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At least 289 records · Page 16

Orion Optical Navigation Performance and Testing

The Orion Optical Navigation System, which is designed to perform the navigation which will allow the crew to return safely to Earth in the event of a permanent loss of communications with the ground, has been matured through analysis and testing. This paper will detail the extensive tests and analysis that have gone into fleshing out the performance of the system in the face of numerous constraints placed on the optical navigation system.

D'Souza, Christopher↗

Thrust vectoring systems

The design, fabrication, and testing of thrust vectorable ion optical systems capable of controlling the thrust direction from both 5- and 30-cm diameter ion thrusters is described. Both systems are capable of greater than 10 deg thrust deflection in any azimuthal direction. The 5-cm system is electrostatic and hence has a short response time and minimal power consumption. It has recently been tested for more than 7500 hours on an operational thruster. The 30-cm system is mechanical, has a response time of the order of 1 min, and consumes less than 0.3% of the total system input power at full deflection angle.

King, H. J.↗

Deep space optical communications development program

The technology development, spacecraft systems impact, design examples and overall development plan for optical deep space communications are described. Design examples include moderate distance links like ones from Mars to Earth, out through a potential mission to a distance of 1000 A.U. The technology development plan, which includes both ground-based as well as Earth orbit-based reception considerations, spans the period from 1985 to the year 2003. Past technology developments in high efficiency lasers, optical modulation and coding, and high power efficiency communications techniques at multiple bits of information per detected photon are also discussed.

Lesh, James R.↗

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors

Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

Kirkham, Harold↗

Polarization aberrations in the solar activity measurements experiments (SAMEX) solar vector magnetograph

An optical design and polarization analysis of the Air Force/NASA Solar Activity Measurements Experiments solar vector magnetograph optical system is performed. Polarization aberration theory demonstrates that conventional telescope coating designs introduce unacceptably high levels of polarization aberrations into the optical system. Several ultralow polarization mirror and lens coatings designs for this instrument are discussed. Balancing of polarization aberrations at different surfaces is demonstrated.

Mcguire, James P., Jr.↗

An optical profilometer for spatial characterization of three-dimensional surfaces

The design concept and system operation of an optical profilometer are discussed, and a preliminary evaluation of a breadboard system is presented to demonstrate the feasibility of the optical profilometer technique. Measurement results are presented for several test surfaces; and to illustrate a typical application, results are shown for a cleft palate cast used by dental surgeons. Finally, recommendations are made for future development of the optical profilometer technique for specific engineering or scientific applications.

Kelly, W. L., IV↗

Differential collision cross-sections for atomic oxygen: Analysis of space flight instruments for solar terrestrial physics

A summary of the status of the Cross-section Facility at MSFC is presented. A facility was designed, fabricated, assembled, tested, and operated for measurement of differential scattering cross sections important to understand the induced environment for a vehicle (e.g., Space Station) in low earth orbit. A user's manual for the facility is also presented. The performance of the facility was evaluated and found to be satisfactory in all the essential areas. Differential scattering cross sections were measured and results for the scattering measurements are included. Input to the development of the Ultraviolet Imager Optical System is also discussed. Design, fabrication, and evaluation of UV filters using a four-layer aluminum base are reported.

Torr, Douglas G.↗

Fiber optics for controls

The design, development, and testing of a fiber optic integrated propulsion/flight control system for an advanced supersonic dash aircraft (flies at supersonic speeds for short periods of time) is the goal of the joint NASA/DOD Fiber Optic Control System Integration (FOCSI) program. Phase 1 provided a comparison of electronic and optical control systems, identified the status of current optical sensor technology, defined the aircraft sensor/actuator environment, proposed architectures for fully optical control systems, and provided schedules for development. Overall, it was determined that there are sufficient continued efforts to develop such a system. It was also determined that it is feasible to build a fiber optic control system for the development of a data base for this technology, but that further work is necessary in sensors, actuators, and components to develop an optimum design, fully fiber optic integrated control system compatible with advanced aircraft environments. Phase 2 is to design, construct, and ground test a fly by light control system. Its first task is to provide a detailed design of the electro-optic architecture.

Seng, Gary T.↗

Design and Performance Evaluation of Sensors and Actuators for Advanced Optical Systems

Current state-of-the-art commercial sensors and actuators do not meet many of NASA s next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers. Keywords: Photonics, Adaptive Optics, Tunable Filters, MEMs., MOEMs, Coronagraph, Star Tracker

Clark, Natalie↗

Transmission Telescope Optical Dynamic Alignment

The Integrated Radio Optical Communication System (iROC) is designed to transmit data between Mars and Earth by means of radio waves at 32.67 GHz (Ka Band) and laser beam at 1550 nm, both transmitted via a combined teletenna. The iROC terminal will provide ‘beaconless’ operations to allow full function from the outer planets. In order to point without the aid of an uplink beacon, the proof of concept presented here is addressing the need for an accurate determination and control of the relative position of the laser beam with respect to a reference star. The experiment presented simulates a surrogate transmission telescope system in laboratory setting and presents the model used in the correction of the outgoing beam. The results of the model show a nonlinear dependence between the outgoing and the reference beam, indicating the necessity of a minimum of two metrology instruments placed along the optical system for increased pointing precision.

optical communication↗

A l% and 1cm Perspective Leads to a Novel CDOM Absorption Algorithm

A next-generation in-water profiler designed to measure the apparent optical properties of seawater was developed and validated across a wide dynamic range of water properties. This new Compact-Optical Profiling System (C-OPS) design uses a novel, kite-shaped, free-falling backplane with adjustable buoyancy and is based on 19 state-of-the-art microradiometers, spanning 320-780 nm. Data collected as part of the field commissioning were of a previously unachievable quality and showed that systematic uncertainties in the sampling protocols were discernible at the 1% optical and 1cm depth resolution levels. A sensitivity analysis as a function of three water types, established by the peak in the remote sensing reflectance spectra, revealed which water types and spectral domains were the most indicative of data acquisition uncertainties. The unprecedented vertical resolution of C-OPS measurements provided near-surface data products at the spectral endpoints with a quality level that has not been obtainable. The improved data allowed development of an algorithm for predicting the spectral absorption due to chromophoric dissolved organic matter (CDOM) using ratios of diffuse attenuation coefficients with over 99% of the variance in the data explained.

Morrow, J. H.↗

Design and Performance of the Terrestrial Planet Finder Coronagraph

Terrestrial Planet Finder Coronagraph, one of two potential architectures, is described. The telescope is designed to make a visible wavelength survey of the habitable zones of at least thirty stars in search of earth-like planets. The preliminary system requirements, optical parameters, mechanical and thermal design, operations scenario and predicted performance is presented. The 6-meter aperture telescope has a monolithic primary mirror, which along with the secondary tower, are being designed to meet the stringent optical tolerances of the planet-finding mission. Performance predictions include dynamic and thermal finite element analysis of the telescope optics and structure, which are used to make predictions of the optical performance of the system.

designs↗

Phased-array-fed antenna configuration study, volume 2

Increased capacity in future satellite systems can be achieved through antenna systems which provide multiplicity of frequency reuses at K sub a band. A number of antenna configurations which can provide multiple fixed spot beams and multiple independent spot scanning beams at 20 GHz are addressed. Each design incorporates a phased array with distributed MMIC amplifiers and phasesifters feeding a two reflector optical system. The tradeoffs required for the design of these systems and the corresponding performances are presented. Five final designs are studied. In so doing, a type of MMIC/waveguide transition is described, and measured results of the breadboard model are presented. Other hardware components developed are described. This includes a square orthomode transducer, a subarray fed with a beamforming network to measure scanning performance, and another subarray used to study mutual coupling considerations. Discussions of the advantages and disadvantages of the final design are included.

Sorbello, R. M.↗

Challenges of developing an electro-optical system for measuring man's operational envelope

In designing work stations and restraint systems, and in planning tasks to be performed in space, a knowledge of the capabilities of the operator is essential. Answers to such questions as whether a specific control or work surface can be reached from a given restraint and how much force can be applied are of particular interest. A computer-aided design system has been developed for designing and evaluating work stations, etc., and the Anthropometric Measurement Laboratory (AML) has been charged with obtaining the data to be used in design and modeling. Traditional methods of measuring reach and force are very labor intensive and require bulky equipment. The AML has developed a series of electro-optical devices for collecting reach data easily, in computer readable form, with portable systems. The systems developed, their use, and data collected with them are described.

Woolford, B.↗

Optical materials for space based laser systems

The design features and performance characteristics of a sensitized holmium laser applicable to differential lidar and Doppler windshear measurements are presented, giving attention to the optimal choice of sensitizing/activating dopant ions. This development of a 2-micron region eye-safe laser, where holmium is sensitized by either hulium or erbium, has called for interionic energy transfer processes whose rate will not result in gain-switched pulses that are excessively long for atmospheric lidar and Doppler windshear detection. The application of diamond films for optical component hardening is noted.

Buoncristiani, A. M.↗

Active phase compensation system for fiber optic holography

Fiber optic delivery systems promise to extend the application of holography to severe environments by simplifying test configurations and permitting the laser to be remotely placed in a more benign location. However, the introduction of optical fiber leads to phase stability problems. Environmental effects cause the pathlengths of the fibers to change randomly, preventing the formation of stationary interference patterns which are required for holography. An active phase control system has been designed and used with an all-fiber optical system to stabilize the phase difference between light emitted from two fibers, and to step the phase difference by 90 deg without applying any constraints on the placement of the fibers. The accuracy of the phase steps is shown to be better than 0.02 deg., and a stable phase difference can be maintained for 30 min. This system can be applied to both conventional and electro-optic holography, as well as to any system where the maintenance of an accurate phase difference between two coherent beams is required.

Mercer, Carolyn R.↗

Active phase compensation system for fiber optic holography

Fiber optic delivery systems promise to extend the application of holography to severe environments by simplifying test configurations and permitting the laser to be remotely placed in a more benign location. However, the introduction of optical fiber leads to phase stability problems. Environmental effects cause the pathlengths of the fibers to change randomly, preventing the formation of stationary interference patterns which are required for holography. An active phase control system has been designed and used with an all-fiber optical system to stabilize the phase difference between light emitted from two fibers, and to step the phase difference by 90 deg without applying any constraints on the placement of the fibers. The accuracy of the phase steps is shown to be better than 0.02 deg., and a stable phase difference can be maintained for 30 min. This system can be applied to both conventional and electro-optic holography, as well as to any system where the maintenance of an accurate phase difference between two coherent beams is required.

Mercer, Carolyn R.↗