Lower stress, higher quality assemblies as well as quantum increases in productivity are now possible with `new generation', light curing adhesives. This new technology makes obsolete the industry-accepted assumption that low strain requires slow curing UV adhesives, epoxies and cements. Curing in only seconds and without the need for secondary thermal cure, these new light curing adhesives produce laminates which are essentially strain-free, and edge bonds with shrinkage as low as 0.2%. This paper will compare and contrast these new adhesives with existing bonding technologies in typical applications. Included are comparison between epoxies, UV curing mercaptoesters, and the new light curing Aerobic Acrylates, as well as the incorporation of adhesives into optical component design.

This paper will present a method for rapidly developing MEMS micro-mirrors by utilizing CAD tools currently available. Design begins with a mask layout which leads to analysis of one mirror. These results are then used to model a complete array.

As MOEMS transition from laboratory curiosities to production products inserted into telecommunication systems, a complete design flow is necessary for rapid product development to minimize time-to-market. We present a MOEMS design flow that provides efficient top-down design and accurate bottom-up verification. The detailed MOEMS device design is addressed along with an integrated capability for including other optical elements, packaging, opto- electronics, as well as drive and control electronics.

Computer Aided Design (CAD) tools for modeling optical MEM systems must not only model three distinct domains (optical, electrical, and mechanical), these tools must also model the interactions between the signals of these domains. We strive to create system-level models that are applicable for an optical MEM CAD tool using techniques that support accurate results and interactive computation times. This paper discusses our modeling efforts for multi-domain optical MEM systems with the implementation of these models into our CAD framework, Chatoyant. As an example of our mixed-modeling research, we present the simulation and analysis of a 2 X 2 optical cross connect using Chatoyant. The simulations include the dynamic response of a mechanical beam, diffractive optical effects, and the interaction between these domains.

This study demonstrates the use of the latest thermal analysis software in determining the primary mirror temperature gradients in a telescope tube with varying L/D, tube temperature, and mirror materials. It extends previous thermal radiation analysis work to include radial conduction in the mirror. Tube ID is fixed at 24'. Tube length varies as follows: 20', 40', 60', 100', and 200'. The focal length assumed for the parabolic mirror is the tube length. 1/2 tube length and flat mirror were also tried. The mirror material/thickness is varied as follows: ULE - 21/2' thick, QFS - lightweighted - 1/2' thick, aluminum - 21/2' thick. Space temperature is fixed at 3 K. The tube temperature is fixed at five values, 300 K, 250 K, 200 K, 150 K, 100 K, and 50 K. The mirror coating is Denton Ag, with an IR emissivity of 0.035. The tube inside surface coating is diffuse black, with an IR emissivity of 0.9. The mirror is assumed to be conductively isolated from the tube. The outside of the tube and the back of the mirror are adiabatic. The mirror is simply in thermal equilibrium with the fixed temperature tube and space.

The use of stray light fore-baffles in space-borne optical systems solves the problem of protecting the optical system from unwanted radiation. However, this introduces the problem of adding a large area black cavity at the system entrance aperture, and this cavity will run hot due to capture of solar, planetary albedo, and planetary emission radiation. The optical system may need to be baffled by a cool shield to keep system absolute temperatures sufficiently low. Alternately, a reflecting baffle system can be used that retro-reflects the input environment radiation. This reduces absorbed heat loads by the baffle system and reduces system absolute temperature levels.

Optics 1, Inc. has successfully designed and developed a 180 degree(s) field of view long wave infrared lens for USAF/AFRL under SBIR phase I and II funded projects in support of the multi-national Programmable Integrated Ordinance Suite (PIOS) program. In this paper, a procedure is presented on how to evaluate image degradation caused by asymmetric aerodynamic dome heating. In addition, a thermal gradient model is proposed to evaluate degradation caused by axial temperature gradient throughout the entire PIOS lens. Finally, a ghost reflection analysis is demonstrated with non-sequential model.

A study was conducted by Boeing-Houston to determine how the morphology and surface porosity of various materials and coatings used for ISS applications will influence the way contaminant molecules condense and deposit on sensitive optical and thermal control surfaces. The coatings used for these studies included: (1) clad aluminum, which served as a baseline reference material; (2) Silver Teflon film, which is used as a reflective surface for the ISS passive radiators' (3) Chromic Acid Anodized Aluminum, which is used as a thermal control coating for the ISS debris shields; (4) Sulfuric Acid Anodized Aluminum, which is used as a thermal control coating for the ISS truss elements, and Z-93P potassium silicate paint, which is used as a white reflective coating for the ISS active thermal radiators. The results of this study have shown that surface morphology, surface porosity, and surface texture greatly influence the way in which liquid silicone contaminant films condense in a vacuum environment and deposit on ISS materials and surface coatings.

Optical components such as mirrors or windows consisting of a substrate and a coating made up of thin films created at elevated temperatures exhibit substantial residual stresses induced by growth strains as well as thermoelastic strains that develop during the cool-down phase. A comprehensive description of these stresses must include not only the normal stresses in the film layers and the substrate but also the interfacial shearing stresses, which may cause delamination to occur. The primary purpose of this paper is to take advantage of recent progress in describing elastic interactions in multilayered laminates for obtaining conceptually correct formulas for the residual stresses and the substrate's curvature of thin-film coated optics. Available analytical solutions for the normal stresses of elastically isotropic structures made no assumptions regarding layer thicknesses but disregard the potential impact of edge effects.

This paper reports research into the beam wander in argon ion lasers caused by the unsymmetrical natural convection cooling on the outside of the laser's envelope. The phenomenon is studied using `Unified Analysis' techniques to solve the heat transfer and thermo-elastic distortion problems. The effectiveness of a high performance internal heat exchanger is shown and the analytical results are compared to test data from a sample laser.

As modern optomechanical engineers, we have the good fortune of having very sophisticated software programs available to us. The current optical design, mechanical design, industrial design, and CAM programs are very powerful tools with some very desirable features. However, no one program can do everything necessary to complete an entire optomechanical system design. Each program has a unique set of features and benefits, and typically two or mo re will be used during the product development process. At a minimum, an optical design program and a mechanical CAD package will be employed. As we strive for efficient, cost-effective, and rapid progress in our development projects, we must use these programs to their full advantage, while keeping redundant tasks to a minimum. Together, these programs offer the promise of a `seamless' flow of data from concept all the way to the download of part designs directly to the machine shop for fabrication. In reality, transferring data from one software package to the next is often frustrating. Overcoming these problems takes some know-how, a bit of creativity, and a lot of persistence. This paper describes a complex optomechanical development effort in which a variety of software tools were used from the concept stage to prototyping. It will describe what software was used for each major design task, how we learned to use them together to best advantage, and how we overcame the frustrations of software that didn't get along.

The finite element method is used to perform optimization of an actively controlled mirror's structural design. The theory of the method of modeling actuators is developed followed by execution of a test case demonstrating the effectiveness of this method in improving the correctability of a lightweight mirror. Design variables include shape and sizing optimization of the mirror's structural design. The design objective is the root-mean-square optical surface error after best correction of a wavefront with power aberration. Design constraints are applied to the mirror weight and the mounted natural frequency.

This paper discusses a framework for microdynamic analysis-- analyzing a structure for nonlinear dynamics behavior in the nanometric regime--and illustrates how microdynamic behaviors such as microlurch, joint snaps, and harmonic distortion fit within the framework. The framework is based on three types of nonlinear load-displacement behaviors associated with hysteresis in joints: deadzone, nonlinear elasticity, and hysteretic damping. The second part of the paper describes microdynamic analyses currently being used to flow optical performance requirements down to stability requirements at the component level. Such analyses are useful during error budget allocation exercises early in the mission design cycle.

This paper provides a summary of the cryogenic performance of the SIRTF optical system. The SIRTF optical system includes a primary mirror, a secondary mirror, a metering structure, an interface simulator and an autocollimation test flat. For each of these elements, the room temperature and cryogenic performance has been established.

NASA's Chandra X-ray Observatory (formerly AXAF) was launched on July 23, 1999 and is currently in orbit performing scientific studies. Chandra is the third of NASA's Great Observatories to be launched, following the Hubble Space Telescope and the Compton Gamma Ray Observatory. One of four primary science instruments on Chandra, and one of only two focal plane instruments, is the Advanced CCD Imaging Spectrometer, or ACIS. The ACIS focal plane and Optical Blocking Filter needed to be launched under vacuum, so a tightly sealed, functioning door and venting subsystem were implemented. The door was opened two and one-half weeks after launch (after most out-gassing of composite materials) and allowed X-rays to be imaged by the ACIS CCD's in the focal plane. A failure of this door to open on-orbit would have eliminated all ACIS capabilities, severely degrading mirror science. During the final pre- flight thermal-vacuum test of the fully integrated Chandra Observatory at TRW, the ACIS door failed to open when commanded to do so. This paper provides a somewhat technically expanded description of the efforts, under considerable time pressure, by NASA, its contractors and outside review teams to investigate the failure and to develop modified hardware and procedures which would correct the problem.

The Space Optics Manufacturing Technology Center of Marshall Space Flight Center is involved in the development of lightweight optics for space-based systems. The NGST and other future NASA programs require large aperture space- based instruments. This paper reviews the technologies under development for NGST including discussions of the environmental testing of candidate segment for the NGST primary mirror.

The Space Optics Manufacturing Technology Center of NASA's Marshall Space Flight Center is involved in the development of nickel and nickel alloy electroformed mirrors for rapid low cost production of space-based optical systems. The current state of the process is discussed for both Wolter type x-ray mirrors and normal incidence mirrors for visible and infrared applications.

The ongoing progress of shape-controlled mirrors for enabling lower mass, large segmented mirrors is described in the context of Raytheon's AMSD Program. This approach has been successfully applied in the past for room temperature telescopes as large as 4-meters in aperture (at 70 kg/m²) and for cryogenic mirrors as large as 3-meters in aperture (at 30 kg/m²). The AMSD Program is producing similar mirror segments at 15 kg/m² while simultaneously investigating advanced manufacturing techniques with the potential for significant reductions in cost and schedule for multiple segments of a large aperture.

Ball Aerospace is currently under contract to Marshall Space Flight Center (MSFC) in Huntsville, AL to design, build, and test a state-of-the-art lightweight beryllium mirror for cryogenic space applications, the Next Generation Space Telescope Sub-scale Beryllium Mirror Demonstrator (SBMD). The mirror is manufactured from spherical powder beryllium and optimized for cryogenic use. This 0.53-meter diameter lightweight mirror (< 12 kg/m²) has been tested at MSFC at ambient and cryogenic temperatures down to 23 K, cryofigured for optimal performance at 35 K, and subsequently retested at cryogenic temperatures. In addition, Ball has a separate contract with MSFC for an Advanced Mirror system Demonstrator (AMSD) to fabricate and test an ultra-lightweight mirror system which extends the semi-rigid SBMD mirror design to a 1.4-meter point-to-point beryllium hexagon mirror, flexures, rigid body and radius of curvature actuators, and reaction structure. This paper will describe the SBMD mirror performance and its cryogenic testing and present an overview of the AMSD semi-rigid beryllium mirror.

Lightweight mirrors for space can be made using a thin flexible substrate for the optical surface and a rigid lightweight frame with actuators for support. The accuracy of the optical surface is actively maintained by adjusting the actuators using feedback from wavefront measurements. The University of Arizona is now in the final stages of fabricating two such mirrors. A 2-m NGST Mirror System Demonstrator, with an areal density of 13 kg/m², is being built for NASA and will be tested at cryogenic temperatures. A 50 cm development mirror, with an areal density of only 5 kg/m², is also being fabricated. This paper discusses the fabrication processes involved with both of these mirrors.

The Advanced Mirror System Demonstrator program sponsored by NASA, the Space Based Laser Joint Venture Team, and the National Reconnaissance Office provides an opportunity to design and build a demonstration model of the next generation primary mirrors that will be needed for future space programs. This paper discusses the history of this technology at Kodak and provides an overview of the analysis techniques used in the design and performance prediction process.

We contend that carbon fiber reinforced silicon carbide material (C/SiC), developed by IABG, represents the state- of-the-art for ultra-lightweight, high precision optomechanical structures that must operate in adverse environments and over wide ranges of temperature. C/SiC employs conventional NC machining/milling equipment to rapidly fabricate near-net shape parts, providing substantial schedule, cost, and risk savings for high precision components. Unlike power based SiC ceramics, C/SiC does not experience significant shrinkage during processing, nor does it suffer from incomplete densification. By modifying certain process steps, the thermal and mechanical properties of C/SiC are tunable in certain ranges. This paper focuses on recent advances in C/SiC technology and application of this technology to high precision, lightweight applications such as meter-class optics and optical mounts. We also introduce a design for new, high precision mounts based upon standard optical grade C/SiC (formulation A-3) and a custom formulation of C/SiC (D-4) which was engineered for Schafer Corporation by IABG. The A- 3 and D-4 formulations have a near-perfect CTE match with silicon, making them the ideal material to athermally support ultra-lightweight silicon optics that will operate in a cryogenic environment.

Silicon offers significant advantages over other optical substrate materials such as beryllium, silicon carbide and glass for both cryogenic and high-energy laser applications. Silicon is quickly and inexpensively super-polishable (surface figure < (lambda) 10 p-v at (lambda) equals 632.8 nm; surface roughness < 5 angstroms rms), has superior thermal properties at cryogenic temperatures, and can be lightweighted. This paper updates our progress towards producing dimensionally stable ultra-lightweight silicon optics for both cryogenic instruments and high-energy infrared laser systems. We review cryogenic figure test results for three-inch diameter coupons, present analysis results for a half-meter diameter silicon foam-core mirror and tell how these results apply to a Silicon Lightweight Demonstration Mirror, and describe optics being designed for an Offner Relay System.

The author has recently completed the development of a series of structural actuators for supporting the segments of the primary mirror in various configurations of NASA's Next Generation Space Telescope. Separately, the author has been developing a `calibrated displacement actuator' for use in calibrating metrology instruments used to make nanometer- scale measurements. This paper reports on the performance of both the calibrated displacement actuator called `HECTOR- 100^tm' and the Rubicon^tm structural actuator. It also discusses the benefits of incorporating a HECTOR-100- type actuator as a hyperfine third stage in a structural actuator for controlling mirror surfaces for very high resolution imaging as possibly in the visible or UV portions of the spectrum.

This paper considers a variety of techniques for an optomechanical system in which optical elements are mounted on cylinders that are located in Vs.