Workshop Proceedings: Optical Systems Technology for Space Astrophysics in the 21st Century, volume 3

A technology development program, Astrotech 21, is being proposed by NASA to enable the launching of the next generation of space astrophysical observatories during the years 1995-2015. Astrotech 21 is being planned and will ultimately be implemented jointly by the Astrophysics Division of the Office of Space Science and Applications and the Space Directorate of the Office of Aeronautics and Space Technology. A summary of the Astrotech 21 Optical Systems Technology Workshop is presented. The goal of the workshop was to identify areas of development within advanced optical systems that require technology advances in order to meet the science goals of the Astrotech 21 mission set, and to recommend a coherent development program to achieve the required capabilities

Solar radiation effects on the Sardinia Radio Telescope performances

The Sardinia Radio Telescope, a 64-metre diameter fully steerable radio telescope operated by INAF, will be upgraded in order to extend its current operating frequency range 0.3-26.5 GHz up to 116 GHz, thanks to a National Operational Program (PON) funding assigned to INAF by the Italian Ministry of University and Research. The PON project is organized in nine Work Packages, one of which is dedicated to the accomplishment of a sophisticated metrology system designed to monitor the cause of the pointing errors and the reflector surface deformations. The entire antenna structure will therefore be equipped with a network of sensors, like thermal sensors, inclinometers, accelerometers, collimators, anemometers, strain gauges and others, to study environmental stresses and how they affect the SRT performances. This work is devoted to the investigation of the thermal stress effects produced by solar radiation. In particular, two analyses are carried out to confirm the relevance of a thorough temperature monitoring system, both conducted using Finite Element Analysis. First, a possible approach for the simulation of realistic thermal scenarios due to insolation is proposed and the effects on the pointing accuracy are analysed. Second, a feasible method to study the impacts that a differential heating of the Back Up Structure (BUS) produces on the radio telescope main reflector surface is presented. Finally, these effects are analysed as optical aberrations and modelled in terms of Zernike polynomials

NASA Tech Briefs, October 1990

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical' Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Report of the Asilomar 3 LDR Workshop

The conclusions and recommendations of the workshop held to study technology development issues critical to the Large Deployable Reflector (LDR) are summarized. LDR is to be a dedicated, orbiting, astronomical observatory, operating at wavelengths from 30 to 1000 microns, a spectral region where the Earth's atmosphere is almost completely opaque. Because it will have a large, segmented, passively cooled aperture, LDR addresses a wide range of technology areas. These include lightweight, low cost, structural composite reflector panels, primary support structures, wavefront sensing and adaptive optics, thermal background management, and integrated vibration and pointing control systems. The science objectives for LDR present instrument development challenges for coherent and direct arrayed detectors which can operate effectively at far infrared and submillimeter wavelengths, and for sub-Kelvin cryogenic systems

Advanced manufacturing techniques for X-ray and VHE gamma-ray astronomical mirrors.

The main theme of this thesis is on the development of the technologies for the future X-ray astronomy telescopes and specifically for the New Hard X-ray Mission and eROSITA (Spectrum-RG) missions. Other important next future X-ray missions, currently under advanced study and/or manufacturing are NuSTAR (USA), ASTRO-H (Japan) and GEMS (USA). The New Hard X-ray Mission (NHXM) is being developed in Italy as an evolution of the original HEXIT-SAT project and is now the hard x-ray project of reference for the Italian high energy community. NHXM is meant to provide a real breakthrough on a number of hot astrophysical issues, by exploiting the most advanced technology in broad-band (0.2 \u2013 80 keV) high angular resolution (<20 arc seconds HEW) grazing incidence mirrors and spectroscopic detectors, together with the use of a high efficiency imaging polarimeter. Such issues can be summarized in two main headings: \u25cf making the census of the population of black holes in the Universe and probing the physics of accretion in the most diverse conditions; \u25cf investigating the particle acceleration mechanisms at work in different contexts, and the effects of radiative transfer in highly magnetized plasmas and strong gravitational fields. These topics were identified as top priority in the study commissioned by the Italian Space Agency (ASI) in 2004 to the Italian scientific community with contracts involving Thales-Alenia Space Italy (TAS-I, Turin), the Media Lario Technologies (MLT, Lecco) company and the INAF institution. NHXM benefits from the phase A study of the canceled French-Italian-German SIMBOL-X mission (2007-2008) and has been recently subjected to a scientific phase B study financed by ASI. Media Lario Technologies company received a contract from ASI in 2009 for a Technology Development Program (ASI-TDP) aiming at improving the technology readiness level with also in-house adoption of hardware for the metrology/manufacturing of the multilayer x-ray optics. Spectrum-RG is a Russian - German x-ray astrophysical observatory scheduled for lunch in 2013. German Space Agency (DLR) is responsible for the development of the key mission instrument - the x-ray grazing incident mirror telescope eROSITA. The second experiment is ART-XC - an x-ray mirror telescope with a harder response than eROSITA, which is being developed by Russia (IKI, Moscow and VNIIEF, Sarov). The name eROSITA stands for extended Roentgen Survey with an Imaging Telescope Array. The general design of the eROSITA x-ray telescope is derived from that of ABRIXAS: a bundle of 7 mirror modules with short focal lengths make up a compact telescope which is ideal for survey observations. Similar designs had been proposed for the missions DUO and ROSITA but were not realized. Compared to those, however, the effective area in the soft x-ray band has now much increased by adding 27 additional outer mirror shells to the original 27 ones of each mirror module. The requirement on the on-axis resolution has also been confined, namely to 15 arc seconds HEW. For these reasons the prefix \u201cextended\u201d to the original name \u201cROSITA\u201d had been added. The scientific motivation for this extension is founded in the ambitious goal to detect about 100000 clusters of galaxies which trace the large scale structure of the Universe in space and time. The main scientific goals are: \u25cf to detect the hot intergalactic medium of 50-100 thousand galaxy clusters and groups and hot gas in filaments between clusters to map out the large scale structure in the Universe for the study of cosmic structure evolution; \u25cf to detect systematically all obscured accreting Black Holes in nearby galaxies and many (up to 3 Million) new, distant active galactic nuclei; \u25cf to study in detail the physics of galactic x-ray source populations, like pre-main sequence stars, supernova remnants and x-ray binaries. Max-Planck-Institute f\ufcr extraterrestrische Physik (MPE) is the scientific institute responsible for the eROSITA Payload. Media Lario Technologies (MLT) is the industrial enabler for the manufacturing of the Optical Payload for eROSITA - including the flight quality mandrels, and it is currently in the C/D Phase of the project. The research activity described in this thesis has been carried out at Media Lario Technologies company and at the Brera Astronomical Observatory under the supervision of INAF-OAB researchers Dott. Giovanni Pareschi and Dott. Gianpiero Tagliaferri. The research activity of the author of this thesis is focused on the development of an advance polishing technique for the mandrels to be used as masters in the mirrors replication by electroforming. The goal is to implement a process where the mandrels can be manufactured with a high accuracy (< 6 arc seconds HEW) and low roughness (< 0.2 nm rms) within a consistent short time. In the contest of the eROSITA and NHXM (projects currently running in MLT) the author participated as technical/scientific responsible, investigating innovative mandrels manufacturing technologies (e.g. Single Point Diamond Turning, shape corrective polishing) representing an evolution of the standard approach used so far. In this frame the author has also contributed to the adoption of a customized deterministic polishing machine and a customized 3D metrology device for the mandrel geometrical characterization. An additional research activity, performed by the author at Media Lario Technologies company and at the Brera Astronomical Observatory, is focused on the development of lightweight glass mirrors manufactured via cold-slumping technique for Imaging Atmospheric Cherenkov Telescopes (IACT). Very High Energy (VHE) gamma rays, with photon energies in the TeV range, can be detected by ground based experiments. In fact, such high energy photons interact high in the upper atmosphere and generate an air shower of secondary particles. These particles emit the so-called Cherenkov light, a faint blue light. The mirror elements here developed have a sandwich-like structure where the reflecting and backing facets are composed by glass sheets with an interposed honeycomb aluminum core. This effort found application at the world\u2019s largest IACT, the 17m MAGIC II telescope (currently operating in Roque de los Muchachos - La Palma, Canary Islands), where 112 mirrors (~ 1 squared meter each), manufactured with the newly developed cold-slumping technique here described, are installed

Index to 1983 NASA Tech Briefs, volume 8, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1983 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Report on active and planned spacecraft and experiments

Information is presented, concerning active and planned spacecraft and experiments known to the National Space Science Data Center. The information included a wide range of disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. These spacecraft projects represented the efforts and funding of individual countries as well as cooperative arrangements among different countries

Interferometry-based Free Space Communication And Information Processing

This dissertation studies, analyzes, and experimentally demonstrates the innovative use of interference phenomenon in the field of opto-electronic information processing and optical communications. A number of optical systems using interferometric techniques both in the optical and the electronic domains has been demonstrated in the filed of signal transmission and processing, optical metrology, defense, and physical sensors. Specifically it has been shown that the interference of waves in the form of holography can be exploited to realize a novel optical scanner called Code Multiplexed Optical Scanner (C-MOS). The C-MOS features large aperture, wide scan angles, 3-D beam control, no moving parts, and high beam scanning resolution. A C-MOS based free space optical transceiver for bi-directional communication has also been experimentally demonstrated. For high speed, large bandwidth, and high frequency operation, an optically implemented reconfigurable RF transversal filter design is presented that implements wide range of filtering algorithms. A number of techniques using heterodyne interferometry via acousto-optic device for optical path length measurements have been described. Finally, a whole new class of interferometric sensors for optical metrology and sensing applications is presented. A non-traditional interferometric output signal processing scheme has been developed. Applications include, for example, temperature sensors for harsh environments for a wide temperature range from room temperature to 1000 degree C

Optical pulse distortion and manipulation through polarization effects and chromatic dispersion

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 112-129).Pulse distortion and shaping mechanisms play a significant role in optical fiber communication and sensing. In this thesis we shall investigate techniques which alleviate pulse deterioration due to polarization effects, and utilize large chromatic dispersion for system performance enhancement. We first demonstrate a method of mitigating polarization mode dispersion (PMD) in fiber optic communication systems. PMD has been a known effect for over a decade. However, it was not an impediment to system performance until recent advances in communication system bit rates. Today, with 10 Gb/s and 40 Gb/s channel rates appearing in new system equipment, PMD prohibits the use of many fiber cables already installed. Current PMD compensation techniques that require feedback control have difficulty meeting the speed and reliability requirements of telecom standards. In the first part of this thesis we investigate alternative compensation schemes which reduce the complexity of the feedback schemes. We next exploit the recent availability of ultra-long length chirped fiber Bragg gratings (FBG). Their enormous chromatic dispersion enables methods of improving current techniques in sensing and high speed optical sampling. In one experiment, we modulate the frequency of a standard distributed Bragg reflector (DBR) laser, and then apply the dispersion of the ultra-long FBG. Picosecond pulses are formed, whose repetition rate is independent of the laser cavity length. Since the gain of the laser is not modulated, the timing jitter is fundamentally limited only by the frequency noise of the laser. Finally, we again utilize the large delay of an ultra-long chirped FBG to implement arbitrary dynamic optical filtering of pulse spectra. In sensing applications such as fiber gyroscopes and optical coherence tomography (OCT), a wide Gaussian spectrum is ideal for low error in the gyro, and high image resolution in OCT. A modelocked fiber laser provides very wide spectra, but the shape can be irregular. We stretch the modelocked pulse temporally with an FBG, and access the frequency components in the time domain. We can then selectively suppress frequencies with an amplitude modulator to synthesize a Gaussian spectrum. Polarization effects and chromatic dispersion will inevitably appear in many optical systems. It is the goal of this thesis to show that their effects can be minimized or utilized for system performance enhancement.by Patrick Chien-pang Chou.Ph.D

NASA Tech Briefs, January 2012

Contents of this issue are: (1) Energy-Based Tetrahedron Sensor for High-Temperature, High-Pressure Environments (2) Handheld Universal Diagnostic Sensor (3) Large-Area Vacuum Ultraviolet Sensors (4) Fiber Bragg Grating Sensor System for Monitoring Smart Composite Aerospace Structures (5) Health-Enabled Smart Sensor Fusion Technology (6) Extended-Range Passive RFID and Sensor Tags (7) Hybrid Collaborative Learning for Classification and Clustering in Sensor Networks (8) Self-Healing, Inflatable, Rigidizable Shelter (9) Improvements in Cold-Plate Fabrication (10) Technique for Radiometer and Antenna Array Calibration - TRAAC (11) Real-Time Cognitive Computing Architecture for Data Fusion in a Dynamic Environment (12) Programmable Digital Controller (13) Use of CCSDS Packets Over SpaceWire to Control Hardware (14) Key Decision Record Creation and Approval Module (15) Enhanced Graphics for Extended Scale Range (16) Debris Examination Using Ballistic and Radar Integrated Software (17) Data Distribution System (DDS) and Solar Dynamic Observatory Ground Station (SDOGS) (18) Integration Manager (19) Eclipse-Free-Time Assessment Tool for IRIS (20) Automated and Manual Rocket Crater Measurement Software (21) MATLAB Stability and Control Toolbox Trim and Static Stability Module (22) Patched Conic Trajectory Code (23) Ring Image Analyzer (24) SureTrak Probability of Impact Display (25) Implementation of a Non-Metallic Barrier in an Electric Motor (26) Multi-Mission Radioisotope Thermoelectric Generator Heat Exchangers for the Mars Science Laboratory Rover (27) Uniform Dust Distributor for Testing Radiative Emittance of Dust-Coated Surfaces (28) MicroProbe Small Unmanned Aerial System (29) Highly Stable and Active Catalyst for Sabatier Reactions (30) Better Proton-Conducting Polymers for Fuel-Cell Membranes (31) CCD Camera Lens Interface for Real-Time Theodolite Alignment (32) Peregrine 100-km Sounding Rocket Project (33) SOFIA Closed- and Open-Door Aerodynamic Analyses (34) Sonic Thermometer for High-Altitude Balloons (35) Near-Infrared Photon-Counting Camera for High-Sensitivity Observations (36) Integrated Optics Achromatic Nuller for Stellar Interferometry (37) High-Speed Digital Interferometry (38) Ultra-Miniature Lidar Scanner for Launch Range Data Collection (39) Shape and Color Features for Object Recognition Search (40) Explanation Capabilities for Behavior-Based Robot Control (41) A DNA-Inspired Encryption Methodology for Secure, Mobile Ad Hoc Networks (42) Quality Control Method for a Micro-Nano-Channel Microfabricated Device (43) Corner-Cube Retroreflector Instrument for Advanced Lunar Laser Ranging (44) Electrospray Collection of Lunar Dust (45) Fabrication of a Kilopixel Array of Superconducting Microcalorimeters with Microstripline Wiring Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators (46) Coherent Detector for Near-Angle Scattering and Polarization Characterization of Telescope Mirror Coating