful information in formats that are readily available. Work that has been done on evaluating fiber optic cables for the NEPP program and other GSFC projects by GSFC can be found on the Technology Validation Assurance website under "Photonics" (http://misspiggy.gsfc.nasa.gov/tva/photonics.htm). See references. Technical Approach:        Obtain samples of commercially available cable being considered for use from projects or from manufacturers with strong product bases. Perform a process inspection for manufacturers which whom NASA has little experience. Note materials and processes that have critical impact on the reliability of the cable. Survey the latest project needs for re-evaluation of test plans if necessary. Design tests that address the critical design aspects and rugged environmental conditions based on the current upcoming missions or generic typical environment Feedback results to the manufacturers and projects and establish a partnership with manufacturers who are willing to modify their processes to satisfy NASA needs and whose product has good potential for wide-ranging usage. Assess modified products Issue report of findings and test results. NASA Customers: Projects that benefit from this work include: MAP, GLAS, NGST and any other programs who request information on optical fiber cable assemblies that will function in space flight environments. Clearly Stated Deliverables:  With each round of testing that yields significant results, a report is published for the projects to download from the NEPP web site and a report is published at an international conference. This report is provided at the end of the year and includes: the reasons for the testing, the environmental parameters, the failures modes based on the research to date, justification for testing to the parameters described, objectives of the testing, equipment set up, description of the candidates cables tested with significant specifications, data, results of testing and relevant conclusions. A summary of all results is presented to evaluate candidates under testing for the specific environments. This report will be published at the end of each fiscal year. Top Level Schedule: Q1/02: Select cable candidates for testing based on construction and lessons learned. Survey most upto-date mission requirements and write test plan for testing based on known failure mechanisms associated with candidates for test. Q2/02: Assemble equipment for testing and begin testing. Q3/02: Complete testing and perform analysis on available data. Q4/02: Write final report and presentations for NEPP deliverables. References: Fiber Optic Cable Assemblies for Space Flight Applications III: Characterization of Commercial Cables for Thermal Effects, Melanie Ott, March 31, 2000, Report to the NEPP. Characterization of Commercial Optical Fiber Cables for Space Flight Environments at NASA Goddard Space Flight Center, Melanie Ott, Presentation to the IMAPS/NEPP Advanced Technology Workshop, Washington D.C., May 24, 2000. Assurance of COTS Fiber Optic Cable Assemblies for Space Flight, Presentation to the Commercialization of Military and Space, Melanie Ott, Electronics Conference, Los Angeles, CA, February 10, 1999 Twelve Channel Optical Fiber Connector Assembly: From Commercial off the Shelf to Space Flight Use, Melanie Ott, Joy Bretthauer SPIE Proceedings Vol. 3440 Photonics for Space Environments VI, 1998 Fiber Optic Cable Assemblies for Space Flight II: Thermal and Radiation Effects, Melanie Ott, SPIE Proceedings Vol. 3440 Photonics for Space Environments VI, 1998, Aerospace Electrical Interconnection System Conference, Williamsburg VA, October 29,1997, JPL Packaging Workshop January 14, 1998. Fiber Optic Cable Assemblies for Space Flight Applications: Issues and Remedies, Melanie Ott and Jeannette Plante, American Institute of Aeronautics and Astronautics/Society of Automotive Engineers World Aviation Congress Anaheim, CA, Oct 1997 Fiber Optic System Qualification at Goddard Space Flight Center, Melanie Ott, JPL Packaging Workshop, 1997 Assurance of COTS Fiber Optic Cable Assemblies for Space Flight, Melanie Ott List of Procurements GSFC: Cable/fixtures Materials for testing set-ups: GSFC Contractor Labor GRC Labor FY02 FY03 Manpower Loading: Average Heads (FTEs) Q1 NASA/GSFC GSFC Contractor GRC 0.36 0.23 Q2 0.36 0.23 Q3 0.36 0.23 Q4 0.36 0.23 Leveraging: Work performed for NEPP in past years as well as work performed for space flight projects such as MAP, ISS, GLAS and EO-1 is all incorporated in our lessons learned and continued testing. This work, prior and continuing, has enabled characterization studies to be fostered by knowledge based assessments.