Frank LaRocca

Development, qualification, and integration of the optical fiber array assemblies for the Lunar Reconnaissance Orbiter

The NASA Goddard Fiber Optics Team in the Electrical Engineering Division of the Applied Engineering and Technology Directorate designed, developed and integrated the space flight optical fiber array hardware for the Lunar Reconnaissance Orbiter (LRO). The two new assemblies that were designed and manufactured at GSFC for the LRO exist in configurations that are unique in the world for the application of ranging and LIDAR. Described here is an account of the journey and the lessons learned from design to integration for the Lunar Orbiter Laser Altimeter and the Laser Ranging Application on the LRO.

Applications of optical fiber assemblies in harsh environments: the journey past, present, and future

Over the past ten years, NASA has studied the effects of harsh environments on optical fiber assemblies for communication systems, lidar systems, and science missions. The culmination of this has resulted in recent technologies that are unique and tailored to meeting difficult requirements under challenging performance constraints. This presentation will focus on the past mission applications of optical fiber assemblies, including: qualification information, lessons learned, and new technological advances that will enable the road ahead.

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 (ELC), 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.

Vibration performance comparison study on current fiber optic connector technologies

Fiber optic cables are increasingly being used in harsh environments where they are subjected to vibration. Understanding the degradation in performance under these conditions is essential for integration of the fibers into the given application. System constraints often require fiber optic connectors so that subsystems can be removed or assembled as needed. In the present work, various types of fiber optic connectors were monitored in-situ during vibration testing to examine the transient change in optical transmission and the steady-state variation following the event. The fiber endfaces and connectors were inspected at selected intervals throughout the testing.

The optical fiber array bundle assemblies for the NASA lunar reconnaissance orbiter; evaluation lessons learned for flight implementation from the NASA electronic parts and packaging program

The United States, National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC), Fiber Optics Team in the Electrical Engineering Division of the Applied Engineering and Technology Directorate, designed, developed and integrated the space flight optical fiber array hardware assemblies for the Lunar Reconnaissance Orbiter (LRO). The two new assemblies that were designed and manufacturing at NASA GSFC for the LRO exist in configurations that are unique in the world for the application of ranging and lidar. These assemblies were developed in coordination with Diamond Switzerland, and the NASA GSFC Mechanical Systems Division. The assemblies represent a strategic enhancement for NASA’s Laser Ranging and Laser Radar (LIDAR) instrument hardware by allowing light to be moved to alternative locations that were not feasible in past space flight implementations. An account will be described of the journey and the lessons learned from design to integration for the Lunar Orbiter Laser Altimeter and the Laser Ranging Application on the LRO. The LRO is scheduled to launch end of 2008.

Fiber optic cable thermal preparation to ensure stable operation

Fiber optic cables are widely used in modern systems that must provide stable operation during exposure to changing environmental conditions. For example, a fiber optic cable on a satellite may have to reliably function over a temperature range of -50°C up to 125°C. While the system requirements for a particular application will dictate the exact method by which the fibers should be prepared, this work will examine multiple ruggedized fibers prepared in different fashions and subjected to thermal qualification testing. The data show that if properly conditioned the fiber cables can provide stable operation, but if done incorrectly, they will have large fluctuations in transmission.

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.