This PDF file contains the front matter associated with SPIE Proceedings Volume 8150, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Recent visible wavelength observations of Multiwalled Carbon Nanotubes (MWCNT) coatings have revealed that they represent the blackest materials known in nature with a Total Hemispherical Reflectance (THR) of less than 0.25%. This makes them exceptionally good as absorbers, with the potential to provide order-ofmagnitude improvement in stray-light suppression over current black surface treatments when used in an optical system. Here we extend the characterization of this class of materials into the infrared spectral region to further evaluate their potential for use on instrument baffles for stray-light suppression and to manage spacecraft thermal properties through radiant heat transfer process. These characterizations will include the wavelength-dependent Total Hemispherical Reflectance (THR) properties in the mid- and far-infrared spectral regions (2-110 μm). Determination of the temperature-dependent emittance will be investigated in the temperature range of 40 to 300 K. These results will be compared with other more conventional black coatings such as Acktar Fractal Black or Z306 coatings among others.

When dealing with high-tech equipment, accurate positioning is of the utmost importance to ensure durability and a productive lifetime. Unexpected high friction or wear of positioning mechanisms can lead to unnecessary down-time or products that are not up to specification. To ensure a sufficient lifetime, it is necessary to know beforehand how the sliding and rolling contacts will behave over time. This demand becomes more stringent when the machine operates at extreme conditions, e.g. vacuum or extremely low temperatures. Traditional greases and mineral oil based lubricants do not perform adequately in such extreme environments, as they either contaminate the vacuum or do not provide sufficient film thickness. TNO recently developed a unique measuring application, the TNO cryotribometer, in order to measure friction and wear of position mechanisms at harsh conditions. Preliminary results show that the contact pressure and the sliding velocity influenced the friction level greatly. This set-up is currently used to find and analyze different material combinations, which demonstrate a constant friction level under cryogenic vacuum conditions.

We present the design and measured performance of the superconducting magnetic bearing (SMB) that was used successfully as the rotation mechanism in the half-wave plate polarimeter of the E and B Experiment (EBEX) during its North American test flight. EBEX is a NASA-supported balloon-borne experiment that is designed to measure the polarization of the cosmic microwave background. In this implementation the half-wave plate is mounted to the rotor of an SMB that is operating at the sink temperature of 4 K. We demonstrate robust, remote operation on a balloon-borne payload, with angular encoding accuracy of 0.01°. We find rotational speed variation to be 0.2% RMS. We measure vibrational modes and find them to be consistent with a simple SMB model. We search for but do not find magnetic field interference in the detectors and readout. We set an upper limit of 3% of the receiver noise level after 5 minutes of integration on such interference. At 2 Hz rotation we measure a power dissipation of 56 mW. If this power dissipation is reduced, such an SMB implementation is a candidate for low-noise space applications because of the absence of stick-slip friction and low wear.

Currently, the most compelling astrophysics questions include how planets and the first stars formed and whether there are protostellar disks that contain large organic molecules. Although answering these questions requires space telescopes with apertures of at least 10 meters, such large primaries are challenging to construct by scaling up previous designs; the limited capacity of a launch vehicle bounds the maximum diameter of a monolithic primary, and beyond a certain size, deployable telescopes cannot fit in current launch vehicle fairings. One potential solution is connecting the primary mirror segments edgewise using flux-pinning mechanisms, which are analogous to non-contacting damped springs. In the baseline design, a flux-pinning mechanism consists of a magnet and a superconductor separated by a predetermined gap, with the damping adjusted by placing aluminum near the interface. Since flux pinning is possible only when the superconductor is cooled below a critical temperature, flux-pinning mechanisms are uniquely suited for cryogenic space telescopes. By placing these mechanisms along the edges of the mirror segments, a primary can be built up over time. Since flux pinning requires no mechanical deployments, the assembly process could be robotic or use some other noncontacting scheme. Advantages of this approach include scalability and passive stability.

Performance testing of space imaging systems is crucial to meeting the requirements of such systems for all types of space applications. For over 30 years, the space chambers at the Arnold Engineering Development Center (AEDC) have performed space sensor characterization, calibration, and mission simulation testing on space-based, interceptor, and airborne sensors. The use of infrared scene projection systems in the cryovacuum ground-test environment is essential to this testing and is a challenging task. Experiences from the space test facilities at AEDC offer lessons learned from its experience in projection technologies, optical system design, optical material characteristics and measurement (including cryodeposition), and positioning systems involved in performing ground testing of a sensor system under flight conditions.

The James Webb Space Telescope Optical Telescope Element (OTE) and Optical Telescope Element/Integrated Science Instrument Module (OTIS) will be tested at the same time in the final and only cryogenic optical test of the observatory. Due to the size and temperature of JWST, this is a complex test which has undergone changes in the last year aimed at reducing test execution risk. We will summarize the test plan changes, architecture changes, and predicted timeline changes for this test. We will also explain the checkout plans for assuring the test will go smoothly.

The JWST (James Webb Space Telescope) primary mirror consists of 18 hexagonal mirror segments each approximately 1.5 meters point to point. The mirror segments are constructed from a lightweight beryllium substrate with both a radius-of-curvature actuation system and a six degree-of-freedom hexapod actuation system. The manufacturing process for each individual mirror assembly takes approximately six years due to limitations dealing with the number of segments and manufacturing & test facilities. In order to catch any manufacturing or technology roadblocks, as well as to streamline specific processes, an Engineering Development Unit (EDU) was built to lead the mirror manufacturing flow. This development unit has all of the same requirements as the flight units and is actually considered to be one of the flight spare mirrors. The EDU was manufactured with a lead time of approximately six months over the other mirrors to assure adequate time to optimize each step in the manufacturing process. Manufacturing and tests occurred at six locations across the U.S. with multiple trips between each. The EDU recently completed this arduous process with the final cryogenic performance test of the mirror assembly taking place at Marshall Space Flight Center's (MSFC) X-Ray & Cryogenic Facility (XRCF). Testing included survivability tests to 25 Kelvin, hexapod & radius-of-curvature actuation systems testing, and cryogenic figure & prescription testing. Presented here is a summary of the tests performed along with the results of that testing.

The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Structure is a precision optical metering structure for the JWST science instruments. Optomechanical performance requirements place stringent limits on the allowable thermal distortion of the metering structure between ambient and cryogenic operating temperature (~35 K). This paper focuses on thermal distortion testing and successful verification of performance requirements for the flight ISIM Structure. The ISIM Structure Cryoset Test was completed in Spring 2010 at NASA Goddard Space Flight Center in the Space Environment Simulator Chamber. During the test, the ISIM Structure was thermal cycled twice between ambient and cryogenic (~35 K) temperatures. Photogrammetry was used to measure the Structure in the ambient and cryogenic states for each cycle to assess both cooldown thermal distortion and repeatability. This paper will provide details on the post-processing of the metrology datasets completed to compare measurements with performance requirements.

The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Structure is a precision optical metering structure for the JWST science instruments. Optomechanical performance requirements place stringent limits on the allowable thermal distortion of the metering structure. A significant effort was completed to develop capabilities to predict and metrologize cryogenic thermal distortion of the ISIM Structure. This paper focuses on thermal distortion finite element modeling, analysis, and model validation. Extensive thermal distortion analysis was completed during the design phase for the ISIM Structure to demonstrate that thermal distortion requirements were achieved. Comparison of measurements from recently completed cryogenic testing and model predictions demonstrate the adequacy of thermal distortion modeling uncertainty factors adopted during the design phase, and provide bounds on the accuracy of the model predictions. This paper will provide an overview of the test configurations, describe the thermal distortion models of the tests, and provide a comparison of test results and analytical predictions from the models.

The Near Infrared Spectrograph (NIRSpec) is one of four science instruments aboard the James Webb Space Telescope (JWST) that is to be launched later this decade. NIRSpec is sensitive in the wavelength range from 0.6 to 5.0 μm and operates at temperatures ≤ 40 K. It offers multi-object, fixed slit, and integral field spectroscopy with seven selectable dispersers. The on-ground spectrophotometric calibration of the instrument is performed by means of continuum and line emission lamps. NIRSpec also contains an internal calibration assembly (CAA) that will provide the wavelength and radiometric calibration in orbit. Due to thermal constraints, the CAA features low power tungsten filament lamps in combination with long-pass and Fabry-Perot-like interference filters, which need to be calibrated at instrument level. We will report on the wavelength calibration of the NIRSpec flight model and the CAA, carried out during the first cryogenic performance testing.

The Near Infrared Spectrograph (NIRSpec) is one of four science instruments on board the James Webb Space Telescope (JWST). NIRSpec offers multi-object, fixed slit, and integral field spectroscopy. There are eight optical elements mounted on the grating wheel assembly (GWA), six gratings, a double-pass prism, and a mirror. The precise knowledge of the position and tilt of these elements is critical for target acquisition and an accurate extraction and calibration of science data. We present the concept of calibrating the position/tilt sensors during the NIRSpec flight model ground calibration campaign, the performance of the sensors and first results concerning the GWA repeatability.

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which includes numerous fold mirror assemblies. The instrument will operate at 35K after experiencing launch loads at ~293K. The optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain exceptional optical quality during operation. Lockheed Martin Space Systems Company (LMSSC) conceived, designed, analyzed, assembled, tested, and integrated the mirror assemblies for the NIRCam instrument. This paper covers the design, analysis, assembly, and test of two of the instruments key fold mirrors.

The NIRCam instrument on the James Webb Space Telescope (JWST) will provide a coronagraphic imaging capability to search for extrasolar planets in the 2 - 5 microns wavelength range. This capability is realized by a set of Lyot pupil stops with patterns matching the occulting mask located in the JWST intermediate focal plane in the NIRCam optical system. The complex patterns with transparent apertures are made by photolithographic process using a metal coating in the opaque region. The optical density needs to be high for the opaque region, and transmission needs to be high at the aperture. In addition, the Lyot stop needs to operate under cryogenic conditions. We will report on the Lyot stop design, fabrication and testing in this paper.

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which employs three triplet lens cells. The instrument will operate at 35K after experiencing launch loads at ~293K and the optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain an exceptional wavefront during operation. The Lockheed Martin Advanced Technology Center (LMATC) has built and tested the collimator and camera optics for use on the NIRCam flight instrument. This paper presents an overview of the driving requirements, a brief overview of the changes in the opto-mechanical design and analysis since our last presentation, a discussion of the collimator and shortwave camera triplet assembly processes, and finally a summary of the mechanical and optical test results.

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which terminates at two focal plane arrays for each module. The instrument will operate at 35K after experiencing launch loads at ~293K and the focal plane array housings must accommodate all associated thermal and mechanical stresses, while keeping the FPAs aligned. The main purpose of the FPAH is to provide a stray light, contamination, and radiation shield to the Focal Planes. The design includes a fold mirror used to direct incoming light up to the detectors and mechanical support for the Application Specific Integrated Circuits (ASIC). A six degree of freedom shim is used to align the Focal Plane Assembly at the operating temperature of 35 Kelvin. This paper will provide an overview of the FPAH design including an update to the Fold Mirror design described in previous papers. Analysis and test results of the ambient temperature optical and vibration testing will be presented.

The Pick Off Mirror (POM) is the business end of the Focus and Alignment Mechanism (FAM) of NIRCam. The POM harnesses the light delivered by the telescope and steers it into the Near Infrared Camera. At strategic points during the build and test of the Pick Off Mirror and its mechanism (the FAM) the surface figure error (SFE) of the mirror was monitored. This metric was used to track the health of the mirror throughout this testing regime. For example, the team ran an SFE test before and after Vibration testing the FAM. In this paper, we will provide an overview of the testing regime and the results of these periodic SFE tests. These results lead to the qualification of the POM and FAM designs for flight on the James Webb Space Telescope.

The Focus and Alignment Mechanism (FAM) is the opto-mechanical, cryogenic mechanism that positions the Pick Off Mirror (POM) for the Near Infrared Camera of the James Webb Space Telescope. The POM is used to direct the light collected by the telescope into the Near Infrared Camera. This paper is a follow on to SPIE Paper 7439C-49. In this paper, we will summarize the design and role of this opto-mechanical mechanism and present the results of the environmental testing of the Qualification Unit. The testing consisted of 7 thermal cycles from ambient temperature to 26 Kelvin, as well as a 2 × Mechanism Life test at this cryogenic temperature plateau. These results lead to the qualification of the POM and FAM designs for flight on the James Webb Space Telescope.

The near infrared camera (NIRCam) instrument for NASA is one of four science instruments installed into the integrated science instrument module (ISIM) of the James Webb space telescope (JWST) intended to conduct scientific observations over a five year mission lifetime. The NIRCam instrument will have a pupil imaging lens actuator assembly (PIL) to provide a means of imaging the primary mirror for ground testing, instrument commissioning, and diagnostics which must operate from 293 - 37 Kelvin and be in support of the usual launch environments. More refined optic prescriptions and initial PIL vibration test data led to the redesign of the PIL. This paper discusses the redesign of the lens mounts to accommodate a new optic prescription. This paper also details the analysis of vibration test data that led to the redesign of a stiffer bearing mount for the PIL flight mechanism that would ultimately be tested to show appropriate margins for meeting program vibration test requirements.

We will discuss a fret wear solution developed for the James Webb Space Telescope NIRCam filter wheel assembly by implementation of a hard coating. With mechanisms and structures designed for space flight application, titanium is often selected as the choice material of construction. Titanium offers a low-density high strength material that is good for use with many optical instruments due to its' favorable thermal properties. An important factor to consider with titanium mechanisms and structures are component fits and the vibration environment that must be survived during launch. In many instances, small (slip) fits between titanium components can cause fret wear during launch induced vibration. Titanium is particularly susceptible to fret wear, although other materials also demonstrate the fret wear. Fretting is adhesive failure of a material that experiences impact and micro-slip with an adjacent part. The mechanism of fret wear involves small particles that are pulled from the surface of parts that turn into hard oxides that further accelerate the wear between the parts. To mitigate fret wear, the mechanism or structure can be designed to eliminate all slip fits altogether, lubricants may be added to the wear surfaces or hard coatings can be applied to the wear surfaces when the other approaches are not feasible. For the NIRCam filter wheel assembly, which must operate at 35K and remain optically clean, only hard coatings are feasible. A discussion of several coating alternatives and associated wear testing will be presented along with the selection of an optimal solution.

The Near Infrared Camera (NIRCam) for the James Webb Space Telescope (JWST) has been developed over the last several years and during the course of development, the team of engineers has overcome several technical difficulties and discovered many things that could be improved about the design. The instrument employs a Beryllium optical bench, mounted transmissive and reflective optics, several mechanisms and the electronics to control them. This paper will discuss some of the technical issues encountered and the lessons learned as a result of them. These issues involve tapping of threads in and anodic coating of Beryllium, material interfaces within mechanisms, paints and coatings of metals, mounting of optics and general engineering practice. The issues, root causes and resolutions for problems will be presented in addition to suggestions and recommendations for future designs.

Three phase plates were designed to simulate the JWST segmented primary mirror wavefront at three on-orbit alignment stages: coarse phasing, intermediate phasing, and fine phasing. The purpose is to verify JWST's on-orbit wavefront sensing capability. Amongst the three stages, coarse alignment is defined to have piston error between adjacent segments being 30 μm to 300 μm, intermediate being 0.4 μm to 10 μm, and fine being below 0.4 μm. The phase plates were made of fused silica, and were assembled in JWST Optical Simulator (OSIM). The piston difference was realized by the thickness difference of two adjacent segments. The two important parameters to phase plates are piston and wavefront errors. Dispersed Fringe Sensor (DFS) method was used for initial coarse piston evaluation, which is the emphasis of this paper. Point Diffraction Interferometer (PDI) is used for fine piston and wavefront error. In order to remove piston's 2π uncertainty with PDI, three laser wavelengths, 640nm, 660nm, and 780nm, are used for the measurement. The DHS test setup, analysis algorithm and results are presented. The phase plate design concept and its application (i.e. verifying the JWST on-orbit alignment algorithm) are described. The layout of JWST OSIM and the function of phase plates in OSIM are also addressed briefly.

This paper summarizes the design and development of the Panchromatic Imaging Fourier Transform Spectrometer (PanFTS) for the NASA Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission. The PanFTS instrument will advance the understanding of the global climate and atmospheric chemistry by measuring spectrally resolved outgoing thermal and reflected solar radiation. With continuous spectral coverage from the near-ultraviolet through the thermal infrared, this instrument is designed to measure pollutants, greenhouse gases, and aerosols as called for by the U.S. National Research Council Decadal Survey; Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond¹. The PanFTS instrument is a hybrid based on spectrometers like the Tropospheric Emissions Spectrometer (TES) that measures thermal emission, and those like the Orbiting Carbon Observatory (OCO), and the Ozone Monitoring Instrument (OMI) that measure scattered solar radiation. Simultaneous measurements over the broad spectral range from IR to UV is accomplished by a two sided interferometer with separate optical trains and detectors for the UV-visible and IR spectral domains. This allows each side of the instrument to be independently optimized for its respective spectral domain. The overall interferometer design is compact because the two sides share a single high precision cryogenic optical path difference mechanism (OPDM) and metrology laser as well as a number of other instrument systems including the line-of-sight pointing mirror, the data management system, thermal control system, electrical system, and the mechanical structure. The PanFTS breadboard instrument has been tested in the laboratory and demonstrated the basic functionality for simultaneous measurements in the visible and IR. It is set to begin operations in the field at the California Laboratory for Atmospheric Remote Sensing (CLARS) observatory on Mt. Wilson measuring the atmospheric chemistry across the Los Angeles basin. Development has begun on a flight size PanFTS engineering model (EM) that addresses all critical scaling issues and demonstrates operation over the full spectral range of the flight instrument which will show the PanFTS instrument design is mature.