Failure Analysis Study and Long-Term Reliability of Optical Assemblies with End-Face Damage

In June 2005, the NESC received a multi-faceted request to determine the long term reliability of fiber optic termini on the ISS that exhibited flaws not manufactured to best workmanship practices. There was a lack of data related to fiber optic workmanship as it affects the long term reliability of optical fiber assemblies in a harsh environment. A fiber optic defect analysis was requested which would find and/or create various types of chips, spalls, scratches, etc., that were identified by the ISS personnel. Once the defects and causes were identified the next step would be to perform long term reliability testing of similar assemblies with similar defects. The goal of the defect analysis would be for the defects to be observed and documented for deterioration of fiber optic performance. Though this report mostly discusses what has been determined as evidence of poor manufacturing processes, it also concludes the majority of the damage could have been avoided with a rigorous process in place

Space Flight Qualification on a Multi-Fiber Ribbon Cable and Array Connector Assembly

NASA's Goddard Space Flight Center (GSFC) cooperatively with Sandia National Laboratories completed a series of tests on three separate configurations of multi-fiber ribbon cable and MTP connector assemblies. These tests simulate the aging process of components during launch and long-term space environmental exposure. The multi-fiber ribbon cable assembly was constructed of non-outgassing materials, with radiation-hardened, graded index 100/140-micron optical fiber. The results of this characterization presented here include vibration testing, thermal vacuum monitoring, and extended radiation exposure testing data

Photonic Component Qualification and Implementation Activities at NASA Goddard Space Flight Center

The photonics group in Code 562 at NASA Goddard Space Flight Center supports a variety of space flight programs at NASA including the: International Space Station (ISS), Shuttle Return to Flight Mission, Lunar Reconnaissance Orbiter (LRO), Express Logistics Carrier, and the NASA Electronic Parts and Packaging Program (NEPP). Through research, development, and testing of the photonic systems to support these missions much information has been gathered on practical implementations for space environments. Presented here are the highlights and lessons learned as a result of striving to satisfy the project requirements for high performance and reliable commercial optical fiber components for space flight systems. The approach of how to qualify optical fiber components for harsh environmental conditions, the physics of failure and development lessons learned will be discussed

Requirements validation testing on the 7 optical fiber array connector/cable assemblies for the Lunar Reconnaissance Orbiter (LRO)

In the past year, a unique capability has been created by NASA Goddard Space Flight Center (GSFC) in support of Lunar Exploration. The photonics group along with support from the Mechanical Systems Division, developed a seven fiber array assembly using a custom Diamond AVIM PM connector for space flight applications. This technology enabled the Laser Ranging Application for the LRO to be possible. Laser pulses at 532 nm will be transmitted from the earth to the LRO stationed at the moon and used to make distance assessments. The pulses will be collected with the Laser Ranging telescope and focused into the array assemblies. The array assemblies span down a boom, through gimbals and across the space craft to the instrument the Lunar Orbiter Laser Altimeter (LOLA). Through use of a LOLA detector the distance between the LRO and the Earth will be calculated simultaneously while LOLA is mapping the surface of the moon. The seven fiber array assemblies were designed in partnership with W.L. Gore, Diamond Switzerland, and GSFC, manufactured by the Photonics Group at NASA Goddard Space Flight Center (GSFC) and tested for environmental effects there as well. Presented here are the requirements validation testing and results used to insure that these unique assemblies would function adequately during the Laser Ranging 14-month mission. The data and results include in-situ monitoring of the optical assemblies during cold gimbal motion life-testing, radiation, vibration and thermal testing

Investigation of hermetically sealed commercial LiNbO3 optical modulator for use in laser/LIDAR space-flight applications

This paper is the first in a series of publications to investigate the use of commercial-off-the-shelf (COTS) components for space flight fiber laser transmitter systems and LIDAR (laser imaging detection and ranging) detection systems. In the current study, a hermetically sealed COTS LiNbO3 optical modulator is characterized for space flight applications. The modulator investigated was part of the family of “High-Extinction Ratio Modulators ” with part number MXPE-LN from Photline Technologies in Besancon, France. Device performance was monitored during exposure to a Cobalt 60 gamma-ray source. Results from the testing show little change in device operation for a total accumulated dose of 52 krad

Space flight qualification on a novel five-fiber array assembly for the Lunar Orbiter Laser Altimeter (LOLA) at NASA Goddard Space

A novel multi-mode 5-fiber array assembly was developed, manufactured, characterized and then qualified for the Lunar Orbiter Laser Altimeter (LOLA). LOLA is a science data gathering instrument used for lunar topographical mapping located aboard the Lunar Reconnaissance Orbiter (LRO) mission. This LRO mission is scheduled for launch sometime in late 2008. The fiber portion of the array assembly was comprised of step index 200/220µm multi-mode optical fiber with a numerical aperture of 0.22. Construction consisted of five fibers inside of a single polarization maintaining (PM) Diamond AVIM connector. The PM construction allows for a unique capability allowing the array side to be “clocked” to a desired angle of degree. The array side “fans-out ” to five individual standard Diamond AVIM connectors. In turn, each of the individual standard AVIM connectors is then connected to five separate detectors. The qualification test plan was designed to best replicate the aging process during launch and long term space flight environmental exposure. The characterization data presented here includes results from: vibration testing, thermal performance characterization, and radiation testing

Space Flight Qualification on a Multi-Fiber Ribbon Cable and Array Connector Assembly

NASA’s Goddard Space Flight Center (GSFC) cooperatively with Sandia National Laboratories completed a series of tests on three separate configurations of multi-fiber ribbon cable and MTP connector assemblies. These tests simulate the aging process of components during launch and long-term space environmental exposure. The multi-fiber ribbon cable assembly was constructed of non-outgassing materials, with radiation-hardened, graded index 100/140-micron optical fiber. The results of this characterization presented here include vibration testing, thermal vacuum monitoring, and extended radiation exposure testing data