Overview and Accomplishments of Advanced Mirror Technology Development Phase 2 (AMTD-2) Project

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2015-01-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD Phase 1 completed all of its goals and accomplished all of its milestones. AMTD Phase 2 started in 2014. Key accomplishments include deriving primary mirror engineering specifications from science requirements; developing integrated modeling tools and using those tools to perform parametric design trades; and demonstrating new mirror technologies via sub-scale fabrication and test. AMTD-1 demonstrated the stacked core technique by making a 43-cm diameter 400 mm thick 'biscuit-cut' of a 4-m class mirror. AMTD-2 is demonstrating lateral scalability of the stacked core method by making a 1.5 meter 1/3rd scale model of a 4-m class mirror.

Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

Accomplishments include: Assembled outstanding team from academia, industry and government with expertise in science and space telescope engineering. Derived engineering specifications for monolithic primary mirror from science measurement needs & implementation constraints. Pursuing long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Successfully demonstrated capability to make 0.5 m deep mirror substrate and polish it to UVOIR traceable figure specification.

AMTD: update of engineering specifications derived from science requirements for future UVOIR space telescopes

NASA Astrophysics Data System (ADS)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-08-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope.

AMTD: Update of Engineering Specifications Derived from Science Requirements for Future UVOIR Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-01-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope

Thermal Testing of a Stacked Core Mirror for UV Applications

NASA Technical Reports Server (NTRS)

Matthews, Gary; Kirk, Charles S.; Maffett, Steven; Hanson, Craig; Eng, Ron; Stahl, H. Philip

2013-01-01

The ASTRO2010 Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. Under Science and Technology funding, NASA's Marshall Space Flight Center and ITT Exelis have developed a more cost effective process to make 4m monolithic spaceflight UV quality, low areal density, thermally and dynamically stable primary mirrors. A proof of concept mirror was built and tested down to 250K which would allow imaging out to 2.5 microns. This mirror was thermally tested at the Marshall Spaceflight Center to understand the thermal changes between the processing temperature of 293K and the potential low end of the operational temperature of 250K. Isothermal testing results and front plate gradient results have been evaluated and compared to analysis predictions. Measurement of gravity effects on surface figure will be compared to analytical predictions. Future testing of a larger Pathfinder mirror will also be discussed.

Development of Stacked Core Technology for the Fabrication of Deep Lightweight UV Quality Space Mirrors

NASA Technical Reports Server (NTRS)

Matthews, Gary; Kirk, Charlie; Maffett, Steve; Abplanalp, Cal; Stahl, H. Philip

2013-01-01

Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. Under Science and Technology funding, NASA's Marshall Space Flight Center (MSFC) and ITT Exelis have developed a more cost effective process to make up to 4m monolithic spaceflight UV quality, low areal density, thermally and dynamically stable primary mirrors. A proof of concept mirror was completed at ITT Exelis and tested down to 250K at MSFC which would allow imaging out to 2.5 microns. The parameters and test results of this concept mirror will be shown. The scale-up process will be discussed and the technology development path to a 4m mirror system by 2018 will also be outlined.

The Development of Stacked Core Technology for the Fabrication of Deep Lightweight UV-quality Space Mirrors

NASA Technical Reports Server (NTRS)

Matthews, Gary W.; Kirk, Charles S.; Maffett, Steven P.; Abplanalp, Calvin E.; Stahl, H. Philip; Effinger, Michael R.

2013-01-01

The Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. Under Science and Technology funding, NASA's Marshall Space Flight Center (MSFC) and Exelis have developed a more cost effective process to make up to 4m monolithic spaceflight UV quality, low areal density, thermally and dynamically stable primary mirrors. A proof of concept mirror was completed at Exelis and tested down to 250K at MSFC which would allow imaging out to 2.5 microns. The parameters and test results of this concept mirror will be shown. The scale-up process will be discussed and the technology development path to a 4m mirror system by 2018 will also be outlined.

Advanced UVOIR Mirror Technology Development (AMTD) for Very Large Space Telescopes

NASA Technical Reports Server (NTRS)

Postman, Marc; Soummer, Remi; Sivramakrishnan, Annand; Macintosh, Bruce; Guyon, Olivier; Krist, John; Stahl, H. Philip; Smith, W. Scott; Mosier, Gary; Kirk, Charles;

The Development of Stacked Core for the Fabrication of Deep Lightweight UV-Quality Space Mirrors

NASA Technical Reports Server (NTRS)

Matthews, Gary W.; Egerman, Robert; Maffett, Steven P.; Stahl, H. Philip; Eng, Ron; Effinger, Michael R.

2014-01-01

The 2010 Decadal Survey stated that an advanced large-aperture ultraviolet, optical, near-infrared (UVOIR) telescope is required to enable the next generation of compelling astrophysics and exoplanet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. Under Science and Technology funding, NASA's Marshall Space Flight Center (MSFC) and Exelis have developed a more cost effective process to make 4m class or larger monolithic spaceflight UV quality, low areal density, thermally and dynamically stable primary mirrors. A proof of concept 0.43m mirror was completed at Exelis optically tested at 250K at MSFC which demonstrated the ability for imaging out to 2.5 microns. The parameters and test results of this concept mirror are shown. The next phase of the program includes a 1.5m subscale mirror that will be optically and dynamically tested. The scale-up process will be discussed and the technology development path to a 4m mirror system by 2018 will be outlined.

A Future Large-Aperture UVOIR Space Observatory: Key Technologies and Capabilities

NASA Technical Reports Server (NTRS)

Bolcar, Matthew Ryan; Stahle, Carl M.; Balasubramaniam, Kunjithapatham; Clampin, Mark; Feinberg, Lee D.; Mosier, Gary E.; Quijada, Manuel A.; Rauscher, Bernard J.; Redding, David C.; Rioux, Norman M.;

Overview and Recent Accomplishments of Advanced Mirror Technology Development Phase 2 (AMTD-2)

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2015-01-01

AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

Aluminum Mirror Coatings for UVOIR Telescope Optics Including the Far UV

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatha; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Ayala, Michael; Shaklan, Stuart; Scowen, Paul; Del Hoyo, Javier; Quijada, Manuel

2015-01-01

NASA Cosmic Origins (COR) Program identified the development of high reflectivity mirror coatings for large astronomical telescopes particularly for the far ultra violet (FUV) part of the spectrum as a key technology requiring significant materials research and process development. In this paper we describe the challenges and accomplishments in producing stable high reflectance aluminum mirror coatings with conventional evaporation and advanced Atomic Layer Deposition (ALD) techniques. We present the current status of process development with reflectance of approx. 55 to 80% in the FUV achieved with little or no degradation over a year. Keywords: Large telescope optics, Aluminum mirror, far UV astrophysics, ALD, coating technology development.

A future large-aperture UVOIR space observatory: reference designs

NASA Astrophysics Data System (ADS)

Rioux, Norman; Thronson, Harley; Feinberg, Lee; Stahl, H. Philip; Redding, Dave; Jones, Andrew; Sturm, James; Collins, Christine; Liu, Alice

2015-09-01

Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. We describe the feasibility assessment of system thermal and dynamic stability for supporting coronagraphy. The observatory is in a Sun-Earth L2 orbit providing a stable thermal environment and excellent field of regard. Reference designs include a 36-segment 9.2 m aperture telescope that stows within a five meter diameter launch vehicle fairing. Performance needs developed under the study are traceable to a variety of reference designs including options for a monolithic primary mirror.

A Future Large-Aperture UVOIR Space Observatory: Reference Designs

NASA Technical Reports Server (NTRS)

Thronson, Harley; Rioux, Norman; Feinberg, Lee; Stahl, H. Philip; Redding, Dave; Jones, Andrew; Sturm, James; Collins, Christine; Liu, Alice

2015-01-01

Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. We describe the feasibility assessment of system thermal and dynamic stability for supporting coronagraphy. The observatory is in a Sun-Earth L2 orbit providing a stable thermal environment and excellent field of regard. Reference designs include a 36-segment 9.2 m aperture telescope that stows within a five meter diameter launch vehicle fairing. Performance needs developed under the study are traceable to a variety of reference designs including options for a monolithic primary mirror.

Overview and Recent Accomplishments of Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

AMTD: Update of Engineering Specifications Derived from Science Requirements for Future UVOIR Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2014-01-01

AMTD is using a Science Driven Systems Engineering approach to develop Engineering Specifications based on Science Measurement Requirements and Implementation Constraints. Science requirements meet the needs of both Exoplanet and General Astrophysics science. Engineering Specifications are guiding our effort to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review.

An Engineering Design Reference Mission for a Future Large-Aperture UVOIR Space Observatory

NASA Astrophysics Data System (ADS)

Thronson, Harley A.; Bolcar, Matthew R.; Clampin, Mark; Crooke, Julie A.; Redding, David; Rioux, Norman; Stahl, H. Philip

2016-01-01

From the 2010 NRC Decadal Survey and the NASA Thirty-Year Roadmap, Enduring Quests, Daring Visions, to the recent AURA report, From Cosmic Birth to Living Earths, multiple community assessments have recommended development of a large-aperture UVOIR space observatory capable of achieving a broad range of compelling scientific goals. Of these priority science goals, the most technically challenging is the search for spectroscopic biomarkers in the atmospheres of exoplanets in the solar neighborhood. Here we present an engineering design reference mission (EDRM) for the Advanced Technology Large-Aperture Space Telescope (ATLAST), which was conceived from the start as capable of breakthrough science paired with an emphasis on cost control and cost effectiveness. An EDRM allows the engineering design trade space to be explored in depth to determine what are the most demanding requirements and where there are opportunities for margin against requirements. Our joint NASA GSFC/JPL/MSFC/STScI study team has used community-provided science goals to derive mission needs, requirements, and candidate mission architectures for a future large-aperture, non-cryogenic UVOIR space observatory. The ATLAST observatory is designed to operate at a Sun-Earth L2 orbit, which provides a stable thermal environment and excellent field of regard. Our reference designs have emphasized a serviceable 36-segment 9.2 m aperture telescope that stows within a five-meter diameter launch vehicle fairing. As part of our cost-management effort, this particular reference mission builds upon the engineering design for JWST. Moreover, it is scalable to a variety of launch vehicle fairings. Performance needs developed under the study are traceable to a variety of additional reference designs, including options for a monolithic primary mirror.

Fundamental Performance Improvement of Microwave Kinetic Inductance Detectors for UVOIR Astrophysics

NASA Astrophysics Data System (ADS)

Mazin, Benjamin

Ultraviolet, Optical, and near-Infrared Microwave Kinetic Inductance Detectors (UVOIR MKIDs) are one of the most powerful new technologies to emerge out of the NASA APRA detectors program in the last decade. This proposal seeks to build on previous APRA grants to drastically improve the performance of UVOIR MKIDs. Like an X-ray microcalorimeter ultraviolet, optical, and near-IR (UVOIR) MKIDs are cryogenic detectors capable of detecting single photons and measuring their energy without filters or gratings. Our team has created this technology from the ground up, and fielded a 2024-pixel UVOIR MKID array on five separate observing runs at 5-m class telescopes. With 34 observing nights successfully completed and two astronomy papers published using MKID data (the first astronomy papers published using MKID data at any wavelength), UVOIR MKIDs are at TRL 5-6 for ground-based astronomy, and TRL 3 for space-based astronomy. The outstanding potential of these detectors was recognized in the recent NASA long term vision, "Enduring Quests, Daring Visions'', which recognized on page 88 that MKIDs have tremendous potential for future NASA UVOIR space missions, especially for finding Earth twins around nearby stars: "..microwave kinetic inductance detectors (MKIDs) would be a game-changing capability..''. Current UVOIR MKIDs feature array sizes in the 10-30 kpix range, energy resolution R=16 at 254 nm, ~70% pixel yield, and quantum efficiency that goes from 70% in the UV to 25% in the near-IR. These arrays, fabricated out of Titanium Nitride (TiN) on a high resistivity silicon substrate, are fully functional for ground-based science. However, our current MKIDs are far away from their theoretical limits, especially in yield (70% vs. 100%) and energy resolution (R=10 vs. R=100 at 400 nm). The yield is of especially urgent concern as missing pixels make accurate photometry difficult, especially for rapidly time variable sources like compact binaries that we have been studying

Advanced Mirror System Demonstrator (AMSD) Risk Management

NASA Technical Reports Server (NTRS)

Byberg, Alicia; Russell, J. Kevin; Kaukler, Donna; Burdine, Robert V. (Technical Monitor)

2002-01-01

This paper will report risk issues associated with designing, manufacturing, and testing the Advanced Mirror System Demonstrator (AMSD). The Advanced Mirror System Demonstrator (AMSD) will be developed as a lightweight primary mirror system that can be produced at a low cost and with a short manufacturing schedule. This technology will add to the knowledge base for selection for the Next Generation Space Telescope (NGST), Space Based Laser (SBL), Research Laboratory mission (AFRL), and other government agency programs.

Advanced Curvature Deformable Mirrors

DTIC Science & Technology

2010-09-01

ORGANIZATION NAME(S) AND ADDRESS(ES) University of Hawaii ,Institute for Astronomy,640 North A‘ohoku Place, #209 , Hilo ,HI,96720-2700 8. PERFORMING...Advanced Curvature Deformable Mirrors Christ Ftaclas1,2, Aglae Kellerer2 and Mark Chun2 Institute for Astronomy, University of Hawaii

Breakthrough Capability for UVOIR Space Astronomy: Reaching the Darkest Sky

NASA Technical Reports Server (NTRS)

Greenhouse, Matthew A.; Benson, Scott W.; Englander, Jacob; Falck, Robert D.; Fixsen, Dale J.; Gardner, Jonathan P.; Kruk, Jeffery W.; Oleson, Steven R.; Thronson, Harley A.

2015-01-01

We describe how availability of new solar electric propulsion (SEP) technology can substantially increase the science capability of space astronomy missions working within the near-UV to far-infrared (UVOIR) spectrum by making dark sky orbits accessible for the first time. We present two case studies in which SEP is used to enable a 700 kg Explorer-class and 7000 kg flagship-class observatory payload to reach an orbit beyond where the zodiacal dust limits observatory sensitivity. The resulting scientific performance advantage relative to a Sun-Earth L2 point (SEL2) orbit is presented and discussed. We find that making SEP available to astrophysics Explorers can enable this small payload program to rival the science performance of much larger long development-time systems. Similarly, we find that astrophysics utilization of high power SEP being developed for the Asteroid Redirect Robotics Mission (ARRM) can have a substantial impact on the sensitivity performance of heavier flagship-class astrophysics payloads such as the UVOIR successor to the James Webb Space Telescope.

Breakthrough Capability for UVOIR Space Astronomy: Reaching the Darkest Sky

NASA Technical Reports Server (NTRS)

Greenhouse, Matthew A.; Benson, Scott W.; Englander, Jacob; Falck, Robert D.; Fixsen, Dale J.; Gardner, Jonathan P.; Kruk, Jeffrey W.; Oleson, Steven R.; Thronson, Harley A.

2014-01-01

We describe how availability of new solar electric propulsion (SEP) technology can substantially increase the science capability of space astronomy missions working within the near-UV to far-infrared (UVOIR) spectrum by making dark sky orbits accessible for the first time. We present a proof of concept case study in which SEP is used to enable a 700 kg Explorer-class observatory payload to reach an orbit beyond where the zodiacal dust limits observatory sensitivity. The resulting scientific performance advantage relative to a Sun-Earth L2 point orbit is presented and discussed. We find that making SEP available to astrophysics Explorers can enable this small payload program to rival the science performance of much larger long development-time systems. We also present flight dynamics analysis which illustrates that this concept can be extended beyond Explorers to substantially improve the sensitivity performance of heavier (7000 kg) flagship-class astrophysics payloads such as the UVOIR successor to the James Webb Space Telescope by using high power SEP that is being developed for the Asteroid Redirect Robotics Mission.

Managing Risk on a Technology Development Project/Advanced Mirror System Demonstrator

NASA Technical Reports Server (NTRS)

Byberg, Alicia; Russell, J. Kevin; Stahl, Phil (Technical Monitor)

2002-01-01

The risk management study applied to the Advanced Mirror System Demonstrator (AMSD), a precursor mirror technology development for the Next Generation Space Telescope (NGST) is documented. The AMSD will be developed as a segment of a lightweight primary mirror system that can be produced at a low cost and with a short manufacturing schedule. The technology gained from the program will support the risk mitigation strategy for the NGST, as well as other government agency space mirror programs.

The Advanced Technology Large-Aperture Space Telescope (ATLAST) Technology Roadmap

NASA Technical Reports Server (NTRS)

Stahle, Carl; Balasubramanian, K.; Bolcar, M.; Clampin, M.; Feinberg, L.; Hartman, K.; Mosier, C.; Quijada, M.; Rauscher, B.; Redding, D.;

Engineering Specifications derived from Science Requirements

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Arnold, William; Bevan, Ryan M.; Smith, W. Scott; Kirk, Charles S.; Postman, Marc

2013-01-01

Advanced Mirror Technology Development (AMTD) is a multi-year effort to systematically mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. This technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. To accomplish our objective, we use a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system.

Advanced X-Ray Telescope Mirrors Provide Sharpest Focus Ever

NASA Astrophysics Data System (ADS)

1997-03-01

Performing beyond expectations, the high- resolution mirrors for NASA's most powerful orbiting X-ray telescope have successfully completed initial testing at Marshall Space Flight Center's X-ray Calibration Facility, Huntsville, AL. "We have the first ground test images ever generated by the telescope's mirror assembly, and they are as good as -- or better than -- expected," said Dr. Martin Weisskopf, Marshall's chief scientist for NASA's Advanced X-ray Astrophysics Facility (AXAF). The mirror assembly, four pairs of precisely shaped and aligned cylindrical mirrors, will form the heart of NASA's third great observatory. The X-ray telescope produces an image by directing incoming X-rays to detectors at a focal point some 30 feet beyond the telescope's mirrors. The greater the percentage of X-rays brought to focus and the smaller the size of the focal spot, the sharper the image. Tests show that on orbit, the mirror assembly of the Advanced X-ray Astrophysics Facility will be able to focus approximately 70 percent of X-rays from a source to a spot less than one-half arc second in radius. The telescope's resolution is equivalent to being able to read the text of a newspaper from half a mile away. "The telescope's focus is very clear, very sharp," said Weisskopf. "It will be able to show us details of very distant sources that we know are out there, but haven't been able to see clearly." In comparison, previous X-ray telescopes -- Einstein and Rosat -- were only capable of focusing X- rays to five arc seconds. The Advanced X-ray Telescope's resolving power is ten times greater. "Images from the new telescope will allow us to make major advances toward understanding how exploding stars create and disperse many of the elements necessary for new solar systems and for life itself," said Dr. Harvey Tananbaum, director of the Advanced X- ray Astrophysics Facility Science Center at the Smithsonian Astrophysical Observatory, in Cambridge, MA -- responsible for the telescope

Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes

NASA Technical Reports Server (NTRS)

Spechler, Joshua A.; Hoppe, Daniel J.; Sigrist, Norbert; Shi, Fang; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.

2013-01-01

Segment mirror phasing, a critical step of segment mirror alignment, requires the ability to sense and correct the relative pistons between segments from up to a few hundred microns to a fraction of wavelength in order to bring the mirror system to its full diffraction capability. When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical. The performance of a telescope with a segmented primary mirror strongly depends on how well those primary mirror segments can be phased. One such process to phase primary mirror segments in the axial piston direction is dispersed fringe sensing (DFS). DFS technology can be used to co-phase the ACFs. DFS is essentially a signal fitting and processing operation. It is an elegant method of coarse phasing segmented mirrors. DFS performance accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to substantial enhancements in DFS performance. The Advanced Dispersed Fringe Sensing (ADFS) Algorithm is designed to reduce the sensitivity to calibration errors by determining the optimal fringe extraction line. Applying an angular extraction line dithering procedure and combining this dithering process with an error function while minimizing the phase term of the fitted signal, defines in essence the ADFS algorithm.

Crack Branching and Fracture Mirror Data of Glasses and Advanced Ceramics

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Gyekenyesi, John P.

1998-01-01

The fracture mirror and crack branching constants were determined from three glasses and nine advanced ceramics tested under various loading and specimen configurations in an attempt to use the constants as a data base for fractography. The ratios of fracture mirror or crack branching constant to fracture toughness were found to be approximately two for most ceramic materials tested. A demonstration of how to use the two constants as a tool for verifying stress measurements was presented for silicon nitride disk specimens subjected to high-temperature, constant stress-rate biaxial flexure testing.

Beyond JWST: Science Drivers for the Next Great UVOIR Space Telescope

NASA Astrophysics Data System (ADS)

Tumlinson, Jason; Seager, Sara; Dalcanton, Julianne; Postman, Marc; Aigrain, Suzanne; battel, Steven; Brandt, W. Niel; Conroy, Charlie; Feinberg, Lee; Gezari, Suvi; Guyon, Olivier; Harris, Walter M.; Hirata, Chris; Mather, John C.; Redding, David; Schiminovich, David; Stahl, H. Philip

2015-01-01

We report on the AURA 'Beyond JWST' committee's considerations and conclusions regarding the science case for the development of a large UVOIR observatory, to be launched following JWST and WFIRST-AFTA. We find that a space-based UVOIR telescope of 10 meters or more in aperture will uniquely enable a wide range of transformational science investigations by itself and in tandem with ground-based OIR and radio facilities in its era. The chief goal of this facility is to assess the possibility of life beyond our Solar System by discovering Earth-like planets in the habitable zones of their host stars, via direct imaging, and by searching spectroscopically for biosignature gases in the atmospheres of the best exo-Earth candidates. The large aperture and mission architecture required to characterize the atmospheres of a significant number of potentially life-bearing planets will also transform studies of the galaxies and stars that led up to them. At 10 meters or larger, the telescope will spatially resolve scales of 100 AU everywhere in the Milky Way, 0.1 parsec everywhere in the Local Group, and 100 parsec everywhere in the observable Universe. This unprecedented spatial resolution over large fields, with stable optics and low backgrounds, will allow astronomers to follow, in high definition, the formation and evolution of the star forming regions inside galaxies over the past 10 Gyr, to robustly determine the complete star formation histories in every galaxy within the local volume (to 10 Mpc), and to track the motions of virtually any star in the Milky Way. High spectral resolution and multi-object spectroscopy in the UV will enable revolutionary new studies of gas flows in galaxies, bodies in the outer solar system, and the evolution of the most massive stars. We present these compelling science drivers and their associated observational requirements here; we summarize the technology requirements for high angular resolution, sensitivity, wavefront stability

Production of the 4.26 m ZERODUR mirror blank for the Advanced Technology Solar telescope (ATST)

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Werner, Thomas; Westerhoff, Thomas

2014-07-01

The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) will be the most powerful solar telescope in the world. It is currently being built by the Association of Universities for Research in Astronomy (AURA) in a height of 3000 m above sea level on the mountain Haleakala of Maui, Hawaii. The primary mirror blank of diameter 4.26 m is made of the extremely low thermal expansion glass ceramic ZERODUR® of SCHOTT AG Advanced Optics. The DKIST primary mirror design is extremely challenging. With a mirror thickness of only 78 to 85 mm it is the smallest thickness ever machined on a mirror of 4.26 m in diameter. Additionally the glassy ZERODUR® casting is one of the largest in size ever produced for a 4 m class ZERODUR® mirror blank. The off axis aspherical mirror surface required sophisticated grinding procedures to achieve the specified geometrical tolerance. The small thickness of about 80 mm required special measures during processing, lifting and transport. Additionally acid etch treatment was applied to the convex back-surface and the conical shaped outer diameter surface to improve the strength of the blank. This paper reports on the challenging tasks and the achievements on the material property and dimensional specification parameter during the production of the 4.26 m ZERODUR® primary mirror blank for AURA.

Recent Progress on 2012 SAT for UVOIR Coatings

NASA Technical Reports Server (NTRS)

Quijada, Manuel A.; Del Hoyo, Javier G.; Rice, Stephen H.

2014-01-01

Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+MgF2 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the MgF2 overcoat at elevated substrate temperatures. We will also present optical characterization of little studied rare-earth fluorides such as GdF3 and LuF3 that exhibit low-absorption over a wide wavelength range and could therefore be used as high refractive index alternatives fordielectric coatings at FUV wavelengths.

End-to-End Assessment of a Large Aperture Segmented Ultraviolet Optical Infrared (UVOIR) Telescope Architecture

NASA Technical Reports Server (NTRS)

Feinberg, Lee; Bolcar, Matt; Liu, Alice; Guyon, Olivier; Stark,Chris; Arenberg, Jon

2016-01-01

Key challenges of a future large aperture, segmented Ultraviolet Optical Infrared (UVOIR) Telescope capable of performing a spectroscopic survey of hundreds of Exoplanets will be sufficient stability to achieve 10-10 contrast measurements and sufficient throughput and sensitivity for high yield Exo-Earth spectroscopic detection. Our team has collectively assessed an optimized end to end architecture including a high throughput coronagraph capable of working with a segmented telescope, a cost-effective and heritage based stable segmented telescope, a control architecture that minimizes the amount of new technologies, and an Exo-Earth yield assessment to evaluate potential performance.

Lightweight ZERODUR mirror blanks: recent advances supporting faster, cheaper, and better spaceborne optical telescope assemblies

NASA Astrophysics Data System (ADS)

Hull, Tony; Westerhoff, Thomas

2014-10-01

While there is no single material solution ideal for all missions, recent advances by SCHOTT in fabricating lightweight mirror blanks makes ZERODUR® a highly viable solution for many spaceborne telescopes. ZERODUR® is a well-characterized very low-expansion material. Monolithic mirrors are made without bonding or fusing out of highly homogeneous and isotropic blanks currently available in sizes up to 4m plus. We will summarize results recently given in a series of papers on the characteristics of these lightweight mirror blanks in sizes from 0.3m up, and describe the method of blank fabrication, with its compatibility to contemporary optical fabrication techniques that control of all optical spatial frequencies. ZERODUR® has a 35 year heritage in space on numerous missions, including the secondary mirror of Hubble, and all the Chandra mirrors. With the lightweighting we will discuss, ZERODUR® is now a high performing, affordable and rapidly produced mirror substrate suitable for lightweight imaging telescopes.

Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Postman, Marc; Smith, W. Scott

2013-01-01

The Advance Mirror Technology Development (AMTD) project is a three year effort initiated in FY12 to mature by at least a half TRL step six critical technologies required to enable 4 to 8 meter UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. A key accomplishment is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints.

Lessons Learned During Cryogenic Optical Testing of the Advanced Mirror System Demonstrators (AMSDs)

NASA Technical Reports Server (NTRS)

Hadaway, James; Reardon, Patrick; Geary, Joseph; Robinson, Brian; Stahl, Philip; Eng, Ron; Kegley, Jeff

2004-01-01

Optical testing in a cryogenic environment presents a host of challenges above and beyond those encountered during room temperature testing. The Advanced Mirror System Demonstrators (AMSDs) are 1.4 m diameter, ultra light-weight (<20 kg/mA2), off-axis parabolic segments. They are required to have 250 nm PV & 50 nm RMS surface figure error or less at 35 K. An optical testing system, consisting of an Instantaneous Phase Interferometer (PI), a diffractive null corrector (DNC), and an Absolute Distance Meter (ADM), was used to measure the surface figure & radius-of-curvature of these mirrors at the operational temperature within the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The Ah4SD program was designed to improve the technology related to the design, fabrication, & testing of such mirrors in support of NASA s James Webb Space Telescope (JWST). This paper will describe the lessons learned during preparation & cryogenic testing of the AMSDs.

Topological mirror superconductivity.

PubMed

Zhang, Fan; Kane, C L; Mele, E J

2013-08-02

We demonstrate the existence of topological superconductors (SCs) protected by mirror and time-reversal symmetries. D-dimensional (D=1, 2, 3) crystalline SCs are characterized by 2(D-1) independent integer topological invariants, which take the form of mirror Berry phases. These invariants determine the distribution of Majorana modes on a mirror symmetric boundary. The parity of total mirror Berry phase is the Z(2) index of a class DIII SC, implying that a DIII topological SC with a mirror line must also be a topological mirror SC but not vice versa and that a DIII SC with a mirror plane is always time-reversal trivial but can be mirror topological. We introduce representative models and suggest experimental signatures in feasible systems. Advances in quantum computing, the case for nodal SCs, the case for class D, and topological SCs protected by rotational symmetries are pointed out.

Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror

NASA Technical Reports Server (NTRS)

Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

2010-01-01

The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.

End-to-End Assessment of a Large Aperture Segmented Ultraviolet Optical Infrared (UVOIR) Telescope Architecture

NASA Technical Reports Server (NTRS)

Feinberg, Lee; Rioux, Norman; Bolcar, Matthew; Liu, Alice; Guyon, Oliver; Stark, Chris; Arenberg, Jon

2016-01-01

Key challenges of a future large aperture, segmented Ultraviolet Optical Infrared (UVOIR) Telescope capable of performing a spectroscopic survey of hundreds of Exoplanets will be sufficient stability to achieve 10^-10 contrast measurements and sufficient throughput and sensitivity for high yield Exo-Earth spectroscopic detection. Our team has collectively assessed an optimized end to end architecture including a high throughput coronagraph capable of working with a segmented telescope, a cost-effective and heritage based stable segmented telescope, a control architecture that minimizes the amount of new technologies, and an Exo-Earth yield assessment to evaluate potential performance. These efforts are combined through integrated modeling, coronagraph evaluations, and Exo-Earth yield calculations to assess the potential performance of the selected architecture. In addition, we discusses the scalability of this architecture to larger apertures and the technological tall poles to enabling it.

Integration of Mirror Design with Suspension System using NASA's New Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William; Bevan Ryan M.; Stahl, Philip

2013-01-01

Advances in mirror fabrication is making very large space based telescopes possible. In the many applications, only monolithic mirrors meet the performance requirements. The existing and near-term planned heavy launch vehicles place a premium on lowest possible mass. Again, available and planned payload shroud size limits near term designs to 4 meter class mirror. Practical 8 meter and beyond designs could encourage planners to include larger shrouds if it can be proven that such mirrors can be manufactured. These two factors lower mass and larger mirrors, presents the classic optimization problem. There is a practical upper limit to how large a mirror can be supported by a purely kinematic mount system and be launched. This paper shows how the design of the suspension system and mirror blank needs to be designed simultaneously. We will also explore the concepts of auxiliary support systems, which act only during launch and disengage on orbit. We will define required characteristics of these systems and show how they can substantially reduce the mirror mass. The AMTD project is developing and maturing the processes for future replacements for HUBBLE, creating the design tools, validating the methods and techniques necessary to manufacture, test and launch extremely large optical missions. This paper will use the AMTD 4 meter "design point" as an illustration of the typical use of the modeler in generating the multiple models of mirror and suspension systems used during the conceptual design phase of most projects. The influence of Hexapod geometry, mirror depth, cell size and construction techniques (Exelsis Deep Core Low Temperature Fusion (c) versus Corning Frit Bonded (c) versus Schott Pocket Milled Zerodur (c) in this particular study) are being evaluated. Due to space and time consideration we will only be able to present snippets of the study in this paper. The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low

SiC lightweight telescopes for advanced space applications. I - Mirror technology

NASA Technical Reports Server (NTRS)

Anapol, Michael I.; Hadfield, Peter

1992-01-01

A SiC based telescope is an extremely attractive emerging technology which offers the lightweight and stiffness features of beryllium, the optical performance of glass to diffraction limited visible resolution, superior optical/thermal stability to cryogenic temperatures, and the cost advantages of an aluminum telescope. SSG has developed various SiC mirrors with and without a silicon coating and tested these mirrors over temperature ranges from +50 C to -250 C. Our test results show less than 0.2 waves P-V in visible wavefront change and no hysteresis over this wide temperature range. Several SSG mirrors are representative of very lightweight SiC/Si mirrors including (1) a 9 cm diameter, high aspect ratio mirror weighing less than 30 grams and (2) a 23 cm diameter eggcrated mirror weighing less than 400 grams. SSG has also designed and analyzed a 0.6 meter SiC based, on axis, three mirror reimaging telescope in which the primary mirror weighs less than 6 kg and a 0.5 meter GOES-like scan mirror. SSG has also diamond turned several general aspheric SiC/Si mirrors with excellent cryo optical performance.

Fused silica mirror development for SIRTF

NASA Technical Reports Server (NTRS)

Barnes, W. P., Jr.

1983-01-01

An advanced design, lightweight, fuse-quartz mirror of sandwich construction was evaluated for optical figure performance at cryogenic temperatures. A low temperature shroud was constructed with an integral mirror mount and interface to a cryostat for use in a vacuum chamber. The mirror was tested to 13 K. Cryogenic distortion of the mirror was measured interferometrically. Separate interferometry of the chamber window during the test permitted subtraction of the small window distortions from the data. Results indicate that the imaging performance of helium cooled, infrared telescopes will be improved using this type of mirror without correction of cryogenic distortion of the primary mirror.

Visible light scatter measurements of the Advanced X-ray Astronomical Facility /AXAF/ mirror samples

NASA Technical Reports Server (NTRS)

Griner, D. B.

1981-01-01

NASA is studying the properties of mirror surfaces for X-ray telescopes, the data of which will be used to develop the telescope system for the Advanced X-ray Astronomical Facility. Visible light scatter measurements, using a computer controlled scanner, are made of various mirror samples to determine surface roughness. Total diffuse scatter is calculated using numerical integration techniques and used to estimate the rms surface roughness. The data measurements are then compared with X-ray scatter measurements of the same samples. A summary of the data generated is presented, along with graphs showing changes in scatter on samples before and after cleaning. Results show that very smooth surfaces can be polished on the common substrate materials (from 2 to 10 Angstroms), and nickel appears to give the lowest visible light scatter.

Integration of Mirror Design with Suspension System Using NASA's New Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Bevan, Ryan M.; Stahl, H. Philip

2013-01-01

Advances in mirror fabrication are making very large space based telescopes possible. In many applications, only monolithic mirrors can meet the performance requirements. The existing and near-term planned heavy launch vehicles place a premium on lowest possible mass, and then available payload shroud sizes limit near term designs to 4 meter class mirrors. Practical 8 meter class and beyond designs could encourage planners to include larger shrouds, if it can be proven that such mirrors can be manufactured. These two factors, lower mass and larger mirrors, present the classic optimization problem. There is a practical upper limit to how large of a mirror can be supported by a purely kinematic mount system handling both operational and launch loads. This paper shows how the suspension system and mirror blank need to be designed simultaneously. We will also explore the concepts of auxiliary support systems which act only during launch and disengage on orbit. We will define required characteristics of these systems and show how they can substantially reduce the mirror mass.

Integration of Mirror Design with Suspension System using NASA's New Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold,William R., Sr.; Bevan, Ryan M.; Stahl, Philip

2013-01-01

Advances in mirror fabrication are making very large space based telescopes possible. In many applications, only monolithic mirrors can meet the performance requirements. The existing and near-term planned heavy launch vehicles place a premium on lowest possible mass, and then available payload shroud sizes limit near term designs to 4 meter class mirrors. Practical 8 meter class and beyond designs could encourage planners to include larger shrouds, if it can be proven that such mirrors can be manufactured. These two factors, lower mass and larger mirrors, present the classic optimization problem. There is a practical upper limit to how large of a mirror can be supported by a purely kinematic mount system handling both operational and launch loads. This paper shows how the suspension system and mirror blank need to be designed simultaneously. We will also explore the concepts of auxiliary support systems which act only during launch and disengage on orbit. We will define required characteristics of these systems and show how they can substantially reduce the mirror mass.

Improved Advanced Actuated Hybrid Mirrors Final Report CRADA No. TC02130.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbee, T. W.; Ealey, M. A.

2017-08-25

This was a collaborative effort to develop and demonstrate an improved Advanced Actuated Hybrid Mirrors (AAHM) for commercial or Government purposes. The AAHM consists of a nanolaminate film replicating a precision optical surface bonded to a Silicon Carbide (SiC) substrate with active figure control capability. The goal of this project was to further the development of specific AAHM technologies. The intent of the CRADA was to combine the expertise of LLNL and NG Xinetics in the manufacture and test of a very high quality AAHM, incorporating lessons learned from earlier joint efforts.

Mirror Image Proteins

PubMed Central

Zhao, Le; Lu, Wuyuan

2017-01-01

Proteins composed entirely of unnatural D-amino acids and the achiral amino acid glycine are mirror image forms of their native L-protein counterparts. Recent advances in chemical protein synthesis afford unique and facile synthetic access to domain-sized mirror image D-proteins, enabling protein research to be conducted through “the looking glass” and in a way previously unattainable. D-proteins can facilitate structure determination of their native L-forms that are difficult to crystallize (racemic X-ray crystallography); D-proteins can serve as the bait for library screening to ultimately yield pharmacologically superior D-peptide/D-protein therapeutics (mirror image phage display); D-proteins can also be used as a powerful mechanistic tool for probing molecular events in biology. This review examines recent progress in the application of mirror image proteins to structural biology, drug discovery, and immunology. PMID:25282524

Shell Separation for Mirror Replication

NASA Technical Reports Server (NTRS)

1999-01-01

NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery, and materials to replicate electro-formed nickel mirrors. Optics replication uses reusable forms, called mandrels, to make telescope mirrors ready for final finishing. MSFC optical physicist Bill Jones monitors a device used to chill a mandrel, causing it to shrink and separate from the telescope mirror without deforming the mirror's precisely curved surface.

JWST Mirror Technology Development Results

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2007-01-01

Mirror technology is a critical enabling capability for the James Webb Space Telescope (JWST). JWST requires a Primary Mirror Segment Assembly (PMSA) that can survive launch, deploy and align itself to form a 25 square meter collecting area 6.5 meter diameter primary mirror with a 131 nm rms wavefront error at temperatures less than 50K and provide stable optical performance. At the inception of JWST in 1996, such a capability did not exist. A highly successful technology development program was initiated including the Sub-scale Beryllium Mirror Demonstrator (SBMD) and Advanced Mirror System Demonstrator (AMSD) projects. These projects along with flight program activities have matured and demonstrated mirror technology for JWST. Directly traceable prototypes or flight hardware has been built, tested and operated in a relevant environment. This paper summarizes that technology development effort.

AMTD - Advanced Mirror Technology Development in Mechanical Stability

NASA Technical Reports Server (NTRS)

Knight, J. Brent

2015-01-01

Analytical tools and processes are being developed at NASA Marshal Space Flight Center in support of the Advanced Mirror Technology Development (AMTD) project. One facet of optical performance is mechanical stability with respect to structural dynamics. Pertinent parameters are: (1) the spacecraft structural design, (2) the mechanical disturbances on-board the spacecraft (sources of vibratory/transient motion such as reaction wheels), (3) the vibration isolation systems (invariably required to meet future science needs), and (4) the dynamic characteristics of the optical system itself. With stability requirements of future large aperture space telescopes being in the lower Pico meter regime, it is paramount that all sources of mechanical excitation be considered in both feasibility studies and detailed analyses. The primary objective of this paper is to lay out a path to perform feasibility studies of future large aperture space telescope projects which require extreme stability. To get to that end, a high level overview of a structural dynamic analysis process to assess an integrated spacecraft and optical system is included.

Kodak AMSD Mirror Development Program

NASA Technical Reports Server (NTRS)

Matthews, Gary; Dahl, Roger; Barrett, David; Bottom, John; Russell, Kevin (Technical Monitor)

2002-01-01

The Advanced Mirror System Demonstration Program is developing minor technology for the next generation optical systems. Many of these systems will require extremely lightweight and stable optics due to the overall size of the primary mirror. These segmented, deployable systems require new technology that AMSD is developing. The on-going AMSD program is a critical enabler for Next Generation Space Telescope (NGST) which will start in 2002. The status of Kodak's AMSD mirror and future plans will be discussed with respect to the NGST program.

Finite Element Modeling of a Semi-Rigid Hybrid Mirror and a Highly Actuated Membrane Mirror as Candidates for the Next Generation Space Telescope

NASA Technical Reports Server (NTRS)

Craig, Larry; Jacobson, Dave; Mosier, Gary; Nein, Max; Page, Timothy; Redding, Dave; Sutherlin, Steve; Wilkerson, Gary

2000-01-01

Advanced space telescopes, which will eventually replace the Hubble Space Telescope (HTS), will have apertures of 8 - 20 n. Primary mirrors of these dimensions will have to be foldable to fit into the space launcher. By necessity these mirrors will be extremely light weight and flexible and the historical approaches to mirror designs, where the mirror is made as rigid as possible to maintain figure and to serve as the anchor for the entire telescope, cannot be applied any longer. New design concepts and verifications will depend entirely on analytical methods to predict optical performance. Finite element modeling of the structural and thermal behavior of such mirrors is becoming the tool for advanced space mirror designs. This paper discusses some of the preliminary tasks and study results, which are currently the basis for the design studies of the Next Generation Space Telescope.

Solar Mirror Fabrication in the Technical Services Building

NASA Image and Video Library

1966-02-21

Daniel Bernatowicz, Chief of the Advanced Power Systems Branch at the National Aeronautics and Space Administration (NASA) Lewis Research Center, examines a 20-foot section of a solar mirror being fabricated in the Jig Bore Room of the Technical Services Building. NASA Lewis was conducting a wide-ranging effort to explore methods of generating electrical power for spacecraft. One method employed a large parabolic mirror to concentrate the sun’s energy. The mirror had to remain rigid and withstand micrometeoroids, but remain light and compact enough to be easily launched. In 1963 Bernatowicz and his researchers undertook a program to design a solar mirror to work with the Brayton cycle system on a space station. The mirror in this photograph was prepared for a conference on Advanced Technology in Space Power Systems held at Lewis in late August 1966. Lewis experts discussed advances with batteries, fuel cells, isotope and thermoelectric generators, and the SNAP-8 space power system. Lewis was developing several types of solar mirrors to work with a Brayton cycle electric generating system. The mirror’s 12 sections were shaped using a unique forming process developed at Lewis, coated with an epoxy, and plated with aluminum. The mirror concentrated the Sun's rays on a heat storage receiver containing lithium fluoride. This material was heated to produce power in a turbogenerator system, while additional heat was stored for use when the unit was in the Earth's shadow.

Alignment error of mirror modules of advanced telescope for high-energy astrophysics due to wavefront aberrations

NASA Astrophysics Data System (ADS)

Zocchi, Fabio E.

2017-10-01

One of the approaches that is being tested for the integration of the mirror modules of the advanced telescope for high-energy astrophysics x-ray mission of the European Space Agency consists in aligning each module on an optical bench operated at an ultraviolet wavelength. The mirror module is illuminated by a plane wave and, in order to overcome diffraction effects, the centroid of the image produced by the module is used as a reference to assess the accuracy of the optical alignment of the mirror module itself. Among other sources of uncertainty, the wave-front error of the plane wave also introduces an error in the position of the centroid, thus affecting the quality of the mirror module alignment. The power spectral density of the position of the point spread function centroid is here derived from the power spectral density of the wave-front error of the plane wave in the framework of the scalar theory of Fourier diffraction. This allows the defining of a specification on the collimator quality used for generating the plane wave starting from the contribution to the error budget allocated for the uncertainty of the centroid position. The theory generally applies whenever Fourier diffraction is a valid approximation, in which case the obtained result is identical to that derived by geometrical optics considerations.

JWST Lightweight Mirror TRL-6 Results

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2007-01-01

Mirror technology for a Primary Mirror Segment Assembly (PMSA) is a system of components: reflective coating; polished optical surface; mirror substrate; actuators, mechanisms and flexures; and reaction structure. The functional purpose of a PMSA is to survive launch, deploy and align itself to form a 25 square meter collecting area 6.5 meter diameter primary mirror with a 131 nm rms wavefront error at temperatures less than 50K and provide stable optical performance for the anticipated thermal environment. At the inception of JWST in 1996, such a capability was at a Technology Readiness Level (TRL) of 3. A highly successful technology development program was initiated including the Sub-scale Beryllium Mirror Demonstrator (SBMD) and Advanced Mirror System Demonstrator (AMSD) projects. These projects along with flight program activities have matured mirror technology for JWST to TRL-6. A directly traceable prototype (and in some cases the flight hardware itself) has been built, tested and operated in a relevant environment.

Space Optic Manufacturing - X-ray Mirror

NASA Technical Reports Server (NTRS)

1998-01-01

NASA's Space Optics Manufacturing Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century - including the long-term goal of imaging Earth-like planets in distant solar systems. To reduce the cost of mirror fabrication, Marshall Space Flight Center (MSFC) has developed replication techniques, the machinery and materials to replicate electro-formed nickel mirrors. The process allows fabricating precisely shaped mandrels to be used and reused as masters for replicating high-quality mirrors. This image shows a lightweight replicated x-ray mirror with gold coatings applied.

Next Generation Space Telescope Ultra-Lightweight Mirror Program

NASA Technical Reports Server (NTRS)

Bilbro, James W.

1998-01-01

The Next Generation Space Telescope is currently envisioned as a eight meter diameter cryogenic deployable telescope that will operate at the earth sun libration point L2. A number of different designs are being examined within NASA and under industry studies by Ball Aerospace, Lockheed-Martin and TRW. Although these designs differ in many respects, they all require significant advancements in the state-of-the-art with respect to large diameter, ultra-lightweight, mirrors. The purpose of this paper is to provide insight into the current status of the mirror development program NGST is a tremendously ambitious undertaking that sets the mark for new NASA missions. In order to achieve the weight, cost and performance requirements of NGST, the primary mirror must be made lighter, cheaper and better than anything that has ever been done. In order to accomplish this an aggressive technology program has been put in place. The scope of the program was determined by examining historically what has been accomplished; assessing recent technological advances in fabrication and testing; and evaluating the effect of these advances relative to enabling the manufacture of lightweight mirrors that meet NGST requirements. As it is currently envisioned, the primary mirror for NGST is on the order of eight meters in diameter, it is to be diffraction limited at a wave length of 2 microns and has an overall weight requirement of 15 kilograms per square meter. Two large scale demonstration projects are under way along with a number of smaller scale demonstrations on a variety of mirror materials and concepts. The University of Arizona (UA) mirror concept is based around a 2mm thick Borosilicate glass face sheet mounted to a composite backplane structure via actuators for mirror figure correction. The Composite Optics Inc.(COI) concept consists of a 3.2mm thick Zerodur face sheet bonded to a composite support structure which in turn is mounted to a composite backplane structure via

Testing Dark Energy with the Advanced Liquid-Mirror Probe of Asteroids, Cosmology and Astrophysics

NASA Astrophysics Data System (ADS)

LoVerde, M.; Corasaniti, P. S.; Crotts, A.; Blake, C.

2006-06-01

The Advanced Liquid-Mirror Probe of Asteroids, Cosmology and Astrophysics (ALPACA) is a proposed 8-meter liquid mirror telescope surveying ˜ 1000 deg2 of the southern-hemisphere sky. It will be a remarkably simple and inexpensive telescope that will nonetheless deliver a powerful sample of optical data for studying dark energy. The bulk of the cosmological data consists of nightly, high signal-to-noise, multiband light curves of SN Ia. At the end of the three-year run ALPACA is expected to collect ˜ 100,000 SN Ia up to z ˜ 1. This will allow accurate calibration of the standard-candle relation and reduce the systematic uncertainties. The survey will also provide several other datasets such as the detection of baryon acoustic oscillations in the matter power spectrum and shear weak lensing measurements. In this preliminary analysis we forecast constraints on dark energy parameters from SN Ia and baryon acoustic oscillations. The combination of these two datasets will provide competitive constraints on the dark energy parameters with minimal prior assumptions. Further studies are needed to address the accuracy of weak lensing measurements.

Testing dark energy with the Advanced Liquid-mirror Probe of Asteroids, Cosmology and Astrophysics

NASA Astrophysics Data System (ADS)

Corasaniti, Pier Stefano; LoVerde, Marilena; Crotts, Arlin; Blake, Chris

2006-06-01

The Advanced Liquid-mirror Probe of Asteroids, Cosmology and Astrophysics (ALPACA) is a proposed 8-m liquid-mirror telescope surveying ~1000deg2 of the Southern hemisphere sky. It will be a remarkably simple and inexpensive telescope that none the less will deliver a powerful sample of optical data for studying dark energy. The bulk of the cosmological data consist of nightly, high signal-to-noise ratio, multiband light curves of Type Ia supernovae (SNe Ia). At the end of the 3-yr run, ALPACA is expected to collect >~100000 SNe Ia up to z ~ 1. This will allow us to reduce present systematic uncertainties affecting the standard-candle relation. The survey will also provide several other data sets such as the detection of baryon acoustic oscillations in the matter power spectrum and shear weak-lensing measurements. In this preliminary analysis, we forecast constraints on dark energy parameters from SNe Ia and baryon acoustic oscillations. The combination of these two data sets will provide competitive constraints on the dark energy parameters under minimal prior assumptions. Further studies are needed to address the accuracy of weak-lensing measurements.

Space Adaptation of Active Mirror Segment Concepts

NASA Technical Reports Server (NTRS)

Ames, Gregory H.

1999-01-01

This report summarizes the results of a three year effort by Blue Line Engineering Co. to advance the state of segmented mirror systems in several separate but related areas. The initial set of tasks were designed to address the issues of system level architecture, digital processing system, cluster level support structures, and advanced mirror fabrication concepts. Later in the project new tasks were added to provide support to the existing segmented mirror testbed at Marshall Space Flight Center (MSFC) in the form of upgrades to the 36 subaperture wavefront sensor. Still later, tasks were added to build and install a new system processor based on the results of the new system architecture. The project was successful in achieving a number of important results. These include the following most notable accomplishments: 1) The creation of a new modular digital processing system that is extremely capable and may be applied to a wide range of segmented mirror systems as well as many classes of Multiple Input Multiple Output (MIMO) control systems such as active structures or industrial automation. 2) A new graphical user interface was created for operation of segmented mirror systems. 3) The development of a high bit rate serial data loop that permits bi-directional flow of data to and from as many as 39 segments daisy-chained to form a single cluster of segments. 4) Upgrade of the 36 subaperture Hartmann type Wave Front Sensor (WFS) of the Phased Array Mirror, Extendible Large Aperture (PAMELA) testbed at MSFC resulting in a 40 to 5OX improvement in SNR which in turn enabled NASA personnel to achieve many significant strides in improved closed-loop system operation in 1998. 5) A new system level processor was built and delivered to MSFC for use with the PAMELA testbed. This new system featured a new graphical user interface to replace the obsolete and non-supported menu system originally delivered with the PAMELA system. The hardware featured Blue Line's new stackable

[Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

PubMed

Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

2015-01-01

Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.

Rollable Thin-Shell Nanolaminate Mirrors

NASA Technical Reports Server (NTRS)

Hickey, Gregory; Lih, Shyh-Shiuh; Barbee, Troy, Jr.

2003-01-01

A class of lightweight, deployable, thin-shell, curved mirrors with built-in precise-shape-control actuators is being developed for high-resolution scientific imaging. This technology incorporates a combination of advanced design concepts in actuation and membrane optics that, heretofore, have been considered as separate innovations. These mirrors are conceived to be stowed compactly in a launch shroud and transported aboard spacecraft, then deployed in outer space to required precise shapes at much larger dimensions (diameters of the order of meters or tens of meters). A typical shell rollable mirror structure would include: (1) a flexible single- or multiple-layer face sheet that would include an integrated reflective surface layer that would constitute the mirror; (2) structural supports in the form of stiffeners made of a shape-memory alloy (SMA); and (3) piezoelectric actuators. The actuators, together with an electronic control subsystem, would implement a concept of hierarchical distributed control, in which (1) the SMA actuators would be used for global shape control and would generate the large deformations needed for the deployment process and (2) the piezoelectric actuators would generate smaller deformations and would be used primarily to effect fine local control of the shape of the mirror.

Advances in thermal control and performance of the MMT M1 mirror

NASA Astrophysics Data System (ADS)

Gibson, J. D.; Williams, G. G.; Callahan, S.; Comisso, B.; Ortiz, R.; Williams, J. T.

2010-07-01

Strategies for thermal control of the 6.5-meter diameter borosilicate honeycomb primary (M1) mirror at the MMT Observatory have included: 1) direct control of ventilation system chiller setpoints by the telescope operator, 2) semiautomated control of chiller setpoints, using a fixed offset from the ambient temperature, and 3) most recently, an automated temperature controller for conditioned air. Details of this automated controller, including the integration of multiple chillers, heat exchangers, and temperature/dew point sensors, are presented here. Constraints and sanity checks for thermal control are also discussed, including: 1) mirror and hardware safety, 2) aluminum coating preservation, and 3) optimization of M1 thermal conditions for science acquisition by minimizing both air-to-glass temperature differences, which cause mirror seeing, and internal glass temperature gradients, which cause wavefront errors. Consideration is given to special operating conditions, such as high dew and frost points. Precise temperature control of conditioned ventilation air as delivered to the M1 mirror cell is also discussed. The performance of the new automated controller is assessed and compared to previous control strategies. Finally, suggestions are made for further refinement of the M1 mirror thermal control system and related algorithms.

James Webb Space Telescope's Golden Mirror Unveiled

NASA Image and Video Library

2017-12-08

NASA engineers unveil the giant golden mirror of NASA's James Webb Space Telescope, and it's goldenly delicious! The 18 mirrors that make up the primary mirror were individually protected with a black covers when they were assembled on the telescope structure. Now, for the first time since the primary mirror was completed, the covers have been lifted. Standing tall and glimmering gold inside NASA's Goddard Space Flight Center's clean room in Greenbelt, Maryland, this mirror will be the largest yet sent into space. Currently, engineers are busy assembling and testing the other pieces of the telescope. Read more: go.nasa.gov/1TejHg4 Credit: NASA/Goddard/Chris Gunn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The mirror neuron system in post-stroke rehabilitation

PubMed Central

2013-01-01

Different treatments for stroke patients have been proposed; among them the mirror therapy and motion imagery lead to functional recovery by providing a cortical reorganization. Up today the basic concepts of the current literature on mirror neurons and the major findings regarding the use of mirror therapy and motor imagery as potential tools to promote reorganization and functional recovery in post-stroke patients. Bibliographic research was conducted based on publications over the past thirteen years written in English in the databases Scielo, Pubmed/MEDLINE, ISI Web of Knowledge. The studies showed how the interaction among vision, proprioception and motor commands promotes the recruitment of mirror neurons, thus providing cortical reorganization and functional recovery of post-stroke patients. We conclude that the experimental advances on Mirror Neurons will bring new rational therapeutic approaches to post-stroke rehabilitation. PMID:24134862

The mirror neuron system in post-stroke rehabilitation.

PubMed

Carvalho, Diana; Teixeira, Silmar; Lucas, Marina; Yuan, Ti-Fei; Chaves, Fernanda; Peressutti, Caroline; Machado, Sergio; Bittencourt, Juliana; Menéndez-González, Manuel; Nardi, Antonio Egidio; Velasques, Bruna; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro; Arias-Carrión, Oscar

2013-10-17

Different treatments for stroke patients have been proposed; among them the mirror therapy and motion imagery lead to functional recovery by providing a cortical reorganization. Up today the basic concepts of the current literature on mirror neurons and the major findings regarding the use of mirror therapy and motor imagery as potential tools to promote reorganization and functional recovery in post-stroke patients. Bibliographic research was conducted based on publications over the past thirteen years written in English in the databases Scielo, Pubmed/MEDLINE, ISI Web of Knowledge. The studies showed how the interaction among vision, proprioception and motor commands promotes the recruitment of mirror neurons, thus providing cortical reorganization and functional recovery of post-stroke patients. We conclude that the experimental advances on Mirror Neurons will bring new rational therapeutic approaches to post-stroke rehabilitation.

A 4-m evolvable space telescope configured for NASA's HabEx Mission: the initial stage of LUVOIR

NASA Astrophysics Data System (ADS)

Lillie, Charles F.; MacEwen, Howard A.; Polidan, Ronald S.; Breckinridge, James B.

2017-09-01

Previous papers have described our concept for a large telescope that would be assembled in space in several stages (in different configurations) over a period of fifteen to 20 years. Spreading the telescope development, launch and operations cost over 20 years would minimize the impact on NASA's annual budget and drastically shorten the time between program start and "first light" for this space observatory. The first Stage of this Evolvable Space Telescope (EST) would consist of an instrument module located at the prime focus of three 4-meter hexagonal mirrors arranged in a semi-circle to form one-half of a 12-m segmented mirror. After several years three additional 4-m mirrors would be added to create a 12-m filled aperture. Later, twelve more 4-m mirrors will be added to this Stage 2 telescope to create a 20-m filled aperture space telescope. At each stage the telescope would have an unparalleled capability for UVOIR observations, and the results of these observations will guide the evolution of the telescope and its instruments. In this paper we describe our design concept for an initial configuration of our Evolvable Space Telescope that can meet the requirements of the 4-m version of the HabEx spacecraft currently under consideration by NASA's Habitable Exoplanet Science and Technology Definition Team. This "Stage Zero" configuration will have only one 4-m mirror segment with the same 30-m focal length and a prime focus coronagraph with normal incidence optics to minimize polarization effects. After assembly and checkout in cis-lunar space, the telescope would transfer to a Sun-Earth L2 halo orbit and obtain high sensitivity, high resolution, high contrast UVOIR observations that address the scientific objectives of the Habitable-Exoplanet Imaging Missions.

A high fusion power gain tandem mirror

NASA Astrophysics Data System (ADS)

Fowler, T. K.; Moir, R. W.; Simonen, T. C.

2017-10-01

Utilizing advances in high field superconducting magnet technology and microwave gyrotrons we illustrate the possibility of a high power gain (Q = 10-20) tandem mirror fusion reactor. Inspired by recent Gas Dynamic Trap (GDT) achievements we employ a simple axisymmetric mirror magnet configuration. We consider both DT and cat. DD fuel options that utilize existing as well as future technology development. We identify subjects requiring further study such as hot electron physics, trapped particle modes and plasma startup.

Mirror image agnosia.

PubMed

Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

2014-10-01

Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles reflected self-images. A new observation involving failure

Mirror Image Agnosia

PubMed Central

Chandra, Sadanandavalli Retnaswami; Issac, Thomas Gregor

2014-01-01

Background: Gnosis is a modality-specific ability to access semantic knowledge of an object or stimulus in the presence of normal perception. Failure of this is agnosia or disorder of recognition. It can be highly selective within a mode. self-images are different from others as none has seen one's own image except in reflection. Failure to recognize this image can be labeled as mirror image agnosia or Prosopagnosia for reflected self-image. Whereas mirror agnosia is a well-recognized situation where the person while looking at reflected images of other objects in the mirror he imagines that the objects are in fact inside the mirror and not outside. Material and Methods:: Five patients, four females, and one male presented with failure to recognize reflected self-image, resulting in patients conversing with the image as a friend, fighting because the person in mirror is wearing her nose stud, suspecting the reflected self-image to be an intruder; but did not have prosopagnosia for others faces, non living objects on self and also apraxias except dressing apraxia in one patient. This phenomena is new to our knowledge. Results: Mirror image agnosia is an unique phenomena which is seen in patients with parietal lobe atrophy without specificity to a category of dementing illness and seems to disappear as disease advances. Discussion: Reflected self-images probably have a specific neural substrate that gets affected very early in posterior dementias specially the ones which predominantly affect the right side. At that phase most patients are mistaken as suffering from psychiatric disorder as cognition is moderately preserved. As disease becomes more widespread this symptom becomes masked. A high degree of suspicion and proper assessment might help physicians to recognize the organic cause of the symptom so that early therapeutic interventions can be initiated. Further assessment of the symptom with FMRI and PET scan is likely to solve the mystery of how brain handles

Arc-Second Alignment of International X-Ray Observatory Mirror Segments in a Fixed Structure

NASA Technical Reports Server (NTRS)

Evans, Tyler, C.; Chan, Kai-Wing; Saha, Timo T.

2010-01-01

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc-seconds. These mirror segments are 0.4 mm thick, and 200 to 400 mm in size, which makes it hard to meet the strict angular resolution requirement of 5 arc-seconds for the telescope. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of transferring thin mirror segments from a temporary mount to a fixed structure with arc-second alignment and minimal figure distortion. Recent advances in technology development in addition to the automation of several processes have produced significant results. Recent advances in the mirror fixture process known as the suspension mount has allowed for a mirror to be mounted to a fixture with minimal distortion. Once on the fixture, mirror segments have been aligned to around 5 arc-seconds which is halfway to the goal of 2.5 arc-seconds per mirror segment. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced.

Design and Analysis of Mirror Modules for IXO and Beyond

NASA Technical Reports Server (NTRS)

McClelland, Ryan S.; Powell, Cory; Saha, Timo T.; Zhang, William W.

2011-01-01

Advancements in X-ray astronomy demand thin, light, and closely packed thin optics which lend themselves to segmentation of the annular mirrors and, in turn, a modular approach to the mirror design. The functionality requirements of such a mirror module are well understood. A baseline modular concept for the proposed International X-Ray Observatory (IXO) Flight Mirror Assembly (FMA) consisting of 14,000 glass mirror segments divided into 60 modules was developed and extensively analyzed. Through this development, our understanding of module loads, mirror stress, thermal performance, and gravity distortion have greatly progressed. The latest progress in each of these areas is discussed herein. Gravity distortion during horizontal X-ray testing and on-orbit thermal performance have proved especially difficult design challenges. In light of these challenges, fundamental trades in modular X-ray mirror design have been performed. Future directions in module X-ray mirror design are explored including the development of a 1.8 m diameter FMA utilizing smaller mirror modules. The effect of module size on mirror stress, module self-weight distortion, thermal control, and range of segment sizes required is explored with advantages demonstrated from smaller module size in most cases.

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

PubMed Central

Corballis, Michael C.

2018-01-01

Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia. PMID:29706878

Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal.

PubMed

Corballis, Michael C

2018-01-01

Mirror-image confusions are common, especially in children and in some cases of neurological impairment. They can be a special impediment in activities such as reading and writing directional scripts, where mirror-image patterns (such as b and d ) must be distinguished. Treating mirror images as equivalent, though, can also be adaptive in the natural world, which carries no systematic left-right bias and where the same object or event can appear in opposite viewpoints. Mirror-image equivalence and confusion are natural consequences of a bilaterally symmetrical brain. In the course of learning, mirror-image equivalence may be established through a process of symmetrization, achieved through homotopic interhemispheric exchange in the formation of memory circuits. Such circuits would not distinguish between mirror images. Learning to discriminate mirror-image discriminations may depend either on existing brain asymmetries, or on extensive learning overriding the symmetrization process. The balance between mirror-image equivalence and mirror-image discrimination may nevertheless be precarious, with spontaneous confusions or reversals, such as mirror writing, sometimes appearing naturally or as a manifestation of conditions like dyslexia.

Stroboscopic Interferometer for Measuring Mirror Vibrations

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Robers, Ted

2005-01-01

-function generator (that is, a signal generator), an oscilloscope, a trigger filter, and an advanced charge-coupled-device (CCD) camera. The optical components are positioned to form a pupil image of the mirror under test on the CCD chip, so that the interference pattern representative of the instantaneous mirror shape is imaged on the CCD chip.

Mirror Neurons and Mirror-Touch Synesthesia.

PubMed

Linkovski, Omer; Katzin, Naama; Salti, Moti

2016-05-30

Since mirror neurons were introduced to the neuroscientific community more than 20 years ago, they have become an elegant and intuitive account for different cognitive mechanisms (e.g., empathy, goal understanding) and conditions (e.g., autism spectrum disorders). Recently, mirror neurons were suggested to be the mechanism underlying a specific type of synesthesia. Mirror-touch synesthesia is a phenomenon in which individuals experience somatosensory sensations when seeing someone else being touched. Appealing as it is, careful delineation is required when applying this mechanism. Using the mirror-touch synesthesia case, we put forward theoretical and methodological issues that should be addressed before relying on the mirror-neurons account. © The Author(s) 2016.

Bonding Thin Mirror Segments Without Distortion for the International X-Ray Observatory

NASA Technical Reports Server (NTRS)

Evans, Tyler C.; Chan, Kai-Wing; Saha, Timo T.

2011-01-01

The International X-Ray Observatory (IXO) uses thin glass optics to maximize large effective area and precise low angular resolution. The thin glass mirror segments must be transferred from their fabricated state to a permanent structure without imparting distortion. IXO will incorporate about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arcseconds. To preserve figure and alignment, the mirror segment must be bonded with sub-micron movement at each corner. Recent advances in technology development have produced significant x-ray test results of a bonded pair of mirrors. Three specific bonding cycles will be described highlighting the improvements in procedure, temperature control, and precision bonding. This paper will highlight the recent advances in alignment and permanent bonding as well as the results they have produced.

Nanolaminate Mirrors With "Piston" Figure-Control Actuators

NASA Technical Reports Server (NTRS)

Lowman, Andrew; Redding, David; Hickey, Gregory; Knight, Jennifer; Moynihan, Philip; Lih, Shyh0Shiuh; Barbee, Troy

2003-01-01

Efforts are under way to develop a special class of thin-shell curved mirrors for high-resolution imaging in visible and infrared light in a variety of terrestrial or extraterrestrial applications. These mirrors can have diameters of the order of a meter and include metallic film reflectors on nanolaminate substrates supported by multiple distributed piezoceramic gpiston h-type actuators for micron-level figure control. Whereas conventional glass mirrors of equivalent size and precision have areal mass densities between 50 and 150 kg/sq m, the nanolaminate mirrors, including not only the reflector/ shell portions but also the actuators and the backing structures needed to react the actuation forces, would have areal mass densities that may approach .5 kg/m2. Moreover, whereas fabrication of a conventional glass mirror of equivalent precision takes several years, the reflector/shell portion of a nanolaminate mirror can be fabricated in less than a week, and its actuation system can be fabricated in 1 to 2 months. The engineering of these mirrors involves a fusion of the technological heritage of multisegmented adaptive optics and deformable mirrors with more recent advances in metallic nanolaminates and in mathematical modeling of the deflections of thin, curved shells in response to displacements by multiple, distributed actuators. Because a nanolaminate shell is of the order of 10 times as strong as an otherwise identical shell made of a single, high-strength, non-nanolaminate metal suitable for mirror use, a nanolaminate mirror can be made very thin (typically between 100 and 150 m from the back of the nanolaminate substrate to the front reflecting surface). The thinness and strength of the nanolaminate are what make it possible to use distributed gpiston h-type actuators for surface figure control with minimal local concentrated distortion (called print-through in the art) at the actuation points.

Chandra X-Ray Observatory High Resolution Mirror Assembly

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph shows the mirrors of the High Resolution Mirror Assembly (HRMA) for the Chandra X-Ray Observatory (CXO), formerly Advanced X-Ray Astrophysics Facility (AXAF), being assembled in the Eastman Kodak Company in Rochester, New York. The AXAF was renamed CXO in 1999. The CXO is the most sophisticated and the world's most powerful x-ray telescope ever built. It observes x-rays from high-energy regions of the universe, such as hot gas in the remnants of exploded stars. The HRMA, the heart of the telescope system, is contained in the cylindrical 'telescope' portion of the observatory. Since high-energy x-rays would penetrate a normal mirror, special cylindrical mirrors were created. The two sets of four nested mirrors resemble tubes within tubes. Incoming x-rays graze off the highly polished mirror surface and are furneled to the instrument section for detection and study. TRW, Inc. was the prime contractor for the development of the CXO and NASA's Marshall Space Flight Center was responsible for its project management. The Observatory was launched July 22, 1999 aboard the Space Shuttle Columbia, STS-93 mission.

The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers and Technology Developments

NASA Technical Reports Server (NTRS)

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Phillip;

Advanced Environmentally Resistant Lithium Fluoride Mirror Coatings for the Next Generation of Broadband Space Observatories

NASA Technical Reports Server (NTRS)

Fleming, Brian; Quijada, Manuel A.; Hennessy, John; Egan, Arika; Del Hoyo, Javier G.

2017-01-01

Recent advances in the physical vapor deposition (PVD) of protective fluoride films have raised the far-ultraviolet (FUV: 912-1600 A) reflectivity of aluminum-based mirrors closer to the theoretical limit. The greatest gains, at more than 20%, have come for lithium fluoride-protected aluminum, which has the shortest wavelength cutoff of any conventional overcoat. Despite the success of the NASA FUSE mission, the use of lithium fluoride (LiF)-based optics is rare, as LiF is hygroscopic and requires handling procedures that can drive risk. With NASA now studying two large mission concepts for astronomy, Large UV-Optical-IR Surveyor (LUVOIR) and the Habitable Exoplanet Imaging Mission (HabEx), which mandate throughput down to 1000 , the development of LiF-based coatings becomes crucial. This paper discusses steps that are being taken to qualify these new enhanced LiF-protected aluminum (eLiF) mirror coatings for flight. In addition to quantifying the hygroscopic degradation, we have developed a new method of protecting eLiF with an ultrathin (10-20 A) capping layer of a nonhygroscopic material to increase durability. We report on the performance of eLiF-based optics and assess the steps that need to be taken to qualify such coatings for LUVOIR, HabEx, and other FUV-sensitive space missions.

Analytical Verifications in Cryogenic Testing of NGST Advanced Mirror System Demonstrators

NASA Technical Reports Server (NTRS)

Cummings, Ramona; Levine, Marie; VanBuren, Dave; Kegley, Jeff; Green, Joseph; Hadaway, James; Presson, Joan; Cline, Todd; Stahl, H. Philip (Technical Monitor)

2002-01-01

Ground based testing is a critical and costly part of component, assembly, and system verifications of large space telescopes. At such tests, however, with integral teamwork by planners, analysts, and test personnel, segments can be included to validate specific analytical parameters and algorithms at relatively low additional cost. This paper opens with strategy of analytical verification segments added to vacuum cryogenic testing of Advanced Mirror System Demonstrator (AMSD) assemblies. These AMSD assemblies incorporate material and architecture concepts being considered in the Next Generation Space Telescope (NGST) design. The test segments for workmanship testing, cold survivability, and cold operation optical throughput are supplemented by segments for analytical verifications of specific structural, thermal, and optical parameters. Utilizing integrated modeling and separate materials testing, the paper continues with support plan for analyses, data, and observation requirements during the AMSD testing, currently slated for late calendar year 2002 to mid calendar year 2003. The paper includes anomaly resolution as gleaned by authors from similar analytical verification support of a previous large space telescope, then closes with draft of plans for parameter extrapolations, to form a well-verified portion of the integrated modeling being done for NGST performance predictions.

Engineers Clean Mirror with Carbon Dioxide Snow

NASA Image and Video Library

2015-05-07

Just like drivers sometimes use snow to clean their car mirrors in winter, two Exelis Inc. engineers are practicing "snow cleaning'" on a test telescope mirror for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland. By shooting carbon dioxide snow at the surface, engineers are able to clean large telescope mirrors without scratching them. "The snow-like crystals (carbon dioxide snow) knock contaminate particulates and molecules off the mirror," said Lee Feinberg, NASA optical telescope element manager. This technique will only be used if the James Webb Space Telescope's mirror is contaminated during integration and testing. The Webb telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. With a mirror seven times as large as Hubble's and infrared capability, Webb will be capturing light from 13.5 billion light years away. To do this, its mirror must be kept super clean. "Small dust particles or molecules can impact the science that can be done with the Webb," said Feinberg. "So cleanliness especially on the mirrors is critical." Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency. Image credit: NASA/Goddard/Chris Gunn Text credit: Laura Betz, NASA's Goddard Space Flight Center, Greenbelt, Maryland NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Kinematic Alignment and Bonding of Silicon Mirrors for High-Resolution Astronomical X-Ray Optics

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Mazzarella, James R.; Saha, Timo T.; Zhang, William W.; Mcclelland, Ryan S.; Biskack, Michael P.; Riveros, Raul E.; Allgood, Kim D.; Kearney, John D.; Sharpe, Marton V.;

Alignment and Integration of Lightweight Mirror Segments

NASA Technical Reports Server (NTRS)

Evans, Tyler; Biskach, Michael; Mazzarella, Jim; McClelland, Ryan; Saha, Timo; Zhang, Will; Chan, Kai-Wing

2011-01-01

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc-seconds. These mirror segments are 0.4 mm thick, and 200 to 400 mm in size, which makes it difficult not to impart distortion at the sub-arc-second level. This paper outlines the precise alignment, permanent bonding, and verification testing techniques developed at NASA's Goddard Space Flight Center (GSFC). Improvements in alignment include new hardware and automation software. Improvements in bonding include two module new simulators to bond mirrors into, a glass housing for proving single pair bonding, and a Kovar module for bonding multiple pairs of mirrors. Three separate bonding trials were x-ray tested producing results meeting the requirement of sub ten arc-second alignment. This paper will highlight these recent advances in alignment, testing, and bonding techniques and the exciting developments in thin x-ray optic technology development.

Nonimaging polygonal mirrors achieving uniform irradiance distributions on concentrating photovoltaic cells.

PubMed

Schmitz, Max; Dähler, Fabian; Elvinger, François; Pedretti, Andrea; Steinfeld, Aldo

2017-04-10

We introduce a design methodology for nonimaging, single-reflection mirrors with polygonal inlet apertures that generate a uniform irradiance distribution on a polygonal outlet aperture, enabling a multitude of applications within the domain of concentrated photovoltaics. Notably, we present single-mirror concentrators of square and hexagonal perimeter that achieve very high irradiance uniformity on a square receiver at concentrations ranging from 100 to 1000 suns. These optical designs can be assembled in compound concentrators with maximized active area fraction by leveraging tessellation. More advanced multi-mirror concentrators, where each mirror individually illuminates the whole area of the receiver, allow for improved performance while permitting greater flexibility for the concentrator shape and robustness against partial shading of the inlet aperture.

Mirror agnosia and the mirrored-self misidentification delusion: a hypnotic analogue.

PubMed

Connors, Michael H; Cox, Rochelle E; Barnier, Amanda J; Langdon, Robyn; Coltheart, Max

2012-05-01

Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants' expectations and interpretations, are discussed.

Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation

PubMed Central

Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey

2014-01-01

The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. PMID:23709352

NASA funding opportunities for optical fabrication and testing technology development

NASA Astrophysics Data System (ADS)

Stahl, H. Philip

2013-09-01

NASA requires technologies to fabricate and test optical components to accomplish its highest priority science missions. The NRC ASTRO2010 Decadal Survey states that an advanced large-aperture UVOIR telescope is required to enable the next generation of compelling astrophysics and exo-planet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. The NRC 2012 NASA Space Technology Roadmaps and Priorities Report states that the highest priority technology in which NASA should invest to `Expand our understanding of Earth and the universe' is next generation X-ray and UVOIR telescopes. Each of the Astrophysics division Program Office Annual Technology Reports (PATR) identifies specific technology needs. NASA has a variety of programs to fund enabling technology development: SBIR (Small Business Innovative Research); the ROSES APRA and SAT programs (Research Opportunities in Space and Earth Science; Astrophysics Research and Analysis program; Strategic Astrophysics Technology program); and several Office of the Chief Technologist (OCT) programs.

NASA Funding Opportunities for Optical Fabrication and Testing Technology Development

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

NASA requires technologies to fabricate and test optical components to accomplish its highest priority science missions. The NRC ASTRO2010 Decadal Survey states that an advanced large-aperture UVOIR telescope is required to enable the next generation of compelling astrophysics and exo-planet science; and, that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. The NRC 2012 NASA Space Technology Roadmaps and Priorities Report states that the highest priority technology in which NASA should invest to 'Expand our understanding of Earth and the universe' is next generation X-ray and UVOIR telescopes. Each of the Astrophysics division Program Office Annual Technology Reports (PATR) identifies specific technology needs. NASA has a variety of programs to fund enabling technology development: SBIR (Small Business Innovative Research); the ROSES APRA and SAT programs (Research Opportunities in Space and Earth Science; Astrophysics Research and Analysis program; Strategic Astrophysics Technology program); and several Office of the Chief Technologist (OCT) programs

Novel high-bandwidth bimorph deformable mirrors

NASA Astrophysics Data System (ADS)

Griffith, Michael S.; Laycock, Leslie C.; Archer, Nick J.

2004-12-01

Adaptive Optics (AO) is a critical underpinning technology for future laser delivery (including free-space optical communications), target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS Advanced Technology Centre is developing multi-element bimorph deformable mirrors for such an applications. Our initial designs were based on a standard construction and exhibited a resonant frequency of 1kHz with a maximum stroke of +/-20μm for an active aperture of 50mm. These devices were limited by the necessity to have a 'dead space' between the inner active area and the mirror boundary; this ensured that both the requirements for the stroke and the fixed boundary conditions could be met simultaneously. However, there was a significant penalty to pay in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. In a series of iteration steps, we have created novel mounting arrangements that reduce dead space and thus provide the optimum trade-off between bandwidth and stroke. These schemes include supporting the mirror from underneath, rather than at its edge. As a result, models of 60mm active diameter mirrors predict a resonance in excess of 5kHz, combined with a maximum stroke greater than +/-40μm. This paper will discuss a number of different mirror designs and present experimental results for recently assembled devices.

Chiral mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plum, Eric, E-mail: erp@orc.soton.ac.uk; Zheludev, Nikolay I., E-mail: niz@orc.soton.ac.uk; The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637378

2015-06-01

Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spacedmore » by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media.« less

Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

PubMed

Cavallo, Andrea; Heyes, Cecilia; Becchio, Cristina; Bird, Geoffrey; Catmur, Caroline

2014-08-01

The human mirror system has been the subject of much research over the past two decades, but little is known about the timecourse of mirror responses. In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse. We used single-pulse transcranial magnetic stimulation to investigate the timecourse of mirror and counter-mirror responses in the human brain. Experiment 1 demonstrated that mirror responses can be measured from around 200 ms after observed action onset. Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse. By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development. More generally, they contribute to theorizing regarding mirror neuron function by providing some constraints on how quickly mirror responses can influence social cognition. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

JWST Flight Mirrors

NASA Image and Video Library

2011-05-25

Project scientist Mark Clampin is reflected in the flight mirrors of the Webb Space Telescope at Marshall Space Flight Center. Portions of the Webb telescope are being built at NASA Goddard. Credit: Ball Aerospace/NASA NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook Find us on Instagram

Virtual Mirrors

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

2010-01-01

The multiple-reflection photograph in Fig. 1 was taken in an elevator on board the cruise ship Norwegian Jade in March 2008. Three of the four walls of the elevator were mirrored, allowing me to see the combination of two standard arrangements of plane mirrors: two mirrors set at 90 degrees to each other and two parallel mirrors. Optical phenomena…

Possibilities of application of the swirling flows in cooling systems of laser mirrors

NASA Astrophysics Data System (ADS)

Shanin, Yu; Chernykh, A.

2018-03-01

The paper presents analytical investigations into advanced cooling systems of the laser mirrors with heat exchange intensification by methods of ordered vortex impact on a coolant flow structure. Advantages and effectiveness of the proposed cooling systems have been estimated to reduction displacement of an optical mirror surface due to a flexure.

Yes, the James Webb Space Telescope Mirrors 'Can'

NASA Image and Video Library

2017-12-08

The powerful primary mirrors of the James Webb Space Telescope will be able to detect the light from distant galaxies. The manufacturer of those mirrors, Ball Aerospace & Technologies Corp. of Boulder, Colo., recently celebrated their successful efforts as mirror segments were packed up in special shipping canisters (cans) for shipping to NASA. The Webb telescope has 21 mirrors, with 18 primary mirror segments working together as one large 21.3-foot (6.5-meter) primary mirror. The mirror segments are made of beryllium, which was selected for its stiffness, light weight and stability at cryogenic temperatures. Bare beryllium is not very reflective of near-infrared light, so each mirror is coated with about 0.12 ounce of gold. Northrop Grumman Corp. Aerospace Systems is the principal contractor on the telescope and commissioned Ball for the optics system's development, design, manufacturing, integration and testing. The Webb telescope is the world's next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, the Webb telescope will provide images of the first galaxies ever formed, and explore planets around distant stars. It is a joint project of NASA, the European Space Agency and the Canadian Space Agency. For more information about the James Webb Space Telescope, visit: www.jwst.nasa.gov Credit: Ball Aerospace NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Mirror, Mirror on the Wall...?

ERIC Educational Resources Information Center

Pflaster, Gail

1979-01-01

The study determined the value of using a mirror for speech teaching by recording manner, place, voicing, and blend errors produced by 27 hearing-impaired children (5-13 years old) while imitating consonant-vowel syllables under three conditions (audition alone, audition plus direct vision, and audition plus vision using a mirror). (Author)

Electrotunable nanoplasmonic liquid mirror

NASA Astrophysics Data System (ADS)

Montelongo, Yunuen; Sikdar, Debabrata; Ma, Ye; McIntosh, Alastair J. S.; Velleman, Leonora; Kucernak, Anthony R.; Edel, Joshua B.; Kornyshev, Alexei A.

2017-11-01

Recently, there has been a drive to design and develop fully tunable metamaterials for applications ranging from new classes of sensors to superlenses among others. Although advances have been made, tuning and modulating the optical properties in real time remains a challenge. We report on the first realization of a reversible electrotunable liquid mirror based on voltage-controlled self-assembly/disassembly of 16 nm plasmonic nanoparticles at the interface between two immiscible electrolyte solutions. We show that optical properties such as reflectivity and spectral position of the absorption band can be varied in situ within +/-0.5 V. This observed effect is in excellent agreement with theoretical calculations corresponding to the change in average interparticle spacing. This electrochemical fully tunable nanoplasmonic platform can be switched from a highly reflective `mirror' to a transmissive `window' and back again. This study opens a route towards realization of such platforms in future micro/nanoscale electrochemical cells, enabling the creation of tunable plasmonic metamaterials.

Chinese "Magic" Mirrors.

ERIC Educational Resources Information Center

Swinson, Derek B.

1992-01-01

Chinese "magic" mirrors are made from bronze with the front side a mirror and the reverse side a molded image. When light is reflected from the mirror,the image on the reverse side appears. Discusses reflections of conventional mirrors, possible explanations for the magic mirror phenomenon, and applications of the phenomenon to…

Robotic Mirror Therapy System for Functional Recovery of Hemiplegic Arms.

PubMed

Beom, Jaewon; Koh, Sukgyu; Nam, Hyung Seok; Kim, Wonshik; Kim, Yoonjae; Seo, Han Gil; Oh, Byung-Mo; Chung, Sun Gun; Kim, Sungwan

2016-08-15

Mirror therapy has been performed as effective occupational therapy in a clinical setting for functional recovery of a hemiplegic arm after stroke. It is conducted by eliciting an illusion through use of a mirror as if the hemiplegic arm is moving in real-time while moving the healthy arm. It can facilitate brain neuroplasticity through activation of the sensorimotor cortex. However, conventional mirror therapy has a critical limitation in that the hemiplegic arm is not actually moving. Thus, we developed a real-time 2-axis mirror robot system as a simple add-on module for conventional mirror therapy using a closed feedback mechanism, which enables real-time movement of the hemiplegic arm. We used 3 Attitude and Heading Reference System sensors, 2 brushless DC motors for elbow and wrist joints, and exoskeletal frames. In a feasibility study on 6 healthy subjects, robotic mirror therapy was safe and feasible. We further selected tasks useful for activities of daily living training through feedback from rehabilitation doctors. A chronic stroke patient showed improvement in the Fugl-Meyer assessment scale and elbow flexor spasticity after a 2-week application of the mirror robot system. Robotic mirror therapy may enhance proprioceptive input to the sensory cortex, which is considered to be important in neuroplasticity and functional recovery of hemiplegic arms. The mirror robot system presented herein can be easily developed and utilized effectively to advance occupational therapy.

Developmental long trace profiler using optimally aligned mirror based pentaprism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barber, Samuel K; Morrison, Gregory Y.; Yashchuk, Valeriy V.

2010-07-21

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory [Nucl. Instr. and Meth. A 616, 212-223 (2010)]. The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror basedmore » pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.« less

The AXAF technology mirror assembly program - An overview

NASA Technical Reports Server (NTRS)

Wyman, Charles L.; Dailey, Carroll C.; Reily, Cary; Weisskopf, Martin; Mckinnon, Phil

1986-01-01

The manufacture and testing of the Technology Mirror Assembly (TMA), a prototype Wolter I telescope scaled to the dimensions of the innermost element of the High-Resolution Mirror Assembly for the NASA Advanced X-ray Astrophysics Facility (AXAF), are reviewed. Consideration is given to the grinding, polishing, coating, and assembly of the zerodur TMA blanks, the TMA mount design, and the test procedures used at the MSFC X-ray Calibration Facility. Test results indicate FWHM resolution less than 0.5 arcsec, but with significant near-field scattering attributed to ripple; further long-lap polishing is suggested.

Correcting Surface Figure Error in Imaging Satellites Using a Deformable Mirror

DTIC Science & Technology

2013-12-01

background understanding about the Naval Postgraduate School’s SMT test- bed and the required performance for mirror surface figures. The...Postgraduate School. Larger than the Hubble Space Telescope, but smaller than the JWST (see Figure 2), the SMT is an advanced test- bed to research the...orientation (from [3]). The six segments of the primary mirror have a lightweight, deformable, nano- laminate face with actuators across the rear

Advances in Strapdown Sensors

DTIC Science & Technology

1984-04-01

axis laser gyro sensor assembly (1, 24) in a single Zerodur structure using interleaved laser paths to reduce net size/weight. If advances in mirror ...laser gyros, special design considerations - associated with mechanically dithered laaer gyros, the state-of-the-art in magnetic mirror and...from the lasing action of a helium-noon gas discharge within the optical cavity. The reflecting surfaces are die- lectric mirrors designed to

Compensation of X-ray mirror shape-errors using refractive optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawhney, Kawal, E-mail: Kawal.sawhney@diamond.ac.uk; Laundy, David; Pape, Ian

2016-08-01

Focusing of X-rays to nanometre scale focal spots requires high precision X-ray optics. For nano-focusing mirrors, height errors in the mirror surface retard or advance the X-ray wavefront and after propagation to the focal plane, this distortion of the wavefront causes blurring of the focus resulting in a limit on the spatial resolution. We describe here the implementation of a method for correcting the wavefront that is applied before a focusing mirror using custom-designed refracting structures which locally cancel out the wavefront distortion from the mirror. We demonstrate in measurements on a synchrotron radiation beamline a reduction in the sizemore » of the focal spot of a characterized test mirror by a factor of greater than 10 times. This technique could be used to correct existing synchrotron beamline focusing and nanofocusing optics providing a highly stable wavefront with low distortion for obtaining smaller focus sizes. This method could also correct multilayer or focusing crystal optics allowing larger numerical apertures to be used in order to reduce the diffraction limited focal spot size.« less

Mirror man: a case of skilled deliberate mirror writing.

PubMed

McIntosh, Robert D; De Lucia, Natascia; Della Sala, Sergio

2014-01-01

Mirror writing is a striking behaviour that is common in children and can reemerge in adults following brain damage. Skilled deliberate mirror writing has also been reported, but only anecdotally. We provide the first quantitative study of skilled deliberate mirror writing. K.B. can write forward or backward, vertically upright or inverted, with the hands acting alone or simultaneously. K.B. is predominantly left handed, but writes habitually with his right hand. Of his writing formats, his left hand mirror writing is by far the most similar in style to his normal handwriting. When writing bimanually, he performs better when his two hands make mirror-symmetrical movements to write opposite scripts than if they move in the same direction to write similar scripts. He has no special facility for reading mirrored text. These features are consistent with prior anecdotal cases and support a motor basis for K.B.'s ability, according to which his skilled mirror writing results from the left hand execution of a low-level motor program for a right hand abductive writing action. Our methods offer a novel framework for investigating the sharing of motor representations across effectors.

Deterministic magnetorheological finishing of optical aspheric mirrors

NASA Astrophysics Data System (ADS)

Song, Ci; Dai, Yifan; Peng, Xiaoqiang; Li, Shengyi; Shi, Feng

2009-05-01

A new method magnetorheological finishing (MRF) used for deterministical finishing of optical aspheric mirrors is applied to overcome some disadvantages including low finishing efficiency, long iterative time and unstable convergence in the process of conventional polishing. Based on the introduction of the basic principle of MRF, the key techniques to implement deterministical MRF are also discussed. To demonstrate it, a 200 mm diameter K9 class concave asphere with a vertex radius of 640mm was figured on MRF polish tool developed by ourselves. Through one process about two hours, the surface accuracy peak-to-valley (PV) is improved from initial 0.216λ to final 0.179λ and root-mean-square (RMS) is improved from 0.027λ to 0.017λ (λ = 0.6328um ). High-precision and high-efficiency convergence of optical aspheric surface error shows that MRF is an advanced optical manufacturing method that owns high convergence ratio of surface figure, high precision of optical surfacing, stabile and controllable finishing process. Therefore, utilizing MRF to finish optical aspheric mirrors determinately is credible and stabile; its advantages can be also used for finishing optical elements on varieties of types such as plane mirrors and spherical mirrors.

Advanced ultraviolet-resistant silver mirrors for use in solar reflectors

DOEpatents

Jorgensen, Gary J [Pine, CO; Gee, Randy [Arvada, CO

2009-11-03

A silver mirror construction that maintains a high percentage of hemispherical reflectance throughout the UV and visible spectrum when used in solar reflectors, comprising:a) a pressure sensitive adhesive layer positioned beneath a silver overlay;b) a polymer film disposed on the silver overlay;c) an adhesive layer positioned on the polymer film; andd) a UV screening acrylic film disposed on the adhesive layer.

Is that me in the mirror? Depersonalisation modulates tactile mirroring mechanisms.

PubMed

Adler, Julia; Schabinger, Nadine; Michal, Matthias; Beutel, Manfred E; Gillmeister, Helge

2016-05-01

Our sense of self is thought to develop through sensory-motor contingencies provided, not only by observing one's own body, but also by mirroring interactions with others. This suggests that there is a strong link between mirroring mechanisms and the bodily self. The present study tested whether this link is expressed at early, implicit stages of the mirroring process or at later, more cognitive stages. We also provide, to the best of our knowledge, the first demonstration of how inter-individual differences in our sense of bodily self may affect mirroring mechanisms. We used somatosensory event-related potentials (SEPs) to investigate the temporal dynamics of mirroring highly self-related information (viewed touch on one's own face) compared to other-related information (viewed touch on a stranger's face), in individuals with low and high levels of depersonalisation, a mental condition characterised by feeling detached or estranged from one's self and body. For the low-depersonalisation group, mirroring for self-related events (P45) preceded mirroring for other-related events (N80). At later stages (P200), mirroring was stronger for other-related than self-related events. This shows that early, implicit and later, more cognitive processes play different relative roles in mirroring self- and other-related bodily events. Critically, mirroring differed in the high-depersonalisation group, specifically for self-related events. An absence of early, implicit mirroring for self-related events over P45 suggests that the associated processes may be the neural correlates of the disembodiment experienced in depersonalisation. A lack of differential mirroring for self- and other-related events over P200 may reflect compensatory mechanisms that redress deficiencies in mirroring at earlier stages, which may break down to give rise to symptoms of depersonalisation. Alternatively, or in addition, they may represent an attenuation of processes related to self-other distinction

Precision Optical Coatings for Large Space Telescope Mirrors

NASA Astrophysics Data System (ADS)

Sheikh, David

This proposal “Precision Optical Coatings for Large Space Telescope Mirrors” addresses the need to develop and advance the state-of-the-art in optical coating technology. NASA is considering large monolithic mirrors 1 to 8-meters in diameter for future telescopes such as HabEx and LUVOIR. Improved large area coating processes are needed to meet the future requirements of large astronomical mirrors. In this project, we will demonstrate a broadband reflective coating process for achieving high reflectivity from 90-nm to 2500-nm over a 2.3-meter diameter coating area. The coating process is scalable to larger mirrors, 6+ meters in diameter. We will use a battery-driven coating process to make an aluminum reflector, and a motion-controlled coating technology for depositing protective layers. We will advance the state-of-the-art for coating technology and manufacturing infrastructure, to meet the reflectance and wavefront requirements of both HabEx and LUVOIR. Specifically, we will combine the broadband reflective coating designs and processes developed at GSFC and JPL with large area manufacturing technologies developed at ZeCoat Corporation. Our primary objectives are to: Demonstrate an aluminum coating process to create uniform coatings over large areas with near-theoretical aluminum reflectance Demonstrate a motion-controlled coating process to apply very precise 2-nm to 5- nm thick protective/interference layers to large areas, Demonstrate a broadband coating system (90-nm to 2500-nm) over a 2.3-meter coating area and test it against the current coating specifications for LUVOIR/HabEx. We will perform simulated space-environment testing, and we expect to advance the TRL from 3 to >5 in 3-years.

Einstein's Mirror

ERIC Educational Resources Information Center

Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

2008-01-01

Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

ATLAST ULE mirror segment performance analytical predictions based on thermally induced distortions

NASA Astrophysics Data System (ADS)

Eisenhower, Michael J.; Cohen, Lester M.; Feinberg, Lee D.; Matthews, Gary W.; Nissen, Joel A.; Park, Sang C.; Peabody, Hume L.

2015-09-01

The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for a 9.2 m aperture space-borne observatory operating across the UV/Optical/NIR spectra. The primary mirror for ATLAST is a segmented architecture with pico-meter class wavefront stability. Due to its extraordinarily low coefficient of thermal expansion, a leading candidate for the primary mirror substrate is Corning's ULE® titania-silicate glass. The ATLAST ULE® mirror substrates will be maintained at `room temperature' during on orbit flight operations minimizing the need for compensation of mirror deformation between the manufacturing temperature and the operational temperatures. This approach requires active thermal management to maintain operational temperature while on orbit. Furthermore, the active thermal control must be sufficiently stable to prevent time-varying thermally induced distortions in the mirror substrates. This paper describes a conceptual thermal management system for the ATLAST 9.2 m segmented mirror architecture that maintains the wavefront stability to less than 10 pico-meters/10 minutes RMS. Thermal and finite element models, analytical techniques, accuracies involved in solving the mirror figure errors, and early findings from the thermal and thermal-distortion analyses are presented.

Double arch mirror study

NASA Technical Reports Server (NTRS)

Vukobratovich, D.; Hillman, D.

1983-01-01

The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

Mirror mount

DOEpatents

Kuklo, Thomas C.; Bender, Donald A.

1994-01-01

A unique lens or mirror mount having adjustable constraints at two key locations to allow for "X" and "Y" tilts of the mirror only. The device uses two pair of flexures of a type such that the pivots of the mirror gimble are rigidly fixed in all planes allowing the device to have zero stacking tolerance and zero wear over time.

A new simpler way to obtain high fusion power gain in tandem mirrors

NASA Astrophysics Data System (ADS)

Fowler, T. K.; Moir, R. W.; Simonen, T. C.

2017-05-01

From the earliest days of fusion research, Richard F. Post and other advocates of magnetic mirror confinement recognized that mirrors favor high ion temperatures where nuclear reaction rates < σ v> begin to peak for all fusion fuels. In this paper we review why high ion temperatures are favored, using Post’s axisymmetric Kinetically Stabilized Tandem Mirror as the example; and we offer a new idea that appears to greatly improve reactor prospects at high ion temperatures. The idea is, first, to take advantage of recent advances in superconducting magnet technology to minimize the size and cost of End Plugs; and secondly, to utilize parallel advances in gyrotrons that would enable intense electron cyclotron heating (ECH) in these high field End Plugs. The yin-yang magnets and thermal barriers that complicated earlier tandem mirror designs are not required. We find that, concerning end losses, intense ECH in symmetric End Plugs could increase the fusion power gain Q, for both DT and Catalyzed DD fuel cycles, to levels competitive with steady-state tokamaks burning DT fuel. Radial losses remain an issue that will ultimately determine reactor viability.

Silicon Carbide Technologies for Lightweighted Aerospace Mirrors

NASA Astrophysics Data System (ADS)

Matson, L.; Chen, M.; Deblonk, B.; Palusinski, I.

The use of monolithic glass and beryllium to produce lightweighted aerospace mirror systems has reached its limits due to the long lead times, high processing costs, environmental effects and launch load/weight requirements. New material solutions and manufacturing processes are required to meet DoD's directed energy weapons, reconnaissance/surveillance, and secured communications needs. Over the past several years the Air Force, MDA, and NASA has focused their efforts on the fabrication, lightweighting, and scale-up of numerous silicon carbide (SiC) based materials. It is anticipated that SiC can be utilized for most applications from cryogenic to high temperatures. This talk will focus on describing the SOA for these (near term) SiC technology solutions for making mirror structural substrates, figuring and finishing technologies being investigated to reduce cost time and cost, and non-destructive evaluation methods being investigated to help eliminate risk. Mirror structural substrates made out of advanced engineered materials (far term solutions) such as composites, foams, and microsphere arrays for ultra lightweighting will also be briefly discussed.

Amorphous Metals and Composites as Mirrors and Mirror Assemblies

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C. (Inventor); Davis, Gregory L. (Inventor); Agnes, Gregory S. (Inventor); Shapiro, Andrew A. (Inventor)

2016-01-01

A mirror or mirror assembly fabricated by molding, pressing, assembling, or depositing one or more bulk metal glass (BMG), bulk metal glass composite (BMGMC), or amorphous metal (AM) parts and where the optical surface and backing of the mirror can be fabricated without machining or polishing by utilizing the unique molding capabilities of this class of materials.

Optical magnetic mirrors without metals

DOE PAGES

Liu, Sheng; Sinclair, Michael B.; Mahony, Thomas S.; ...

2014-01-01

The reflection of an optical wave from metal, arising from strong interactions between the optical electric field and the free carriers of the metal, is accompanied by a phase reversal of the reflected electric field. A far less common route to achieving high reflectivity exploits strong interactions between the material and the optical magnetic field to produce a “magnetic mirror” that does not reverse the phase of the reflected electric field. At optical frequencies, the magnetic properties required for strong interaction can be achieved only by using artificially tailored materials. Here, we experimentally demonstrate, for the first time to themore » best of our knowledge, the magnetic mirror behavior of a low-loss all-dielectric metasurface at infrared optical frequencies through direct measurements of the phase and amplitude of the reflected optical wave. The enhanced absorption and emission of transverse-electric dipoles placed close to magnetic mirrors can lead to exciting new advances in sensors, photodetectors, and light sources.« less

Mirror mount

DOEpatents

Kuklo, T.C.; Bender, D.A.

1994-10-04

A unique lens or mirror mount having adjustable constraints at two key locations to allow for ''X'' and ''Y'' tilts of the mirror only is disclosed. The device uses two pair of flexures of a type such that the pivots of the mirror gimble are rigidly fixed in all planes allowing the device to have zero stacking tolerance and zero wear over time. 4 figs.

Research on a bimorph piezoelectric deformable mirror for adaptive optics in optical telescope.

PubMed

Wang, Hairen

2017-04-03

We have proposed a discrete-layout bimorph piezoelectric deformable mirror (DBPDM) and developed its realistic electromechanical model. Compared with the conventional piezoelectric deformable mirror (CPDM) and the bimorph piezoelectric deformable mirror (BPDM), the DBPDM has both a larger stroke and a higher resonance frequency by integrating the strengths of the CPDM and the BPDM. To verify the advancement, a 21-elements DBPDM is studied in this paper. The results have suggested that the stroke of the DBPDM is larger than 10 microns and its resonance frequency is 53.3 kHz. Furthermore, numerical simulation is conducted on the deformation of the mirror using the realistic electromechanical model, and the dependence of the influence function upon the size of the radius of push pad is analyzed.

Phase-Controlled Magnetic Mirror for Wavefront Correction

NASA Technical Reports Server (NTRS)

Hagopian, John; Wollack, Edward

2011-01-01

Typically, light interacts with matter via the electric field and interaction with weakly bound electrons. In a magnetic mirror, a patterned nanowire is fabricated over a metallic layer with a dielectric layer in between. Oscillation of the electrons in the nanowires in response to the magnetic field of incident photons causes a re-emission of photons and operation as a "magnetic mirror." By controlling the index of refraction in the dielectric layer using a local applied voltage, the phase of the emitted radiation can be controlled. This allows electrical modification of the reflected wavefront, resulting in a deformable mirror that can be used for wavefront control. Certain applications require wavefront quality in the few-nanometer regime, which is a major challenge for optical fabrication and alignment of mirrors or lenses. The use of a deformable magnetic mirror allows for a device with no moving parts that can modify the phase of incident light over many spatial scales, potentially with higher resolution than current approaches. Current deformable mirrors modify the incident wavefront by using nano-actuation of a substrate to physically bend the mirror to a desired shape. The purpose of the innovation is to modify the incident wavefront for the purpose of correction of fabrication and alignment-induced wavefront errors at the system level. The advanced degree of precision required for some applications such as gravity wave detection (LISA - Laser Interferometer Space Antenna) or planet finding (FKSI - Fourier-Kelvin Stellar Interferometer) requires wavefront control at the limits of the current state of the art. All the steps required to fabricate a magnetic mirror have been demonstrated. The modification is to apply a bias voltage to the dielectric layer so as to change the index of refraction and modify the phase of the reflected radiation. Light is reflected off the device and collected by a phase-sensing interferometer. The interferometer determines the

Optical integration of SPO mirror modules in the ATHENA telescope

NASA Astrophysics Data System (ADS)

Valsecchi, G.; Marioni, F.; Bianucci, G.; Zocchi, F. E.; Gallieni, D.; Parodi, G.; Ottolini, M.; Collon, M.; Civitani, M.; Pareschi, G.; Spiga, D.; Bavdaz, M.; Wille, E.

2017-08-01

ATHENA (Advanced Telescope for High-ENergy Astrophysics) is the next high-energy astrophysical mission selected by the European Space Agency for launch in 2028. The X-ray telescope consists of 1062 silicon pore optics mirror modules with a target angular resolution of 5 arcsec. Each module must be integrated on a 3 m structure with an accuracy of 1.5 arcsec for alignment and assembly. This industrial and scientific team is developing the alignment and integration process of the SPO mirror modules based on ultra-violet imaging at the 12 m focal plane. This technique promises to meet the accuracy requirement while, at the same time, allowing arbitrary integration sequence and mirror module exchangeability. Moreover, it enables monitoring the telescope point spread function during the planned 3-year integration phase.

Verification procedure for the wavefront quality of the primary mirrors for the MRO interferometer

NASA Astrophysics Data System (ADS)

Bakker, Eric J.; Olivares, Andres; Schmell, Reed A.; Schmell, Rodney A.; Gartner, Darren; Jaramillo, Anthony; Romero, Kelly; Rael, Andres; Lewis, Jeff

2009-08-01

We present the verification procedure for the 1.4 meter primary mirrors of the Magdalena Ridge Observatory Interferometer (MROI). Six mirrors are in mass production at Optical Surface Technologies (OST) in Albuquerque. The six identical parabolic mirrors will have a radius of curvature of 6300 mm and a final surface wavefront quality of 29 nm rms. The mirrors will be tested in a tower using a computer generated hologram, and the Intellium⢠H2000 interferometer from Engineering Synthesis Design, Inc. (ESDI). The mirror fabrication activities are currently in the early stage of polishing and have already delivered some promising results with the interferometer. A complex passive whiffle tree has been designed and fabricated by Advanced Mechanical and Optical Systems (AMOS, Belgium) that takes into account the gravity loading for an alt-alt mount. The final testing of the primary mirrors will be completed with the mirror cells that will be used in the telescopes. In addition we report on shear tests performed on the mirror cell pads on the back of the primary mirrors. These pads are glued to the mirror. The shear test has demonstrated that the glue can withstand at least 4.9 kilo Newton. This is within the requirements.

The first aluminum coating of the 3700mm primary mirror of the Devasthal Optical Telescope

NASA Astrophysics Data System (ADS)

Bheemireddy, Krishna Reddy; Gopinathan, Maheswar; Pant, Jayshreekar; Omar, Amitesh; Kumar, Brijesh; Uddin, Wahab; Kumar, Nirmal

2016-07-01

Initially the primary mirror of the 3.6m Devasthal Optical Telescope is uncoated polished zerodur glass supplied by Lytkarino Optical Glass Factory, Russia/Advanced Mechanical and Optical Systems, Belgium. In order to do the aluminium coating on the primary mirror the coating plant including washing unit is installed near the telescope (extension building of telescope) by Hind High Vacuum (HHV) Bangalore, India. Magnetron sputtering technique is used for the coating. Several coating trials are done before the primary mirror coating; samples are tested for reflectivity, uniformity, adhesivity and finally commissioned. The primary mirror is cleaned, coated by ARIES. We present here a brief description of the coating plant installation, Mirror cleaning and coating procedures and the testing results of the samples.

Assessing Human Mirror Activity With EEG Mu Rhythm: A Meta-Analysis

PubMed Central

Fox, Nathan A.; Bakermans-Kranenburg, Marian J.; Yoo, Kathryn H.; Bowman, Lindsay C.; Cannon, Erin N.; Vanderwert, Ross E.; Ferrari, Pier F.; van IJzendoorn, Marinus H.

2016-01-01

A fundamental issue in cognitive neuroscience is how the brain encodes others’ actions and intentions. In recent years, a potential advance in our knowledge on this issue is the discovery of mirror neurons in the motor cortex of the nonhuman primate. These neurons fire to both execution and observation of specific types of actions. Researchers use this evidence to fuel investigations of a human mirror system, suggesting a common neural code for perceptual and motor processes. Among the methods used for inferring mirror system activity in humans are changes in a particular frequency band in the electroencephalogram (EEG) called the mu rhythm. Mu frequency appears to decrease in amplitude (reflecting cortical activity) during both action execution and action observation. The current meta-analysis reviewed 85 studies (1,707 participants) of mu that infer human mirror system activity. Results demonstrated significant effect sizes for mu during execution (Cohen’s d = 0.46, N = 701) as well as observation of action (Cohen’s d = 0.31, N = 1,508), confirming a mirroring property in the EEG. A number of moderators were examined to determine the specificity of these effects. We frame these meta-analytic findings within the current discussion about the development and functions of a human mirror system, and conclude that changes in EEG mu activity provide a valid means for the study of human neural mirroring. Suggestions for improving the experimental and methodological approaches in using mu to study the human mirror system are offered. PMID:26689088

Next generation lightweight mirror modeling software

NASA Astrophysics Data System (ADS)

Arnold, William R.; Fitzgerald, Matthew; Rosa, Rubin Jaca; Stahl, H. Philip

2013-09-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 3-5 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any text editor, all the shell thickness parameters and suspension spring rates are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite

Next-Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, Phil

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models possible

Next Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William; Fitzgerald, Matthew; Stahl, Philip

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models possible.

Next Generation Lightweight Mirror Modeling Software

NASA Technical Reports Server (NTRS)

Arnold, William R., Sr.; Fitzgerald, Mathew; Rosa, Rubin Jaca; Stahl, H. Philip

2013-01-01

The advances in manufacturing techniques for lightweight mirrors, such as EXELSIS deep core low temperature fusion, Corning's continued improvements in the Frit bonding process and the ability to cast large complex designs, combined with water-jet and conventional diamond machining of glasses and ceramics has created the need for more efficient means of generating finite element models of these structures. Traditional methods of assembling 400,000 + element models can take weeks of effort, severely limiting the range of possible optimization variables. This paper will introduce model generation software developed under NASA sponsorship for the design of both terrestrial and space based mirrors. The software deals with any current mirror manufacturing technique, single substrates, multiple arrays of substrates, as well as the ability to merge submodels into a single large model. The modeler generates both mirror and suspension system elements, suspensions can be created either for each individual petal or the whole mirror. A typical model generation of 250,000 nodes and 450,000 elements only takes 5-10 minutes, much of that time being variable input time. The program can create input decks for ANSYS, ABAQUS and NASTRAN. An archive/retrieval system permits creation of complete trade studies, varying cell size, depth, and petal size, suspension geometry with the ability to recall a particular set of parameters and make small or large changes with ease. The input decks created by the modeler are text files which can be modified by any editor, all the key shell thickness parameters are accessible and comments in deck identify which groups of elements are associated with these parameters. This again makes optimization easier. With ANSYS decks, the nodes representing support attachments are grouped into components; in ABAQUS these are SETS and in NASTRAN as GRIDPOINT SETS, this make integration of these models into large telescope or satellite models easier.

Mirrors design, analysis and manufacturing of the 550mm Korsch telescope experimental model

NASA Astrophysics Data System (ADS)

Huang, Po-Hsuan; Huang, Yi-Kai; Ling, Jer

2017-08-01

In 2015, NSPO (National Space Organization) began to develop the sub-meter resolution optical remote sensing instrument of the next generation optical remote sensing satellite which follow-on to FORMOSAT-5. Upgraded from the Ritchey-Chrétien Cassegrain telescope optical system of FORMOSAT-5, the experimental optical system of the advanced optical remote sensing instrument was enhanced to an off-axis Korsch telescope optical system which consists of five mirrors. It contains: (1) M1: 550mm diameter aperture primary mirror, (2) M2: secondary mirror, (3) M3: off-axis tertiary mirror, (4) FM1 and FM2: two folding flat mirrors, for purpose of limiting the overall volume, reducing the mass, and providing a long focal length and excellent optical performance. By the end of 2015, we implemented several important techniques including optical system design, opto-mechanical design, FEM and multi-physics analysis and optimization system in order to do a preliminary study and begin to develop and design these large-size lightweight aspheric mirrors and flat mirrors. The lightweight mirror design and opto-mechanical interface design were completed in August 2016. We then manufactured and polished these experimental model mirrors in Taiwan; all five mirrors ware completed as spherical surfaces by the end of 2016. Aspheric figuring, assembling tests and optical alignment verification of these mirrors will be done with a Korsch telescope experimental structure model in 2018.

By the Dozen: NASA's James Webb Space Telescope Mirrors

NASA Image and Video Library

2017-12-08

tennis-court-sized sunshield are the largest and most visible components of the Webb telescope. However, there are four smaller components that are less visible, yet critical. The instruments that will fly aboard Webb - cameras and spectrographs with detectors able to record extremely faint signals — are part of the Integrated Science Instrument Module (ISIM), which is currently undergoing its final cryogenic vacuum test and will be integrated with the mirror later this year. Read more: www.nasa.gov/feature/goddard/2016/by-the-dozen-nasas-jame... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

By the Dozen: NASA's James Webb Space Telescope Mirrors

NASA Image and Video Library

2016-01-07

-court-sized sunshield are the largest and most visible components of the Webb telescope. However, there are four smaller components that are less visible, yet critical. The instruments that will fly aboard Webb - cameras and spectrographs with detectors able to record extremely faint signals — are part of the Integrated Science Instrument Module (ISIM), which is currently undergoing its final cryogenic vacuum test and will be integrated with the mirror later this year. Read more: www.nasa.gov/feature/goddard/2016/by-the-dozen-nasas-jame... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Relating the "mirrorness" of mirror neurons to their origins.

PubMed

Kilner, James M; Friston, Karl J

2014-04-01

Ever since their discovery, mirror neurons have generated much interest and debate. A commonly held view of mirror neuron function is that they transform "visual information into knowledge," thus enabling action understanding and non-verbal social communication between con-specifics (Rizzolatti & Craighero 2004). This functionality is thought to be so important that it has been argued that mirror neurons must be a result of selective pressure.

[Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

PubMed

Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

2012-08-01

The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.

Pancreatic cancer ascites xenograft–an expeditious model mirroring advanced therapeutic resistant disease

PubMed Central

Schvimer, Michael; Atias, Dikla; Halperin, Sharon; Buzhor, Ella; Raitses-Gurevich, Maria; Cohen, Keren; Pri-Chen, Sara; Wilson, Julie; Denroche, Robert E.; Lungu, Ilinca; Bartlett, John M.S.; Mbabaali, Faridah; Yarden, Yosef; Nataraj, Nishanth Belugali; Gallinger, Steven; Berger, Raanan

2017-01-01

Pancreatic ductal adenocarcinoma has limited treatment options. There is an urgent need for developing appropriate pre-clinical models recapitulating metastatic disease, the most common clinical scenario at presentation. Ascites accumulation occurs in up to 20–30% of patients with pancreatic cancer; this milieu represents a highly cellular research resource of metastatic peritoneal spread. In this study, we utilized pancreatic ascites/pleural effusion cancer cells to establish patient derived xenografts. Ascites/pleural effusion-patient derived xenografts were established from twelve independent cases. Xenografts were serially passed in nude mice and tissue bio-specimen banking has been established. Histopathology of emergent tumors demonstrates poorly to moderately differentiated, glandular and mucin producing tumors, mirroring morphology of primary pancreatic cancer tumors. Whole genome sequencing of six patient derived xenografts samples demonstrates common mutations and structural variations similar to those reported in primary pancreatic cancer. Xenograft tumors were dissociated to single-cells and in-vitro drug sensitivity screen assays demonstrated chemo-resistance, correlating with patient clinical scenarios, thus serving as a platform for clinically relevant translational research. Therefore, establishment of this novel ascites/pleural effusion patient derived xenograft model, with extensive histopathology and genomic characterization, opens an opportunity for the study of advanced aggressive pancreatic cancer. Characterization of metastatic disease and mechanisms of resistance to therapeutics may lead to the development of novel drug combinations. PMID:28489577

Status of Mirror Technology for the Next Generation Space Telescope

NASA Astrophysics Data System (ADS)

Jacobson, D. N.

2000-10-01

establish credibility that the goals of NGST could be achieved. The past two years of the program has seen major steps in the development of several mirror materials, which not only might have NGST applicability but could also support other programs for other customers. Additionally, a second large mirror procurement, the Advanced Mirror System Demonstrator (AMSD), has been implemented providing a focal point to complete the mirror technology development and lead ultimately to the production of mirrors that will fly on NEXUS (NGST flight experimentand) and NGST. This talk will focus on a status of the mirror technology developed over the past 4 years on the NGST program.

NASA Webb Mirror is 'CIAF' and Sound

NASA Image and Video Library

2017-12-08

A James Webb Space Telescope flight spare primary mirror segment is loaded onto the CMM (Configuration Measurement Machine) at the CIAF (Calibration, Integration and Alignment Facility) at NASA's Goddard Space Flight Center in Greenbelt, Md. The CMM is used for precision measurements of the mirrors. These precision measurements must be accurate to 0.1 microns or 1/400th the thickness of a human hair. Image credit: NASA/Goddard/Chris Gunn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Fabrication of near-net shape graphite/magnesium composites for large mirrors

NASA Astrophysics Data System (ADS)

Wendt, Robert; Misra, Mohan

1990-10-01

Successful development of space-based surveillance and laser systems will require large precision mirrors which are dimensionally stable under thermal, static, and dynamic (i.e., structural vibrations and retargeting) loading conditions. Among the advanced composites under consideration for large space mirrors, graphite fiber reinforced magnesium (Gr/Mg) is an ideal candidate material that can be tailored to obtain an optimum combination of properties, including a high modulus of elasticity, zero coefficient of thermal expansion, low density, and high thermal conductivity. In addition, an innovative technique, combining conventional filament winding and vacuum casting has been developed to produce near-net shape Gr/Mg composites. This approach can significantly reduce the cost of fabricating large mirrors by decreasing required machining. However, since Gr/Mg cannot be polished to a reflective surface, plating is required. This paper will review research at Martin Marietta Astronautics Group on Gr/Mg mirror blank fabrication and measured mechanical and thermal properties. Also, copper plating and polishing methods, and optical surface characteristics will be presented.

Mirrors, Mirrors on the Wall...The Ubiquitous Multiple Reflection Error

ERIC Educational Resources Information Center

Lawson, Rebecca

2012-01-01

Participants decided when somebody, Janine, could see their face in a horizontal row of adjacent mirrors mounted flat on the same wall. They saw real mirrors and a shop-dummy representing Janine. Such coplanar mirrors reflect different, non-overlapping areas of a scene. However, almost everybody made an unexpected error: they claimed that Janine…

Castable Amorphous Metal Mirrors and Mirror Assemblies

NASA Technical Reports Server (NTRS)

Hofmann, Douglas C.; Davis, Gregory L.; Agnes, Gregory S.; Shapiro, Andrew A.

2013-01-01

A revolutionary way to produce a mirror and mirror assembly is to cast the entire part at once from a metal alloy that combines all of the desired features into the final part: optical smoothness, curvature, flexures, tabs, isogrids, low CTE, and toughness. In this work, it has been demonstrated that castable mirrors are possible using bulk metallic glasses (BMGs, also called amorphous metals) and BMG matrix composites (BMGMCs). These novel alloys have all of the desired mechanical and thermal properties to fabricate an entire mirror assembly without machining, bonding, brazing, welding, or epoxy. BMGs are multi-component metal alloys that have been cooled in such a manner as to avoid crystallization leading to an amorphous (non-crystalline) microstructure. This lack of crystal structure and the fact that these alloys are glasses, leads to a wide assortment of mechanical and thermal properties that are unlike those observed in crystalline metals. Among these are high yield strength, carbide-like hardness, low melting temperatures (making them castable like aluminum), a thermoplastic processing region (for improving smoothness), low stiffness, high strength-to-weight ratios, relatively low CTE, density similar to titanium alloys, high elasticity and ultra-smooth cast parts (as low as 0.2-nm surface roughness has been demonstrated in cast BMGs). BMGMCs are composite alloys that consist of a BMG matrix with crystalline dendrites embedded throughout. BMGMCs are used to overcome the typically brittle failure observed in monolithic BMGs by adding a soft phase that arrests the formation of cracks in the BMG matrix. In some cases, BMGMCs offer superior castability, toughness, and fatigue resistance, if not as good a surface finish as BMGs. This work has demonstrated that BMGs and BMGMCs can be cast into prototype mirrors and mirror assemblies without difficulty.

Status of the secondary mirrors (M2) for the Gemini 8-m telescopes

NASA Astrophysics Data System (ADS)

Knohl, Ernst-Dieter; Schoeppach, Armin; Pickering, Michael A.

1998-08-01

The 1-m diameter lightweight secondary mirrors (M2) for the Gemini 8-m telescopes will be the largest CVD-SiC mirrors ever produced. The design and manufacture of these mirrors is a very challenging task. In this paper we will discuss the mirror design, structural and mechanical analysis, and the CVD manufacturing process used to produce the mirror blanks. The lightweight design consist of a thin faceplate (4-mm) and triangular backstructure cells with ribs of varying heights. The main drivers in the design were weight (40 kg) and manufacturing limitations imposed on the backstructure cells and mirror mounts. Finite element modeling predicts that the mirror design will meet all of the Gemini M2 requirements for weight, mechanical integrity, resonances, and optical performance. Special design considerations were necessary to avoid stress concentration in the mounting areas and to meet the requirement that the mirror survive an 8-g earthquake. The highest risk step in the mirror blank manufacturing process is the near-net-shape CVD deposition of the thin, curved faceplate. Special tooling and procedures had to be developed to produce faceplates free of fractures, cracks, and stress during the cool-down from deposition temperature (1350 C) to room temperature. Due to time delay with the CVD manufacturing process in the meantime a backup solution from Zerodur has been started. This mirror is now in the advanced polishing process. Because the design of both mirrors is very similar an excellent comparison of both solutions is possible.

Mirror mount

DOEpatents

Humpal, H.H.

1987-11-10

A mirror mount is provided that allows free pitch, yaw and roll motion of the mirror while keeping the location of a point on the surface of the mirror fixed in the rest frame of reference of the mount. Yaw movement is provided by two yaw cylinders that are bearing mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell that is air bearing mounted to move between a clamp and an upper pedestal bearing. The centers of curvature of the spherical surfaces of the shell lie upon the point. Pitch motion and roll motion are separately and independently imparted to mirror by a pair of pitch paddles and a pair of roll paddles that are independently and separately moved by control rods driven by motors. 5 figs.

Mirror mount

DOEpatents

Humpal, H.H.

1986-03-21

A mirror mount is provided that allows free pitch, yaw and roll motion of the mirror while keeping the location of a point on the surface of the mirror fixed in the rest frame of reference of the mount. Yaw movement is provided by two yaw cylinders that are bearing mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell that is air bearing mounted to move between a clamp and an upper pedestal bearing. The centers of curvature of the spherical surfaces of the shell lie upon the point. Pitch motion and roll motion are separately and independently imparted to mirror by a pair of pitch paddles and a pair of roll paddles that are independently and separately moved by control rods driven by motors.

Study Of Pre-Shaped Membrane Mirrors And Electrostatic Mirrors With Nonlinear-Optical Correction

DTIC Science & Technology

2002-01-01

mirrors have been manufactured of glass-like material Zerodur with very low coefficient of linear expansion. They have a more light cellular construction...primary and flat secondary mirrors are both segmented ones. In the case of the primary mirror made of traditional materials such as Zerodur or fused...FINAL REPORT ISTC Project #2103p “Study of Pre-Shaped Membrane Mirrors and Electrostatic Mirrors with Nonlinear-Optical Correction” Manager

Scaling laws for light weight optics, studies of light weight mirrors mounting and dynamic mirror stress, and light weight mirror and mount designs

NASA Technical Reports Server (NTRS)

Vukobratovich, Daniel; Richard, Ralph M.; Valente, Tina M.; Cho, Myung K.

1990-01-01

Scaling laws for light-weight optical systems are examined. A cubic relationship between mirror diameter and weight has been suggested and used by many designers of optical systems as the best description for all light-weight mirrors. A survey of existing light-weight systems in the open literature was made to clarify this issue. Fifty existing optical systems were surveyed with all varieties of light-weight mirrors including glass and beryllium structured mirrors, contoured mirrors, and very thin solid mirrors. These mirrors were then categorized and weight to diameter ratio was plotted to find a best curve for each case. A best fitting curve program tests nineteen different equations and ranks a goodness-to-fit for each of these equations. The resulting relationship found for each light-weight mirror category helps to quantify light-weight optical systems and methods of fabrication and provides comparisons between mirror types.

Being "Secondary" is Important for a Webb Telescope Mirror

NASA Image and Video Library

2017-12-08

NASA release July 19, 2011 Click here to learn about the James Webb Space Telescope The secondary mirror (shown here) was polished at the L3 Integrated Optical Systems - Tinsley in Richmond, Calif. to accuracies of less than one millionth of an inch. That accuracy is important for forming the sharpest images when the mirrors cool to -400°F (-240°C) in the cold of space. The Webb's secondary mirror was recently completed, following polishing and gold-coating. "Secondary" may not sound as important as "primary" but when it comes to the next-generation James Webb Space Telescope a secondary mirror plays a critical role in ensuring the telescope gathers information from the cosmos. The Webb's secondary mirror was recently completed, following polishing and gold-coating. There are four different types of mirrors that will fly on the James Webb Space Telescope, and all are made of a light metal called beryllium. It is very strong for its weight and holds its shape across a range of temperatures. There are primary mirror segments (18 total that combined make the large primary mirror providing a collecting area of 25 meters squared/269.1 square feet), the secondary mirror, tertiary mirror and the fine steering mirror. Unlike the primary mirror, which is molded into the shape of a hexagon, the secondary mirror is perfectly rounded. The mirror is also convex, so the reflective surface bulges toward a light source. It looks much like a curved mirror that you'll see on the wall near the exit of a parking garage that lets motorists see around a corner. This mirror is coated with a microscopic layer of gold to enable it to efficiently reflect infrared light (which is what the Webb telescope's cameras see). The quality of the secondary mirror surface is so good that the final convex surface at cold temperatures does not deviate from the design by more than a few millionths of a millimeter - or about one ten thousandth the diameter of a human hair. "As the only convex mirror on

Arc Second Alignment of International X-Ray Observatory Mirror Segments in a Fixed Structure

NASA Technical Reports Server (NTRS)

Evans, Tyler C.; Chan, Kai-Wing

2009-01-01

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc seconds. These mirror segments are 0.4mm thick, and 200 to 400mm in size, which makes it hard not to impart distortion at the subarc second level. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of transferring thin mirror segments from a temporary mount to a fixed structure with arc second alignment and minimal figure distortion. Recent advances in technology development in addition to the automation of several processes have produced significant results. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced.

Arc-Second Alignment of International X-Ray Observatory Mirror Segments in a Fixed Structure

NASA Technical Reports Server (NTRS)

Evans, Tyler C.; Chan, Kai-Wing; Saha, Timo T.

2010-01-01

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc-seconds. These mirror segments are 0.4 mm thick, and 200 to 400 mm in size, which makes it hard not to impart distortion at the subare- second level. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of transferring thin mirror segments from a temporary mount to a fixed structure with arc-second alignment and minimal figure distortion. Recent advances in technology development in addition to the automation of several processes have produced significant results. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced.

Mirror and (absence of) counter-mirror responses to action sounds measured with TMS.

PubMed

Ticini, Luca F; Schütz-Bosbach, Simone; Waszak, Florian

2017-11-01

To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed 'mirror' and 'counter-mirror' trainings (a 'mirror' training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. © The Author (2017). Published by Oxford University Press.

Cost effective aluminum beryllium mirrors for critical optics applications

NASA Astrophysics Data System (ADS)

Say, Carissa; Duich, Jack; Huskamp, Chris; White, Ray

2013-09-01

The unique performance of aluminum-beryllium frequently makes it an ideal material for manufacturing precision optical-grade metal mirrors. Traditional methods of manufacture utilize hot-pressed powder block in billet form which is subsequently machined to final dimensions. Complex component geometries such as lightweighted, non-plano mirrors require extensive tool path programming, fixturing, and CNC machining time and result in a high buy-to-fly ratio (the ratio of the mass of raw material purchased to the mass of the finished part). This increases the cost of the mirror structure as a significant percentage of the procurement cost is consumed in the form of machining, tooling, and scrap material that do not add value to the final part. Inrad Optics, Inc. and IBC Advanced Alloys Corp. undertook a joint study to evaluate the suitability of investment-cast Beralcast® 191 and 363 aluminum-beryllium as a precision mirror substrate material. Net shape investment castings of the desired geometry minimizes machining to just cleanup stock, thereby reducing the recurring procurement cost while still maintaining performance. The thermal stability of two mirrors, (one each of Beralcast® 191 and Beralcast® 363), was characterized from -40°F to +150°F. A representative pocketed mirror was developed, including the creation of a relevant geometry and production of a cast component to validate the approach. Information from the demonstration unit was used as a basis for a comparative cost study of the representative mirror produced in Beralcast® and one machined from a billet of AlBeMet® 162 (AlBeMet® is a registered trademark of Materion Corporation). The technical and financial results of these studies will be discussed in detail.

Fabrication of the LSST monolithic primary-tertiary mirror

NASA Astrophysics Data System (ADS)

Tuell, Michael T.; Martin, Hubert M.; Burge, James H.; Ketelsen, Dean A.; Law, Kevin; Gressler, William J.; Zhao, Chunyu

2012-09-01

As previously reported (at the SPIE Astronomical Instrumentation conference of 2010 in San Diego1), the Large Synoptic Survey Telescope (LSST) utilizes a three-mirror design in which the primary (M1) and tertiary (M3) mirrors are two concentric aspheric surfaces on one monolithic substrate. The substrate material is Ohara E6 borosilicate glass, in a honeycomb sandwich configuration, currently in production at The University of Arizona’s Steward Observatory Mirror Lab. We will provide an update to the status of the mirrors and metrology systems, which have advanced from concepts to hardware in the past two years. In addition to the normal requirements for smooth surfaces of the appropriate prescriptions, the alignment of the two surfaces must be accurately measured and controlled in the production lab, reducing the degrees of freedom needed to be controlled in the telescope. The surface specification is described as a structure function, related to seeing in excellent conditions. Both the pointing and centration of the two optical axes are important parameters, in addition to the axial spacing of the two vertices. This paper details the manufacturing process and metrology systems for each surface, including the alignment of the two surfaces. M1 is a hyperboloid and can utilize a standard Offner null corrector, whereas M3 is an oblate ellipsoid, so it has positive spherical aberration. The null corrector is a phase-etched computer-generated hologram (CGH) between the mirror surface and the center-of-curvature. Laser trackers are relied upon to measure the alignment and spacing as well as rough-surface metrology during looseabrasive grinding.

The mirror neuron system.

PubMed

Cattaneo, Luigi; Rizzolatti, Giacomo

2009-05-01

Mirror neurons are a class of neurons, originally discovered in the premotor cortex of monkeys, that discharge both when individuals perform a given motor act and when they observe others perform that same motor act. Ample evidence demonstrates the existence of a cortical network with the properties of mirror neurons (mirror system) in humans. The human mirror system is involved in understanding others' actions and their intentions behind them, and it underlies mechanisms of observational learning. Herein, we will discuss the clinical implications of the mirror system.

The Webb Telescope's Actuators: Curving Mirrors in Space

NASA Image and Video Library

2017-12-08

NASA image release December 9, 2010 Caption: The James Webb Space Telescope's Engineering Design Unit (EDU) primary mirror segment, coated with gold by Quantum Coating Incorporated. The actuator is located behind the mirror. Credit: Photo by Drew Noel NASA's James Webb Space Telescope is a wonder of modern engineering. As the planned successor to the Hubble Space telescope, even the smallest of parts on this giant observatory will play a critical role in its performance. A new video takes viewers behind the Webb's mirrors to investigate "actuators," one component that will help Webb focus on some of the earliest objects in the universe. The video called "Got Your Back" is part of an on-going video series about the Webb telescope called "Behind the Webb." It was produced at the Space Telescope Science Institute (STScI) in Baltimore, Md. and takes viewers behind the scenes with scientists and engineers who are creating the Webb telescope's components. During the 3 minute and 12 second video, STScI host Mary Estacion interviewed people involved in the project at Ball Aerospace in Boulder, Colo. and showed the actuators in action. The Webb telescope will study every phase in the history of our universe, ranging from the first luminous glows after the big bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own solar system. Measuring the light this distant light requires a primary mirror 6.5 meters (21 feet 4 inches) across – six times larger than the Hubble Space telescope’s mirror! Launching a mirror this large into space isn’t feasible. Instead, Webb engineers and scientists innovated a unique solution – building 18 mirrors that will act in unison as one large mirror. These mirrors are packaged together into three sections that fold up - much easier to fit inside a rocket. Each mirror is made from beryllium and weighs approximately 20 kilograms (46 pounds). Once in space, getting these mirrors to

Water Cooled Mirror Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dale, Gregory E.; Holloway, Michael Andrew; Pulliam, Elias Noel

2015-03-30

This design is intended to replace the current mirror setup being used for the NorthStar Moly 99 project in order to monitor the target coupon. The existing setup has limited movement for camera alignment and is difficult to align properly. This proposed conceptual design for a water cooled mirror will allow for greater thermal transfer between the mirror and the water block. It will also improve positioning of the mirror by using flexible vacuum hosing and a ball head joint capable of a wide range of motion. Incorporating this design into the target monitoring system will provide more efficient coolingmore » of the mirror which will improve the amount of diffraction caused by the heating of the mirror. The process of aligning the mirror for accurate position will be greatly improved by increasing the range of motion by offering six degrees of freedom.« less

Design of optical mirror structures

NASA Technical Reports Server (NTRS)

Soosaar, K.

1971-01-01

The structural requirements for large optical telescope mirrors was studied with a particular emphasis placed on the three-meter Large Space Telescope primary mirror. Analysis approaches through finite element methods were evaluated with the testing and verification of a number of element types suitable for particular mirror loadings and configurations. The environmental conditions that a mirror will experience were defined and a candidate list of suitable mirror materials with their properties compiled. The relation of the mirror mechanical behavior to the optical performance is discussed and a number of suitable design criteria are proposed and implemented. A general outline of a systematic method to obtain the best structure for the three-meter diffraction-limited system is outlined. Finite element programs, using the STRUDL 2 analysis system, were written for specific mirror structures encompassing all types of active and passive mirror designs. Parametric studies on support locations, effects of shear deformation, diameter to thickness ratios, lightweight and sandwich mirror configurations, and thin shell active mirror needs were performed.

Cosmology with liquid mirror telescopes

NASA Technical Reports Server (NTRS)

Hogg, David W.; Gibson, Brad K.; Hickson, Paul

1993-01-01

Liquid mirrors provide an exciting means to obtain large optical telescopes for substantially lower costs than conventional technologies. The liquid mirror concept has been demonstrated in the lab with the construction of a diffraction limited 1.5 m mirror. The mirror surface, using liquid mercury, forms a perfect parabolic shape when the mirror cell is rotated at a uniform velocity. A liquid mirror must be able to support a heavy mercury load with minimal flexure and have a fundamental resonant frequency that is as high as possible, to suppress the amplitude of surface waves caused by small vibrations transmitted to the mirror. To minimize the transmission of vibrations to the liquid surface, the entire mirror rests on an air bearing. This necessitates the mirror cell being lightweight, due to the limited load capabilities of the air bearing. The mirror components must also have physical characteristics which minimize the effects of thermal expansion with ambient temperature fluctuations in the observatory. In addition, the 2.7 m mirror construction is designed so that the techniques used may be readily extended to the construction of large mirrors. To attain the goals of a lightweight, rigid mirror, a composite laminant construction was used. The mirror consists of a foam core cut to the desired parabolic shape, with an accuracy of a few mm. An aluminum hub serves as an anchor for the foam and skin, and allows precise centering of the mirror on the air bearing and drive system. Several plys of Kevlar, covered in an epoxy matrix, are then applied to the foam. A final layer of pure epoxy is formed by spin casting. This final layer is parabolic to within a fraction of a mm. An aluminum ring bonded to the circumference of the mirror retains the mercury, and incorporates stainless-steel hard-points for the attachment of balance weights.

MSFC Test Results for Selected Mirrors: Brush-Wellman/Goodrich 0.5 meter Joined-Beryllium Mirror; IABG 0.5 meter C/SiC Mirror; Xinetics 0.5 meter SiC Mirror; and Kodak 0.23 meter SiO2 Mirror

NASA Technical Reports Server (NTRS)

Hadaway, James; Blackwell, Lisa; Matthews, Gary; Eng, Ron; Stahl, Phil; Hraba, John; Thornton, Gary

2002-01-01

The results of cryo tests performed at the XRCF on the above mirrors will be presented. Each mirror was tested from room-temperature to around 30 K. The first three were tested together on a 3-mirror stand in the large chamber using the PhaseCam interferometer, while the Kodak mirror was tested in the small chamber using the EPI interferometer.

Ion beam figuring of highly steep mirrors with a 5-axis hybrid machine tool

NASA Astrophysics Data System (ADS)

Yin, Xiaolin; Tang, Wa; Hu, Haixiang; Zeng, Xuefeng; Wang, Dekang; Xue, Donglin; Zhang, Feng; Deng, Weijie; Zhang, Xuejun

2018-02-01

Ion beam figuring (IBF) is an advanced and deterministic method for optical mirror surface processing. The removal function of IBF varies with the different incident angles of ion beam. Therefore, for the curved surface especially the highly steep one, the Ion Beam Source (IBS) should be equipped with 5-axis machining capability to remove the material along the normal direction of the mirror surface, so as to ensure the stability of the removal function. Based on the 3-RPS parallel mechanism and two dimensional displacement platform, a new type of 5-axis hybrid machine tool for IBF is presented. With the hybrid machine tool, the figuring process of a highly steep fused silica spherical mirror is introduced. The R/# of the mirror is 0.96 and the aperture is 104mm. The figuring result shows that, PV value of the mirror surface error is converged from 121.1nm to32.3nm, and RMS value 23.6nm to 3.4nm.

Adaptive optics using a MEMS deformable mirror for a segmented mirror telescope

NASA Astrophysics Data System (ADS)

Miyamura, Norihide

2017-09-01

For small satellite remote sensing missions, a large aperture telescope more than 400mm is required to realize less than 1m GSD observations. However, it is difficult or expensive to realize the large aperture telescope using a monolithic primary mirror with high surface accuracy. A segmented mirror telescope should be studied especially for small satellite missions. Generally, not only high accuracy of optical surface but also high accuracy of optical alignment is required for large aperture telescopes. For segmented mirror telescopes, the alignment is more difficult and more important. For conventional systems, the optical alignment is adjusted before launch to achieve desired imaging performance. However, it is difficult to adjust the alignment for large sized optics in high accuracy. Furthermore, thermal environment in orbit and vibration in a launch vehicle cause the misalignments of the optics. We are developing an adaptive optics system using a MEMS deformable mirror for an earth observing remote sensing sensor. An image based adaptive optics system compensates the misalignments and wavefront aberrations of optical elements using the deformable mirror by feedback of observed images. We propose the control algorithm of the deformable mirror for a segmented mirror telescope by using of observed image. The numerical simulation results and experimental results show that misalignment and wavefront aberration of the segmented mirror telescope are corrected and image quality is improved.

Laser correcting mirror

DOEpatents

Sawicki, Richard H.

1994-01-01

An improved laser correction mirror (10) for correcting aberrations in a laser beam wavefront having a rectangular mirror body (12) with a plurality of legs (14, 16, 18, 20, 22, 24, 26, 28) arranged into opposing pairs (34, 36, 38, 40) along the long sides (30, 32) of the mirror body (12). Vector force pairs (49, 50, 52, 54) are applied by adjustment mechanisms (42, 44, 46, 48) between members of the opposing pairs (34, 36, 38, 40) for bending a reflective surface 13 of the mirror body 12 into a shape defining a function which can be used to correct for comatic aberrations.

Mirror mount

DOEpatents

Humpal, Harold H.

1987-01-01

A mirror mount (10) is provided that allows free pitch, yaw and roll motion of the mirror (28) while keeping the location of a point (56) on the surface of the mirror (28) fixed in the rest frame of reference of the mount (10). Yaw movement is provided by two yaw cylinders (30,32) that are bearing (52) mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell (42) that is air bearing (72,74) mounted to move between a clamp (60) and an upper pedestal bearing (44). The centers of curvature of the spherical surfaces of the shell (42) lie upon the point (56). Pitch motion and roll motion are separately and independently imparted to mirror (28) by a pair of pitch paddles (34) and a pair of roll paddles (36) that are independently and separately moved by control rods (76,80) driven by motors (78,82).

Durable solar mirror films

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.

The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

Durable solar mirror films

DOEpatents

O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

2017-02-14

The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

Alignment and Distortion-Free Integration of Lightweight Mirrors into Meta-Shells for High-Resolution Astronomical X-Ray Optics

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Zhang, William W.; Schofield, Mark J.; Numata, Ai; Mazzarella, James R.; Saha, Timo T.; Biskach, Michael P.; McCelland, Ryan S.; Niemeyer, Jason; Sharpe, Marton V.;

JWST Primary Mirror Tilt and Rollover Timelapse

NASA Image and Video Library

2017-12-08

On May 4th 2016 engineers at the Goddard Space Flight Center tilted the uncovered primary mirror of the James Webb Space Telescope upright and to a rollover position. In this rare timelapse video see inside the world's largest clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland as the James Webb Space Telescope team lifts and turns the telescope for the first time. With glimmering gold surfaces, the large primary and rounded secondary mirror on this telescope are specially designed to reflect infrared light from some of the first stars ever born. The team will now begin to prepare to install the telescope's science instruments to the back of the mirrors. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency. For more information, visit: www.jwst.nasa.gov or www.nasa.gov/webb Credit: NASA/Goddard NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Space Mirror Alignment System

NASA Technical Reports Server (NTRS)

Jau, Bruno M.; McKinney, Colin; Smythe, Robert F.; Palmer, Dean L.

2011-01-01

An optical alignment mirror mechanism (AMM) has been developed with angular positioning accuracy of +/-0.2 arcsec. This requires the mirror s linear positioning actuators to have positioning resolutions of +/-112 nm to enable the mirror to meet the angular tip/tilt accuracy requirement. Demonstrated capabilities are 0.1 arc-sec angular mirror positioning accuracy, which translates into linear positioning resolutions at the actuator of 50 nm. The mechanism consists of a structure with sets of cross-directional flexures that enable the mirror s tip and tilt motion, a mirror with its kinematic mount, and two linear actuators. An actuator comprises a brushless DC motor, a linear ball screw, and a piezoelectric brake that holds the mirror s position while the unit is unpowered. An interferometric linear position sensor senses the actuator s position. The AMMs were developed for an Astrometric Beam Combiner (ABC) optical bench, which is part of an interferometer development. Custom electronics were also developed to accommodate the presence of multiple AMMs within the ABC and provide a compact, all-in-one solution to power and control the AMMs.

[The mirror neuron system in motor and sensory rehabilitation].

PubMed

Oouchida, Yutaka; Izumi, Shinichi

2014-06-01

The discovery of the mirror neuron system has dramatically changed the study of motor control in neuroscience. The mirror neuron system provides a conceptual framework covering the aspects of motor as well as sensory functions in motor control. Previous studies of motor control can be classified as studies of motor or sensory functions, and these two classes of studies appear to have advanced independently. In rehabilitation requiring motor learning, such as relearning movement after limb paresis, however, sensory information of feedback for motor output as well as motor command are essential. During rehabilitation from chronic pain, motor exercise is one of the most effective treatments for pain caused by dysfunction in the sensory system. In rehabilitation where total intervention unifying the motor and sensory aspects of motor control is important, learning through imitation, which is associated with the mirror neuron system can be effective and suitable. In this paper, we introduce the clinical applications of imitated movement in rehabilitation from motor impairment after brain damage and phantom limb pain after limb amputation.

Lightweight Zerodur Mirror Technology

DTIC Science & Technology

1982-10-01

17 September 1981 Contract Expiration Date: 15 May 1982 Short Title of Work: Lightweight Zerodur Mirror Technology Program Code Number: 1LIO Period of...iepRA LIGHTWEIGHT ZERODUR MIRROR TECHNOLOGY 21 Sep 81 - 21 May 82 1. PERFORMING 0,10. REPORT NUMWERn 15512 7: AUTHOR(*J S. CONTRACT OR GRANT NUMSER[JlII...1S. KIEV WORDS (Continue on reverse aide If necesery 1nd Identify b? block nwi nhm ) Zerodur Lightweight Mirrors Mirror Blank Fabrication Frit

COI NMSD Hybrid Mirror

NASA Technical Reports Server (NTRS)

Mehle, Greg; Stahl, Phil (Technical Monitor)

2002-01-01

This presentation provides an overview of the development of the 1.6 meter hybrid mirror demonstrator for the NGST Mirror System Demonstrator (NMSD) program. The COI design approach for the NGST program combines the optical performance of glass, with the high specific stiffness capabilities of composite materials The foundation technologies being exploited in the development of the hybrid mirror focus upon precision Composite Materials for cryogenic operation, and non-contact optical processing (ion figuring) of the lightweight mirror surface. The NGST Mirror System Demonstrator (NMSD) has been designed and built by Composite Optics, Inc. (COI) with optical processing performed by SAGEM (REOSC). The sponsors of these efforts are the NASA Marshall and Goddard Space Flight Centers.

Clinical characteristics of mirror syndrome: a comparison of 10 cases of mirror syndrome with non-mirror syndrome fetal hydrops cases.

PubMed

Hirata, Go; Aoki, Shigeru; Sakamaki, Kentaro; Takahashi, Tsuneo; Hirahara, Fumiki; Ishikawa, Hiroshi

2016-01-01

To investigate clinical features of mirror syndrome. We retrospectively reviewed 71 cases of fetal hydrops with or without mirror syndrome, and compared with respect to maternal age, the body mass index, the primipara rate, the gestational age at delivery, the timing of fetal hydrops onset, the severity of fetal edema, placental swelling, the laboratory data and the fetal mortality. The data are expressed as the medians. Mirror syndrome developed in 29% (10/35) of the cases with fetal hydrops. In mirror group, the onset time of fetal hydrops was significantly earlier (29 weeks versus 31 weeks, p = 0.011), and the severity of fetal hydrops (fetal edema/biparietal diameter) was significantly higher than non-mirror group (0.23 versus 0.16, p < 0.001). There was significantly higher serum human chorionic gonadotropin (hCG) (453,000 IU/L versus 80,000 IU/L, p < 0.001) and lower hemoglobin (8.9 g/dL versus 10.1 g/dL, p =0.002), hypoalbuminemia (2.3 mg/dL versus 2.7 mg/dL, p = 0.007), hyperuricemia (6.4 mg/dL versus 5.0 mg/dL, p = 0.043) in mirror group. Mirror syndrome is occurred frequently in early and severe fetal hydrops and cause hemodilution and elevation of serum hCG.

Mirror mechanism and dedicated circuits are the scaffold for mirroring processes.

PubMed

Fogassi, Leonardo

2014-04-01

In the past decade many studies have demonstrated the existence of a mirror mechanism that matches the sensory representation of a biological stimulus with its somatomotor and visceromotor representation. This mechanism, likely phylogenetically very old, explains several types of mirroring behaviours, at different levels of complexity. The presence in primates of dedicated neuroanatomical pathways for specific sensorimotor integrations processes implies, at least in the primate lineage, a hard-wired mirror mechanism for social cognitive functions.

Design, Construction, and Testing of Lightweight X-ray Mirror Modules

NASA Technical Reports Server (NTRS)

McClelland, Ryan S.; Biskach, Michael P.; Chan, Kai-Wing; Espina, Rebecca A.; Hohl, Bruce R.; Matson, Elizabeth A.; Saha, Timo C.; Zhang, William W.

2013-01-01

Lightweight and high resolution optics are needed for future space-based X-ray telescopes to achieve advances in high-energy astrophysics. The Next Generation X-ray Optics (NGXO) team at NASA GSFC is nearing mission readiness for a 10 arc-second Half Power Diameter (HPD) slumped glass mirror technology while laying the groundwork for a future 1-2 arc-second technology based on polished silicon mirrors. Technology Development Modules (TDMs) have been designed, fabricated, integrated with mirrors segments, and extensively tested to demonstrate technology readiness. Tests include X-ray performance, thermal vacuum, acoustic load, and random vibration. The thermal vacuum and acoustic load environments have proven relatively benign, while the random vibration environment has proven challenging due to large input amplification at frequencies above 500 Hz. Epoxy selection, surface preparation, and larger bond area have increased bond strength while vibration isolation has decreased vibration amplification allowing for space launch requirements to be met in the near term. The next generation of TDMs, which demonstrates a lightweight structure supporting more mirror segments, is currently being fabricated. Analysis predicts superior performance characteristics due to the use of E-60 Beryllium-Oxide Metal Matrix Composite material, with only a modest cost increase. These TDMs will be larger, lighter, stiffer, and stronger than the current generation. Preliminary steps are being taken to enable mounting and testing of 1-2 arc-second mirror segments expected to be available in the future. A Vertical X-ray Test Facility (VXTF) will minimize module gravity distortion and allow for less constrained mirror mounts, such as fully kinematic mounts. Permanent kinematic mounting into a modified TDM has been demonstrated to achieve 2 arc-second level distortion free alignment.

Enhancing nanoparticle electrodynamics with gold nanoplate mirrors.

PubMed

Yan, Zijie; Bao, Ying; Manna, Uttam; Shah, Raman A; Scherer, Norbert F

2014-05-14

Mirrors and optical cavities can modify and enhance matter-radiation interactions. Here we report that chemically synthesized Au nanoplates can serve as micrometer-size mirrors that enhance electrodynamic interactions. Because of their plasmonic properties, the Au nanoplates enhance the brightness of scattered light from Ag nanoparticles near the nanoplate surface in dark-field microscopy. More importantly, enhanced optical trapping and optical binding of Ag nanoparticles are demonstrated in interferometric optical traps created from a single laser beam and its reflection from individual Au nanoplates. The enhancement of the interparticle force constant is ≈20-fold more than expected from the increased intensity due to standing wave interference. We show that the additional stability for optical binding arises from the restricted axial thermal motion of the nanoparticles that couples to and reduces the fluctuations in the lateral plane. This new mechanism greatly advances the photonic synthesis of ultrastable nanoparticle arrays and investigation of their properties.

Bronze rainbow hologram mirrors

NASA Astrophysics Data System (ADS)

Dawson, P.

2006-02-01

This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

Using two MEMS deformable mirrors in an adaptive optics test bed for multiconjugate correction

NASA Astrophysics Data System (ADS)

Andrews, Jonathan R.; Martinez, Ty; Teare, Scott W.; Restaino, Sergio R.; Wilcox, Christopher C.; Santiago, Freddie; Payne, Don M.

2010-02-01

Adaptive optics systems have advanced considerably over the past decade and have become common tools for optical engineers. The most recent advances in adaptive optics technology have lead to significant reductions in the cost of most of the key components. Most significantly, the cost of deformable elements and wavefront sensor components have dropped to the point where multiple deformable mirrors and Shack- Hartmann array based wavefront sensor cameras can be included in a single system. Matched with the appropriate hardware and software, formidable systems can be operating in nearly any sized research laboratory. The significant advancement of MEMS deformable mirrors has made them very popular for use as the active corrective element in multi-conjugate adaptive optics systems so that, in particular for astronomical applications, this allows correction in more than one plane. The NRL compact AO system and atmospheric simulation systems has now been expanded to support Multi Conjugate Adaptive Optics (MCAO), taking advantage of using the liquid crystal spatial light modulator (SLM) driven aberration generators in two conjugate planes that are well separated spatially. Thus, by using two SLM based aberration generators and two separate wavefront sensors, the system can measure and apply wavefront correction with two MEMS deformable mirrors. This paper describes the multi-conjugate adaptive optics system and the testing and calibration of the system and demonstrates preliminary results with this system.

A novel collinear optical system with annulus mirrors for holographic disc driver

NASA Astrophysics Data System (ADS)

Wang, Ye

2008-12-01

This paper focus on a novel collinear lens system with annulus mirrors for holographic disc driver, both information beam and reference beam are use same laser beam. The expanded and parallel laser beam, center part of it as the information beam then through Fourier transform lens, the beam around center part as a reference beam. On this axis, the ring reference beam reflected by two annulus shaped mirrors, then became a convergent beam, together with the information beam which through the first Fourier transform lens then produce holographic pattern to be write into the holographic disc behind of them, this lens system with two mirrors made the angle between information beam and reference beam more wide, can improved the multiplex level of holographic storage. Pair of Fourier transform lens with advance performance is designed in this paper.

Mirror Metrology Using Nano-Probe Supports

NASA Technical Reports Server (NTRS)

Robinson, David; Hong, Maoling; Byron, Glenn; McClelland, Ryan; Chan, Kai-Wing

2012-01-01

Thin, lightweight mirrors are needed for future x-ray space telescopes in order to increase x-ray collecting area while maintaining a reduced mass and volume capable of being launched on existing rockets. However, it is very difficult to determine the undistorted shape of such thin mirrors because the mounting of the mirror during measurement causes distortion. Traditional kinematic mounts have insufficient supports to control the distortion to measurable levels and prevent the mirror from vibrating during measurement. Over-constrained mounts (non-kinematic) result in an unknown force state causing mirror distortion that cannot be determined or analytically removed. In order to measure flexible mirrors, it is necessary to over-constrain the mirror. Over-constraint causes unknown distortions to be applied to the mirror. Even if a kinematic constraint system can be used, necessary imperfections in the kinematic assumption can lead to an unknown force state capable of distorting the mirror. Previously, thicker, stiffer, and heavier mirrors were used to achieve low optical figure distortion. These mirrors could be measured to an acceptable level of precision using traditional kinematic mounts. As lighter weight precision optics have developed, systems such as the whiffle tree or hydraulic supports have been used to provide additional mounting supports while maintaining the kinematic assumption. The purpose of this invention is to over-constrain a mirror for optical measurement without causing unacceptable or unknown distortions. The invention uses force gauges capable of measuring 1/10,000 of a Newton attached to nano-actuators to support a thin x-ray optic with known and controlled forces to allow for figure measurement and knowledge of the undeformed mirror figure. The mirror is hung from strings such that it is minimally distorted and in a known force state. However, the hanging mirror cannot be measured because it is both swinging and vibrating. In order to

Variable focal length deformable mirror

DOEpatents

Headley, Daniel [Albuquerque, NM; Ramsey, Marc [Albuquerque, NM; Schwarz, Jens [Albuquerque, NM

2007-06-12

A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

Mesmerising mirror neurons.

PubMed

Heyes, Cecilia

2010-06-01

Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. Copyright 2010 Elsevier Inc. All rights reserved.

Mirror plasma apparatus

DOEpatents

Moir, Ralph W.

1981-01-01

A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma.

The ontogenetic origins of mirror neurons: evidence from 'tool-use' and 'audiovisual' mirror neurons.

PubMed

Cook, Richard

2012-10-23

Since their discovery, mirror neurons--units in the macaque brain that discharge both during action observation and execution--have attracted considerable interest. Whether mirror neurons are an innate endowment or acquire their sensorimotor matching properties ontogenetically has been the subject of intense debate. It is widely believed that these units are an innate trait; that we are born with a set of mature mirror neurons because their matching properties conveyed upon our ancestors an evolutionary advantage. However, an alternative view is that mirror neurons acquire their matching properties during ontogeny, through correlated experience of observing and performing actions. The present article re-examines frequently overlooked neurophysiological reports of 'tool-use' and 'audiovisual' mirror neurons within the context of this debate. It is argued that these findings represent compelling evidence that mirror neurons are a product of sensorimotor experience, and not an innate endowment.

Mirror systems.

PubMed

Fogassi, Leonardo; Ferrari, Pier Francesco

2011-01-01

Mirror neurons are a class of visuomotor neurons, discovered in the monkey premotor cortex and in an anatomically connected area of the inferior parietal lobule, that activate both during action execution and action observation. They constitute a circuit dedicated to match actions made by others with the internal motor representations of the observer. It has been proposed that this matching system enables individuals to understand others' behavior and motor intentions. Here we will describe the main features of mirror neurons in monkeys. Then we will present evidence of the presence of a mirror system in humans and of its involvement in several social-cognitive functions, such as imitation, intention, and emotion understanding. This system may have several implications at a cognitive level and could be linked to specific social deficits in humans such as autism. Recent investigations addressed the issue of the plasticity of the mirror neuron system in both monkeys and humans, suggesting also their possible use in rehabilitation. WIREs Cogn Sci 2011 2 22-38 DOI: 10.1002/wcs.89 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

Mirror and (absence of) counter-mirror responses to action sounds measured with TMS

PubMed Central

Schütz-Bosbach, Simone; Waszak, Florian

2017-01-01

Abstract To what extent is the mirror neuron mechanism malleable to experience? The answer to this question can help characterising its ontogeny and its role in social cognition. Some suggest that it develops through sensorimotor associations congruent with our own actions. Others argue for its extreme volatility that will encode any sensorimotor association in the environment. Here, we added to this debate by exploring the effects of short goal-directed ‘mirror’ and ‘counter-mirror’ trainings (a ‘mirror’ training is defined as the first type of training encountered by the participants) on human auditory mirror motor-evoked potentials (MEPs). We recorded MEPs in response to two tones void of previous motor meaning, before and after mirror and counter-mirror trainings in which participants generated two tones of different pitch by performing free-choice button presses. The results showed that mirror MEPs, once established, were protected against an equivalent counter-mirror experience: they became manifest very rapidly and the same number of training trials that lead to the initial association did not suffice to reverse the MEP pattern. This steadiness of the association argues that, by serving direct-matching purposes, the mirror mechanism is a good solution for social cognition. PMID:29036454

Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students.

PubMed

Hodgin, Katie L; Graham, Dan J

2016-01-01

Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one's personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair-elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their "transportation choices" at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants' choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14-0.96], males (OR = 0.33, 95% CI: 0.13-0.85), those with lower BMI (OR = 0.84, 95% CI: 0.71-0.99), those

Mirror, Mirror by the Stairs: The Impact of Mirror Exposure on Stair versus Elevator Use in College Students

PubMed Central

Hodgin, Katie L.; Graham, Dan J.

2016-01-01

Previous research has indicated that self-awareness-inducing mirrors can successfully incite behaviors that align with one’s personal values, such as helping others. Other research has found a large discrepancy between the high percentage of young adults who report valuing the healthfulness of physical activity (PA) and the low percentage who actually meet PA participation standards. However, few studies have examined how mirror exposure and both perceived and actual body size influence highly valued PA participation among college students. The present study assessed stair versus elevator use on a western college campus and hypothesized that mirror exposure would increase the more personally healthy transportation method of stair use. In accordance with previous research, it was also hypothesized that males and those with a lower body mass index (BMI) would be more likely to take the stairs, and that body size distorting mirrors would impact the stair–elevator decision. One hundred sixty-seven students (51% male) enrolled in an introductory psychology course were recruited to take a survey about their “transportation choices” at an indoor campus parking garage. Participants were individually exposed to either no mirror, a standard full-length mirror, or a full-length mirror manipulated to make the reflected body size appear either slightly thinner or slightly wider than normal before being asked to go to the fourth floor of the garage for a survey. Participants’ choice of floor-climbing method (stairs or elevator) was recorded, and they were administered an Internet-based survey assessing demographic information, BMI, self-awareness, perceived body size, and other variables likely to be associated with stair use. Results from logistic regression analyses revealed that participants who were not exposed to a mirror [odds ratios (OR) = 0.37, 95% CI: 0.14–0.96], males (OR = 0.33, 95% CI: 0.13–0.85), those with lower BMI (OR = 0.84, 95% CI: 0

Fabrication of ф 160 mm convex hyperbolic mirror for remote sensing instrument

NASA Astrophysics Data System (ADS)

Kuo, Ching-Hsiang; Yu, Zong-Ru; Ho, Cheng-Fang; Hsu, Wei-Yao; Chen, Fong-Zhi

2012-10-01

In this study, efficient polishing processes with inspection procedures for a large convex hyperbolic mirror of Cassegrain optical system are presented. The polishing process combines the techniques of conventional lapping and CNC polishing. We apply the conventional spherical lapping process to quickly remove the sub-surface damage (SSD) layer caused by grinding process and to get the accurate radius of best-fit sphere (BFS) of aspheric surface with fine surface texture simultaneously. Thus the removed material for aspherization process can be minimized and the polishing time for SSD removal can also be reduced substantially. The inspection procedure was carried out by using phase shift interferometer with CGH and stitching technique. To acquire the real surface form error of each sub aperture, the wavefront errors of the reference flat and CGH flat due to gravity effect of the vertical setup are calibrated in advance. Subsequently, we stitch 10 calibrated sub-aperture surface form errors to establish the whole irregularity of the mirror in 160 mm diameter for correction polishing. The final result of the In this study, efficient polishing processes with inspection procedures for a large convex hyperbolic mirror of Cassegrain optical system are presented. The polishing process combines the techniques of conventional lapping and CNC polishing. We apply the conventional spherical lapping process to quickly remove the sub-surface damage (SSD) layer caused by grinding process and to get the accurate radius of best-fit sphere (BFS) of aspheric surface with fine surface texture simultaneously. Thus the removed material for aspherization process can be minimized and the polishing time for SSD removal can also be reduced substantially. The inspection procedure was carried out by using phase shift interferometer with CGH and stitching technique. To acquire the real surface form error of each sub aperture, the wavefront errors of the reference flat and CGH flat due to

Design for an 8 Meter Monolithic UV/OIR Space Telescope

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Postman, Marc; Hornsby, Linda; Hopkins, Randall; Mosier, Gary E.; Pasquale, Bert A.; Arnold, William R.

2009-01-01

ATLAST-8 is an 8-meter monolithic UV/optical/NIR space observatory to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V cargo launch vehicle. The ATLAST-8 will yield fundamental astronomical breakthroughs. The mission concept utilizes two enabling technologies: planned Ares-V launch vehicle (scheduled for 2019) and autonomous rendezvous and docking (AR&D). The unprecedented Ares-V payload and mass capacity enables the use of a massive, monolithic, thin-meniscus primary mirror - similar to a VLT or Subaru. Furthermore, it enables simple robust design rules to mitigate cost, schedule and performance risk. AR&D enables on-orbit servicing, extending mission life and enhancing science return.

Point Relay Scanner Utilizing Ellipsoidal Mirrors

NASA Technical Reports Server (NTRS)

Manhart, Paul K. (Inventor); Pagano, Robert J. (Inventor)

1997-01-01

A scanning system uses a polygonal mirror assembly with each facet of the polygon having an ellipsoidal mirror located thereon. One focal point of each ellipsoidal mirror is located at a common point on the axis of rotation of the polygonal mirror assembly. As the mirror assembly rotates. a second focal point of the ellipsoidal mirrors traces out a scan line. The scanner can be utilized for scanned output display of information or for scanning information to be detected.

[Mirror therapy in hemiplegic patient].

PubMed

Lisalde-Rodríguez, María Elena; Garcia-Fernández, José Antonio

2016-01-01

Mirror therapy is a relatively new intervention, every time more used and with easy access for the rehabilitation treatment of stroke patient. The patient moves the unaffected limb in front of a mirror watching the reflection of that move as if he was moving de affected limb. To analyze the effectiveness of mirror therapy in the sensorimotor function, hemineglect and activities of daily living of stroke patients. We defined a strategy of bibliography search in Medline, EMBASE, PEDro y Cochrane Central Register of Controlled Trials (CENTRAL) looking for randomised controlled trials (RCT) conducted with hemiplegic patients considering mirror therapy as the main rehabilitation intervention. Seven trials met the inclusion criteria with medium-high methodological quality. Most of them evaluate the mirror therapy effect on motor outcomes showing significant improvements. Three of this RCTs evaluate the effect of mirror therapy on the hemineglect with positive result. A combination of mirror therapy with conventional rehabilitation obtained significant improvements mainly in motor function but not that much on sensory function and functional performance. About the effect of mirror therapy on hemineglect, there are significant improvements but supported only with a few RCTs with small sample sizes producing promising but inconclusive results.

Gasdynamic Mirror Fusion Propulsion Experiment

NASA Technical Reports Server (NTRS)

Emrich, Bill; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies with out requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma "b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.

Mirror coatings for large aperture UV optical infrared telescope optics

NASA Astrophysics Data System (ADS)

Balasubramanian, Kunjithapatham; Hennessy, John; Raouf, Nasrat; Nikzad, Shouleh; Del Hoyo, Javier; Quijada, Manuel

2017-09-01

Large space telescope concepts such as LUVOIR and HabEx aiming for observations from far UV to near IR require advanced coating technologies to enable efficient gathering of light with important spectral signatures including those in far UV region down to 90nm. Typical Aluminum mirrors protected with MgF2 fall short of the requirements below 120nm. New and improved coatings are sought to protect aluminum from oxidizing readily in normal environment causing severe absorption and reduction of reflectance in the deep UV. Choice of materials and the process of applying coatings present challenges. Here we present the progress achieved to date with experimental investigations of coatings at JPL and at GSFC and discuss the path forward to achieve high reflectance in the spectral region from 90 to 300nm without degrading performance in the visible and NIR regions taking into account durability concerns when the mirrors are exposed to normal laboratory environment as well as high humidity conditions. Reflectivity uniformity required on these mirrors is also discussed.

Archetypal-imaging and mirror-gazing.

PubMed

Caputo, Giovanni B

2014-03-01

Mirrors have been studied by cognitive psychology in order to understand self-recognition, self-identity, and self-consciousness. Moreover, the relevance of mirrors in spirituality, magic and arts may also suggest that mirrors can be symbols of unconscious contents. Carl G. Jung investigated mirrors in relation to the unconscious, particularly in Psychology and Alchemy. However, the relationship between the conscious behavior in front of a mirror and the unconscious meaning of mirrors has not been clarified. Recently, empirical research found that gazing at one's own face in the mirror for a few minutes, at a low illumination level, produces the perception of bodily dysmorphic illusions of strange-faces. Healthy observers usually describe huge distortions of their own faces, monstrous beings, prototypical faces, faces of relatives and deceased, and faces of animals. In the psychiatric population, some schizophrenics show a dramatic increase of strange-face illusions. They can also describe the perception of multiple-others that fill the mirror surface surrounding their strange-face. Schizophrenics are usually convinced that strange-face illusions are truly real and identify themselves with strange-face illusions, diversely from healthy individuals who never identify with them. On the contrary, most patients with major depression do not perceive strange-face illusions, or they perceive very faint changes of their immobile faces in the mirror, like death statues. Strange-face illusions may be the psychodynamic projection of the subject's unconscious archetypal contents into the mirror image. Therefore, strange-face illusions might provide both an ecological setting and an experimental technique for "imaging of the unconscious". Future researches have been proposed.

Partially segmented deformable mirror

DOEpatents

Bliss, Erlan S.; Smith, James R.; Salmon, J. Thaddeus; Monjes, Julio A.

1991-01-01

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

Design, fabrication and characterization of MEMS deformable mirrors for ocular adaptive optics

NASA Astrophysics Data System (ADS)

Park, Hyunkyu

this research are described and characterized. The fabrication process of the optimized deformable mirror is presented and advanced techniques used in the process are described in detail. The fabricated deformable mirrors are characterized and the comparison with FEM is described. Finally, the dissertation ends up with suggestions for further developments and tests for the mirror.

The neuronal correlates of mirror therapy: an fMRI study on mirror induced visual illusions in patients with stroke.

PubMed

Michielsen, Marian E; Smits, Marion; Ribbers, Gerard M; Stam, Henk J; van der Geest, Jos N; Bussmann, Johannes B J; Selles, Ruud W

2011-04-01

To investigate the neuronal basis for the effects of mirror therapy in patients with stroke. 22 patients with stroke participated in this study. The authors used functional MRI to investigate neuronal activation patterns in two experiments. In the unimanual experiment, patients moved their unaffected hand, either while observing it directly (no-mirror condition) or while observing its mirror reflection (mirror condition). In the bimanual experiment, patients moved both hands, either while observing the affected hand directly (no-mirror condition) or while observing the mirror reflection of the unaffected hand in place of the affected hand (mirror condition). A two-factorial analysis with movement (activity vs rest) and mirror (mirror vs no mirror) as main factors was performed to assess neuronal activity resultant of the mirror illusion. Data on 18 participants were suitable for analysis. Results showed a significant interaction effect of movement×mirror during the bimanual experiment. Activated regions were the precuneus and the posterior cingulate cortex (p<0.05 false discovery rate). In this first study on the neuronal correlates of the mirror illusion in patients with stroke, the authors showed that during bimanual movement, the mirror illusion increases activity in the precuneus and the posterior cingulate cortex, areas associated with awareness of the self and spatial attention. By increasing awareness of the affected limb, the mirror illusion might reduce learnt non-use. The fact that the authors did not observe mirror-related activity in areas of the motor or mirror neuron system questions popular theories that attribute the clinical effects of mirror therapy to these systems.

Archetypal-Imaging and Mirror-Gazing

PubMed Central

Caputo, Giovanni B.

2013-01-01

Mirrors have been studied by cognitive psychology in order to understand self-recognition, self-identity, and self-consciousness. Moreover, the relevance of mirrors in spirituality, magic and arts may also suggest that mirrors can be symbols of unconscious contents. Carl G. Jung investigated mirrors in relation to the unconscious, particularly in Psychology and Alchemy. However, the relationship between the conscious behavior in front of a mirror and the unconscious meaning of mirrors has not been clarified. Recently, empirical research found that gazing at one’s own face in the mirror for a few minutes, at a low illumination level, produces the perception of bodily dysmorphic illusions of strange-faces. Healthy observers usually describe huge distortions of their own faces, monstrous beings, prototypical faces, faces of relatives and deceased, and faces of animals. In the psychiatric population, some schizophrenics show a dramatic increase of strange-face illusions. They can also describe the perception of multiple-others that fill the mirror surface surrounding their strange-face. Schizophrenics are usually convinced that strange-face illusions are truly real and identify themselves with strange-face illusions, diversely from healthy individuals who never identify with them. On the contrary, most patients with major depression do not perceive strange-face illusions, or they perceive very faint changes of their immobile faces in the mirror, like death statues. Strange-face illusions may be the psychodynamic projection of the subject’s unconscious archetypal contents into the mirror image. Therefore, strange-face illusions might provide both an ecological setting and an experimental technique for “imaging of the unconscious”. Future researches have been proposed. PMID:25379264

Tandem mirror plasma confinement apparatus

DOEpatents

Fowler, T. Kenneth

1978-11-14

Apparatus and method for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell.

Lightweight ZERODUR: Validation of Mirror Performance and Mirror Modeling Predictions

NASA Technical Reports Server (NTRS)

Hull, Tony; Stahl, H. Philip; Westerhoff, Thomas; Valente, Martin; Brooks, Thomas; Eng, Ron

2017-01-01

Upcoming spaceborne missions, both moderate and large in scale, require extreme dimensional stability while relying both upon established lightweight mirror materials, and also upon accurate modeling methods to predict performance under varying boundary conditions. We describe tests, recently performed at NASA's XRCF chambers and laboratories in Huntsville Alabama, during which a 1.2 m diameter, f/1.2988% lightweighted SCHOTT lightweighted ZERODUR(TradeMark) mirror was tested for thermal stability under static loads in steps down to 230K. Test results are compared to model predictions, based upon recently published data on ZERODUR(TradeMark). In addition to monitoring the mirror surface for thermal perturbations in XRCF Thermal Vacuum tests, static load gravity deformations have been measured and compared to model predictions. Also the Modal Response(dynamic disturbance) was measured and compared to model. We will discuss the fabrication approach and optomechanical design of the ZERODUR(TradeMark) mirror substrate by SCHOTT, its optical preparation for test by Arizona Optical Systems (AOS). Summarize the outcome of NASA's XRCF tests and model validations

Lightweight ZERODUR®: Validation of mirror performance and mirror modeling predictions

NASA Astrophysics Data System (ADS)

Hull, Anthony B.; Stahl, H. Philip; Westerhoff, Thomas; Valente, Martin; Brooks, Thomas; Eng, Ron

2017-01-01

Upcoming spaceborne missions, both moderate and large in scale, require extreme dimensional stability while relying both upon established lightweight mirror materials, and also upon accurate modeling methods to predict performance under varying boundary conditions. We describe tests, recently performed at NASA’s XRCF chambers and laboratories in Huntsville Alabama, during which a 1.2m diameter, f/1.29 88% lightweighted SCHOTT lightweighted ZERODUR® mirror was tested for thermal stability under static loads in steps down to 230K. Test results are compared to model predictions, based upon recently published data on ZERODUR®. In addition to monitoring the mirror surface for thermal perturbations in XRCF Thermal Vacuum tests, static load gravity deformations have been measured and compared to model predictions. Also the Modal Response (dynamic disturbance) was measured and compared to model. We will discuss the fabrication approach and optomechanical design of the ZERODUR® mirror substrate by SCHOTT, its optical preparation for test by Arizona Optical Systems (AOS), and summarize the outcome of NASA’s XRCF tests and model validations.

The mirror-neuron system.

PubMed

Rizzolatti, Giacomo; Craighero, Laila

2004-01-01

A category of stimuli of great importance for primates, humans in particular, is that formed by actions done by other individuals. If we want to survive, we must understand the actions of others. Furthermore, without action understanding, social organization is impossible. In the case of humans, there is another faculty that depends on the observation of others' actions: imitation learning. Unlike most species, we are able to learn by imitation, and this faculty is at the basis of human culture. In this review we present data on a neurophysiological mechanism--the mirror-neuron mechanism--that appears to play a fundamental role in both action understanding and imitation. We describe first the functional properties of mirror neurons in monkeys. We review next the characteristics of the mirror-neuron system in humans. We stress, in particular, those properties specific to the human mirror-neuron system that might explain the human capacity to learn by imitation. We conclude by discussing the relationship between the mirror-neuron system and language.

Partially segmented deformable mirror

DOEpatents

Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

1991-05-21

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

Effects of a mirror-induced visual illusion on a reaching task in stroke patients: implications for mirror therapy training.

PubMed

Selles, Ruud W; Michielsen, Marian E; Bussmann, Johannes B J; Stam, Henk J; Hurkmans, Henri L; Heijnen, Iris; de Groot, Danielle; Ribbers, Gerard M

2014-09-01

Although most mirror therapy studies have shown improved motor performance in stroke patients, the optimal mirror training protocol still remains unclear. To study the relative contribution of a mirror in training a reaching task and of unilateral and bimanual training with a mirror. A total of 93 stroke patients at least 6 months poststroke were instructed to perform a reaching task as fast and as fluently as possible. They performed 70 practice trials after being randomly allocated to 1 of 5 experimental groups: training with (1) the paretic arm with direct view (Paretic-No Mirror), (2) the nonparetic arm with direct view (Nonparetic-No Mirror), (3) the nonparetic arm with mirror reflection (Nonparetic Mirror), (4) both sides and with a nontransparent screen preventing visual control of paretic side (Bilateral-Screen), and (5) both sides with mirror reflection of the nonparetic arm (Bilateral-Mirror). As baseline and follow-up, patients performed 6 trials using only their paretic side. Primary outcome measure was the movement time. We found the largest intervention effect in the Paretic-No Mirror condition. However, the Nonparetic-Mirror condition was not significantly different from the Paretic-No Mirror condition, while the Unaffected-No Mirror condition had significantly less improvement than the Paretic-No Mirror condition. In addition, movement time improved significantly less in the bimanual conditions and there was no difference between both bimanual conditions or between both mirror conditions. The present study confirms that using a mirror reflection can facilitate motor learning. In this task, bimanual movement using mirror training was less effective than unilateral training. © The Author(s) 2014.

Measuring a Precise Ultra-Lightweight Spaceflight Mirror on Earth: The Analysis of the SHARPI PM Mirror Figure Data during Mirror Processing at GSFC

NASA Technical Reports Server (NTRS)

Antonille, Scott; Content, David; Rabin, Douglas; Wallace, Thomas; Wake, Shane

2007-01-01

The SHARPI (Solar High Angular Resolution Photometric Imager) primary mirror is a 5kg, 0.5m paraboloid, diffraction limited at FUV wavelengths when placed in a 0-G environment. The ULE sandwich honeycomb mirror and the attached mount pads were delivered by ITT (then Kodak) in 2003 to NASA s Goddard Space Flight Center (GSFC). At GSFC, we accepted, coated, mounted, and vibration tested this mirror in preparation for flight on the PICTURES (Planet Imaging Concept Testbed Using a Rocket Experiment) mission. At each step, the integrated analysis of interferometer data and FEA models was essential to quantify the 0-G mirror figure. This task required separating nanometer sized variations from hundreds of nanometers of gravity induced distortion. The ability to isolate such features allowed in-situ monitoring of mirror figure, diagnosis of perturbations, and remediation of process errors. In this paper, we describe the technical approach used to achieve these measurements and overcome the various difficulties maintaining UV diffraction-limited performance with this aggressively lightweighted mirror.

Design and verification for front mirror-body structure of on-axis three mirror anastigmatic space camera

NASA Astrophysics Data System (ADS)

Wang, Xiaoyong; Guo, Chongling; Hu, Yongli; He, Hongyan

2017-11-01

The primary and secondary mirrors of onaxis three mirror anastigmatic (TMA) space camera are connected and supported by its front mirror-body structure, which affects both imaging performance and stability of the camera. In this paper, the carbon fiber reinforced plastics (CFRP) thin-walled cylinder and titanium alloy connecting rod have been used for the front mirror-body opto-mechanical structure of the long-focus on-axis and TMA space camera optical system. The front mirror-body component structure has then been optimized by finite element analysis (FEA) computing. Each performance of the front mirror-body structure has been tested by mechanics and vacuum experiments in order to verify the validity of such structure engineering design.

Compact neutron imaging system using axisymmetric mirrors

DOEpatents

Khaykovich, Boris; Moncton, David E; Gubarev, Mikhail V; Ramsey, Brian D; Engelhaupt, Darell E

2014-05-27

A dispersed release of neutrons is generated from a source. A portion of this dispersed neutron release is reflected by surfaces of a plurality of nested, axisymmetric mirrors in at least an inner mirror layer and an outer mirror layer, wherein the neutrons reflected by the inner mirror layer are incident on at least one mirror surface of the inner mirror layer N times, wherein N is an integer, and wherein neutrons reflected by the outer mirror are incident on a plurality of mirror surfaces of the outer layer N+i times, where i is a positive integer, to redirect the neutrons toward a target. The mirrors can be formed by a periodically reversed pulsed-plating process.

The Advanced Technology Large Aperture Space Telescope (ATLAST): Science Drivers, Technology Developments, and Synergies with Other Future Facilities

NASA Technical Reports Server (NTRS)

Postman, Marc; Brown, Tom; Sembach, Kenneth; Giavalisco, Mauro; Traub, Wesley; Stapelfeldt, Karl; Calzetti, Daniela; Oegerle, William; Rich, R. Michael; Stahl, H. Philip;

Stable mirror mount

DOEpatents

Cutburth, Ronald W.

1990-01-01

An improved mirror mount assembly is disclosed. The mirror mount assembly provides a post assembly slidable in a Y-axis orientation and a nut plate assembly slidable in an X-axis orientation and a device for simultaneously locking the post assembly and the key assembly in a fixed position.

Stable mirror mount

DOEpatents

Cutburth, R.W.

1983-11-04

An improved mirror mount assembly is disclosed. The mirror mount assembly provides a post assembly slidable in a Y-axis orientation and a nut plate assembly slidable in an X-axis orientation and means for simultaneously locking said post assembly and said key assembly in a fixed position.

Near-field flat focusing mirrors

NASA Astrophysics Data System (ADS)

Cheng, Yu-Chieh; Staliunas, Kestutis

2018-03-01

This article reviews recent progress towards the design of near-field flat focusing mirrors, focusing/imaging light patterns in reflection. An important feature of such flat focusing mirrors is their transverse invariance, as they do not possess any optical axis. We start with a review of the physical background to the different focusing mechanisms of near- and far-field focusing. These near-field focusing devices like flat lenses and the reviewed near-field focusing mirrors can implement planar focusing devices without any optical axis. In contrast, various types of far-field planar focusing devices, such as high-contrast gratings and metasurfaces, unavoidably break the transverse invariance due to their radially symmetrical structures. The particular realizations of near-field flat focusing mirrors including Bragg-like dielectric mirrors and dielectric subwavelength gratings are the main subjects of the review. The first flat focusing mirror was demonstrated with a chirped mirror and was shown to manage an angular dispersion for beam focusing, similar to the management of chromatic dispersion for pulse compression. Furthermore, the reviewed optimized chirped mirror demonstrated a long near-field focal length, hardly achieved by a flat lens or a planar hyperlens. Two more different configurations of dielectric subwavelength gratings that focus a light beam at normal or oblique incidence are also reviewed. We also summarize and compare focusing performance, limitations, and future perspectives between the reviewed flat focusing mirrors and other planar focusing devices including a flat lens with a negative-index material, a planar hyperlens, a high-contrast grating, and a metasurface.

High stroke pixel for a deformable mirror

DOEpatents

Miles, Robin R.; Papavasiliou, Alexandros P.

2005-09-20

A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

Eliminating mirror responses by instructions.

PubMed

Bardi, Lara; Bundt, Carsten; Notebaert, Wim; Brass, Marcel

2015-09-01

The observation of an action leads to the activation of the corresponding motor plan in the observer. This phenomenon of motor resonance has an important role in social interaction, promoting imitation, learning and action understanding. However, mirror responses not always have a positive impact on our behavior. An automatic tendency to imitate others can introduce interference in action execution and non-imitative or opposite responses have an advantage in some contexts. Previous studies suggest that mirror tendencies can be suppressed after extensive practice or in complementary joint action situations revealing that mirror responses are more flexible than previously thought. The aim of the present study was to gain insight into the mechanisms that allow response flexibility of motor mirroring. Here we show that the mere instruction of a counter-imitative mapping changes mirror responses as indexed by motor evoked potentials (MEPs) enhancement induced by transcranial magnetic stimulation (TMS). Importantly, mirror activation was measured while participants were passively watching finger movements, without having the opportunity to execute the task. This result suggests that the implementation of task instructions activates stimulus-response association that can overwrite the mirror representations. Our outcome reveals one of the crucial mechanisms that might allow flexible adjustments of mirror responses in different contexts. The implications of this outcome are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanolaminate deformable mirrors

DOEpatents

Papavasiliou, Alexandros P.; Olivier, Scot S.

2009-04-14

A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

Fabrication and testing of 4.2m off-axis aspheric primary mirror of Daniel K. Inouye Solar Telescope

NASA Astrophysics Data System (ADS)

Oh, Chang Jin; Lowman, Andrew E.; Smith, Greg A.; Su, Peng; Huang, Run; Su, Tianquan; Kim, Daewook; Zhao, Chunyu; Zhou, Ping; Burge, James H.

2016-07-01

Daniel K. Inouye Solar Telescope (formerly known as Advanced Technology Solar Telescope) will be the largest optical solar telescope ever built to provide greatly improved image, spatial and spectral resolution and to collect sufficient light flux of Sun. To meet the requirements of the telescope the design adopted a 4m aperture off-axis parabolic primary mirror with challenging specifications of the surface quality including the surface figure, irregularity and BRDF. The mirror has been completed at the College of Optical Sciences in the University of Arizona and it meets every aspect of requirement with margin. In fact this mirror may be the smoothest large mirror ever made. This paper presents the detail fabrication process and metrology applied to the mirror from the grinding to finish, that include extremely stable hydraulic support, IR and Visible deflectometry, Interferometry and Computer Controlled fabrication process developed at the University of Arizona.

Observational physics of mirror world

NASA Technical Reports Server (NTRS)

Khlopov, M. YA.; Beskin, G. M.; Bochkarev, N. E.; Pustilnik, L. A.; Pustilnik, S. A.

1989-01-01

The existence of the whole world of shadow particles, interacting with each other and having no mutual interactions with ordinary particles except gravity is a specific feature of modern superstring models, being considered as models of the theory of everything. The presence of shadow particles is the necessary condition in the superstring models, providing compensation of the asymmetry of left and right chirality states of ordinary particles. If compactification of additional dimensions retains the symmetry of left and right states, shadow world turns to be the mirror one, with particles and fields having properties strictly symmetrical to the ones of corresponding ordinary particles and fields. Owing to the strict symmetry of physical laws for ordinary and mirror particles, the analysis of cosmological evolution of mirror matter provides rather definite conclusions on possible effects of mirror particles in the universe. A general qualitative discussion of possible astronomical impact of mirror matter is given, in order to make as wide as possible astronomical observational searches for the effects of mirror world, being the unique way to test the existence of mirror partners of ordinary particles in the Nature.

JWST Primary Mirror Technology Development

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2010-01-01

Mirror Technology was identified as a (if not the) critical capability necessary to achieve the Level 1 science goals. A never before demonstrated space telescope capability was required: 6 to 8 meter class pri mary mirror, diffraction limited at 2 micrometers and operates at temperatures below 50K. Launch vehicle constraints placed significant architectural constraints: deployed/segmented primary mirror (4.5 meter fairing diameter) 20 kg/m2 areal density (PM 1000 kg mass) Such mirror technology had never been demonstrated - and did not exist

Mirror-image-induced magnetic modes.

PubMed

Xifré-Pérez, Elisabet; Shi, Lei; Tuzer, Umut; Fenollosa, Roberto; Ramiro-Manzano, Fernando; Quidant, Romain; Meseguer, Francisco

2013-01-22

Reflection in a mirror changes the handedness of the real world, and right-handed objects turn left-handed and vice versa (M. Gardner, The Ambidextrous Universe, Penguin Books, 1964). Also, we learn from electromagnetism textbooks that a flat metallic mirror transforms an electric charge into a virtual opposite charge. Consequently, the mirror image of a magnet is another parallel virtual magnet as the mirror image changes both the charge sign and the curl handedness. Here we report the dramatic modification in the optical response of a silicon nanocavity induced by the interaction with its image through a flat metallic mirror. The system of real and virtual dipoles can be interpreted as an effective magnetic dipole responsible for a strong enhancement of the cavity scattering cross section.

LED structure with enhanced mirror reflectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergmann, Michael; Donofrio, Matthew; Heikman, Sten

2014-04-01

Embodiments of the present invention are generally related to LED chips having improved overall emission by reducing the light-absorbing effects of barrier layers adjacent mirror contacts. In one embodiment, a LED chip comprises one or more LEDs, with each LED having an active region, a first contact under the active region having a highly reflective mirror, and a barrier layer adjacent the mirror. The barrier layer is smaller than the mirror such that it does not extend beyond the periphery of the mirror. In another possible embodiment, an insulator is further provided, with the insulator adjacent the barrier layer andmore » adjacent portions of the mirror not contacted by the active region or by the barrier layer. In yet another embodiment, a second contact is provided on the active region. In a further embodiment, the barrier layer is smaller than the mirror such that the periphery of the mirror is at least 40% free of the barrier layer, and the second contact is below the first contact and accessible from the bottom of the chip.« less

High current proton beams production at Simple Mirror Ion Source 37.

PubMed

Skalyga, V; Izotov, I; Razin, S; Sidorov, A; Golubev, S; Kalvas, T; Koivisto, H; Tarvainen, O

2014-02-01

This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition. Latest experiments at SMIS 37 were performed using a single-aperture two-electrode extraction system. Proton beams with currents up to 450 mA at high voltages below 45 kV were obtained. The maximum beam current density was measured to be 600 mA/cm(2). A possibility of further improvement through the development of an advanced extraction system is discussed.

Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)

NASA Astrophysics Data System (ADS)

Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2013-09-01

The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

Figures of Merit for Mirror Materials

DTIC Science & Technology

1980-07-10

show higher temporal stability. Mirror figure changes with time have generally been small: - X/30 - X/40 for CER-VIT and silica mirrors .27 Zerodur and...9 III. MIRROR FAILURE CRITERIA ................. s .. .................. 13 A. Mechanical Loading Effects...41 / a3 I.. I • INTRODUCTION Large space mirrors were analyzed I with the objective of comparing the ability of materials to minimize static

Metallic alternative to glass mirrors (active mirrors in aluminium) - A review

NASA Astrophysics Data System (ADS)

Rozelot, Jean P.; Leblanc, Jean-M.

1991-09-01

Present-day glass mirrors for telescopes, including the most recent results obtained with aluminum mirrors developed within the European EUREKA procedure (LAMA program) are reviewed. The major advantages of the aluminum-alloy solution, which can be extrapolated today for large size, are discussed. It is shown that aluminum-alloy meniscus blanks, polished on a thin nickel coating, are appropriate to manufacture mirrors of astronomical quality. With the technique of electron-beam welding, large sizes can be envisaged. The development of active optics makes it possible to easily compensate for real-time deformations. The good thermal diffusivity of aluminum alloys leads to a better and faster thermal equilibrium than all other glass structures.

Spontaneous expression of mirror self-recognition in monkeys after learning precise visual-proprioceptive association for mirror images.

PubMed

Chang, Liangtang; Zhang, Shikun; Poo, Mu-Ming; Gong, Neng

2017-03-21

Mirror self-recognition (MSR) is generally considered to be an intrinsic cognitive ability found only in humans and a few species of great apes. Rhesus monkeys do not spontaneously show MSR, but they have the ability to use a mirror as an instrument to find hidden objects. The mechanism underlying the transition from simple mirror use to MSR remains unclear. Here we show that rhesus monkeys could show MSR after learning precise visual-proprioceptive association for mirror images. We trained head-fixed monkeys on a chair in front of a mirror to touch with spatiotemporal precision a laser pointer light spot on an adjacent board that could only be seen in the mirror. After several weeks of training, when the same laser pointer light was projected to the monkey's face, a location not used in training, all three trained monkeys successfully touched the face area marked by the light spot in front of a mirror. All trained monkeys passed the standard face mark test for MSR both on the monkey chair and in their home cage. Importantly, distinct from untrained control monkeys, the trained monkeys showed typical mirror-induced self-directed behaviors in their home cage, such as using the mirror to explore normally unseen body parts. Thus, bodily self-consciousness may be a cognitive ability present in many more species than previously thought, and acquisition of precise visual-proprioceptive association for the images in the mirror is critical for revealing the MSR ability of the animal.

Design of compact off-axis four-mirror anastigmatic system for space communications

NASA Astrophysics Data System (ADS)

Zhao, Fa-cai; Sun, Quan-she; Chen, Kun-feng; Zhu, Xing-bang; Wang, Shao-shui; Wang, Guo-quan; Zheng, Xiang-liang

2013-08-01

The deployment of advanced hyperspectral imaging and other Earth sensing instruments onboard Earth observing satellites is driving the demand for high-data rate communications. Space laser communications technology offers the potential for significantly increasing in data return capability from space to Earth. Compared to the current state of the art radio frequency communications links, lasercom links operate at much higher carrier frequencies. The use of higher carrier frequencies implies a much smaller diffraction loss, which in turn, results in a much higher efficiency in delivering the signal energy. Optical communications meet the required data rates with small, low-mass, and low-power communications packages. The communications optical system assembly typically consists of a front aperture, reflection or refraction type telescope, with or without a solar rejection filter, aft optics, fine-pointing mirrors, and array detectors. Optical system used in space laser communications usually has long focal length, large aperture compared with common optical systems. So the reflective optical system is widely used. An unobstructed four-mirror anastigmatic telescope system was proposed, which was modified based on the theory about geometry optics of common-axis three-mirror systems. Intermediate image was between secondary and tertiary mirror. In order to fold the optical path, four-mirror was designed by adding the plane reflective mirror at intermediate image. The design was analyzed, then a system with effective aperture of 200mm and field of view of 1.0°x1.0° was designed, total length and magnification are 700mm and 20, respectively. The system has advantages of large magnification, relative short physical size and loose manufacturing tolerances.

Absolute measurements of large mirrors

NASA Astrophysics Data System (ADS)

Su, Peng

The ability to produce mirrors for large astronomical telescopes is limited by the accuracy of the systems used to test the surfaces of such mirrors. Typically the mirror surfaces are measured by comparing their actual shapes to a precision master, which may be created using combinations of mirrors, lenses, and holograms. The work presented here develops several optical testing techniques that do not rely on a large or expensive precision, master reference surface. In a sense these techniques provide absolute optical testing. The Giant Magellan Telescope (GMT) has been designed with a 350 m 2 collecting area provided by a 25 m diameter primary mirror made out from seven circular independent mirror segments. These segments create an equivalent f/0.7 paraboloidal primary mirror consisting of a central segment and six outer segments. Each of the outer segments is 8.4 m in diameter and has an off-axis aspheric shape departing 14.5 mm from the best-fitting sphere. Much of the work in this dissertation is motivated by the need to measure the surfaces or such large mirrors accurately, without relying on a large or expensive precision reference surface. One method for absolute testing describing in this dissertation uses multiple measurements relative to a reference surface that is located in different positions with respect to the test surface of interest. The test measurements are performed with an algorithm that is based on the maximum likelihood (ML) method. Some methodologies for measuring large flat surfaces in the 2 m diameter range and for measuring the GMT primary mirror segments were specifically developed. For example, the optical figure of a 1.6-m flat mirror was determined to 2 nm rms accuracy using multiple 1-meter sub-aperture measurements. The optical figure of the reference surface used in the 1-meter sub-aperture measurements was also determined to the 2 nm level. The optical test methodology for a 1.7-m off axis parabola was evaluated by moving several

Thin Mirror Shaping Technology for High-Throughput X-ray Telescopes

NASA Astrophysics Data System (ADS)

Schattenburg, Mark

This proposal is submitted to the NASA Research Opportunities in Space and Earth Sciences program (ROSES-2012) in response to NASA Research Announcement NNH12ZDA001N- APRA. It is targeted to the Astronomy and Astrophysics Research and Analysis (APRA) program element under the Supporting Technology category. Powerful x-ray telescope mirrors are critical components of a raft of small-to-large mission concepts under consideration by NASA. The science questions addressed by these missions have certainly never been more compelling and the need to fulfill NASA s core missions of exploring the universe and strengthening our nation s technology base has never been greater. Unfortunately, budgetary constraints are driving NASA to consider the cost/benefit and risk factors of new missions more carefully than ever. New technology for producing x-ray telescopes with increased resolution and collecting area, while holding down cost, are key to meeting these goals and sustaining a thriving high-energy astrophysics enterprise in the US. We propose to develop advanced technology which will lead to thin-shell x-ray telescope mirrors rivaling the Chandra x-ray telescope in spatial resolution but with 10-100X larger area all at significantly reduced weight, risk and cost. The proposed effort builds on previous research at MIT and complements NASA-supported research at other institutions. We are currently pursuing two thin-mirror technology development tracks which we propose to extend and accelerate with NASA support. The first research track utilizes rapidly-maturing thermal glass slumping technology which uses porous ceramic air-bearing mandrels to shape glass mirrors without touching, thus avoiding surface-induced mid-range spatial frequency ripples. A second research track seeks to remove any remaining mid- to long-range errors in mirrors by using scanning ion-beam implant to impart small, highly deterministic and very stable amounts of stress into thin glass, utilizing local

Where do mirror neurons come from?

PubMed

Heyes, Cecilia

2010-03-01

Debates about the evolution of the 'mirror neuron system' imply that it is an adaptation for action understanding. Alternatively, mirror neurons may be a byproduct of associative learning. Here I argue that the adaptation and associative hypotheses both offer plausible accounts of the origin of mirror neurons, but the associative hypothesis has three advantages. First, it provides a straightforward, testable explanation for the differences between monkeys and humans that have led some researchers to question the existence of a mirror neuron system. Second, it is consistent with emerging evidence that mirror neurons contribute to a range of social cognitive functions, but do not play a dominant, specialised role in action understanding. Finally, the associative hypothesis is supported by recent data showing that, even in adulthood, the mirror neuron system can be transformed by sensorimotor learning. The associative account implies that mirror neurons come from sensorimotor experience, and that much of this experience is obtained through interaction with others. Therefore, if the associative account is correct, the mirror neuron system is a product, as well as a process, of social interaction. (c) 2009 Elsevier Ltd. All rights reserved.

Studies on dynamic behavior of rotating mirrors

NASA Astrophysics Data System (ADS)

Li, Jingzhen; Sun, Fengshan; Gong, Xiangdong; Huang, Hongbin; Tian, Jie

2005-02-01

A rotating mirror is a kernel unit in a Miller-type high speed camera, which is both as an imaging element in optical path and as an element to implement ultrahigh speed photography. According to Schardin"s Principle, information capacity of an ultrahigh speed camera with rotating mirror depends on primary wavelength of lighting used by the camera and limit linear velocity on edge of the rotating-mirror: the latter is related to material (including specifications in technology), cross-section shape and lateral structure of rotating mirror. In this manuscript dynamic behavior of high strength aluminium alloy rotating mirrors is studied, from which it is preliminarily shown that an aluminium alloy rotating mirror can be absolutely used as replacement for a steel rotating-mirror or a titanium alloy rotating-mirror in framing photographic systems, and it could be also used as a substitute for a beryllium rotating-mirror in streak photographic systems.

Graded Mirror Self-Recognition by Clark's Nutcrackers.

PubMed

Clary, Dawson; Kelly, Debbie M

2016-11-04

The traditional 'mark test' has shown some large-brained species are capable of mirror self-recognition. During this test a mark is inconspicuously placed on an animal's body where it can only be seen with the aid of a mirror. If the animal increases the number of actions directed to the mark region when presented with a mirror, the animal is presumed to have recognized the mirror image as its reflection. However, the pass/fail nature of the mark test presupposes self-recognition exists in entirety or not at all. We developed a novel mirror-recognition task, to supplement the mark test, which revealed gradation in the self-recognition of Clark's nutcrackers, a large-brained corvid. To do so, nutcrackers cached food alone, observed by another nutcracker, or with a regular or blurry mirror. The nutcrackers suppressed caching with a regular mirror, a behavioural response to prevent cache theft by conspecifics, but did not suppress caching with a blurry mirror. Likewise, during the mark test, most nutcrackers made more self-directed actions to the mark with a blurry mirror than a regular mirror. Both results suggest self-recognition was more readily achieved with the blurry mirror and that self-recognition may be more broadly present among animals than currently thought.

Mirror neurons: from origin to function.

PubMed

Cook, Richard; Bird, Geoffrey; Catmur, Caroline; Press, Clare; Heyes, Cecilia

2014-04-01

This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively observes a similar action performed by another agent. It is widely believed that mirror neurons are a genetic adaptation for action understanding; that they were designed by evolution to fulfill a specific socio-cognitive function. In contrast, we argue that mirror neurons are forged by domain-general processes of associative learning in the course of individual development, and, although they may have psychological functions, they do not necessarily have a specific evolutionary purpose or adaptive function. The evidence supporting this view shows that (1) mirror neurons do not consistently encode action "goals"; (2) the contingency- and context-sensitive nature of associative learning explains the full range of mirror neuron properties; (3) human infants receive enough sensorimotor experience to support associative learning of mirror neurons ("wealth of the stimulus"); and (4) mirror neurons can be changed in radical ways by sensorimotor training. The associative account implies that reliable information about the function of mirror neurons can be obtained only by research based on developmental history, system-level theory, and careful experimentation.

NASA superconducting magnetic mirror facility

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Swanson, M. C.; Nichols, C. R.; Obloy, S. J.; Nagy, L. A.; Brady, F. J.

1973-01-01

This report summarizes the design details and initial test results of a superconducting magnetic mirror facility that has been constructed at NASA Lewis Research Center for use in thermonuclear research. The magnet system consists of four solenoidal coils which are individually rated at 5.0 T. Each coil is composed of an inner, middle, and outer winding. The inner winding is wound of stabilized Nb3SN superconducting ribbon, and the middle and outer windings are wound of stabilized Nb-Ti superconducting wire. When arranged in the mirror geometry, the four coils will produce 8.7 T at the mirrors and a 1.8 mirror ratio. The magnet has a 41-cm diameter clear bore which is open to atmosphere. Distance between the mirrors is 111 cm. Presently there are only three magnets in the facility; the fourth magnet is being rebuilt.

Mirror Technology

NASA Technical Reports Server (NTRS)

1992-01-01

Under a NASA contract, MI-CVD developed a process for producing bulk silicon carbide by means of a chemical vapor deposition process. The technology allows growth of a high purity material with superior mechanical/thermal properties and high polishability - ideal for mirror applications. The company employed the technology to develop three research mirrors for NASA Langley and is now marketing it as CVD SILICON CARBIDE. Its advantages include light weight, thermal stability and high reflectivity. The material has nuclear research facility applications and is of interest to industrial users of high power lasers.

Speckle measuring instrument based on biological characteristics of the human eyes and speckle reduction with advanced electromagnetic micro-scanning mirror

NASA Astrophysics Data System (ADS)

Yuan, Yuan; Fang, Tao; Sun, Min Yuan; Gao, Wei Nan; Zhang, Shuo; Bi, Yong

2018-07-01

Laser speckle is a major issue for laser projection displays. In various techniques of speckle reduction, speckle is quantified with a speckle contrast value. However, the measured speckle contrast is poorly suited for the subjective speckle perception of a human observer. Here, we investigate the characteristics of human eyes and propose a simplified optical transfer function of human eyes. Accordingly, two human-eye-modeled speckle measuring sets are configured. Based on the experimental set, an advanced electromagnetic micro-scanning mirror (EM-MSM) is exploited; which is of 6.5 mm in diameter and its half angle is 7.8° for a horizontal scan and 6.53° for a vertical scan. Finally, we quantitatively show that images generated with an EM-MSM exhibit superior quality. By providing human-eye-modeled speckle measuring instruments and an EM-MSM for speckle reduction, it has a promising promotion to laser projector development.

Mirror with thermally controlled radius of curvature

DOEpatents

Neil, George R.; Shinn, Michelle D.

2010-06-22

A radius of curvature controlled mirror for controlling precisely the focal point of a laser beam or other light beam. The radius of curvature controlled mirror provides nearly spherical distortion of the mirror in response to differential expansion between the front and rear surfaces of the mirror. The radius of curvature controlled mirror compensates for changes in other optical components due to heating or other physical changes. The radius of curvature controlled mirror includes an arrangement for adjusting the temperature of the front surface and separately adjusting the temperature of the rear surface to control the radius of curvature. The temperature adjustment arrangements can include cooling channels within the mirror body or convection of a gas upon the surface of the mirror. A control system controls the differential expansion between the front and rear surfaces to achieve the desired radius of curvature.

Design and Analysis of an X-Ray Mirror Assembly Using the Meta-Shell Approach

NASA Technical Reports Server (NTRS)

McClelland, Ryan S.; Bonafede, Joseph; Saha, Timo T.; Solly, Peter M.; Zhang, William W.

2016-01-01

Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in high-energy astrophysics. Past missions such as Chandra and XMM-Newton have achieved excellent angular resolution using a full shell mirror approach. Other missions such as Suzaku and NuSTAR have achieved lightweight mirrors using a segmented approach. This paper describes a new approach, called meta-shells, which combines the fabrication advantages of segmented optics with the alignment advantages of full shell optics. Meta-shells are built by layering overlapping mirror segments onto a central structural shell. The resulting optic has the stiffness and rotational symmetry of a full shell, but with an order of magnitude greater collecting area. Several meta-shells so constructed can be integrated into a large x-ray mirror assembly by proven methods used for Chandra and XMM-Newton. The mirror segments are mounted to the meta-shell using a novel four point semi-kinematic mount. The four point mount deterministically locates the segment in its most performance sensitive degrees of freedom. Extensive analysis has been performed to demonstrate the feasibility of the four point mount and meta-shell approach. A mathematical model of a meta-shell constructed with mirror segments bonded at four points and subject to launch loads has been developed to determine the optimal design parameters, namely bond size, mirror segment span, and number of layers per meta-shell. The parameters of an example 1.3 m diameter mirror assembly are given including the predicted effective area. To verify the mathematical model and support opto-mechanical analysis, a detailed finite element model of a meta-shell was created. Finite element analysis predicts low gravity distortion and low sensitivity to thermal gradients.

Spontaneous expression of mirror self-recognition in monkeys after learning precise visual-proprioceptive association for mirror images

PubMed Central

Chang, Liangtang; Zhang, Shikun; Poo, Mu-ming; Gong, Neng

2017-01-01

Mirror self-recognition (MSR) is generally considered to be an intrinsic cognitive ability found only in humans and a few species of great apes. Rhesus monkeys do not spontaneously show MSR, but they have the ability to use a mirror as an instrument to find hidden objects. The mechanism underlying the transition from simple mirror use to MSR remains unclear. Here we show that rhesus monkeys could show MSR after learning precise visual-proprioceptive association for mirror images. We trained head-fixed monkeys on a chair in front of a mirror to touch with spatiotemporal precision a laser pointer light spot on an adjacent board that could only be seen in the mirror. After several weeks of training, when the same laser pointer light was projected to the monkey's face, a location not used in training, all three trained monkeys successfully touched the face area marked by the light spot in front of a mirror. All trained monkeys passed the standard face mark test for MSR both on the monkey chair and in their home cage. Importantly, distinct from untrained control monkeys, the trained monkeys showed typical mirror-induced self-directed behaviors in their home cage, such as using the mirror to explore normally unseen body parts. Thus, bodily self-consciousness may be a cognitive ability present in many more species than previously thought, and acquisition of precise visual-proprioceptive association for the images in the mirror is critical for revealing the MSR ability of the animal. PMID:28193875

Mirror, Mirror, on the Wall.

ERIC Educational Resources Information Center

Flowers, Jim; Rose, M. Annette

1998-01-01

Students use tables of anthropometric data, their own measurements, underlying principles of physics, and math to solve a problem. The problem is to determine the height of a wall mirror, and where to mount it, so that 90% of the clientele can view their entire length without stretching or bending. (Author)

Cavity-induced mirror-mirror entanglement in a single-atom Raman laser

NASA Astrophysics Data System (ADS)

Teklu, Berihu; Byrnes, Tim; Khan, Faisal Shah

2018-02-01

We address an experimental scheme to analyze the optical bistability and the entanglement of two movable mirrors coupled to a two-mode laser inside a doubly resonant cavity. With this aim we investigate the master equations of the atom-cavity subsystem in conjunction with the quantum Langevin equations that describe the interaction of the mirror cavity. The parametric amplification-type coupling induced by the two-photon coherence on the optical bistability of the intracavity mean photon numbers is found and investigated. Under this condition, the optical intensities exhibit bistability for all large values of cavity laser detuning. We also provide numerical evidence for the generation of strong entanglement between the movable mirrors and show that it is robust against environmental thermalization.

Process of constructing a lightweight x-ray flight mirror assembly

NASA Astrophysics Data System (ADS)

McClelland, Ryan S.; Biskach, Michael P.; Chan, Kai-Wing; Espina, Rebecca A.; Hohl, Bruce R.; Saha, Timo T.; Zhang, William W.

2014-07-01

Lightweight and high resolution optics are needed for future space-based x-ray telescopes to achieve advances in highenergy astrophysics. NASA's Next Generation X-ray Optics (NGXO) project has made significant progress towards building such optics, both in terms of maturing the technology for spaceflight readiness and improving the angular resolution. Technology Development Modules (TDMs) holding three pairs of mirrors have been regularly and repeatedly integrated and tested both for optical performance and mechanical strength. X-ray test results have been improved over the past year from 10.3 arc-seconds Half Power Diameter (HPD) to 8.3 arc-seconds HPD. A vibration test has been completed to NASA standard verification levels showing the optics can survive launch and pointing towards improvements in strengthening the modules through redundant bonds. A Finite Element Analysis (FEA) study was completed which shows the mirror distortion caused by bonding is insensitive to the number of bonds. Next generation TDMs, which will demonstrate a lightweight structure and mount additional pairs of mirrors, have been designed and fabricated. The light weight of the module structure is achieved through the use of E-60 Beryllium Oxide metal matrix composite material. As the angular resolution of the development modules has improved, gravity distortion during horizontal x-ray testing has become a limiting factor. To address this issue, a facility capable of testing in the vertical orientation has been designed and planned. Test boring at the construction site suggest standard caisson construction methods can be utilized to install a subterranean vertical vacuum pipe. This facility will also allow for the testing of kinematically mounted mirror segments, which greatly reduces the effect of bonding displacements. A development platform demonstrating the feasibility of kinematically mounting mirror segments has been designed, fabricated, and successfully tested.

Large active mirror in aluminium

NASA Astrophysics Data System (ADS)

Leblanc, Jean-M.; Rozelot, Jean-Pierre

1991-11-01

The Large Active Mirrors in Aluminum Project (LAMA) is intended as a metallic alternative to the conventional glass mirrors. This alternative is to bring about definite improvements in terms of lower cost, shorter manufacturing, and reduced brittleness. Combined in a system approach that integrates design, development, and manufacturing of both the aluminum meniscus and its active support, the LAMA project is a technologically consistent product for astronomical and laser telescopes. Large size mirrors can be delivered, up to 8 m diameter. Recent progress in active optics makes possible control, as well as real-time adjustment, of a metallic mirror's deformations, especially those induced by temperature variations and/or aging. It also enables correction of whatever low-frequency surface waves escaped polishing. Besides, the manufacturing process to produce the aluminum segments together with the electron welding technique ensure the material's homogeneity. Quality of the surface condition will result from optimized implementation of the specific aluminum machining and polishing techniques. This paper highlights the existing aluminum realizations compared to glass mirrors, and gives the main results obtained during a feasibility demonstration phase, based on 8 m mirror requirements.

EAGLE: relay mirror technology development

NASA Astrophysics Data System (ADS)

Hartman, Mary; Restaino, Sergio R.; Baker, Jeffrey T.; Payne, Don M.; Bukley, Jerry W.

2002-06-01

EAGLE (Evolutionary Air & Space Global Laser Engagement) is the proposed high power weapon system with a high power laser source, a relay mirror constellation, and the necessary ground and communications links. The relay mirror itself will be a satellite composed of two optically-coupled telescopes/mirrors used to redirect laser energy from ground, air, or space based laser sources to distant points on the earth or space. The receiver telescope captures the incoming energy, relays it through an optical system that cleans up the beam, then a separate transmitter telescope/mirror redirects the laser energy at the desired target. Not only is it a key component in extending the range of DoD's current laser weapon systems, it also enables ancillary missions. Furthermore, if the vacuum of space is utilized, then the atmospheric effects on the laser beam propagation will be greatly attenuated. Finally, several critical technologies are being developed to make the EAGLE/Relay Mirror concept a reality, and the Relay Mirror Technology Development Program was set up to address them. This paper will discuss each critical technology, the current state of the work, and the future implications of this program.

Development of silicon carbide mirrors: the example of the Sofia secondary mirror

NASA Astrophysics Data System (ADS)

Fruit, Michel; Antoine, Pascal

2017-11-01

The 352 mm tip-tilt SOFIA Secondary Mirror has been developed by the ASTRIUM / BOOSTEC joint venture SiCSPACE, taking full benefit of the intrinsic properties of the BOOSTEC S-SiC sintered material, associated to qualified processes specifically developed for space borne mirrors by ASTRIUM SAS. Achieved performances include a low mass of 1.7 kg, a very high stiffness with a first resonant frequency higher than 2000 Hz and an optical surface accuracy corresponding to a maximum WFE of 50 nm rms. This mirror is part of the joint NASA-DLR project for a 2.5 m airborne Stratospheric Observatory For Infrared Astronomy (SOFIA).

Laser cleaning of ITER's diagnostic mirrors

NASA Astrophysics Data System (ADS)

Skinner, C. H.; Gentile, C. A.; Doerner, R.

2012-10-01

Practical methods to clean ITER's diagnostic mirrors and restore reflectivity will be critical to ITER's plasma operations. We report on laser cleaning of single crystal molybdenum mirrors coated with either carbon or beryllium films 150 - 420 nm thick. A 1.06 μm Nd laser system provided 220 ns pulses at 8 kHz with typical power densities of 1-2 J/cm^2. The laser beam was fiber optically coupled to a scanner suitable for tokamak applications. The efficacy of mirror cleaning was assessed with a new technique that combines microscopic imaging and reflectivity measurements [1]. The method is suitable for hazardous materials such as beryllium as the mirrors remain sealed in a vacuum chamber. Excellent restoration of reflectivity for the carbon coated Mo mirrors was observed after laser scanning under vacuum conditions. For the beryllium coated mirrors restoration of reflectivity has so far been incomplete and modeling indicates that a shorter duration laser pulse is needed. No damage of the molybdenum mirror substrates was observed.[4pt][1] C.H. Skinner et al., Rev. Sci. Instrum. at press.

Scanning mirror for infrared sensors

NASA Technical Reports Server (NTRS)

Anderson, R. H.; Bernstein, S. B.

1972-01-01

A high resolution, long life angle-encoded scanning mirror, built for application in an infrared attitude sensor, is described. The mirror uses a Moire' fringe type optical encoder and unique torsion bar suspension together with a magnetic drive to meet stringent operational and environmental requirements at a minimum weight and with minimum power consumption. Details of the specifications, design, and construction are presented with an analysis of the mirror suspension that allows accurate prediction of performance. The emphasis is on mechanical design considerations, and brief discussions are included on the encoder and magnetic drive to provide a complete view of the mirror system and its capabilities.

[The ontogeny of the mirror neuron system].

PubMed

Myowa-Yamakoshi, Masako

2014-06-01

Abstract Humans utilize the mirror neuron system to understand and predict others' actions. However, the ontogeny of the mirror neuron system remains unknown. Whether mirror neuron function is an innate trait or whether mirror neurons acquire their sensorimotor matching properties ontogenetically remains to be clarified. In this paper, I review the ontogenetic theory of the mirror neuron system. I then discuss the functioning of the mirror neuron system in the context of social cognitive abilities, which are unique to humans. Recently, some researchers argue that it is too early to interpret the function of mirror neurons as an understanding of the underlying psychological states of others. They imply that such functioning would require inferential cognitive processes that are known to involve areas outside the mirror neuron system. Filling in this missing link may be the key to elucidating the unique ability of humans to understand others' actions.

Progress on SOFIA primary mirror

NASA Astrophysics Data System (ADS)

Geyl, Roland; Tarreau, Michel

2000-06-01

REOSC, SAGEM Group, has a significant contribution to the SOFIA project with the design and fabrication of the 2.7-m primary mirror and its fixtures as well as the M3 mirror tower assembly. This paper will primarily report the progress made on the primary mirror design and the first important manufacturing step: its lightweighting by machining pockets from the rear side of the blank.

Cryogenic mirror analysis

NASA Technical Reports Server (NTRS)

Nagy, S.

1988-01-01

Due to extraordinary distances scanned by modern telescopes, optical surfaces in such telescopes must be manufactured to unimaginable standards of perfection of a few thousandths of a centimeter. The detection of imperfections of less than 1/20 of a wavelength of light, for application in the building of the mirror for the Space Infrared Telescope Facility, was undertaken. Because the mirror must be kept very cold while in space, another factor comes into effect: cryogenics. The process to test a specific morror under cryogenic conditions is described; including the follow-up analysis accomplished through computer work. To better illustrate the process and analysis, a Pyrex Hex-Core mirror is followed through the process from the laser interferometry in the lab, to computer analysis via a computer program called FRINGE. This analysis via FRINGE is detailed.

Spherical mirror grazing incidence x-ray optics

NASA Technical Reports Server (NTRS)

Cash, Jr., Webster C. (Inventor)

1997-01-01

An optical system for x-rays combines at least two spherical or near spherical mirrors for each dimension in grazing incidence orientation to provide the functions of a lens in the x-ray region. To focus x-ray radiation in both the X and the Y dimensions, one of the mirrors focusses the X dimension, a second mirror focusses the Y direction, a third mirror corrects the X dimension by removing comatic aberration and a fourth mirror corrects the Y dimension. Spherical aberration may also be removed for an even better focus. The order of the mirrors is unimportant.

Four-mirror extreme ultraviolet (EUV) lithography projection system

DOEpatents

Cohen, Simon J; Jeong, Hwan J; Shafer, David R

2000-01-01

The invention is directed to a four-mirror catoptric projection system for extreme ultraviolet (EUV) lithography to transfer a pattern from a reflective reticle to a wafer substrate. In order along the light path followed by light from the reticle to the wafer substrate, the system includes a dominantly hyperbolic convex mirror, a dominantly elliptical concave mirror, spherical convex mirror, and spherical concave mirror. The reticle and wafer substrate are positioned along the system's optical axis on opposite sides of the mirrors. The hyperbolic and elliptical mirrors are positioned on the same side of the system's optical axis as the reticle, and are relatively large in diameter as they are positioned on the high magnification side of the system. The hyperbolic and elliptical mirrors are relatively far off the optical axis and hence they have significant aspherical components in their curvatures. The convex spherical mirror is positioned on the optical axis, and has a substantially or perfectly spherical shape. The spherical concave mirror is positioned substantially on the opposite side of the optical axis from the hyperbolic and elliptical mirrors. Because it is positioned off-axis to a degree, the spherical concave mirror has some asphericity to counter aberrations. The spherical concave mirror forms a relatively large, uniform field on the wafer substrate. The mirrors can be tilted or decentered slightly to achieve further increase in the field size.

Manufacturing Large Membrane Mirrors at Low Cost

NASA Technical Reports Server (NTRS)

2007-01-01

Relatively inexpensive processes have been developed for manufacturing lightweight, wide-aperture mirrors that consist mainly of reflectively coated, edge-supported polyimide membranes. The polyimide and other materials in these mirrors can withstand the environment of outer space, and the mirrors have other characteristics that make them attractive for use on Earth as well as in outer space: With respect to the smoothness of their surfaces and the accuracy with which they retain their shapes, these mirrors approach the optical quality of heavier, more expensive conventional mirrors. Unlike conventional mirrors, these mirrors can be stowed compactly and later deployed to their full sizes. In typical cases, deployment would be effected by inflation. Potential terrestrial and outer-space applications for these mirrors include large astronomical telescopes, solar concentrators for generating electric power and thermal power, and microwave reflectors for communication, radar, and short-distance transmission of electric power. The relatively low cost of manufacturing these mirrors stems, in part, from the use of inexpensive tooling. Unlike in the manufacture of conventional mirrors, there is no need for mandrels or molds that have highly precise surface figures and highly polished surfaces. The surface smoothness is an inherent property of a polyimide film. The shaped area of the film is never placed in contact with a mold or mandrel surface: Instead the shape of a mirror is determined by a combination of (1) the shape of a fixture that holds the film around its edge and (2) control of manufacturing- process parameters. In a demonstration of this manufacturing concept, spherical mirrors having aperture diameters of 0.5 and 1.0 m were fabricated from polyimide films having thicknesses ranging from <20 m to 150 m. These mirrors have been found to maintain their preformed shapes following deployment.

Removing Silicon Monoxide From Nickel Mirrors

NASA Technical Reports Server (NTRS)

Zaniewski, John J.

1987-01-01

Combination of polishing tool and polishing mixture used to remove adherent fragments of silicon monoxide protective coatings from nickel/aluminum mirrors without altering shapes or harming polishes of mirror surfaces. Polishing technique developed to prepare stained mirrors for recoating to restore high reflectance.

Deformable mirrors development program at ESO

NASA Astrophysics Data System (ADS)

Stroebele, Stefan; Vernet, Elise; Brinkmann, Martin; Jakob, Gerd; Lilley, Paul; Casali, Mark; Madec, Pierre-Yves; Kasper, Markus

2016-07-01

Over the last decade, adaptive optics has become essential in different fields of research including medicine and industrial applications. With this new need, the market of deformable mirrors has expanded a lot allowing new technologies and actuation principles to be developed. Several E-ELT instruments have identified the need for post focal deformable mirrors but with the increasing size of the telescopes the requirements on the deformable mirrors become more demanding. A simple scaling up of existing technologies from few hundred actuators to thousands of actuators will not be sufficient to satisfy the future needs of ESO. To bridge the gap between available deformable mirrors and the future needs for the E-ELT, ESO started a development program for deformable mirror technologies. The requirements and the path to get the deformable mirrors for post focal adaptive optics systems for the E-ELT is presented.

Passivation coating for flexible substrate mirrors

DOEpatents

Tracy, C. Edwin; Benson, David K.

1990-01-01

A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors. Also, the silver or other reflective metal layer on mirrors comprising thin, lightweight, flexible substrates of metal or polymer sheets coated with glassy layers can be protected with silicon nitride according to this invention.

[Mirror neurons].

PubMed

Rubia Vila, Francisco José

2011-01-01

Mirror neurons were recently discovered in frontal brain areas of the monkey. They are activated when the animal makes a specific movement, but also when the animal observes the same movement in another animal. Some of them also respond to the emotional expression of other animals of the same species. These mirror neurons have also been found in humans. They respond to or "reflect" actions of other individuals in the brain and are thought to represent the basis for imitation and empathy and hence the neurobiological substrate for "theory of mind", the potential origin of language and the so-called moral instinct.

Constraints on mirror models of dark matter from observable neutron-mirror neutron oscillation

NASA Astrophysics Data System (ADS)

Mohapatra, Rabindra N.; Nussinov, Shmuel

2018-01-01

The process of neutron-mirror neutron oscillation, motivated by symmetric mirror dark matter models, is governed by two parameters: n -n‧ mixing parameter δ and n -n‧ mass splitting Δ. For neutron mirror neutron oscillation to be observable, the splitting between their masses Δ must be small and current experiments lead to δ ≤ 2 ×10-27 GeV and Δ ≤10-24 GeV. We show that in mirror universe models where this process is observable, this small mass splitting constrains the way that one must implement asymmetric inflation to satisfy the limits of Big Bang Nucleosynthesis on the number of effective light degrees of freedom. In particular we find that if asymmetric inflation is implemented by inflaton decay to color or electroweak charged particles, the oscillation is unobservable. Also if one uses SM singlet fields for this purpose, they must be weakly coupled to the SM fields.

Stitching interferometry for ellipsoidal x-ray mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yumoto, Hirokatsu, E-mail: yumoto@spring8.or.jp; Koyama, Takahisa; Matsuyama, Satoshi

2016-05-15

Ellipsoidal mirrors, which can efficiently produce a two-dimensional focusing beam with a single mirror, are superior x-ray focusing optics, especially when compared to elliptical-cylinder mirrors in the Kirkpatrick–Baez geometry. However, nano-focusing ellipsoidal mirrors are not commonly used for x-ray optics because achieving the accuracy required for the surface metrology of nano-focusing ellipsoidal mirrors is difficult due to their small radius of curvature along the short ellipsoidal axis. Here, we developed a surface metrology system for nano-focusing ellipsoidal mirrors using stitching interferometric techniques. The developed system simultaneously measures sub-aperture shapes with a microscopic interferometer and the tilt angles of the sub-aperturemore » shapes with a large Fizeau interferometer. After correcting the systematic errors included in the sub-aperture shapes, the entire mirror shape is calculated by stitching the sub-aperture shapes based on the obtained relative angles between partially overlapped sub-apertures. In this study, we developed correction methods for systematic errors in sub-aperture shapes that originated from off-axis aberrations produced in the optics of the microscopic interferometer. The systematic errors on an ellipsoidal mirror were estimated by measuring a series of tilted plane substrates and the ellipsoidal substrate. From measurements of an ellipsoidal mirror with a 3.6-mm radius of curvature at the mirror center, we obtained a measurement repeatability of 0.51 nm (root-mean-square) in an assessment area of 0.5 mm × 99.18 mm. This value satisfies the requirements for surface metrology of nano-focusing x-ray mirrors. Thus, the developed metrology system should be applicable for fabricating nano-focusing ellipsoidal mirrors.« less

The mirror neuron system: new frontiers.

PubMed

Keysers, Christian; Fadiga, Luciano

2008-01-01

Since the discovery of mirror neurons, much effort has been invested into studying their location and properties in the human brain. Here we review these original findings and introduce the main topics of this special issue of Social Neuroscience. What does the mirror system code? How is the mirror system embedded into the mosaic of circuits that compose our brain? How does the mirror system contribute to communication, language and social interaction? Can the principle of mirror neurons be extended to emotions, sensations and thoughts? Papers using a wide range of methods, including single cell recordings, fMRI, TMS, EEG and psychophysics, collected in this special issue, start to give us some impressive answers.

The magic of relay mirrors

NASA Astrophysics Data System (ADS)

Duff, Edward A.; Washburn, Donald C.

2004-09-01

Laser weapon systems would be significantly enhanced with the addition of high altitude or space-borne relay mirrors. Such mirrors, operating alone with a directed energy source, or many in a series fashion, can be shown to effectively move the laser source to the last, so-called fighting mirror. This "magically" reduces the range to target and offers to enhance the performance of directed energy systems like the Airborne Laser and even ground-based or ship-based lasers. Recent development of high altitude airships will be shown to provide stationary positions for such relay mirrors thereby enabling many new and important applications for laser weapons. The technical challenges to achieve this capability are discussed.

Reducing the Surface Performance Requirements of a Primary Mirror by Adding a Deformable Mirror in its Optical Path

DTIC Science & Technology

2015-12-01

carbon fiber reinforced polymer (CFRP) mirrors been proposed for use in future imaging satellites. Compared to traditional glass -based mirrors, CFRP...SUBJECT TERMS carbon fiber reinforced polymer mirror, adaptive optics, deformable mirror, surface figure error 15. NUMBER OF PAGES 79 16. PRICE CODE...Department of Mechanical and Aerospace Engineering iv THIS PAGE INTENTIONALLY LEFT BLANK v ABSTRACT In recent years, carbon fiber reinforced

Mirror neurons: functions, mechanisms and models.

PubMed

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael A

2013-04-12

Mirror neurons for manipulation fire both when the animal manipulates an object in a specific way and when it sees another animal (or the experimenter) perform an action that is more or less similar. Such neurons were originally found in macaque monkeys, in the ventral premotor cortex, area F5 and later also in the inferior parietal lobule. Recent neuroimaging data indicate that the adult human brain is endowed with a "mirror neuron system," putatively containing mirror neurons and other neurons, for matching the observation and execution of actions. Mirror neurons may serve action recognition in monkeys as well as humans, whereas their putative role in imitation and language may be realized in human but not in monkey. This article shows the important role of computational models in providing sufficient and causal explanations for the observed phenomena involving mirror systems and the learning processes which form them, and underlines the need for additional circuitry to lift up the monkey mirror neuron circuit to sustain the posited cognitive functions attributed to the human mirror neuron system. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Plasma confinement apparatus using solenoidal and mirror coils

DOEpatents

Fowler, T. Kenneth; Condit, William C.

1979-01-01

A plasma confinement apparatus, wherein multiple magnetic mirror cells are linked by magnetic field lines inside of a solenoid with the mirroring regions for adjacent magnetic mirror cells each formed by a separate mirror coil inside of the solenoid. The magnetic mirror cells may be field reversed.

Industrialization of the mirror plate coatings for the ATHENA mission

NASA Astrophysics Data System (ADS)

Massahi, S.; Christensen, F. E.; Ferreira, D. D. M.; Shortt, B.; Collon, M.; Sforzini, J.; Landgraf, B.; Hinze, F.; Aulhorn, S.; Biedermann, R.

2017-08-01

In the frame of the development of the Advanced Telescope for High-ENergy Astrophysics (Athena) mission, currently in phase A, ESA is continuing to mature the optics technology and the associated mass production techniques. These efforts are driven by the programmatic and technical requirement of reaching TRL 6 prior to proposing the mission for formal adoption (planned for 2020). A critical part of the current phase A preparation activities is addressing the industrialization of the Silicon Pore Optics mirror plates coating. This include the transfer of the well-established coating processes and techniques, performed at DTU Space, to an industrial scale facility suitable for coating the more than 100,000 mirror plates required for Athena. In this paper, we explain the considerations for the planned coating facility including, requirement specification, equipment and supplier selection, preparing the coating facility for the deposition equipment, designing and fabrication.

Poco Graphite Mirror Metrology Report

NASA Technical Reports Server (NTRS)

Kester, Thomas J.

2005-01-01

Recently a lightweight mirror technology was tested at Marshall Space Flight Center's Space Optic Manufacturing Technology Center (MSFC, SOMTC). The mirror is a Poco Graphite CVD Si clad SiC substrate. It was tested for cryogenic (cryo) survivability to 20deg Kelvin in SOMTC's X-ray Calibration and Cryogenic Test Facility. The surface figure of the mirror was measured before and after cry0 cycling. The test technique and results are discussed.

A Deployable Primary Mirror for Space Telescopes

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Phelps, James E.; Dyer, Jack E.; Caudle, David A.; Tam, Anthony

1999-01-01

NASA Langley Research Center, Composite Optics, Inc., and Nyma/ADF have developed jointly a deployable primary mirror for space telescopes that combines over five years of research on deployment of optical-precision structures and over ten years of development of fabrication techniques for optical-precision composite mirror panels and structures. The deployable mirror is directly applicable to a broad class of non-imaging "lidar" (Light direction and ranging) telescopes whose figure-error requirements are in the range of one to ten microns RMS. Furthermore, the mirror design can be readily modified to accommodate imaging-quality reflector panels and active panel-alignment control mechanisms for application to imaging telescopes. The present paper: 1) describes the deployable mirror concept; 2) explains the status of the mirror development; and 3) provides some technical specifications for a 2.55- m-diameter, proof-of-concept mirror.

A Deployable Primary Mirror for Space Telescopes

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Phelps, James E.; Dyer, Jack E.; Caudle, David A.; Tam, Anthony; Escobedo, Javier; Kasl, Eldon P.

1999-01-01

NASA Langley Research Center, Composite Optics, Inc., and Nyma/ADF have developed jointly a deployable primary mirror for space telescopes that combines over five years of research on deployment of optical-precision structures and over ten years of development of fabrication techniques for optical-precision composite mirror panels and structures. The deployable mirror is directly applicable to a broad class of non-imaging "lidar" (light direction and ranging) telescopes whose figure-error requirements are in the range of one to ten microns RMS. Furthermore, the mirror design can be readily modified to accommodate imaging-quality reflector panels and active panel-alignment control mechanisms for application to imaging telescopes. The present paper: 1) describes the deployable mirror concept; 2) explains the status of the mirror development; and 3) provides some technical specifications for a 2.55-m-diameter, proof-of-concept mirror.

Flight solar calibrations using the Mirror Attenuator Mosaic (MAM): Low scattering mirror

NASA Technical Reports Server (NTRS)

Lee, Robert B., III

1992-01-01

Measurements of solar radiances reflected from the mirror attenuator mosaic (MAM) were used to calibrate the shortwave portions of the Earth Radiation Budget Experiment (ERBE) thermistor bolometer scanning radiometers. The MAM is basically a low scattering mirror which has been used to attenuate and reflect solar radiation into the fields of view for the broadband shortwave (0.2 to 5 micrometers) and total (0.2 to 50.0+ micrometers) ERBE scanning radiometers. The MAM assembly consists of a tightly packed array of aluminum, 0.3175-cm diameter concave spherical mirrors and field of view limiting baffles. The spherical mirrors are masked by a copper plate, electro-plated with black chrome. Perforations (0.14 centimeter in diameter) in the copper plate serve as apertures for the mirrors. Black anodized aluminum baffles limit the MAM clear field of view to 7.1 degrees. The MAM assemblies are located on the Earth Radiation Budget Satellite (ERBS) and on the National Oceanic and Atmospheric Administration NOAA-9 and NOAA-10 spacecraft. The 1984-1985 ERBS and 1985-1986 NOAA-9 solar calibration datasets are presented. Analyses of the calibrations indicate that the MAM exhibited no detectable degradation in its reflectance properties and that the gains of the shortwave scanners did not change. The stability of the shortwave radiometers indicates that the transmission of the Suprasil W1 filters did not degrade detectably when exposed to Earth/atmosphere-reflected solar radiation.

Characteristic investigation of Golay9 multiple mirror telescope with a spherical primary mirror

NASA Astrophysics Data System (ADS)

Wu, Feng; Wu, Quanying; Zhu, Xifang; Xiang, Ruxi; Qian, Lin

2017-10-01

The sparse aperture provides a novel solution to the manufacturing difficulties of modern super large telescopes. Golay configurations are optimal in the sparse aperture family. Characteristics of the Golay9 multiple mirror telescope having a spherical primary mirror are investigated. The arrangement of the nine sub-mirrors is discussed after the planar Golay9 configuration is analyzed. The characteristics of the entrance pupil are derived by analyzing the sub-aperture shapes with different relative apertures and sub-mirror sizes. Formulas about the fill factor and the overlay factor are deduced. Their maximal values are presented based on the derived tangency condition. Formulas for the point spread function (PSF) and the modulation transfer function (MTF) of the Golay9 MMT are also deduced. Two Golay9 MMT have been developed by Zemax simulation. Their PSF, MTF, fill factors, and overlay factors prove that our theoretical results are consistent with the practical simulation ones.

More Toda-like (0,2) mirrors

NASA Astrophysics Data System (ADS)

Chen, Zhuo; Guo, Jirui; Sharpe, Eric; Wu, Ruoxu

2017-08-01

In this paper, we extend our previous work to construct (0 , 2) Toda-like mirrors to A/2-twisted theories on more general spaces, as part of a program of understanding (0,2) mirror symmetry. Specifically, we propose (0 , 2) mirrors to GLSMs on toric del Pezzo surfaces and Hirzebruch surfaces with deformations of the tangent bundle. We check the results by comparing correlation functions, global symmetries, as well as geometric blowdowns with the corresponding (0 , 2) Toda-like mirrors. We also briefly discuss Grassmannian manifolds.

The meter-class carbon fiber reinforced polymer mirror and segmented mirror telescope at the Naval Postgraduate School

NASA Astrophysics Data System (ADS)

Wilcox, Christopher; Fernandez, Bautista; Bagnasco, John; Martinez, Ty; Romeo, Robert; Agrawal, Brij

2015-03-01

The Adaptive Optics Center of Excellence for National Security at the Naval Postgraduate School has implemented a technology testing platform and array of facilities for next-generation space-based telescopes and imaging system development. The Segmented Mirror Telescope is a 3-meter, 6 segment telescope with actuators on its mirrors for system optical correction. Currently, investigation is being conducted in the use of lightweight carbon fiber reinforced polymer structures for large monolithic optics. Advantages of this material include lower manufacturing costs, very low weight, and high durability and survivability compared to its glass counterparts. Design and testing has begun on a 1-meter, optical quality CFRP parabolic mirror for the purpose of injecting collimated laser light through the SMT primary and secondary mirrors as well as the following aft optics that include wavefront sensors and deformable mirrors. This paper will present the design, testing, and usage of this CFRP parabolic mirror and the current path moving forward with this ever-evolving technology.

Sensorimotor learning configures the human mirror system.

PubMed

Catmur, Caroline; Walsh, Vincent; Heyes, Cecilia

2007-09-04

Cells in the "mirror system" fire not only when an individual performs an action but also when one observes the same action performed by another agent [1-4]. The mirror system, found in premotor and parietal cortices of human and monkey brains, is thought to provide the foundation for social understanding and to enable the development of theory of mind and language [5-9]. However, it is unclear how mirror neurons acquire their mirror properties -- how they derive the information necessary to match observed with executed actions [10]. We address this by showing that it is possible to manipulate the selectivity of the human mirror system, and thereby make it operate as a countermirror system, by giving participants training to perform one action while observing another. Before this training, participants showed event-related muscle-specific responses to transcranial magnetic stimulation over motor cortex during observation of little- and index-finger movements [11-13]. After training, this normal mirror effect was reversed. These results indicate that the mirror properties of the mirror system are neither wholly innate [14] nor fixed once acquired; instead they develop through sensorimotor learning [15, 16]. Our findings indicate that the human mirror system is, to some extent, both a product and a process of social interaction.

Design and analysis of an active optics system for a 4-m telescope mirror combining hydraulic and pneumatic supports

NASA Astrophysics Data System (ADS)

Lousberg, Gregory P.; Moreau, Vincent; Schumacher, Jean-Marc; Piérard, Maxime; Somja, Aude; Gloesener, Pierre; Flebus, Carlo

2015-09-01

AMOS has developed a hybrid active optics system that combines hydraulic and pneumatic properties of actuators to support a 4-m primary mirror. The mirror is intended to be used in the Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope) that will be installed by the National Solar Observatory (NSO) atop the Haleakala volcano in Hawaii. The mirror support design is driven by the needs of (1) minimizing the support-induced mirror distortions under telescope operating conditions, (2) shaping the mirror surface to the desired profile, and (3) providing a high stiffness against wind loads. In order to fulfill these requirements, AMOS proposes an innovative support design that consist of 118 axial actuators and 24 lateral actuators. The axial support is based on coupled hydraulic and pneumatic actuators. The hydraulic part is a passive system whose main function is to support the mirror weight with a high stiffness. The pneumatic part is actively controlled so as to compensate for low-order wavefront aberrations that are generated by the mirror support itself or by any other elements in the telescope optical chain. The performances of the support and its adequacy with the requirements are assessed with the help of a comprehensive analysis loop involving finite-element, thermal and optical modellings.

ZERODUR thermo-mechanical modelling and advanced dilatometry for the ELT generation

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Kunisch, Clemens; Westerhoff, Thomas

2016-07-01

Large amounts of low thermal expansion material are required for the upcoming ELT projects. The main mirror is designed using several hundreds of hexagonal 1.4 m sized mirror blanks. The M2 and M3 are monolithic 4 m class mirror blanks. The mirror blank material needs to fulfill tight requirements regarding CTE specification and homogeneity. Additionally the mirror blanks need to be dimensionally stable for more than 30 years. In particular, stress effects due to the changes in the environment shall not entail shape variation of more than 0.5 μm PV within 30 years. In 2010 SCHOTT developed a physically based model to describe the thermal and mechanical long time behavior of ZERODUR. The model enables simulation of the long time behavior of ZERODUR mirror blanks under realistic mechanical and thermal constraints. This presentation shows FEM simulation results on the long time behavior of the ELT M1, M2 and M3 mirror blanks under different loading conditions. Additionally the model results will be compared to an already 15 years lasting long time measurement of a ZERODUR sample at the German federal physical standardization institute (PTB). In recent years SCHOTT pushed the push rod dilatometer measurement technology to its limit. With the new Advanced Dilatometer CTE measurement accuracies of +- 3 ppb/K and reproducibilities of better 1 ppb/K have been achieved. The new Advanced Dilatometer exhibits excellent long time stability.

The neuronal correlates of mirror therapy: A functional magnetic resonance imaging study on mirror-induced visual illusions of ankle movements.

PubMed

Guo, Feng; Xu, Qun; Abo Salem, Hassan M; Yao, Yihao; Lou, Jicheng; Huang, Xiaolin

2016-05-15

Recovery in stroke is mediated by neural plasticity. Mirror therapy is an effective method in the rehabilitation of stroke patients, but the mechanism is still obscure. To identify the neural networks associated with the effect of lower-limbs mirror therapy, we investigated a functional magnetic resonance imaging (fMRI) study of mirror-induced visual illusion of ankle movements. Five healthy controls and five left hemiplegic stroke patients performed tasks related to mirror therapy in the fMRI study. Neural activation was compared in a no-mirror condition and a mirror condition. All subjects in the experiment performed the task of flexing and extending the right ankle. In a mirror condition, movement of the left ankle was simulated by mirror reflection of right ankle movement. Changes in neural activation in response to mirror therapy were assessed both in healthy controls and stroke patients. We found strong activation of the motor cortex bilaterally in healthy controls, as well as significant activation of the ipsilateral sensorimotor cortex, the occipital gyrus, and the anterior prefrontal gyrus in stroke patients with respect to the non-mirror condition. We concluded that mirror therapy of ankle movements may induce neural activation of the ipsilesional sensorimotor cortex, and that cortical reorganization may be useful for motor rehabilitation in stroke. Copyright © 2016 Elsevier B.V. All rights reserved.

A Research on the Primary Mirror Manipulator of Large Segmented-mirror Telescope

NASA Astrophysics Data System (ADS)

Zuo, H.

2012-09-01

Since Galileo firstly used the telescope to observe the sky 400 years ago, the aperture of the telescope has become larger and larger to observe the deeper universe, and the segmented-mirror telescope is becoming more and more popular with increasing aperture. In the early 21st century, a series of segmented-mirror telescopes have been constructed including the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) of China. LAMOST is a meridian reflecting Schmidt telescope, and the dimension of the primary mirror is about 6.7 m× 6 m, which is composed of 37 hexagonal sub-mirrors. However, a problem about the mirror installation appears with the increasing aperture. If there are hundreds of sub-mirrors in the telescope, it is a challenging job to mount and dismount them to the truss. This problem is discussed in this paper and a manipulator for the primary mirror of LAMOST is designed to perform the mount and dismount work. In chapter 1, all the segmented-mirror telescopes in the world are introduced and how the sub-mirrors of these telescopes are installed has been investigated. After comparing with the serial and the parallel robot, a serial robot manipulator proposal, which has several redundant degrees of freedom (DOFs), has been chosen from a series of design proposals. In chapter 2, the theoretical analysis has been carried out on the basis of the design proposal, which includes the forward kinematics and the inverse kinematics. Firstly the D-H coordinate is built according to the structure of the manipulator, so it is possible to obtain the end-effector position and orientation from the individual joint motion thanks to the forward kinematics. Because of the redundant DOFs of the manipulator, the inverse kinematics solution can be a very trick task, and the result may not be only, therefore a kind of simulation is carried out to get the numerical solution using ADAMS (Automatic Dynamic Analysis of Mechanical System). In the dynamics analysis the

Membrane Mirrors With Bimorph Shape Actuators

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok

2003-01-01

Deformable mirrors of a proposed type would be equipped with relatively-large-stroke microscopic piezoelectric actuators that would be used to maintain their reflective surfaces in precise shapes. These mirrors would be members of the class of MEMS-DM (for microelectromechanical system deformable mirror) devices, which offer potential for a precise optical control in adaptive-optics applications in such diverse fields as astronomy and vision science. The proposed mirror would be fabricated, in part, by use of a membrane-transfer technique. The actuator design would contain bimorph-type piezoelectric actuators.

SIRTF primary mirror design, analysis, and testing

NASA Technical Reports Server (NTRS)

Sarver, George L., III; Maa, Scott; Chang, LI

1990-01-01

The primary mirror assembly (PMA) requirements and concepts for the Space Infrared Telescope Facility (SIRTF) program are discussed. The PMA studies at NASA/ARC resulted in the design of two engineering test articles, the development of a mirror mount cryogenic static load testing system, and the procurement and partial testing of a full scale spherical mirror mounting system. Preliminary analysis and testing of the single arch mirror with conical mount design and the structured mirror with the spherical mount design indicate that the designs will meet all figure and environmental requirements of the SIRTF program.

Owning the body in the mirror: The effect of visual perspective and mirror view on the full-body illusion

PubMed Central

Preston, Catherine; Kuper-Smith, Benjamin J.; Henrik Ehrsson, H.

2015-01-01

Mirrors allow us to view our own body from a third-person (observer) perspective. However, how viewing ourselves through a mirror affects central body representations compared with true third-person perspective is not fully understood. Across a series of experiments, multisensory full-body illusions were used to modulate feelings of ownership over a mannequin body that was viewed from a third-person perspective through a mirror, from a third-person perspective without a mirror, and from a first-person perspective. In contrast to non-mirror third-person perspective, synchronously touching the participant’s actual body and the mannequin body viewed in the mirror elicited strong feelings of ownership over the mannequin and increased physiological responses to the mannequin being threatened compared to the equivalent asynchronous (non-ownership) control condition. Subjective reports of ownership viewing the mannequin through a mirror were also statistically equivalent to those following the first-person perspective illusion. These findings suggest that mirrors have a special role for viewing the self. The results also support the importance of egocentric reference frames for body ownership and suggest that mirror reflections of one’s own body are related to peripersonal space, which enables updating of central body representations. PMID:26678091

Composite structures for optical mirror applications

NASA Astrophysics Data System (ADS)

Brand, Richard A.; Marks, John E.

1990-10-01

The employment of composites in RF structures such as antennas, feedhorns, and waveguides is outlined, and focus is placed on the parameters of a composite mirror operating in the 3-5- and 8-12-micron areas. A large beam-steering composite mirror fabricated from ultrahigh-modulus graphite/epoxy is described, including its three subassemblies: the core subassembly and two facesheet subassemblies. Attention is given to an alternative approach in which a gel coat resin is applied to the glass surface and the mirror substrate is pressed to the tool to cover the mirror with the resin. Another method is to seal the composite from the effects of moisture expansion by applying a eutectic coating; voids and crystal-grain growth are the main sources of surface perturbation on such mirror surfaces.

A comparison of performance of lightweight mirrors

NASA Technical Reports Server (NTRS)

Cho, Myung K.; Richard, Ralph M.; Hileman, Edward A.

1990-01-01

Four lightweight solid contoured back mirror shapes (a double arch, a single arch, a modified single arch, and a double concave mirror) and a cellular sandwich lightweight meniscus mirror, have been considered for the primary mirror of the Space Infrared Telescope Facility (SIRTF). A parametric design study using these shapes for the SIRTF 40 inch primary mirror with a focal ratio f/2 is presented. Evaluations of the optical performance and fundamental frequency analyses are performed to compare relative merits of each mirror configuration. Included in these are structural, optical, and frequency analyses for (1) different back contour shapes, (2) different number and location of the support points, and (3) two gravity orientations (ZENITH and HORIZON positions). The finite element program NASTRAN is used to obtain the structural deflections of the optical surface. For wavefront error analysis, FRINGE and PCFRINGE programs are used to evaluate the optical performance. A scaling law relating the optical and structural performance for various mirror contoured back shapes is developed.

A Deployable Primary Mirror for Space Telescopes

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Phelps, James E.; Dyer, Jack E.; Caudle, David A.; Tam, Anthony; Escobedo, Javier; Kasl, Eldon P.

1999-01-01

NASA Langley Research Center, Composite Optics, Inc., and Nyma/ADF have developed jointly a deployable primary mirror for space telescopes that combines over five years of research on deployment of optical-precision structures and over ten years of development of fabrication techniques for optical-precision composite mirror panels and structures. The deployable mirror is directly applicable to a broad class of non-imaging "lidar" (light direction a nd ranging) telescopes whose figure-error requirements are in the range of one to ten microns RMS. Furthermore, the mirror design can be readily modified to accommodate imaging-quality reflector panels and active panel-alignment control mechanisms for application to imaging telescopes. The present paper: 1) describes the deployable mirror concept; 2) explains the status of the mirror development; and 3) provides some technical specifications for a 2.55- m-diameter, proof-of-concept mirror. Keywords: precision deployment, hinge joint, latch joint, deployable structures, fabrication, space telescopes, optical instruments, microdynamics.

Rollable Thin Shell Composite-Material Paraboloidal Mirrors

NASA Technical Reports Server (NTRS)

Meinel, Aden; Meinel, Marjorie; Romeo, Robert

2003-01-01

An experiment and calculation have demonstrated the feasibility of a technique of compact storage of paraboloidal mirrors made of thin composite-material (multiple layers of carbon fiber mats in a polymeric matrix) shells coated with metal for reflectivity. Such mirrors are under consideration as simple, lightweight alternatives to the heavier, more complex mirrors now used in space telescopes. They could also be used on Earth in applications in which gravitational sag of the thin shells can be tolerated. The present technique is essentially the same as that used to store large maps, posters, tapestries, and similar objects: One simply rolls up the mirror to a radius small enough to enable the insertion of the mirror in a protective cylindrical case. Provided that the stress associated with rolling the mirror is not so large as to introduce an appreciable amount of hysteresis, the mirror can be expected to spring back to its original shape, with sufficient precision to perform its intended optical function, when unrolled from storage.

Evaluation of microfabricated deformable mirror systems

NASA Astrophysics Data System (ADS)

Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

1998-09-01

This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

Minimal mirror twin Higgs

DOE PAGES

Barbieri, Riccardo; Hall, Lawrence J.; Harigaya, Keisuke

2016-11-29

In a Mirror Twin World with a maximally symmetric Higgs sector the little hierarchy of the Standard Model can be significantly mitigated, perhaps displacing the cutoff scale above the LHC reach. We show that consistency with observations requires that the Z 2 parity exchanging the Standard Model with its mirror be broken in the Yukawa couplings. A minimal such effective field theory, with this sole Z 2 breaking, can generate the Z 2 breaking in the Higgs sector necessary for the Twin Higgs mechanism. The theory has constrained and correlated signals i n Higgs decays, direct Dark Matter Detection andmore » Dark Radiation, all within reach of foreseen experiments, over a region of parameter space where the fine-tuning for the electroweak scale is 10-50%. For dark matter, both mirror neutrons and a variety of self-interacting mirror atoms are considered. Neutrino mass signals and the effects of a possible additional Z 2 breaking from the vacuum expectation values of B-L breaking fields are also discussed.« less

Auditory-vocal mirroring in songbirds.

PubMed

Mooney, Richard

2014-01-01

Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory-vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory-vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory-vocal mirroring in the songbird's brain.

Mounting and Alignment of IXO Mirror Segments

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Zhang, William; Evans, Tyler; McClelland, Ryan; Hong, Melinda; Mazzarella, James; Saha, Timo; Jalota, Lalit; Olsen, Lawrence; Byron, Glenn

2010-01-01

A suspension-mounting scheme is developed for the IXO (International X-ray Observatory) mirror segments in which the figure of the mirror segment is preserved in each stage of mounting. The mirror, first fixed on a thermally compatible strongback, is subsequently transported, aligned and transferred onto its mirror housing. In this paper, we shall outline the requirement, approaches, and recent progress of the suspension mount processes.

Giant pandas failed to show mirror self-recognition.

PubMed

Ma, Xiaozan; Jin, Yuan; Luo, Bo; Zhang, Guiquan; Wei, Rongping; Liu, Dingzhen

2015-05-01

Mirror self-recognition (MSR), i.e., the ability to recognize oneself in a mirror, is considered a potential index of self-recognition and the foundation of individual development. A wealth of literature on MSR is available for social animals, such as chimpanzees, Asian elephants and dolphins, yet little is known about MSR in solitary mammalian species. We aimed to evaluate whether the giant panda can recognize itself in the mirror, and whether this capacity varies with age. Thirty-four captive giant pandas (F:M = 18:16; juveniles, sub-adults and adults) were subjected to four mirror tests: covered mirror tests, open mirror tests, water mark control tests, and mark tests. The results showed that, though adult, sub-adult and juvenile pandas exposed to mirrors spent similar amounts of time in social mirror-directed behaviors (χ(2) = 0.719, P = 0.698), none of them used the mirror to touch the mark on their head, a self-directed behavior suggesting MSR. Individuals of all age groups initially displayed attacking, threatening, foot scraping and backwards walking behaviors when exposed to their self-images in the mirror. Our data indicate that, regardless of age, the giant pandas did not recognize their self-image in the mirror, but instead considered the image to be a conspecific. Our results add to the available information on mirror self-recognition in large mammals, provide new information on a solitary species, and will be useful for enclosure design and captive animal management.

Titanium Alloy Strong Back for IXO Mirror Segments

NASA Technical Reports Server (NTRS)

Byron, Glenn P.; Kai-Wang, Chan

2011-01-01

A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.

SOFIA lightweight primary mirror

NASA Astrophysics Data System (ADS)

Espiard, Jean; Tarreau, Michel; Bernier, Joel; Billet, Jacques; Paseri, Jacques

1998-08-01

Thanks to its experience in lightweighting ceramic glass mirrors by machining, R.E.O.S.C. won the contract for designing and manufacturing the primary mirror and its lateral fixations of the 2.7 m. SOFIA telescope which will be installed aboard a 747 SP Boeing aircraft to constitute the Stratospheric Observatory for Infrared Astronomy (SOFIA).

Solid, 3-mirror Fabry-Perot etalon.

PubMed

Stephen, Mark; Fahey, Molly; Miller, Ian

2017-04-01

We present modeling and performance of a solid, fused silica, 3-mirror Fabry-Perot-type etalon. 3-mirror etalons have been known for decades to have superior theoretical performance but for the first time we demonstrate an etalon with sufficient quality to realize the benefits of the more complex design. 3-mirror etalons have better passband shape and higher contrast ratio enabling significantly improved wavelength separation. We show the optical cavity design and construction of the new etalon and show >95% peak transmission, improved passband shape and 20 dB better out-of-band rejection than a similar 2-mirror etalon.

Background-reducing X-ray multilayer mirror

DOEpatents

Bloch, Jeffrey J.; Roussel-Dupre', Diane; Smith, Barham W.

1992-01-01

Background-reducing x-ray multilayer mirror. A multiple-layer "wavetrap" deposited over the surface of a layered, synthetic-microstructure soft x-ray mirror optimized for reflectivity at chosen wavelengths is disclosed for reducing the reflectivity of undesired, longer wavelength incident radiation incident thereon. In three separate mirror designs employing an alternating molybdenum and silicon layered, mirrored structure overlaid by two layers of a molybdenum/silicon pair anti-reflection coating, reflectivities of near normal incidence 133, 171, and 186 .ANG. wavelengths have been optimized, while that at 304 .ANG. has been minimized. The optimization process involves the choice of materials, the composition of the layer/pairs as well as the number thereof, and the distance therebetween for the mirror, and the simultaneous choice of materials, the composition of the layer/pairs, and their number and distance for the "wavetrap."

Advancement's Sticky Issues

ERIC Educational Resources Information Center

Jackson, Patricia

2011-01-01

The author did not expect to be surprised or disturbed by the data from the latest Council for Advancement and Support of Education (CASE) salary survey; however, she was. CASE has been conducting the survey since 1982, so she assumed the findings would mirror her own salary history and those of her peers. While she suspected that older women…

Dual-use bimorph deformable mirrors

NASA Astrophysics Data System (ADS)

Griffith, M. S.; Laycock, L. C.; Bagshaw, J. M.; Rowe, D.

2005-11-01

Adaptive Optics (AO) is a critical underpinning technology for future optical countermeasures, laser delivery, target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. AO is also well established in ground based astronomy, and is finding applications in free space optical communications and ophthalmology. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS ATC is developing multi-element Deformable Bimorph Mirrors (DBMs) for such applications. A traditional bimorph deformable mirror uses a set of edge electrodes outside the active area in order to meet the required boundary conditions for the active aperture. This inflicts a significant penalty in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. We have devised a number of novel mounting arrangements that reduce dead space and thus provide a much improved trade-off between bandwidth and stroke. These schemes include a novel method for providing vertical displacement at the periphery of the aperture, a method for providing a continuous compliant support underneath the bimorph mirror, and a method for providing a three point support underneath the bimorph. In all three cases, there is no requirement for edge electrodes to provide the boundary conditions, resulting in devices of much higher bandwidth. The target is to broaden the use of these types of mirror beyond the current limits of either low order/low bandwidth, to address the high order, high bandwidth systems required by long range, horizontal path applications. This paper will discuss the different mirror designs, and present experimental results for the most recently assembled mirrors.

Directly polished lightweight aluminum mirror

NASA Astrophysics Data System (ADS)

ter Horst, Rik; Tromp, Niels; de Haan, Menno; Navarro, Ramon; Venema, Lars; Pragt, Johan

2017-11-01

During the last ten years, Astron has been a major contractor for the design and manufacturing of astronomical instruments for Space- and Earth based observatories, such as VISIR, MIDI, SPIFFI, X-Shooter and MIRI. Driven by the need to reduce the weight of optically ultra-stiff structures, two promising techniques have been developed in the last years: ASTRON Extreme Lightweighting [1][2] for mechanical structures and an improved Polishing Technique for Aluminum Mirrors. Using one single material for both optical components and mechanical structure simplifies the design of a cryogenic instrument significantly, it is very beneficial during instrument test and verification, and makes the instrument insensitive to temperature changes. Aluminum has been the main material used for cryogenic optical instruments, and optical aluminum mirrors are generally diamond turned. The application of a polishable hard top coating like nickel removes excess stray light caused by the groove pattern, but limits the degree of lightweighting of the mirrors due to the bi-metal effect. By directly polishing the aluminum mirror surface, the recent developments at Astron allow for using a non-exotic material for light weighted yet accurate optical mirrors, with a lower surface roughness ( 1nm RMS), higher surface accuracy and reduced light scattering. This paper presents the techniques, obtained results and a global comparison with alternative lightweight mirror solutions. Recent discussions indicate possible extensions of the extreme light weight technology to alternative materials such as Zerodur or Silicon Carbide.

Auditory–vocal mirroring in songbirds

PubMed Central

Mooney, Richard

2014-01-01

Mirror neurons are theorized to serve as a neural substrate for spoken language in humans, but the existence and functions of auditory–vocal mirror neurons in the human brain remain largely matters of speculation. Songbirds resemble humans in their capacity for vocal learning and depend on their learned songs to facilitate courtship and individual recognition. Recent neurophysiological studies have detected putative auditory–vocal mirror neurons in a sensorimotor region of the songbird's brain that plays an important role in expressive and receptive aspects of vocal communication. This review discusses the auditory and motor-related properties of these cells, considers their potential role on song learning and communication in relation to classical studies of birdsong, and points to the circuit and developmental mechanisms that may give rise to auditory–vocal mirroring in the songbird's brain. PMID:24778375

Engineers Clean Mirror with Carbon Dioxide Snow

NASA Image and Video Library

2015-01-22

Just like drivers sometimes use snow to clean their car mirrors in winter, two Exelis Inc. engineers are practicing "snow cleaning'" on a test telescope mirror for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland. By shooting carbon dioxide snow at the surface, engineers are able to clean large telescope mirrors without scratching them. "The snow-like crystals (carbon dioxide snow) knock contaminate particulates and molecules off the mirror," said Lee Feinberg, NASA optical telescope element manager. This technique will only be used if the James Webb Space Telescope's mirror is contaminated during integration and testing. The Webb telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. With a mirror seven times as large as Hubble's and infrared capability, Webb will be capturing light from 13.5 billion light years away. To do this, its mirror must be kept super clean. "Small dust particles or molecules can impact the science that can be done with the Webb," said Feinberg. "So cleanliness especially on the mirrors is critical." Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency. Image credit: NASA/Goddard/Chris Gunn

Polarimetry with multiple mirror telescopes

NASA Technical Reports Server (NTRS)

West, S. C.

1986-01-01

The polarizations of multiple mirror telescopes are calculated using Mueller calculus. It is found that the Multiple Mirror Telescope (MMT) produces a constant depolarization that is a function of wavelength and independent of sky position. The efficiency and crosstalk are modeled and experimentally verified. The two- and four-mirror new generation telescopes are found to produce sinusoidal depolarization for which an accurate interpretation of the incident Stokes vector requires inverse matrix calculations. Finally, the depolarization of f/1 paraboloids is calculated and found to be less than 0.1 percent at 3000 A.

Novel unimorph deformable mirror for space applications

NASA Astrophysics Data System (ADS)

Verpoort, Sven; Rausch, Peter; Wittrock, Ulrich

2017-11-01

We have developed a new type of unimorph deformable mirror, designed to correct for low-order Zernike modes. The mirror has a clear optical aperture of 50 mm combined with large peak-to-valley Zernike amplitudes of up to 35 μm. Newly developed fabrication processes allow the use of prefabricated super-polished and coated glass substrates. The mirror's unique features suggest the use in several astronomical applications like the precompensation of atmospheric aberrations seen by laser beacons and the use in woofer-tweeter systems. Additionally, the design enables an efficient correction of the inevitable wavefront error imposed by the floppy structure of primary mirrors in future large space-based telescopes. We have modeled the mirror by using analytical as well as finite element models. We will present design, key features and manufacturing steps of the deformable mirror.

Light-weight spherical mirrors for Cherenkov detectors

NASA Astrophysics Data System (ADS)

Cisbani, E.; Colilli, S.; Crateri, R.; Cusanno, F.; Fratoni, R.; Frullani, S.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Iodice, M.; Iommi, R.; Lucentini, M.; Mostarda, A.; Pierangeli, L.; Santavenere, F.; Urciuoli, G. M.; De Leo, R.; Lagamba, L.; Nappi, E.; Braem, A.; Vernin, P.

2003-01-01

Light-weight spherical mirrors have been appositely designed and built for the gas threshold Cherenkov detectors of the two Hall A spectrometers. The mirrors are made of a 1 mm thick aluminized plexiglass sheet, reinforced by a rigid backing consisting of a phenolic honeycomb sandwiched between two carbon fiber mats epoxy glued. The produced mirrors have a thickness equivalent to 0.55% of radiation length, and an optical slope error of about 5.5 mrad. These characteristics make these mirrors suitable for the implementation in Cherenkov threshold detectors. Ways to improve the mirror features are also discussed in view of their possible employment in RICH detectors.

Enhanced Fluoride Over-Coated Al Mirrors for FUV Astronomy

NASA Technical Reports Server (NTRS)

Quijada, Manuel A.; DelHoyo, Javier; Rice, Steve; Threat, Felix

2014-01-01

Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+MgF2 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the MgF2 overcoat at elevated substrate temperatures. We will also present optical characterization of little studied rare-earth fluorides such as GdF3 and LuF3 that exhibit low-absorption over a wide wavelength range and could therefore be used as high refractive index alternatives for dielectric coatings at FUV wavelengths.

Optical properties of relativistic plasma mirrors

PubMed Central

Vincenti, H.; Monchocé, S.; Kahaly, S.; Bonnaud, G.; Martin, Ph.; Quéré, F.

2014-01-01

The advent of ultrahigh-power femtosecond lasers creates a need for an entirely new class of optical components based on plasmas. The most promising of these are known as plasma mirrors, formed when an intense femtosecond laser ionizes a solid surface. These mirrors specularly reflect the main part of a laser pulse and can be used as active optical elements to manipulate its temporal and spatial properties. Unfortunately, the considerable pressures exerted by the laser can deform the mirror surface, unfavourably affecting the reflected beam and complicating, or even preventing, the use of plasma mirrors at ultrahigh intensities. Here we derive a simple analytical model of the basic physics involved in laser-induced deformation of a plasma mirror. We validate this model numerically and experimentally, and use it to show how such deformation might be mitigated by appropriate control of the laser phase. PMID:24614748

Properties of chirped mirrors manufactured by plasma ion assisted electron beam evaporation

NASA Astrophysics Data System (ADS)

Bischoff, Martin; Stenzel, Olaf; Gäbler, Dieter; Kaiser, Norbert

2005-09-01

Nowadays, chirped dielectric mirrors for ultrafast optics and laser applications are usually manufactured by sputtering techniques. The suitability of Advanced Plasma Source (APS) assisted electron beam evaporation with respect to such coatings is still under investigation. The purpose of this presentation is to show our first results of the deposition of chirped layers produced by plasma ion assisted electron beam evaporation and of the investigation of their properties. The aim was to design and prepare a NIR-mirror for the spectral range of 700 nm to 900 nm. It has been attempted to find a design that is robust with respect to errors of thickness and refractive index. The mirror consists of more than 26 layers composed of alternating high- (Nb2O5) and low-refractive index (SiO2) material. The deposited coatings were tested in terms of their group delay dispersion (GDD) and their reflectivity. We show, that in the wavelength range between 720 nm and 890 nm the GDD exhibits a value of about -50 fs2, whereas the reflectivity is above 99%. However, the subsequent reverse engineering operations show a relatively large thickness error of more than 1% - 2% regarding the particular layers. Nevertheless the effect on the GDD and the reflectivity is tolerable. Furthermore, we present our first experiments concerning the design and fabrication of a chirped mirror, which allows controlling the third order dispersion (TOD), whereas the relative thickness error of the particular layers should not exceed 1%.

Lightweight deformable mirrors for future space telescopes

NASA Astrophysics Data System (ADS)

Patterson, Keith

This thesis presents a concept for ultra-lightweight deformable mirrors based on a thin substrate of optical surface quality coated with continuous active piezopolymer layers that provide modes of actuation and shape correction. This concept eliminates any kind of stiff backing structure for the mirror surface and exploits micro-fabrication technologies to provide a tight integration of the active materials into the mirror structure, to avoid actuator print-through effects. Proof-of-concept, 10-cm-diameter mirrors with a low areal density of about 0.5 kg/m2 have been designed, built and tested to measure their shape-correction performance and verify the models used for design. The low cost manufacturing scheme uses replication techniques, and strives for minimizing residual stresses that deviate the optical figure from the master mandrel. It does not require precision tolerancing, is lightweight, and is therefore potentially scalable to larger diameters for use in large, modular space telescopes. Other potential applications for such a laminate could include ground-based mirrors for solar energy collection, adaptive optics for atmospheric turbulence, laser communications, and other shape control applications. The immediate application for these mirrors is for the Autonomous Assembly and Reconfiguration of a Space Telescope (AAReST) mission, which is a university mission under development by Caltech, the University of Surrey, and JPL. The design concept, fabrication methodology, material behaviors and measurements, mirror modeling, mounting and control electronics design, shape control experiments, predictive performance analysis, and remaining challenges are presented herein. The experiments have validated numerical models of the mirror, and the mirror models have been used within a model of the telescope in order to predict the optical performance. A demonstration of this mirror concept, along with other new telescope technologies, is planned to take place during

The use of mirrors in critical care nursing.

PubMed

Freysteinson, Wyona M

2009-01-01

There is no known literature to guide the critical care nurse in the use of mirrors in patient care. This article explores how the author came to believe that mirrors were essential to nursing practice. Misconceptions and assumptions concerning mirrors are explored. A framework that conceptually explores the experience of viewing self in the mirror from the perspective of a person is presented. Five situations in which the mirror may be used in critical care are discussed. This article does not present an authoritative view on mirrors in nursing; rather, it is an invitation to dialogue about a unique element in the environment that may be used to enhance nursing care.

Polarization Phase-Compensating Coats for Metallic Mirrors

NASA Technical Reports Server (NTRS)

Balasubramanian, Kunjithapatham

2006-01-01

A method of compensating for or minimizing phase differences between orthogonal polarizations of light reflected from metallic mirrors at oblique incidence, as, for example, from weakly curved mirrors, is undergoing development. The method is intended to satisfy a need to maintain precise polarization phase relationships or minimum polarization differences needed for proper operation of telescopes and other scientific instruments that include single or multiple mirrors. The basic idea of the method is to optimally coat mirrors with thin engineered layers of materials that introduce phase differences that, as nearly precisely as possible, are opposite of the undesired phase differences arising in reflection with non-optimum coatings. Depending on the specific optical system, the method could involve any or all of the following elements: a) Optimization of a single coat on all the mirrors in the system. b) Optimization of a unique coat for each mirror such that the polarization phase effects of the coat on one mirror compensate, to an acceptably high degree over an acceptably wide wavelength range, for those of the coat on another mirror. c) Tapering the coat on each mirror. Optimization could involve the choice of a single dielectric coating material and its thickness, or design of a more complex coat consisting of multiple layers of different dielectric materials and possibly some metallic materials. Such designs and coatings are particularly significant and needed for obtaining very high quality of wavefront required in high-contrast imaging instruments such as the NASA Terrestrial Planet Finder Coronagraph.

Do Mirror Glasses Have the Same Effect on Brain Activity as a Mirror Box? Evidence from a Functional Magnetic Resonance Imaging Study with Healthy Subjects

PubMed Central

Milde, Christopher; Rance, Mariela; Kirsch, Pinar; Trojan, Jörg; Fuchs, Xaver; Foell, Jens; Bekrater-Bodmann, Robin

2015-01-01

Since its original proposal, mirror therapy has been established as a successful neurorehabilitative intervention in several neurological disorders to recover motor function or to relieve pain. Mirror therapy seems to operate by reactivating the contralesional representation of the non-mirrored limb in primary motor- and somatosensory cortex. However, mirror boxes have some limitations which prompted the use of additional mirror visual feedback devices. The present study evaluated the utility of mirror glasses compared to a mirror box. We also tested the hypothesis that increased interhemispheric communication between the motor hand areas is the mechanism by which mirror visual feedback recruits the representation of the non-mirrored limb. Therefore, mirror illusion capacity and brain activations were measured in a within-subject design during both mirror visual feedback conditions in counterbalanced order with 20 healthy subjects inside a magnetic resonance imaging scanner. Furthermore, we analyzed task-dependent functional connectivity between motor hand representations using psychophysiological interaction analysis during both mirror tasks. Neither the subjective quality of mirror illusions nor the patterns of functional brain activation differed between the mirror tasks. The sensorimotor representation of the non-mirrored hand was recruited in both mirror tasks. However, a significant increase in interhemispheric connectivity between the hand areas was only observed in the mirror glasses condition, suggesting different mechanisms for the recruitment of the representation of the non-mirrored hand in the two mirror tasks. We conclude that the mirror glasses might be a promising alternative to the mirror box, as they induce similar patterns of brain activation. Moreover, the mirror glasses can be easy applied in therapy and research. We want to emphasize that the neuronal mechanisms for the recruitment of the affected limb representation might differ depending on

History of mirrors dating back 8000 years.

PubMed

Enoch, Jay M

2006-10-01

The purpose of this study is to consider the ancient history and early development of mirrors, because mirrors played a key role in refraction and magnification for an extended period of time before the invention of spectacles, including broad use in Roman times. The earliest known manufactured mirrors (approximately 8000 years old) have been found in Anatolia (south central modern-day Turkey). These were made from obsidian (volcanic glass), had a convex surface and remarkably good optical quality. Mirrors from more recent periods have been found both in Egypt and Mesopotamia and still later in China and in the New World. In each of these areas, mirrors were in use by approximately 2000 BC or 4000 years ago.

Mirror neurons and their clinical relevance.

PubMed

Rizzolatti, Giacomo; Fabbri-Destro, Maddalena; Cattaneo, Luigi

2009-01-01

One of the most exciting events in neurosciences over the past few years has been the discovery of a mechanism that unifies action perception and action execution. The essence of this 'mirror' mechanism is as follows: whenever individuals observe an action being done by someone else, a set of neurons that code for that action is activated in the observers' motor system. Since the observers are aware of the outcome of their motor acts, they also understand what the other individual is doing without the need for intermediate cognitive mediation. In this Review, after discussing the most pertinent data concerning the mirror mechanism, we examine the clinical relevance of this mechanism. We first discuss the relationship between mirror mechanism impairment and some core symptoms of autism. We then outline the theoretical principles of neurorehabilitation strategies based on the mirror mechanism. We conclude by examining the relationship between the mirror mechanism and some features of the environmental dependency syndromes.

SOFIA primary mirror fabrication and testing

NASA Astrophysics Data System (ADS)

Geyl, Roland; Tarreau, Michel; Plainchamp, Patrick

2001-12-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint American-German project dedicated to performing IR astronomy on board a Boeing Aircraft, in near space condition. First flight of the Observatory is planned for 2003. The REOSC Products Unit of SAGEM SA (France) has been contracted by Kayser Threde (Germany) for the design and fabrication of the 2.7-meter diameter, F/1.19 parabolic lightweight SOFIA primary mirror as well as the M3 dichroic and folding mirror assembly. This paper will report the design, fabrication and test of the lightweight primary mirror. The mirror structure has been obtained by machining it out from a solid Zerodur blank. It is the world's largest of this type today. Axial and lateral mirror support system has been conceptually designed and engineered by SAGEM-REOSC engineers in relation with Kayser Threde team. The optical surface is an F/1.19 parabola polished to a high level of quality.

A ferrofluidic deformable mirror for ophthalmology

NASA Astrophysics Data System (ADS)

Macpherson, J. B.; Thibault, S.; Borra, E. F.; Ritcey, A. M.; Carufel, N.; Asselin, D.; Jerominek, H.; Campbell, M. C. W.

2005-09-01

Optical aberrations reduce the imaging quality of the human eye. In addition to degrading vision, this limits our ability to illuminate small points of the retina for therapeutic, surgical or diagnostic purposes. When viewing the rear of the eye, aberrations cause structures in the fundus to appear blurred, limiting the resolution of ophthalmoscopes (diagnostic instruments used to image the eye). Adaptive optics, such as deformable mirrors may be used to compensate for aberrations, allowing the eye to work as a diffraction-limited optical element. Unfortunately, this type of correction has not been widely available for ophthalmic applications because of the expense and technical limitations of current deformable mirrors. We present preliminary design and characterisation of a deformable mirror suitable for ophthalmology. In this ferrofluidic mirror, wavefronts are reflected from a fluid whose surface shape is controlled by a magnetic field. Challenges in design are outlined, as are advantages over traditional deformable mirrors.

CFRP mirror technology for cryogenic space interferometry: review and progress to date

NASA Astrophysics Data System (ADS)

Jones, Martyn L.; Walker, David; Naylor, David A.; Veenendaal, Ian T.; Gom, Brad G.

2016-07-01

The FP7 project, FISICA (Far Infrared Space Interferometer Critical Assessment), called for the investigation into the suitability of Carbon fiber Reinforced Plastic (CFRP) for a 2m primary mirror. In this paper, we focus on the major challenge for application, the development of a mirror design that would maintain its form at cryogenic temperatures. In order to limit self-emission the primary is to be cooled to 4K whilst not exceeding a form error of 275nm PV. We then describe the development of an FEA model that utilizes test data obtained from a cryogenic test undertaken at the University of Lethbridge on CFRP samples. To conclude, suggestions are made in order to advance this technology to be suitable for such an application in order to exploit the low density and superior specific properties of polymeric composites.

Demonstrating Chirality: Using a Mirror with Physical Models To Show Non-superimposability of Chiral Molecules with Their Mirror Images.

ERIC Educational Resources Information Center

Collins, Michael J.

2001-01-01

Presents a remarkable demonstration on chiralty in molecules and the existence of enantiomers, also known as non-superimposable mirror images. Uses a mirror, a physical model of a molecule, and a bit of trickery involving the non-superimposable mirror image. (Author/NB)

Three-point spherical mirror mount

DOEpatents

Cutburth, Ronald W.

1990-01-01

A three-point spherical mirror mount for use with lasers is disclosed. The improved mirror mount is adapted to provide a pivot ring having an outer surface with at least three spaced apart mating points to engage an inner spherical surface of a support housing.

Three-point spherical mirror mount

DOEpatents

Cutburth, R.W.

1984-01-23

A three-point spherical mirror mount for use with lasers is disclosed. The improved mirror mount is adapted to provide a pivot ring having an outer surface with at least three spaced apart mating points to engage an inner spherical surface of a support housing.

Impedance Matched to Vacuum, Invisible Edge, Diffraction Suppressed Mirror

NASA Technical Reports Server (NTRS)

Hagopian, John G. (Inventor); Roman, Patrick A. (Inventor); Shiri, Sharham (Inventor); Wollack, Edward J. (Inventor)

2015-01-01

Diffraction suppressed mirrors having an invisible edge are disclosed for incident light at both targeted wavelengths and broadband incident light. The mirrors have a first having at least one discontiguous portion having a plurality of nanostructured apertures. The discontiguous mirror portion impedance matches a relatively high impedance portion of the mirror to a relatively low impedance portion of the mirror, thereby reducing the diffraction edge effect otherwise present in a conventional mirror.

Compliant deformable mirror approach for wavefront improvement

NASA Astrophysics Data System (ADS)

Clark, James H.; Penado, F. Ernesto

2016-04-01

We describe a compliant static deformable mirror approach to reduce the wavefront concavity at the Navy Precision Optical Interferometer (NPOI). A single actuator pressing on the back surface of just one of the relay mirrors deforms the front surface in a correcting convex shape. Our design uses the mechanical advantage gained from a force actuator sandwiched between a rear flexure plate and the back surface of the mirror. We superimpose wavefront contour measurements with our finite element deformed mirror model. An example analysis showed improvement from 210-nm concave-concave wavefront to 51-nm concave-concave wavefront. With our present model, a 100-nm actuator increment displaces the mirror surface by 1.1 nm. We describe the need for wavefront improvement that arises from the NPOI reconfigurable array, offer a practical design approach, and analyze the support structure and compliant deformable mirror using the finite element method. We conclude that a 20.3-cm-diameter, 1.9-cm-thick Zerodur® mirror shows that it is possible to deform the reflective surface and cancel out three-fourths of the wavefront deformation without overstressing the material.

LUTE primary mirror materials and design study report

NASA Astrophysics Data System (ADS)

Ruthven, Greg

1993-02-01

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

LUTE primary mirror materials and design study report

NASA Technical Reports Server (NTRS)

Ruthven, Greg

1993-01-01

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

Secrets of the Chinese magic mirror replica

NASA Astrophysics Data System (ADS)

Mak, Se-yuen; Yip, Din-yan

2001-03-01

We examine the structure of five Chinese magic mirror replicas using a special imaging technique developed by the authors. All mirrors are found to have a two-layered structure. The reflecting surface that gives rise to a projected magic pattern on the screen is hidden under a polished half-reflecting top layer. An alternative method of making the magic mirror using ancient technology has been proposed. Finally, we suggest a simple method of reconstructing a mirror replica in the laboratory.

The spinning Kerr-black-hole-mirror bomb: A lower bound on the radius of the reflecting mirror

NASA Astrophysics Data System (ADS)

Hod, Shahar

2016-10-01

The intriguing superradiant amplification phenomenon allows an orbiting scalar field to extract rotational energy from a spinning Kerr black hole. Interestingly, the energy extraction rate can grow exponentially in time if the black-hole-field system is placed inside a reflecting mirror which prevents the field from radiating its energy to infinity. This composed Kerr-black-hole-scalar-field-mirror system, first designed by Press and Teukolsky, has attracted the attention of physicists over the last four decades. Previous numerical studies of this spinning black-hole bomb have revealed the interesting fact that the superradiant instability shuts down if the reflecting mirror is placed too close to the black-hole horizon. In the present study we use analytical techniques to explore the superradiant instability regime of this composed Kerr-black-hole-linearized-scalar-field-mirror system. In particular, it is proved that the lower bound rm/r+ >1/2 (√{ 1 +8M/r- } - 1) provides a necessary condition for the development of the exponentially growing superradiant instabilities in this composed physical system, where rm is the radius of the confining mirror and r± are the horizon radii of the spinning Kerr black hole. We further show that, in the linearized regime, this analytically derived lower bound on the radius of the confining mirror agrees with direct numerical computations of the superradiant instability spectrum which characterizes the spinning black-hole-mirror bomb.

Light Weight Silicon Mirrors for Space Instrumentation

NASA Technical Reports Server (NTRS)

Bly, Vincent T.; Hill, Peter C.; Hagopian, John G.; Strojay, Carl R.; Miller, Timothy

2012-01-01

Each mirror is a monolithic structure from a single crystal of silicon. The mirrors are light weighted after the optical surface is ground and polished. Mirrors made during the initial phase of this work were typically 1/50 lambda or better (RMS at 633 n m)

Solar Collector Mirror for Brayton Power System

NASA Image and Video Library

1966-09-21

NASA’s Lewis Research Center conducted extensive research programs in the 1960s and 1970s to develop systems that provide electrical power in space. One system, the Brayton cycle engine, converted solar thermal energy into electrical power. This system operated on a closed-loop Brayton thermodynamic cycle. The Brayton system relied on this large mirror to collect radiation from the sun. The mirror concentrated the Sun's rays on a heat storage receiver which warmed the Brayton system’s working fluid, a helium-xenon gas mixture. The heated fluid powered the system’s generator which produced power. In the mid-1960s Lewis researchers constructed this 30-foot diameter prototype of a parabolic solar mirror for the Brayton cycle system. The mirror had to be rigid, impervious to micrometeorite strikes, and lightweight. This mirror was comprised of twelve 1-inch thick magnesium plate sections that were coated with aluminum. The mirror could be compactly broken into its sections for launch.

The Dizzying Depths of the Cylindrical Mirror

NASA Astrophysics Data System (ADS)

DeWeerd, Alan J.; Hill, S. Eric

2005-02-01

A typical introduction to geometrical optics treats plane and spherical mirrors. At first glance, it may be surprising that texts seldom mention the cylindrical mirror, except for the occasional reference to use in fun houses and to viewing anamorphic art.1,2 However, even a cursory treatment reveals its complexity. Holzberlein used an extended object to qualitatively illustrate that images are produced both before and behind a concave cylindrical mirror.3 He also speculated on how this extreme astigmatism results in an observer's dizziness. By considering a simple point object, we make a more detailed analysis of the cylindrical mirror and the dizziness it induces. First, we illustrate how rays from a point object reflect to form not one point image but two line images. Next, we describe how an observer perceives a likeness of the object. Finally, we suggest how confusing depth cues induce dizziness. Although we focus on the concave cylindrical mirror, the discussion is easy to generalize to the convex cylindrical mirror.

Mirror neurons and imitation: a computationally guided review.

PubMed

Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael

2006-04-01

Neurophysiology reveals the properties of individual mirror neurons in the macaque while brain imaging reveals the presence of 'mirror systems' (not individual neurons) in the human. Current conceptual models attribute high level functions such as action understanding, imitation, and language to mirror neurons. However, only the first of these three functions is well-developed in monkeys. We thus distinguish current opinions (conceptual models) on mirror neuron function from more detailed computational models. We assess the strengths and weaknesses of current computational models in addressing the data and speculations on mirror neurons (macaque) and mirror systems (human). In particular, our mirror neuron system (MNS), mental state inference (MSI) and modular selection and identification for control (MOSAIC) models are analyzed in more detail. Conceptual models often overlook the computational requirements for posited functions, while too many computational models adopt the erroneous hypothesis that mirror neurons are interchangeable with imitation ability. Our meta-analysis underlines the gap between conceptual and computational models and points out the research effort required from both sides to reduce this gap.

Cryogenic Test Results of Hextek Mirror

NASA Technical Reports Server (NTRS)

Hadaway, James; Stahl, H. Philip; Eng, Ron; Hogue, William

2004-01-01

A 250 mm diameter lightweight borosilicate mirror has been interferometrically tested from room-temperature down to 30 K at the X-Ray Calibration Facility (XRCF) at Marshall Space Flight Center (MSFC). The minor blank was manufactured by Hextek Corporation using a high-temperature gas fusion process and was then polished at MSFC. It is a sandwich-type mirror consisting of a thin face-sheet (approx.1.5 mm thick), a core structure (20 mm thick, approx.43 mm diameter cells, & 0.5-1.2 mm thick walls), and a thin back-sheet (3 mm thick). The mirror has a 2500 mm spherical radius-of- curvature @/lo). The areal density is 14 kg/sq m. The mirror was tested in the 1 m x 2 m chamber using an Instantaneous Phase Interferometer (PI) from ADE Phase Shift Technologies. The mirror was tested twice. The first test measured the change in surface figure from ambient to 30 K and the repeatability of the change. An attempt was then made by QED Technologies to cryo-figure the mirror using magnetorheological finishing. The second test measured the effectiveness of the cryo- figuring. This paper will describe the test goals, the test instrumentation, and the test results for these cryogenic tests.

Advanced Wavefront Sensing and Control Testbed (AWCT)

NASA Technical Reports Server (NTRS)

Shi, Fang; Basinger, Scott A.; Diaz, Rosemary T.; Gappinger, Robert O.; Tang, Hong; Lam, Raymond K.; Sidick, Erkin; Hein, Randall C.; Rud, Mayer; Troy, Mitchell

2010-01-01

The Advanced Wavefront Sensing and Control Testbed (AWCT) is built as a versatile facility for developing and demonstrating, in hardware, the future technologies of wave front sensing and control algorithms for active optical systems. The testbed includes a source projector for a broadband point-source and a suite of extended scene targets, a dispersed fringe sensor, a Shack-Hartmann camera, and an imaging camera capable of phase retrieval wavefront sensing. The testbed also provides two easily accessible conjugated pupil planes which can accommodate the active optical devices such as fast steering mirror, deformable mirror, and segmented mirrors. In this paper, we describe the testbed optical design, testbed configurations and capabilities, as well as the initial results from the testbed hardware integrations and tests.

Opto-Mechanics of the Constellation-X SXT Mirrors: Challenges in Mounting and Assembling the Mirror Segments

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Zhang, WIlliam W.; Saha, Timo; Lehan, John P.; Mazzarella, James; Lozipone, Lawrence; Hong, Melinda; Byron, Glenn

2008-01-01

The Constellation-X Spectroscopy X-Ray Telescopes consists of segmented glass mirrors with an axial length of 200 mm, a width of up to 400 mm, and a thickness of 0.4 mm. To meet the requirement of less than 15 arc-second half-power diameter with the small thickness and relatively large size is a tremendous challenge in opto-mechanics. How shall we limit distortion of the mirrors due to gravity in ground tests, that arises from thermal stress, and that occurs in the process of mounting, affixing and assembling of these mirrors? In this paper, we will describe our current opto-mechanical approach to these problems. We will discuss, in particular, the approach and experiment where the mirrors are mounted vertically by first suspending it at two points.

Mirror Neurons through the Lens of Epigenetics

PubMed Central

Ferrari, Pier F.; Tramacere, Antonella; Simpson, Elizabeth A.; Iriki, Atsushi

2013-01-01

The consensus view in mirror neuron research is that mirror neurons comprise a uniform, stable execution-observation matching system. In this article, we argue that, in light of recent evidence, this is, at best, an incomplete and oversimplified view of mirror neurons, whose activity is actually quite variable and more plastic than previously theorized. We propose an epigenetic account for understanding developmental changes in sensorimotor systems, including variations in mirror neuron activity. Although extant associative and genetic accounts fail to consider the complexity of genetic and non-genetic interactions, we propose a new Evo-Devo perspective, which predicts that environmental differences early in development, or through sensorimotor training, should produce variations in mirror neuron response patterns, tuning them to the social environment. PMID:23953747

Neural mechanisms of vocal imitation: The role of sleep replay in shaping mirror neurons.

PubMed

Giret, Nicolas; Edeline, Jean-Marc; Del Negro, Catherine

2017-06-01

Learning by imitation involves not only perceiving another individual's action to copy it, but also the formation of a memory trace in order to gradually establish a correspondence between the sensory and motor codes, which represent this action through sensorimotor experience. Memory and sensorimotor processes are closely intertwined. Mirror neurons, which fire both when the same action is performed or perceived, have received considerable attention in the context of imitation. An influential view of memory processes considers that the consolidation of newly acquired information or skills involves an active offline reprocessing of memories during sleep within the neuronal networks that were initially used for encoding. Here, we review the recent advances in the field of mirror neurons and offline processes in the songbird. We further propose a theoretical framework that could establish the neurobiological foundations of sensorimotor learning by imitation. We propose that the reactivation of neuronal assemblies during offline periods contributes to the integration of sensory feedback information and the establishment of sensorimotor mirroring activity at the neuronal level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optical fabrication of lightweighted 3D printed mirrors

NASA Astrophysics Data System (ADS)

Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan

2015-09-01

Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.

Manufacture of large glass honeycomb mirrors. [for astronomical telescopes

NASA Technical Reports Server (NTRS)

Angel, J. R. P.; Hill, J. M.

1982-01-01

The problem of making very large glass mirrors for astronomical telescopes is examined, and the advantages of honeycomb mirrors made of borosilicate glass are discussed. Thermal gradients in the glass that degrade the figure of thick borosilicate mirrors during use can be largely eliminated in a honeycomb structure by internal ventilation (in air) or careful control of the radiation environment (in space). It is expected that ground-based telescopes with honeycomb mirrors will give better images than those with solid mirrors. Materials, techniques, and the experience that has been gained making trial mirrors and test castings as part of a program to develop 8-10-m-diameter lightweight mirrors are discussed.

Cortical mechanisms of mirror therapy after stroke.

PubMed

Rossiter, Holly E; Borrelli, Mimi R; Borchert, Robin J; Bradbury, David; Ward, Nick S

2015-06-01

Mirror therapy is a new form of stroke rehabilitation that uses the mirror reflection of the unaffected hand in place of the affected hand to augment movement training. The mechanism of mirror therapy is not known but is thought to involve changes in cerebral organization. We used magnetoencephalography (MEG) to measure changes in cortical activity during mirror training after stroke. In particular, we examined movement-related changes in the power of cortical oscillations in the beta (15-30 Hz) frequency range, known to be involved in movement. Ten stroke patients with upper limb paresis and 13 healthy controls were recorded using MEG while performing bimanual hand movements in 2 different conditions. In one, subjects looked directly at their affected hand (or dominant hand in controls), and in the other, they looked at a mirror reflection of their unaffected hand in place of their affected hand. The movement-related beta desynchronization was calculated in both primary motor cortices. Movement-related beta desynchronization was symmetrical during bilateral movement and unaltered by the mirror condition in controls. In the patients, movement-related beta desynchronization was generally smaller than in controls, but greater in contralesional compared to ipsilesional motor cortex. This initial asymmetry in movement-related beta desynchronization between hemispheres was made more symmetrical by the presence of the mirror. Mirror therapy could potentially aid stroke rehabilitation by normalizing an asymmetrical pattern of movement-related beta desynchronization in primary motor cortices during bilateral movement. © The Author(s) 2014.

Federal Motor Carrier Safety Administration’s advanced system testing utilizing a data acquisition system on the highways (FAST DASH) safety technology evaluation project #3 : novel convex mirrors.

DOT National Transportation Integrated Search

2016-11-01

An independent evaluation of a set of novel prototype mirrors was conducted to determine whether the mirrors perform as well as traditional production mirrors across the basic functions of field of view (FOV), image distortion, and distance estimatio...

Extending the mirror neuron system model, II: what did I just do? A new role for mirror neurons.

PubMed

Bonaiuto, James; Arbib, Michael A

2010-04-01

A mirror system is active both when an animal executes a class of actions (self-actions) and when it sees another execute an action of that class. Much attention has been given to the possible roles of mirror systems in responding to the actions of others but there has been little attention paid to their role in self-actions. In the companion article (Bonaiuto et al. Biol Cybern 96:9-38, 2007) we presented MNS2, an extension of the Mirror Neuron System model of the monkey mirror system trained to recognize the external appearance of its own actions as a basis for recognizing the actions of other animals when they perform similar actions. Here we further extend the study of the mirror system by introducing the novel hypotheses that a mirror system may additionally help in monitoring the success of a self-action and may also be activated by recognition of one's own apparent actions as well as efference copy from one's intended actions. The framework for this computational demonstration is a model of action sequencing, called augmented competitive queuing, in which action choice is based on the desirability of executable actions. We show how this "what did I just do?" function of mirror neurons can contribute to the learning of both executability and desirability which in certain cases supports rapid reorganization of motor programs in the face of disruptions.

Ion-assisted coating for large-scale Bimorph deformable mirror

NASA Astrophysics Data System (ADS)

Mikami, Takuya; Okamoto, Takayuki; Yoshida, Kunio; Jitsuno, Takahisa; Motokoshi, Shinji; Samarkin, Vadim V.; Kudryashov, Alexis V.; Kawanaka, Junji; Miyanaga, Noriaki

2016-07-01

We have fabricated a 410 x 468 mm size deformable mirror with 100 Bimorph piezoceramic actuators for the LFEX laser system at Osaka University. In the case of Bimorph-type deformable mirrors, the mirror surface had to be polished and coated after bonding the piezoceramic actuators to the rear side of the thin mirror substrate. This provides a good surface figure, but the coating temperature for the high-reflection mirror was strictly limited because of the thermal fragility of piezoceramic actuators. The mirror substrate with the actuators was polished, and an ion-assisted multilayer dielectric coating was produced at 60 degrees Celsius with our 80-inch coating chamber. The flatness of the mirror just after coating was 7 μm, and reduced by aging to 3.2 μm when the mirror was assembled. The surface figure of the assembled mirror with 20 piezostack bonded actuators is demonstrated and a laser-induced damage threshold tested with a witness sample is also reported.

Space Mirror Memorial

NASA Image and Video Library

2007-01-27

The Space Mirror Memorial, seen in profile, is reflected in the nearby lake at the KSC Visitor Complex. The memorial is the scene of a ceremony being held in remembrance of the astronauts lost in the Apollo 1 fire: Virgil "Gus" Grissom, Edward H. White II and Roger B. Chaffee. The mirror was designated as a national memorial by Congress and President George Bush in 1991 to honor fallen astronauts. Their names are emblazoned on the monument's 42-1/2-foot-high by 50-foot-wide black granite surface as if to be projected into the heavens.

Mirror Measurement Device

NASA Technical Reports Server (NTRS)

1992-01-01

A Small Business Innovation Research (SBIR) contract led to a commercially available instrument used to measure the shape profile of mirror surfaces in scientific instruments. Bauer Associates, Inc.'s Bauer Model 200 Profilometer is based upon a different measurement concept. The local curvature of the mirror's surface is measured at many points, and the collection of data is computer processed to yield the desired shape profile. (Earlier profilometers are based on the principle of interferometry.) The system is accurate and immune to problems like vibration and turbulence. Two profilometers are currently marketed, and a third will soon be commercialized.

Dual actuation micro-mirrors

NASA Astrophysics Data System (ADS)

Alneamy, A. M.; Khater, M. E.; Al-Ghamdi, M. S.; Park, S.; Heppler, G. R.; Abdel-Rahman, E. M.

2018-07-01

This paper investigates the performance of cantilever-type micro-mirrors under electromagnetic, electrostatic and dual actuation. We developed and validated a two-DOFs model of the coupled bending-torsion motions of the mirror and used it in conjunction with experiments in air and in vacuum to compare all three actuation methods. We found that electromagnetic actuation is the most effective delivering a scanning range of  ± out of a geometrically allowable range of  ± at a current amplitude i  =  3 mA and a magnetic field of B  =  30 mT. Electrostatic actuation, whether alone or in conjunction with electromagnetic actuation, limited the stable angular range to smaller values (as small as ) due to the presence of spurious piston motions. This is an innate characteristic of micro-scale electrostatic actuation, the electrostatic force and the undesirable piston motion grow faster than the electrostatic torque and the desired angular displacement as the voltage is increased and they limit the stable angular range. Finally, we found that the dual actuation can be used to design two-DOF mirrors where electromagnetic actuation drives angular motion for optical beam steering and electrostatic actuation drives piston motion to control the mirror focus.

Advanced adaptive optics technology development

NASA Astrophysics Data System (ADS)

Olivier, Scot S.

2002-02-01

The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.

Towards plasma cleaning of ITER first mirrors

NASA Astrophysics Data System (ADS)

Moser, L.; Marot, L.; Eren, B.; Steiner, R.; Mathys, D.; Leipold, F.; Reichle, R.; Meyer, E.

2015-06-01

To avoid reflectivity losses in ITER's optical diagnostic systems, on-site cleaning of metallic first mirrors via plasma sputtering is foreseen to remove deposit build-ups migrating from the main wall. In this work, the influence of aluminium and tungsten deposits on the reflectivity of molybdenum mirrors as well as the possibility to clean them with plasma exposure is investigated. Porous ITER-like deposits are grown to mimic the edge conditions expected in ITER, and a severe degradation in the specular reflectivity is observed as these deposits build up on the mirror surface. In addition, dense oxide films are produced for comparisons with porous films. The composition, morphology and crystal structure of several films were characterized by means of scanning electron microscopy, x-ray photoelectron spectroscopy, x-ray diffraction and secondary ion mass spectrometry. The cleaning of the deposits and the restoration of the mirrors' optical properties are possible either with a Kaufman source or radio frequency directly applied to the mirror (or radio frequency plasma generated directly around the mirror surface). Accelerating ions of an external plasma source through a direct current applied onto the mirror does not remove deposits composed of oxides. A possible implementation of plasma cleaning in ITER is addressed.

49 CFR 393.80 - Rear-vision mirrors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Rear-vision mirrors. 393.80 Section 393.80... NECESSARY FOR SAFE OPERATION Miscellaneous Parts and Accessories § 393.80 Rear-vision mirrors. (a) Every bus, truck, and truck tractor shall be equipped with two rear-vision mirrors, one at each side, firmly...

49 CFR 393.80 - Rear-vision mirrors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Rear-vision mirrors. 393.80 Section 393.80... NECESSARY FOR SAFE OPERATION Miscellaneous Parts and Accessories § 393.80 Rear-vision mirrors. (a) Every bus, truck, and truck tractor shall be equipped with two rear-vision mirrors, one at each side, firmly...

FMRI evidence of 'mirror' responses to geometric shapes.

PubMed

Press, Clare; Catmur, Caroline; Cook, Richard; Widmann, Hannah; Heyes, Cecilia; Bird, Geoffrey

2012-01-01

Mirror neurons may be a genetic adaptation for social interaction. Alternatively, the associative hypothesis proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control.

Design of Off-Axis PIAACMC Mirrors

NASA Technical Reports Server (NTRS)

Pluzhnik, Eugene; Guyon, Olivier; Belikov, Ruslan; Kern, Brian; Bendek, Eduardo

2015-01-01

The Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) provides an efficient way to control diffraction propagation effects caused by the central obstruction/segmented mirrors of the telescope. PIAACMC can be optimized in a way that takes into account both chromatic diffraction effects caused by the telescope obstructed aperture and tip/tilt sensitivity of the coronagraph. As a result, unlike classic PIAA, the PIAACMC mirror shapes are often slightly asymmetric even for an on-axis configuration and require more care in calculating off-axis shapes when an off-axis configuration is preferred. A method to design off-axis PIAA mirror shapes given an on-axis mirror design is presented. The algorithm is based on geometrical ray tracing and is able to calculate off-axis PIAA mirror shapes for an arbitrary geometry of the input and output beams. The method is demonstrated using the third generation PIAACMC design for WFIRST-AFTA (Wide Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets) telescope. Geometrical optics design issues related to the off-axis diffraction propagation effects are also discussed.

Mirror therapy: A potential intervention for pain management.

PubMed

Wittkopf, Priscilla G; Johnson, Mark I

2017-11-01

The consequences of chronic pain and associated disabilities to the patient and to the health care system are well known. Medication is often the first treatment of choice for chronic pain, although side effects and high costs restrict long-term use. Inexpensive, safe and easy to self-administer non-pharmacological therapies, such as mirror therapy, are recommended as adjuncts to pain treatment. The purpose of this review is to describe the principles of use of mirror therapy so it can be incorporated into a health care delivery. The physiological rationale of mirror therapy for the management of pain and the evidence of clinical efficacy based on recent systematic reviews are also discussed. Mirror therapy, whereby a mirror is placed in a position so that the patient can view a reflection of a body part, has been used to treat phantom limb pain, complex regional pain syndrome, neuropathy and low back pain. Research evidence suggests that a course of treatment (four weeks) of mirror therapy may reduce chronic pain. Contraindications and side effects are few. The mechanism of action of mirror therapy remains uncertain, with reintegration of motor and sensory systems, restored body image and control over fear-avoidance likely to influence outcome. The evidence for clinical efficacy of mirror therapy is encouraging, but not yet definitive. Nevertheless, mirror therapy is inexpensive, safe and easy for the patient to self-administer.

Multilayer active shell mirrors for space telescopes

NASA Astrophysics Data System (ADS)

Steeves, John; Jackson, Kathryn; Pellegrino, Sergio; Redding, David; Wallace, J. Kent; Bradford, Samuel Case; Barbee, Troy

2016-07-01

A novel active mirror technology based on carbon fiber reinforced polymer (CFRP) substrates and replication techniques has been developed. Multiple additional layers are implemented into the design serving various functions. Nanolaminate metal films are used to provide a high quality reflective front surface. A backing layer of thin active material is implemented to provide the surface-parallel actuation scheme. Printed electronics are used to create a custom electrode pattern and flexible routing layer. Mirrors of this design are thin (< 1.0 mm), lightweight (2.7 kg/m2), and have large actuation capabilities. These capabilities, along with the associated manufacturing processes, represent a significant change in design compared to traditional optics. Such mirrors could be used as lightweight primaries for small CubeSat-based telescopes or as meter-class segments for future large aperture observatories. Multiple mirrors can be produced under identical conditions enabling a substantial reduction in manufacturing cost and complexity. An overview of the mirror design and manufacturing processes is presented. Predictions on the actuation performance have been made through finite element simulations demonstrating correctabilities on the order of 250-300× for astigmatic modes with only 41 independent actuators. A description of the custom metrology system used to characterize the active mirrors is also presented. The system is based on a Reverse Hartmann test and can accommodate extremely large deviations in mirror figure (> 100 μm PV) down to sub-micron precision. The system has been validated against several traditional techniques including photogrammetry and interferometry. The mirror performance has been characterized using this system, as well as closed-loop figure correction experiments on 150 mm dia. prototypes. The mirrors have demonstrated post-correction figure accuracies of 200 nm RMS (two dead actuators limiting performance).

A mirror control mechanism for space telescope

NASA Astrophysics Data System (ADS)

Cadiergues, L.; Bourdit, C.; Trouchet, D.; Larcher, V.; Sugranes, P.; Leletty, R.; Barillot, F.

2003-09-01

The high resolution optical instruments require more and more stability on the relative position between their different mirrors. The use of a mirror control mechanism (MCM) allows to correct in flight the position of the mirror (in particular the focusing and the 2 tilts). The mechanism described hereafter is designed for a Cassegrain telescope secondary mirror. The selected concept is based on 3 vertical actuators which produce the focusing and tilts movements, and three horizontal actuators which produce the transverse movements. This architecture offers 5 degrees of freedom which guarantee the absence of rejection for any kind of correction. After the design phase, a demonstrator was manufactured and characterised by functional and mechanical tests. This mechanism is able to control any type of axisymmetric mirror within 5 degrees of freedom. The mass of the model presented is 3.5kg with overall dimensions ø280mm/H77mm (except electronics). This concept can be adapted to smaller versions of mirror requiring an active control, and in a more general way to equipments for which the pointing precision is a key requirement.

Optical Performance Modeling of FUSE Telescope Mirror

NASA Technical Reports Server (NTRS)

Saha, Timo T.; Ohl, Raymond G.; Friedman, Scott D.; Moos, H. Warren

2000-01-01

We describe the Metrology Data Processor (METDAT), the Optical Surface Analysis Code (OSAC), and their application to the image evaluation of the Far Ultraviolet Spectroscopic Explorer (FUSE) mirrors. The FUSE instrument - designed and developed by the Johns Hopkins University and launched in June 1999 is an astrophysics satellite which provides high resolution spectra (lambda/Delta(lambda) = 20,000 - 25,000) in the wavelength region from 90.5 to 118.7 nm The FUSE instrument is comprised of four co-aligned, normal incidence, off-axis parabolic mirrors, four Rowland circle spectrograph channels with holographic gratings, and delay line microchannel plate detectors. The OSAC code provides a comprehensive analysis of optical system performance, including the effects of optical surface misalignments, low spatial frequency deformations described by discrete polynomial terms, mid- and high-spatial frequency deformations (surface roughness), and diffraction due to the finite size of the aperture. Both normal incidence (traditionally infrared, visible, and near ultraviolet mirror systems) and grazing incidence (x-ray mirror systems) systems can be analyzed. The code also properly accounts for reflectance losses on the mirror surfaces. Low frequency surface errors are described in OSAC by using Zernike polynomials for normal incidence mirrors and Legendre-Fourier polynomials for grazing incidence mirrors. The scatter analysis of the mirror is based on scalar scatter theory. The program accepts simple autocovariance (ACV) function models or power spectral density (PSD) models derived from mirror surface metrology data as input to the scatter calculation. The end product of the program is a user-defined pixel array containing the system Point Spread Function (PSF). The METDAT routine is used in conjunction with the OSAC program. This code reads in laboratory metrology data in a normalized format. The code then fits the data using Zernike polynomials for normal incidence

White-Light Phase-Conjugate Mirrors as Distortion Correctors

NASA Technical Reports Server (NTRS)

Frazier, Donald; Smith, W. Scott; Abdeldayem, Hossin; Banerjee, Partha

2010-01-01

White-light phase-conjugate mirrors would be incorporated into some optical systems, according to a proposal, as means of correcting for wavefront distortions caused by imperfections in large optical components. The proposal was given impetus by a recent demonstration that white, incoherent light can be made to undergo phase conjugation, whereas previously, only coherent light was known to undergo phase conjugation. This proposal, which is potentially applicable to almost any optical system, was motivated by a need to correct optical aberrations of the primary mirror of the Hubble Space telescope. It is difficult to fabricate large optical components like the Hubble primary mirror and to ensure the high precision typically required of such components. In most cases, despite best efforts, the components as fabricated have small imperfections that introduce optical aberrations that adversely affect imaging quality. Correcting for such aberrations is difficult and costly. The proposed use of white-light phase conjugate mirrors offers a relatively simple and inexpensive solution of the aberration-correction problem. Indeed, it should be possible to simplify the entire approach to making large optical components because there would be no need to fabricate those components with extremely high precision in the first place: A white-light phase-conjugate mirror could correct for all the distortions and aberrations in an optical system. The use of white-light phase-conjugate mirrors would be essential for ensuring high performance in optical systems containing lightweight membrane mirrors, which are highly deformable. As used here, "phase-conjugate mirror" signifies, more specifically, an optical component in which incident light undergoes time-reversal phase conjugation. In practice, a phase-conjugate mirror would typically be implemented by use of a suitably positioned and oriented photorefractive crystal. In the case of a telescope comprising a primary and secondary

Path to a UV/Optical/IR Flagship: Review of ATLAST and Its Predecessors

NASA Technical Reports Server (NTRS)

Thronson, Harley; Bolcar, Matthew R.; Clampin, Mark; Crooke, Julie; Feinberg, Lee; Oegerle, William; Rioux, Norman; Stahl, H. Philip; Stapelfeldt, Karl

2016-01-01

Our recently completed study for the Advanced Technology Large-Aperture Space Telescope (ATLAST) was the culmination of three years of initially internally funded work that built upon earlier engineering designs, science objectives, and technology priorities. Beginning in the mid-1980s, multiple teams of astronomers, technologists, and engineers developed concepts for a large-aperture UV/optical/IR space observatory intended to follow the Hubble Space Telescope (HST). Here, we summarize since the first significant conferences on major post-HST ultraviolet, optical, and infrared (UVOIR) observatories the history of designs, scientific goals, key technology recommendations, and community workshops. Although the sophistication of science goals and the engineering designs both advanced over the past three decades, we note the remarkable constancy of major characteristics of large post-HST UVOIR concepts. As it has been a priority goal for NASA and science communities for a half-century, and has driven much of the technology priorities for major space observatories, we include the long history of concepts for searching for Earth-like worlds. We conclude with a capsule summary of our ATLAST reference designs developed by four partnering institutions over the past three years, which was initiated in 2013 to prepare for the 2020 National Academies' Decadal Survey.

Effects of action observation on corticospinal excitability: Muscle specificity, direction, and timing of the mirror response.

PubMed

Naish, Katherine R; Houston-Price, Carmel; Bremner, Andrew J; Holmes, Nicholas P

2014-11-01

Many human behaviours and pathologies have been attributed to the putative mirror neuron system, a neural system that is active during both the observation and execution of actions. While there are now a very large number of papers on the mirror neuron system, variations in the methods and analyses employed by researchers mean that the basic characteristics of the mirror response are not clear. This review focuses on three important aspects of the mirror response, as measured by modulations in corticospinal excitability: (1) muscle specificity; (2) direction; and (3) timing of modulation. We focus mainly on electromyographic (EMG) data gathered following single-pulse transcranial magnetic stimulation (TMS), because this method provides precise information regarding these three aspects of the response. Data from paired-pulse TMS paradigms and peripheral nerve stimulation (PNS) are also considered when we discuss the possible mechanisms underlying the mirror response. In this systematic review of the literature, we examine the findings of 85 TMS and PNS studies of the human mirror response, and consider the limitations and advantages of the different methodological approaches these have adopted in relation to discrepancies between their findings. We conclude by proposing a testable model of how action observation modulates corticospinal excitability in humans. Specifically, we propose that action observation elicits an early, non-specific facilitation of corticospinal excitability (at around 90ms from action onset), followed by a later modulation of activity specific to the muscles involved in the observed action (from around 200ms). Testing this model will greatly advance our understanding of the mirror mechanism and provide a more stable grounding on which to base inferences about its role in human behaviour. Copyright © 2014. Published by Elsevier Ltd.

Large mirror surface control by corrective coating

NASA Astrophysics Data System (ADS)

Bonnand, Romain; Degallaix, Jerome; Flaminio, Raffaele; Giacobone, Laurent; Lagrange, Bernard; Marion, Fréderique; Michel, Christophe; Mours, Benoit; Mugnier, Pierre; Pacaud, Emmanuel; Pinard, Laurent

2013-08-01

The Advanced Virgo gravitational wave detector aims at a sensitivity ten times better than the initial LIGO and Virgo detectors. This implies very stringent requirement on the optical losses in the interferometer arm cavities. In this paper we focus on the mirrors which form the interferometer arm cavities and that require a surface figure error to be well below one nanometre on a diameter of 150 mm. This ‘sub-nanometric flatness’ is not achievable by classical polishing on such a large diameter. Therefore we present the corrective coating technique which has been developed to reach this requirement. Its principle is to add a non-uniform thin film on top of the substrate in order to flatten its surface. In this paper we will introduce the Advanced Virgo requirements and present the basic principle of the corrective coating technique. Then we show the results obtained experimentally on an initial Virgo substrate. Finally we provide an evaluation of the round-trip losses in the Fabry-Perot arm cavities once the corrected surface is used.

The eROSITA X-ray mirrors: technology and qualification aspects of the production of mandrels, shells and mirror modules

NASA Astrophysics Data System (ADS)

Arcangeli, L.; Borghi, G.; Bräuninger, H.; Citterio, O.; Ferrario, I.; Friedrich, P.; Grisoni, G.; Marioni, F.; Predehl, P.; Rossi, M.; Ritucci, A.; Valsecchi, G.; Vernani, D.

2017-11-01

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 due to programmatic shortfall. 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 "extended" was added to the original name "ROSITA". The scientific motivation for this extension is founded in the ambitious goal to detect about 100,000 clusters of galaxies which trace the large scale structure of the Universe in space and time. The X-ray telescope of eROSITA will consist of 7 identical and co-aligned mirror modules, each with 54 nested Wolter-1 mirror shells. The mirror shells are glued onto a spider wheel which is screwed to the mirror interface structure making a rigid mechanical unit. The assembly of 7 modules forms a compact hexagonal configuration with 1300 mm diameter (see Fig. 1) and will be attached to the telescope structure which connects to the 7 separate CCD cameras in the focal planes. The co-alignment of the mirror module enables eROSITA to perform also pointed observations. The replication process described in chapter III allows the manufacturing in one single piece and at the same time of both the parabola and hyperbola parts of the Wolter 1 mirror.

Ion polished Cr/Sc attosecond multilayer mirrors for high water window reflectivity

DOE PAGES

Guggenmos, Alexander; Radünz, Stefan; Rauhut, Roman; ...

2014-01-20

Recent advances in the development of attosecond soft X-ray sources ranging into the water window spectral range, between the 1s states of carbon and oxygen (284 eV–543 eV), are also driving the development of suited broadband multilayer optics for steering and shaping attosecond pulses. The relatively low intensity of current High Harmonic Generation (HHG) soft X-ray sources calls for an efficient use of photons, thus the development of low-loss multilayer optics is of uttermost importance. Here, we report about the realization of broadband Cr/Sc attosecond multilayer mirrors with nearly atomically smooth interfaces by an optimized ion beam deposition and assistedmore » interface polishing process. This yields to our knowledge highest multilayer mirror reflectivity at 300 eV near normal incidence. The results are verified by transmission electron microscopy (TEM) and soft/hard X-ray reflectometry.« less

Ion polished Cr/Sc attosecond multilayer mirrors for high water window reflectivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guggenmos, Alexander; Radünz, Stefan; Rauhut, Roman

Recent advances in the development of attosecond soft X-ray sources ranging into the water window spectral range, between the 1s states of carbon and oxygen (284 eV–543 eV), are also driving the development of suited broadband multilayer optics for steering and shaping attosecond pulses. The relatively low intensity of current High Harmonic Generation (HHG) soft X-ray sources calls for an efficient use of photons, thus the development of low-loss multilayer optics is of uttermost importance. Here, we report about the realization of broadband Cr/Sc attosecond multilayer mirrors with nearly atomically smooth interfaces by an optimized ion beam deposition and assistedmore » interface polishing process. This yields to our knowledge highest multilayer mirror reflectivity at 300 eV near normal incidence. The results are verified by transmission electron microscopy (TEM) and soft/hard X-ray reflectometry.« less

On the dynamics of a semitransparent moving mirror

NASA Astrophysics Data System (ADS)

Nicolaevici, Nistor

2011-01-01

Perfectly reflecting mirrors in the two-dimensional Minkowski space subjected to the reaction force due to the radiated quantum flux evoluate according to the Abraham-Lorentz-Dirac equation, which admits unphysical solutions. We investigate the non-relativistic equation of motion of a semitransparent mirror and show that the unphysical solutions are absent, provided that the energy which characterizes the reflectivity of the mirror is sufficiently small compared to the mirror's mass.

By the Dozen: NASA's James Webb Space Telescope Mirrors

NASA Image and Video Library

2016-01-03

Caption: One dozen (out of 18) flight mirror segments that make up the primary mirror on NASA's James Webb Space Telescope have been installed at NASA's Goddard Space Flight Center. Credits: NASA/Chris Gunn More: Since December 2015, the team of scientists and engineers have been working tirelessly to install all the primary mirror segments onto the telescope structure in the large clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The twelfth mirror was installed on January 2, 2016. "This milestone signifies that all of the hexagonal shaped mirrors on the fixed central section of the telescope structure are installed and only the 3 mirrors on each wing are left for installation," said Lee Feinberg, NASA's Optical Telescope Element Manager at NASA Goddard. "The incredibly skilled and dedicated team assembling the telescope continues to find ways to do things faster and more efficiently." Each hexagonal-shaped segment measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). After being pieced together, the 18 primary mirror segments will work together as one large 21.3-foot (6.5-meter) mirror. The primary mirror will unfold and adjust to shape after launch. The mirrors are made of ultra-lightweight beryllium. The mirrors are placed on the telescope's backplane using a robotic arm, guided by engineers. The full installation is expected to be completed in a few months. The mirrors were built by Ball Aerospace & Technologies Corp., Boulder, Colorado. Ball is the principal subcontractor to Northrop Grumman for the optical technology and lightweight mirror system. The installation of the mirrors onto the telescope structure is performed by Harris Corporation of Rochester, New York. Harris Corporation leads integration and testing for the telescope. While the mirror assembly is a very significant milestone, there are many more steps involved in assembling the Webb telescope. The primary mirror and the tennis

By the Dozen: NASA's James Webb Space Telescope Mirrors

NASA Image and Video Library

2016-01-03

A view of the one dozen (out of 18) flight mirror segments that make up the primary mirror on NASA's James Webb Space Telescope have been installed at NASA's Goddard Space Flight Center. Credits: NASA/Chris Gunn More: Since December 2015, the team of scientists and engineers have been working tirelessly to install all the primary mirror segments onto the telescope structure in the large clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The twelfth mirror was installed on January 2, 2016. "This milestone signifies that all of the hexagonal shaped mirrors on the fixed central section of the telescope structure are installed and only the 3 mirrors on each wing are left for installation," said Lee Feinberg, NASA's Optical Telescope Element Manager at NASA Goddard. "The incredibly skilled and dedicated team assembling the telescope continues to find ways to do things faster and more efficiently." Each hexagonal-shaped segment measures just over 4.2 feet (1.3 meters) across and weighs approximately 88 pounds (40 kilograms). After being pieced together, the 18 primary mirror segments will work together as one large 21.3-foot (6.5-meter) mirror. The primary mirror will unfold and adjust to shape after launch. The mirrors are made of ultra-lightweight beryllium. The mirrors are placed on the telescope's backplane using a robotic arm, guided by engineers. The full installation is expected to be completed in a few months. The mirrors were built by Ball Aerospace & Technologies Corp., Boulder, Colorado. Ball is the principal subcontractor to Northrop Grumman for the optical technology and lightweight mirror system. The installation of the mirrors onto the telescope structure is performed by Harris Corporation of Rochester, New York. Harris Corporation leads integration and testing for the telescope. While the mirror assembly is a very significant milestone, there are many more steps involved in assembling the Webb telescope. The primary mirror and the

Quantum channels from reflections on moving mirrors.

PubMed

Gianfelici, Giulio; Mancini, Stefano

2017-11-16

Light reflection on a mirror can be thought as a simple physical effect. However if this happens when the mirror moves a rich scenario opens up. Here we aim at analyzing it from a quantum communication perspective. In particular, we study the kind of quantum channel that arises from (Gaussian) light reflection upon an accelerating mirror. Two competing mechanisms emerge in such a context, namely photons production by the mirror's motion and interference between modes. As consequence we find out a quantum amplifier channel and quantum lossy channel respectively below and above a threshold frequency (that depends on parameters determining mirror's acceleration). Exactly at the threshold frequency the channel behaves like a purely classical additive channel, while it becomes purely erasure for large frequencies. In addition the time behavior of the channel is analyzed by employing wave packets expansion of the light field.

The 'not-so-strange' body in the mirror: A principal components analysis of direct and mirror self-observation.

PubMed

Jenkinson, Paul M; Preston, Catherine

2017-02-01

In this study we adopted a psychometric approach to examine how the body is subjectively experienced in a mirror. One hundred and twenty-four healthy participants viewed their body for five minutes directly or via a mirror, and then completed a 20-item questionnaire designed to capture subjective experiences of the body. PCA revealed a two-component structure for both direct and mirror conditions, comprising body evaluations (and alienation) and unusual feelings and perceptions. The relationship between these components and pre-existing tendencies for appearance anxiety, body dysmorphic-type beliefs, dissociative symptomatology, self-objectification and delusion ideation further supported the similarity between direct and mirror conditions; however, the occurrence of strange experiences like those reported to occur during prolonged face viewing was not confirmed. These results suggest that, despite obvious differences in visual feedback, observing the body via a mirror (as an outside observer) is subjectively equivalent to observing the body directly (from our own viewpoint). Copyright © 2016 Elsevier Inc. All rights reserved.

Cooling options for high-average-power laser mirrors

NASA Astrophysics Data System (ADS)

Vojna, D.; Slezak, O.; Lucianetti, A.; Mocek, T.

2015-01-01

Thermally-induced deformations of steering mirrors reflecting 100 J/10 Hz laser pulses in vacuum have been analyzed. This deformation is caused by the thermal stress arisen due to parasitic absorption of 1 kW square-shaped flat-top laser beam in the dielectric multi-layer structure. Deformation depends on amount of absorbed power and geometry of the mirror as well as on the heat removal scheme. In our calculations, the following percentages of absorption of the incident power have been used: 1%, 0.5% and 0.1%. The absorbed power has been considered to be much higher than that expected in reality to assess the worst case scenario. Rectangular and circular mirrors made of zerodur (low thermal expansion glass) were considered for these simulations. The effect of coating layers on induced deformations has been neglected. Induced deformation of the mirror surface can significantly degrade the quality of the laser beam in the beam delivery system. Therefore, the proper design of the cooling scheme for the mirror in order to minimize the deformations is needed. Three possible cooling schemes of the mirror have been investigated. The first one takes advantage of a radiation cooling of the mirror and a copper heatsink fixed to the rear face of the mirror, the second scheme is based on additional heat conduction provided by flexible copper wires connected to the mirror holder, and the last scheme combines two above mentioned methods.

The Advanced Technology Solar Telescope mount assembly

NASA Astrophysics Data System (ADS)

Warner, Mark; Cho, Myung; Goodrich, Bret; Hansen, Eric; Hubbard, Rob; Lee, Joon Pyo; Wagner, Jeremy

2006-06-01

When constructed on the summit of Haleakala on the island of Maui, Hawaii, the Advanced Technology Solar Telescope (ATST) will be the world's largest solar telescope. The ATST is a unique design that utilizes a state-of-the-art off-axis Gregorian optical layout with five reflecting mirrors delivering light to a Nasmyth instrument rotator, and nine reflecting mirrors delivering light to an instrument suite located on a large diameter rotating coude lab. The design of the telescope mount structure, which supports and positions the mirrors and scientific instruments, has presented noteworthy challenges to the ATST engineering staff. Several novel design solutions, as well as adaptations of existing telescope technologies to the ATST application, are presented in this paper. Also shown are plans for the control system and drives of the structure.

An achromatic four-mirror compensator for spectral ellipsometers

NASA Astrophysics Data System (ADS)

Kovalev, V. I.; Rukovishnikov, A. I.; Kovalev, S. V.; Kovalev, V. V.; Rossukanyi, N. M.

2017-07-01

Measurement and calculation results are presented that confirm that design four-mirror compensators can be designed for the spectral range of 200-2000 nm that is widely used in modern spectral ellipsometers. Measurements and calculations according to standard ellipsometric programs have been carried out on a broadband LED spectral ellipsometer with switching of orthogonal polarization states. Mirrors with the structure of glass substrate/Al2O3 layer (20-30 nm thick)/Al layer (150 nm thick)/upper Al2O3 layer (with specified thickness d) have been prepared by vacuum-evaporation method. It is shown that the phase-shift spectra of a four-mirror compensator, two mirrors of which have a native oxide 5.5 nm thick and the two others of which have an oxide layer 36 nm thick, measured on the ellipsometer, are flattened in comparison with similar spectra of a compensator, all four mirrors of which have a native oxide, especially in the short-wavelength spectral region. The results of calculating the phase-shift spectra of the four-mirror compensator with six variable parameters (angles of incidence of radiation on the mirrors and thicknesses of oxide layers on four mirrors) are presented. High-quality achromatization in a wide spectral range can be achieved for certain sets of parameters.

Electromagnetic deformable mirror for space applications

NASA Astrophysics Data System (ADS)

Kuiper, S.; Doelman, N.; Overtoom, T.; Nieuwkoop, E.; Russchenberg, T.; van Riel, M.; Wildschut, J.; Baeten, M.; Spruit, H.; Brinkers, S.; Human, J.

2017-09-01

To increase the collecting power and to improve the angular imaging resolution, space telescopes are evolving towards larger primary mirrors. The aerial density of the telescope mirrors needs to be kept low, however, to be compatible with the launch requirements. A light-weight (primary) mirror will introduce additional optical aberrations to the system. These may be caused by for instance manufacturing errors, gravity release and thermo-elastic effects. Active Optics (AO) is a key candidate technology to correct for the resultant wave front aberrations [1].

Design and optimization of the CFRP mirror components

NASA Astrophysics Data System (ADS)

Wei, Lei; Zhang, Lei; Gong, Xiaoxue

2017-09-01

As carbon fiber reinforced polymer (CFRP) material has been developed and demonstrated as an effective material in lightweight telescope reflector manufacturing recently, the authors of this article have extended to apply this material on the lightweight space camera mirror design and fabrication. By CFRP composite laminate design and optimization using finite element method (FEM) analysis, a spherical mirror with φ316 mm diameter whose core cell reinforcement is an isogrid configuration is fabricated. Compared with traditional ways of applying ultra-low-expansion glass (ULE) on the CFRP mirror surface, the method of nickel electroplating on the surface effectively reduces the processing cost and difficulty of the CFRP mirror. Through the FEM analysis, the first order resonance frequency of the CFRP mirror components reaches up to 652.3 Hz. Under gravity affection coupling with +5°C temperature rising, the mirror surface shape root-mean-square values (RMS) at the optical axis horizontal state is 5.74 nm, which meets mechanical and optical requirements of the mirror components on space camera.

Carbon Fiber Mirror for a CubeSat Telescope

NASA Astrophysics Data System (ADS)

Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

2017-08-01

Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.

Long-Lived Glass Mirrors For Outer Space

NASA Technical Reports Server (NTRS)

Bouquet, Frank L.; Maag, Carl R.; Heggen, Philip M.

1988-01-01

Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.

Silicon Carbide Technologies for Lightweighted Aerospace Mirrors

DTIC Science & Technology

2008-09-01

Silicon Carbide Technologies for Lightweighted Aerospace Mirrors Lawrence E. Matson (1) Ming Y. Chen (1) Brett deBlonk (2) Iwona A...glass and beryllium to produce lightweighted aerospace mirror systems has reached its limits due to the long lead times, high processing costs...for making mirror structural substrates, figuring and finishing technologies being investigated to reduce cost time and cost, and non-destructive

Adjusting Curvatures Of Large Mirrors And Lenses

NASA Technical Reports Server (NTRS)

Birnbaum, Morris M.

1992-01-01

Actuators apply stresses to generate distortions counteracting undesired distortions in technique for adjusting curvature of large focusing mirror or lens. Motor-and-gear assemblies under remote control vary squeeze of ring clamp and push or pull of hollow shaft to make fine adjustments in curvature of mirror. Applicable to large astronomical-telescope mirrors with diameters of 60 cm or more.

Mirror neuron system: basic findings and clinical applications.

PubMed

Iacoboni, Marco; Mazziotta, John C

2007-09-01

In primates, ventral premotor and rostral inferior parietal neurons fire during the execution of hand and mouth actions. Some cells (called mirror neurons) also fire when hand and mouth actions are just observed. Mirror neurons provide a simple neural mechanism for understanding the actions of others. In humans, posterior inferior frontal and rostral inferior parietal areas have mirror properties. These human areas are relevant to imitative learning and social behavior. Indeed, the socially isolating condition of autism is associated with a deficit in mirror neuron areas. Strategies inspired by mirror neuron research recently have been used in the treatment of autism and in motor rehabilitation after stroke.

Silicon nitride protective coatings for silvered glass mirrors

DOEpatents

Tracy, C. Edwin; Benson, David K.

1988-01-01

A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors.

Silicon nitride protective coatings for silvered glass mirrors

DOEpatents

Tracy, C.E.; Benson, D.K.

1984-07-20

A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate prior to metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors.

Mirror therapy in children with hemiplegia: a pilot study.

PubMed

Gygax, Marine Jequier; Schneider, Patrick; Newman, Christopher John

2011-05-01

Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks. Assessments of maximal grasp and pinch strengths, and upper limb function measured by the Shriner's Hospital Upper Extremity Evaluation were performed at weeks 0 (baseline), 3, 6 (intervention), and 9 (wash-out). Testing of grasp strength behind the mirror improved performance by 15% (p=0.004). Training with the mirror significantly improved grasp strength (with mirror +20.4%, p=0.033; without +5.9%, p>0.1) and upper limb dynamic position (with mirror +4.6%, p=0.044; without +1.2%, p>0.1), while training without a mirror significantly improved pinch strength (with mirror +6.9%, p>0.1; without +21.9%, p=0.026). This preliminary study demonstrates the feasibility of mirror therapy in children with hemiplegia and that it may improve strength and dynamic function of the paretic arm. © The Authors. Developmental Medicine & Child Neurology © 2011 Mac Keith Press.

Characterization of a piezo bendable X-ray mirror.

PubMed

Vannoni, Maurizio; Freijo Martín, Idoia; Siewert, Frank; Signorato, Riccardo; Yang, Fan; Sinn, Harald

2016-01-01

A full-scale piezo bendable mirror built as a prototype for an offset mirror at the European XFEL is characterized. The piezo ceramic elements are glued onto the mirror substrate, side-face on with respect to the reflecting surface. Using a nanometre optical component measuring machine and a large-aperture Fizeau interferometer, the mirror profile and influence functions were characterized, and further analysis was made to investigate the junction effect, hysteresis, twisting and reproducibility.

Double arch mirror study. Part 1: Preliminary engineering report

NASA Technical Reports Server (NTRS)

Vukobratovich, D.; Hillman, D.

1983-01-01

In the proposed design, the NASA AMES 20-in double arch mirror is supported by three clamp and flexure assemblies. The mirror clamp consists of a T-shaped Invar-36 member that goes into a similarly shaped socket in the back of the mirror. The mirror socket is made oversize and contacts the clamp only along the conical surface. The clamp is preloaded by a spring washer and pulls the mirror into contact with the flexure. The clamp is then inserted into the mirror socket through a cutout, is rotated 90 deg, and is then pinned in place. Loading conditions considered in socket design are discussed as well as stress in the socket and clamp. Flexure geometry and stress are examined as well as the effects of flexure error and of mirror cell error.

Secondary mirror system for the European Solar Telescope (EST)

NASA Astrophysics Data System (ADS)

Cavaller, L.; Siegel, B.; Prieto, G.; Hernandez, E.; Casalta, J. M.; Mercader, J.; Barriga, J.

2010-07-01

The European Solar Telescope (EST) is a European collaborative project to build a 4m class solar telescope in the Canary Islands, which is now in its design study phase. The telescope will provide diffraction limited performance for several instruments observing simultaneously at the Coudé focus at different wavelengths. A multi-conjugated adaptive optics system composed of a tip-tilt mirror and several deformable mirrors will be integrated in the telescope optical path. The secondary mirror system is composed of the mirror itself (Ø800mm), the alignment drives and the cooling system needed to remove the solar heat load from the mirror. During the design study the feasibility to provide fast tip-tilt capabilities at the secondary mirror to work as the adaptive optics tip-tilt mirror is also being evaluated.

Optomechanical design software for segmented mirrors

NASA Astrophysics Data System (ADS)

Marrero, Juan

2016-08-01

The software package presented in this paper, still under development, was born to help analyzing the influence of the many parameters involved in the design of a large segmented mirror telescope. In summary, it is a set of tools which were added to a common framework as they were needed. Great emphasis has been made on the graphical presentation, as scientific visualization nowadays cannot be conceived without the use of a helpful 3d environment, showing the analyzed system as close to reality as possible. Use of third party software packages is limited to ANSYS, which should be available in the system only if the FEM results are needed. Among the various functionalities of the software, the next ones are worth mentioning here: automatic 3d model construction of a segmented mirror from a set of parameters, geometric ray tracing, automatic 3d model construction of a telescope structure around the defined mirrors from a set of parameters, segmented mirror human access assessment, analysis of integration tolerances, assessment of segments collision, structural deformation under gravity and thermal variation, mirror support system analysis including warping harness mechanisms, etc.

Development of CFRP mirrors for space telescopes

NASA Astrophysics Data System (ADS)

Utsunomiya, Shin; Kamiya, Tomohiro; Shimizu, Ryuzo

2013-09-01

CFRP (Caron fiber reinforced plastics) have superior properties of high specific elasticity and low thermal expansion for satellite telescope structures. However, difficulties to achieve required surface accuracy and to ensure stability in orbit have discouraged CFRP application as main mirrors. We have developed ultra-light weight and high precision CFRP mirrors of sandwich structures composed of CFRP skins and CFRP cores using a replica technique. Shape accuracy of the demonstrated mirrors of 150 mm in diameter was 0.8 μm RMS (Root Mean Square) and surface roughness was 5 nm RMS as fabricated. Further optimization of fabrication process conditions to improve surface accuracy was studied using flat sandwich panels. Then surface accuracy of the flat CFRP sandwich panels of 150 mm square was improved to flatness of 0.2 μm RMS with surface roughness of 6 nm RMS. The surface accuracy vs. size of trial models indicated high possibility of fabrication of over 1m size mirrors with surface accuracy of 1μm. Feasibility of CFRP mirrors for low temperature applications was examined for JASMINE project as an example. Stability of surface accuracy of CFRP mirrors against temperature and moisture was discussed.

Stimulated Mirror Instability From the Interplay of Anisotropic Protons and Electrons, and their Suprathermal Populations

NASA Astrophysics Data System (ADS)

Shaaban, S. M.; Lazar, M.; Astfalk, P.; Poedts, S.

2018-03-01

Mirror instability driven by the temperature anisotropy of protons can offer a plausible explanation for the mirror-like fluctuations observed in planetary magnetosheaths. In the present paper we invoke a realistic kinetic approach which can reproduce nonthermal features of plasma particles reported by the observations, i.e., temperature anisotropies and suprathermal populations. Seeking accuracy, a numerical analysis is performed using an advanced code named DSHARK, recently proposed to resolve the linear dispersion and stability for an arbitrary propagation in bi-Kappa distributed electron-proton plasmas. The stimulating effect of the anisotropic bi-Maxwellian electrons reported in Remya et al. (2013, https://doi.org/10.1002/jgra.50091) is markedly enhanced in the presence of suprathermal electrons described by the bi-Kappa distribution functions. The influence of suprathermal protons is more temperate, but overall, present results demonstrate that these sources of free energy provide natural conditions for a stimulated mirror instability, more efficient than predicted before and capable to compete with other instabilities (e.g., the electromagnetic ion-cyclotron instability) and mechanisms of relaxation.

An Optically Pumped Far-Infrared Folded Mirror-Less Cavity

NASA Astrophysics Data System (ADS)

Liu, Chuang; Wang, Dashuai; Zhang, Peng; Qu, Yanchen

2017-12-01

A compact and efficient mirror-less cavity is presented for an optically pumped 192-μm far-infrared laser. With a gold-coated mirror and 30°-inclined anti-reflection coated Ge plate serving as highly reflective mirrors, a folded mirror-less CH3F cavity is achieved. Maximum energy of 0.72 mJ is obtained with the pump energy of 600 mJ, which gives an energy increment of 75% in comparison with the previous 1.85-m mirror-less system. The beam divergence angle of the FIR radiation from this folded mirror-less cavity is measured to be 14.2 mrad.

Alignment and focus of mirrored facets of a heliosat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yellowhair, Julius E; Ho, Clifford Kuofei; Diver, Richard B

2013-11-12

Various technologies pertaining to aligning and focusing mirrored facets of a heliostat are described herein. Updating alignment and/or focus of mirrored facets is undertaken through generation of a theoretical image, wherein the theoretical image is indicative of a reflection of the target via the mirrored facets when the mirrored facets are properly aligned. This theoretical image includes reference points that are overlaid on an image of the target as reflected by the mirrored facets of the heliostat. A technician adjusts alignment/focus of a mirrored facet by causing reflected reference markings to become aligned with the reference points in the theoreticalmore » image.« less

Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources.

PubMed

Störmer, M; Gabrisch, H; Horstmann, C; Heidorn, U; Hertlein, F; Wiesmann, J; Siewert, F; Rack, A

2016-05-01

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Störmer, M., E-mail: michael.stoermer@hzg.de; Gabrisch, H.; Horstmann, C.

2016-05-15

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity atmore » higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.« less

Distributed microscopic actuation analysis of deformable plate membrane mirrors

NASA Astrophysics Data System (ADS)

Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

2018-02-01

To further reduce the areal density of optical mirrors used in space telescopes and other space-borne optical structures, the concept of flexible membrane deformable mirror has been proposed. Because of their high flexibility, poor stiffness and low damping properties, environmental excitations such as orbital maneuver, path changing, and non-uniform heating may induce unexpected vibrations and thus reduce working performance. Therefore, active vibration control is essential for these membrane mirrors. In this paper, two different mirror models, i.e., the plate membrane model and pure membrane model, are studied respectively. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as actuators. Dynamic equations of the mirror laminated with piezoelectric actuators are presented first. Then, the actuator induced modal control force is defined. When the actuator area shrinks to infinitesimal, the expressions of microscopic local modal control force and its two components are obtained to predict the spatial microscopic actuation behavior of the mirror. Different membrane pretension forces are also applied to reveal the tension effects on the actuation of the mirror. Analyses indicate that the spatial distribution of modal micro-control forces is exactly the same with the sensing signals distribution of the mirror, which provides crucial guidelines for optimal actuator placement of membrane deformable mirrors.

Multilayer deposition and EUV reflectance characterization of 131 ? flight mirrors for AIA at LLNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soufli, R; Robinson, J C; Spiller, E

2006-02-22

Mo/Si multilayer coatings reflecting at 131 {angstrom} were deposited successfully on the AIA primary and secondary flight mirrors and on two coating witness Si wafers, on November 16, 2005, at LLNL. All coatings were characterized by means of EUV reflectance measurements at beamline 6.3.2 of the Advanced Light Source (ALS) synchrotron at LBNL, and were found to be well within specifications.

Performance of lightweight large C/SiC mirror

NASA Astrophysics Data System (ADS)

Yui, Yukari Y.; Goto, Ken; Kaneda, Hidehiro; Katayama, Haruyoshi; Kotani, Masaki; Miyamoto, Masashi; Naitoh, Masataka; Nakagawa, Takao; Saruwatari, Hideki; Suganuma, Masahiro; Sugita, Hiroyuki; Tange, Yoshio; Utsunomiya, Shin; Yamamoto, Yasuji; Yamawaki, Toshihiko

2017-11-01

Very lightweight mirror will be required in the near future for both astronomical and earth science/observation missions. Silicon carbide is becoming one of the major materials applied especially to large and/or light space-borne optics, such as Herschel, GAIA, and SPICA. On the other hand, the technology of highly accurate optical measurement of large telescopes, especially in visible wavelength or cryogenic circumstances is also indispensable to realize such space-borne telescopes and hence the successful missions. We have manufactured a very lightweight Φ=800mm mirror made of carbon reinforced silicon carbide composite that can be used to evaluate the homogeneity of the mirror substrate and to master and establish the ground testing method and techniques by assembling it as the primary mirror into an optical system. All other parts of the optics model are also made of the same material as the primary mirror. The composite material was assumed to be homogeneous from the mechanical tests of samples cut out from the various areas of the 800mm mirror green-body and the cryogenic optical measurement of the mirror surface deformation of a 160mm sample mirror that is also made from the same green-body as the 800mm mirror. The circumstance and condition of the optical testing facility has been confirmed to be capable for the highly precise optical measurements of large optical systems of horizontal light axis configuration. Stitching measurement method and the algorithm for analysis of the measurement is also under study.

Long Focal Length Large Mirror Fabrication System

NASA Technical Reports Server (NTRS)

Bennett, H. E.

2003-01-01

The goals of this ambitious program are (1) to develop systems to make large superpolished optical mirrors, (2) to develop low scatter polishing techniques using centrifugal elutriation, (3) to develop a means of measuring scatter at any point on the mirror, (4) to polish a Hindle sphere to measure the optical figure of a one meter diameter convex mandrel, and (5) to fabricate low scatter, large adaptive optic graphite filled, cyanate ester replica transfer mirrors using these mandrels. Deliverables are a 30 cm diameter superpolished composite AO mirror. We fabricated a 1/3rd meter superpolished zerodur flat mandrel and with the support of our major subcontractor, Composite Mirror Applications Inc (CMA) we have demonstrated a 30 cm lightweight cyanate ester mirror with an rms microroughness between 0.6 and 0.8 nm and 8 faceplate influence function of 5 cm. The influence function was chosen to be comparable to the atmospheric correlation coefficient r(sub 0) which is about 5 cm at sea level. There was no print-thru of the graphite fibers in the cyanate ester surface (the bane of many previous efforts to use cyanate ester mirrors). Our subcontractor has devised a means for developing a 30-50 nm thick layer of graphite free pure ester resin on the surface of the mirrors. This graphite fiber filled material has a thermal expansion coefficient in the 10(exp -8) centimeter per Kelvin range (the same range of expansion coefficient as Zerodur and ULE glasses) and does not take up water and swell, so it is a nearly ideal mirror material in these areas. Unfortunately for these 0.8mm thick faceplates, the number of plies is not enough to result in isometric coverage. Isolated figure irregularities can appear, making it necessary to go to thicker faceplates. The influence function will then only approximate the length of r(sub 0), at higher altitudes or longer wavelengths. The influence function goes as the cube of the thickness, so we are now making a faceplate optimized for

Blind readers break mirror invariance as sighted do.

PubMed

de Heering, Adélaïde; Collignon, Olivier; Kolinsky, Régine

2018-04-01

Mirror invariance refers to a predisposition of humans, including infants and animals, which urge them to consider mirrored images as corresponding to the same object. Yet in order to learn to read a written system that incorporates mirrored letters (e.g., vs. in the Latin alphabet), humans learn to break this perceptual bias. Here we examined the role visual experience and input modality play in the emergence of this bias. To this end, we tested congenital blind (CB) participants in two same-different tactile comparison tasks including pairs of mirrored and non-mirrored Braille letters as well as embossed unfamiliar geometric shapes and Latin letters, and compared their results to those of age-matched sighted participants involved in similar but visually-presented tasks. Sighted participants showed a classical pattern of results for their material of expertise, Latin letters. CB's results signed for their expertise with the Braille script compared to the other two materials that they processed according to an internal frame of reference. They also evidenced that they automatically break mirror invariance for different materials explored through the tactile modality, including Braille letters. Altogether, these results demonstrate that learning to read Braille through the tactile modality allows breaking mirror invariance in a comparable way to what is observed in sighted individuals for the mirrored letters of the Latin alphabet. Copyright © 2018 Elsevier Ltd. All rights reserved.

Research on automatic Hartmann test of membrane mirror

NASA Astrophysics Data System (ADS)

Zhong, Xing; Jin, Guang; Liu, Chunyu; Zhang, Peng

2010-10-01

Electrostatic membrane mirror is ultra-lightweight and easy to acquire a large diameter comparing with traditional optical elements, so its development and usage is the trend of future large mirrors. In order to research the control method of the static stretching membrane mirror, the surface configuration must be tested. However, membrane mirror's shape is always changed by variable voltages on the electrodes, and the optical properties of membrane materials using in our experiment are poor, so it is difficult to test membrane mirror by interferometer and null compensator method. To solve this problem, an automatic optical test procedure for membrane mirror is designed based on Hartmann screen method. The optical path includes point light source, CCD camera, splitter and diffuse transmittance screen. The spots' positions on the diffuse transmittance screen are pictured by CCD camera connected with computer, and image segmentation and centroid solving is auto processed. The CCD camera's lens distortion is measured, and fixing coefficients are given to eliminate the spots' positions recording error caused by lens distortion. To process the low sampling Hartmann test results, Zernike polynomial fitting method is applied to smooth the wave front. So low frequency error of the membrane mirror can be measured then. Errors affecting the test accuracy are also analyzed in this paper. The method proposed in this paper provides a reference for surface shape detection in membrane mirror research.

Acoustic Models of Optical Mirrors

ERIC Educational Resources Information Center

Mayer, V. V.; Varaksina, E. I.

2014-01-01

Students form a more exact idea of the action of optical mirrors if they can observe the wave field being formed during reflection. For this purpose it is possible to organize model experiments with flexural waves propagating in thin elastic plates. The direct and round edges of the plates are used as models of plane, convex and concave mirrors.…

Mirror Technology Development for The International X-Ray Observatory Mission

NASA Technical Reports Server (NTRS)

Zhang, Will

2010-01-01

Presentation slides include: International X-ray Observatory (IXO), Lightweight and High Resolution X-ray Optics is Needed; Modular Design of Mirror Assembly, IXO Mirror Technology Development Objectives, Focus of Technology Development, Slumping - Status, Mirror Fabrication Progress, Temporary Bonding - Status, Alignment - Status, Permanent Bonding - Status, Mirror Housing Simulator (MHS) - TRL-4, Mini-Module (TRL-5), Flight-Like Module (TRL-6), Mirror Technology Development Team, Outlook, and Small Technology Firms that Have Made Direct Contributions to IXO Mirror Technology Development.

49 CFR 571.111 - Standard No. 111; Rearview mirrors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... mirror that reflect images, excluding the mirror rim or mounting brackets. Unit magnification mirror... image of an object is equal to the angular height and width of the object when viewed directly at the... WHILE BUS IS MOVING. IMAGES IN SUCH MIRRORS DO NOT ACCURATELY SHOW ANOTHER VEHICLE'S LOCATION.” S9.4(a...

49 CFR 571.111 - Standard No. 111; Rearview mirrors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... mirror that reflect images, excluding the mirror rim or mounting brackets. Unit magnification mirror... image of an object is equal to the angular height and width of the object when viewed directly at the... WHILE BUS IS MOVING. IMAGES IN SUCH MIRRORS DO NOT ACCURATELY SHOW ANOTHER VEHICLE'S LOCATION.” S9.4(a...

James Webb Space Telescope Optical Telescope Element Mirror Coatings

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A.; Bowers, Charles W.; Quijada, Manuel A.; Heaney, James B.; Gallagher, Benjamin; McKay, Andrew; Stevenson, Ian

2012-01-01

James Webb Space Telescope (JWST) Optical Telescope Element (OTE) mirror coating program has been completed. The science goals of the JWST mission require a uniform, low stress, durable optical coating with high reflectivity over the JWST spectral region. The coating has to be environmentally stable, radiation resistant and compatible with the cryogenic operating environment. The large size, 1.52 m point to point, light weight, beryllium primary mirror (PM) segments and flawless coating process during the flight mirror coating program that consisted coating of 21 flight mirrors were among many technical challenges. This paper provides an overview of the JWST telescope mirror coating program. The paper summarizes the coating development program and performance of the flight mirrors.

Microinstabilities in the Gasdynamic Mirror Propulsion System

NASA Technical Reports Server (NTRS)

Emrich, William

2005-01-01

The gasdynamic mirror has been proposed as a concept which could form the basis of a highly efficient fusion rocket engine. Gasdynamic mirrors differ from most other mirror type plasma confinement schemes in that they have much larger aspect ratios and operate at somewhat higher plasma densities. There are several types of instabilities which are known to plague mirror type confinement schemes. These instabilities fall into two general classes. One class of instability is the Magnetohydrodynamic or MHD instability which induces gross distortions in the plasma geometry. The other class of instability is the "loss cone" microinstability which leads to general plasma turbulence. The "loss cone" microinstability is caused by velocity space asymmetries resulting from the loss of plasma having constituent particle velocities within the angle of the magnetic mirror "loss cone." These instabilities generally manifest themselves in high temperature, moderately dense plasmas. The present study indicates that a GDM configured as a rocket engine might operate in a plasma regime where microinstabilities could potentially be significant.

Microinstabilities in the Gasdynamic Mirror Propulsion System

NASA Technical Reports Server (NTRS)

Emrich, William

2005-01-01

The gasdynamic mirror has been proposed as a concept which could form the basis of a highly efficient fusion rocket engine. Gasdynamic mirrors differ from most other mirror type plasma confinement schemes in that they have much larger aspect ratios and operate at somewhat higher plasma densities. There are several types of instabilities which are known to plague mirror type confinement schemes. These instabilities fall into two general classes. One class of instability is the Magnetohdrodynamic or MHD instability which induces gross distortions in the plasma geometry. The other class of instability is the "loss cone" microinstability which leads to general plasma turbulence. The "loss cone" microinstability is caused by velocity space asymmetries resulting from the loss of plasma having constituent particle velocities within the angle of the magnetic mirror "loss cone." These instabilities generally manifest themselves in high temperature, moderately dense plasmas. The present study indicates that a GDM configured as a rocket engine might operate in a plasma regine where microinstabilities could potentially be significant.

Dynamic deformation analysis of light-weight mirror

NASA Astrophysics Data System (ADS)

Zhang, Yingtao; Cao, Xuedong; Kuang, Long; Yang, Wei

2012-10-01

In the process of optical dynamic target work, under the effort of the arm of dynamic target, the mirror needs to do circular motion, additional accelerated motion and uniform motion. The maximum acceleration is 10°/s2 and the maximum velocity is 30°/s. In this paper, we mostly analyze the dynamic deformation of a 600 mm honeycomb light-weight mirror of a certain dynamic target. Using the FEA (finite element analysis) method, first of all, we analyze the deformation of the light-weight mirror induced in gravity at different position; later, the dynamic deformation of light-weight mirror is analyzed in detailed. The analysis results indicate that, when the maximum acceleration is 10°/s2 and the maximum velocity is 30°/s, the centripetal force is 5% of the gravity at the equal mass, and the dynamic deformation of the mirror is 6.1% of the deformation induced by gravity.

Successful Graded Mirror Therapy in a Patient with Chronic Deafferentation Pain in Whom Traditional Mirror Therapy was Ineffective: A Case Report.

PubMed

Mibu, Akira; Nishigami, Tomohiko; Tanaka, Katsuyoshi; Osumi, Michihiro; Tanabe, Akihito

2016-04-01

A 43-year-old man had deafferentation pain in his right upper extremity secondary to brachial plexus avulsion from a traffic accident 23 years previously. On our initial examination, he had severe tingling pain with numbness in the right fingers rated 10 on the numerical rating scale. The body perception of the affected third and fourth fingers was distorted in the flexed position. Although he performed traditional mirror therapy (TMT) for 4 weeks in the same methods as seen in previous studies, he could not obtain willed motor imagery and pain-alleviation effect. Therefore, we modified the task of TMT: Graded mirror therapy (GMT). GMT consisted of five stages: (1) observation of the mirror reflection of the unaffected side without imagining any movements of the affected side; (2) observation of the mirror reflection of the third and fourth fingers changing shape gradually adjusted from a flexed position to a extended position; (3) observation of the mirror reflection of passive movement; (4) motor imagery of affected fingers with observation of the mirror reflection (similar to TMT); (5) motor imagery of affected fingers without mirror. Each task was performed for 3 to 4 weeks. As a result, pain intensity during mirror therapy gradually decreased and finally disappeared. The body perception of the affected fingers also improved, and he could imagine the movement of the fingers with or without mirror. We suggested that GMT starting from the observation task without motor imagery may effectively decrease deafferentation pain compared to TMT. © 2016 World Institute of Pain.

Double arch mirror study. Part 3: Fabrication and test report

NASA Technical Reports Server (NTRS)

Vukobratovich, D.; Hillman, D.

1983-01-01

A method of mounting a cryogenically cooled, lightweight, double arch, glass mirror was developed for infrared, astronomical telescopes such as the Space Infrared Telescope Facility (SIRTF). A 50 cm, fused silica mirror which was previously fabricated was modified for use with a new mount configuration. This mount concept was developed. The modification of the mirror, the fabrication of the mirror mount, and the room temperature testing of the mounted mirror are reported. A design for a SIRTF class primary mirror is suggested.

Reflections on mirror neurons and speech perception.

PubMed

Lotto, Andrew J; Hickok, Gregory S; Holt, Lori L

2009-03-01

The discovery of mirror neurons, a class of neurons that respond when a monkey performs an action and also when the monkey observes others producing the same action, has promoted a renaissance for the Motor Theory (MT) of speech perception. This is because mirror neurons seem to accomplish the same kind of one to one mapping between perception and action that MT theorizes to be the basis of human speech communication. However, this seeming correspondence is superficial, and there are theoretical and empirical reasons to temper enthusiasm about the explanatory role mirror neurons might have for speech perception. In fact, rather than providing support for MT, mirror neurons are actually inconsistent with the central tenets of MT.

Reflections on mirror neurons and speech perception

PubMed Central

Lotto, Andrew J.; Hickok, Gregory S.; Holt, Lori L.

2010-01-01

The discovery of mirror neurons, a class of neurons that respond when a monkey performs an action and also when the monkey observes others producing the same action, has promoted a renaissance for the Motor Theory (MT) of speech perception. This is because mirror neurons seem to accomplish the same kind of one to one mapping between perception and action that MT theorizes to be the basis of human speech communication. However, this seeming correspondence is superficial, and there are theoretical and empirical reasons to temper enthusiasm about the explanatory role mirror neurons might have for speech perception. In fact, rather than providing support for MT, mirror neurons are actually inconsistent with the central tenets of MT. PMID:19223222

SOFIA secondary mirror Hindle test analysis

NASA Astrophysics Data System (ADS)

Davis, Paul K.

2003-02-01

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a NASA facility, nearing completion, consisting of an infrared telescope of 2.5 meter system aperture flying in a modified Boeing 747. Its Cassegrain secondary mirror has recently completed polishing. The SOFIA Project Office at Ames Research Center considered it important to perform an independent analysis of secondary mirror figure. The polishing was controlled by the standard test for a convex hyperboloid, the Hindle test, in a modified form with a meniscus lens partially reflecting on the concave face, rather than a fully reflecting mirror with a central hole. The spacing between this meniscus lens and the secondary mirror was controlled by three peripherally located spacing spheres. This necessitated special analysis to determine what the resulting curvature and conic constant of the mirror would be, if manufacturing imprecisions of the test set-up components were to be taken into account. This set-up was specially programmed, and the resulting hyperboloid calculated for the nominal case, and all extreme cases from the reported error limits on the manufacturing of the components. The results were then verified using the standard program CODE-V of Optical Research Associates. The conclusion is that the secondary mirror has a vertex radius of curvature of 954.05 mm +/- .1 mm (design value: 954.13), and a conic constant of -1.2965 +/- .001 (dimensionless, design value: -1.298). Such small divergences from design are to be expected, and these are within the refocusing ability of SOFIA, and would result in an acceptably small amount of spherical aberration in the image.

Fabrication Methods for Adaptive Deformable Mirrors

NASA Technical Reports Server (NTRS)

Toda, Risaku; White, Victor E.; Manohara, Harish; Patterson, Keith D.; Yamamoto, Namiko; Gdoutos, Eleftherios; Steeves, John B.; Daraio, Chiara; Pellegrino, Sergio

2013-01-01

Previously, it was difficult to fabricate deformable mirrors made by piezoelectric actuators. This is because numerous actuators need to be precisely assembled to control the surface shape of the mirror. Two approaches have been developed. Both approaches begin by depositing a stack of piezoelectric films and electrodes over a silicon wafer substrate. In the first approach, the silicon wafer is removed initially by plasmabased reactive ion etching (RIE), and non-plasma dry etching with xenon difluoride (XeF2). In the second approach, the actuator film stack is immersed in a liquid such as deionized water. The adhesion between the actuator film stack and the substrate is relatively weak. Simply by seeping liquid between the film and the substrate, the actuator film stack is gently released from the substrate. The deformable mirror contains multiple piezoelectric membrane layers as well as multiple electrode layers (some are patterned and some are unpatterned). At the piezolectric layer, polyvinylidene fluoride (PVDF), or its co-polymer, poly(vinylidene fluoride trifluoroethylene P(VDF-TrFE) is used. The surface of the mirror is coated with a reflective coating. The actuator film stack is fabricated on silicon, or silicon on insulator (SOI) substrate, by repeatedly spin-coating the PVDF or P(VDFTrFE) solution and patterned metal (electrode) deposition. In the first approach, the actuator film stack is prepared on SOI substrate. Then, the thick silicon (typically 500-micron thick and called handle silicon) of the SOI wafer is etched by a deep reactive ion etching process tool (SF6-based plasma etching). This deep RIE stops at the middle SiO2 layer. The middle SiO2 layer is etched by either HF-based wet etching or dry plasma etch. The thin silicon layer (generally called a device layer) of SOI is removed by XeF2 dry etch. This XeF2 etch is very gentle and extremely selective, so the released mirror membrane is not damaged. It is possible to replace SOI with silicon

Selecting mirror materials for high-performance optical systems

NASA Astrophysics Data System (ADS)

Parsonage, Thomas B.

1990-11-01

The properties of four candidate mirror materials--beryllium, silicon carbide, a silicon carbide/aluminum iretal-matrix carposite and aluminum--are corrpared. Because of its high specific stiffness and dirrensional stability under changing mschanical and thermal loads , beryllium is the best choice . Berjllium mirrors have been made irore cost-conpetitive by new processing technologies in which mirror blanks are isostatically pressed to near-net shape directly fran beiyllium pc1ers. Isostatic pressing also improves material properties and mskes it possible to develop mirror rraterials with superior properties.

Study on optical polishing experiment of zerodur mirror

NASA Astrophysics Data System (ADS)

Wang, Huijun; Li, Hang; Wang, Peng; Guo, Wen; Wang, Yonggang; Du, Yan; Dong, Huiwen

2014-08-01

A zerodur mirror whose aperture is 900mm is chosen to be the primary mirror of an optical system. The mirror is polished by rapid polishing and precision polishing methods relatively. The final surface figures of the mirror are as follows: the peak-to-valley value (P-V value) is 0.204λ (λ=632.8nm), and the root-mean-square value (RMS value) is 0.016λ, which meet the requirement of the optical system. The results show that the polishing process is feasible.

JWST Mirror Technology Development

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2010-01-01

Since the initial Design Studies leading to JWST, Mirror Technology was identified as a (if not the) critical capability necessary to enable the next generation of large aperture space telescopes required to achieve the science goals of imaging the earliest galaxies and proto-galaxies after the big bang. Specific telescope architectures were explored via three independent design concept studies conducted during the summer of 1996. Achieving the desired science objectives required a never before demonstrated space telescope capability, one with an 8 meter class primary mirror that is diffraction limited at 2 micrometers and operating in deep space at temperatures well below 70K. Beryllium was identified in the NASA "Yardstick" design as the preferred material because of its ability to provide stable optical performance in the anticipated thermal environment as well as its excellent specific stiffness. Because of launch vehicle constraints, two very significant architectural constraints were placed upon the telescope: segmentation and areal density. Each of these directly resulted in specific technology capability requirements. First, because the maximum launch vehicle payload fairing diameter is approximately 4.5 meters, the only way to launch an 8 meter class mirror is to segment it, fold it and deploy it on orbit - resulting in actuation and control requirements. Second, because of launch vehicle mass limits, the primary mirror allocation was only 1000 kg - resulting in a maximum areal density specification of 20 kilograms per square meter.

Actuated Hybrid Mirrors for Space Telescopes

NASA Technical Reports Server (NTRS)

Hickey, Gregory; Ealey, Mark; Redding, David

2010-01-01

This paper describes new, large, ultra-lightweight, replicated, actively controlled mirrors, for use in space telescopes. These mirrors utilize SiC substrates, with embedded solid-state actuators, bonded to Nanolaminate metal foil reflective surfaces. Called Actuated Hybrid Mirrors (AHMs), they use replication techniques for high optical quality as well as rapid, low cost manufacturing. They enable an Active Optics space telescope architecture that uses periodic image-based wavefront sensing and control to assure diffraction-limited performance, while relaxing optical system fabrication, integration and test requirements. The proposed International Space Station Observatory seeks to demonstrate this architecture in space.

X-ray telescope mirrors made of slumped glass sheets

NASA Astrophysics Data System (ADS)

Winter, A.; Breunig, E.; Friedrich, P.; Proserpio, L.

2017-11-01

For several decades, the field of X-ray astronomy has been playing a major role in understanding the processes in our universe. From binary stars and black holes up to galaxy clusters and dark matter, high energetic events have been observed and analysed using powerful X-ray telescopes like e.g. Rosat, Chandra, and XMM-Newton [1,2,3], giving us detailed and unprecedented views of the high-energy universe. In November 2013, the theme of "The Hot and Energetic Universe" was rated as of highest importance for future exploration and in June 2014 the ATHENA Advanced Telescope for High Energy Astrophysics was selected by ESA for the second large science mission (L2) in the ESA Cosmic Vision program, with launch foreseen in 2028 [4]. By combining a large X-ray telescope with state-of-the-art scientific instruments, ATHENA will address key questions in astrophysics, including: How and why does ordinary matter assemble into the galaxies and galactic clusters that we see today? How do black holes grow and influence their surroundings? In order to answer these questions, ATHENA needs a powerful mirror system which exceed the capabilities of current missions, especially in terms of collecting area. However, current technologies have reached the mass limits of the launching rocket, creating the need for more light-weight mirror systems in order to enhance the effective area without increasing the telescope mass. Hence new mirror technologies are being developed which aim for low-weight systems with large collecting areas. Light material like glass can be used, which are shaped to form an X-ray reflecting system via the method of thermal glass slumping.

Contagious behavior: an alternative approach to mirror-like phenomena.

PubMed

Provine, Robert R

2014-04-01

Contagious behaviors such as yawning and itching/scratching have mirror-like properties and clearly defined stimulus and motor parameters; they are also relatively easy to study and should be part of the debate about mirror neurons and the neurological mechanisms of social behavior. The broadly tuned, multimodal stimuli of contagious behavior challenge present accounts of mirror mechanisms that focus on specific, mirrored acts.

NASA Funding Opportunities for Optical Fabrication and Testing Technology Development

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

Technologies to fabricate and test optical components are required for NASA to accomplish its highest priority science missions. For example, the NRC ASTRO2010 Decadal Survey states that an advanced large-aperture UVOIR telescope is required to enable the next generation of compelling astrophysics and exo-planet science; and that present technology is not mature enough to affordably build and launch any potential UVOIR mission concept. The NRC 2012 NASA Space Technology Roadmaps and Priorities report states that the highest priority technology in which NASA should invest to 'Expand our understanding of Earth and the universe' is a new generation of astronomical telescopes. And, each of the Astrophysics division Program Office Annual Technology Reports (PATR), identifies specific technology needs. NASA has a variety of programs to fund enabling technology development: SBIR (Small Business Innovative Research); the ROSES APRA and SAT programs (Research Opportunities in Space and Earth Science; Astrophysics Research and Analysis program; Strategic Astrophysics Technology program); and several Office of the Chief Technologist (OCT) technology development programs.

Columbia Crew added to Astronaut Memorial Mirror

NASA Image and Video Library

2003-07-15

Workers add to the Astronaut Memorial Mirror the names of the Columbia crew who died in the STS-107 accident. Dedicated May 9, 1991, the Astronaut Memorial honors U.S. astronauts who gave their lives for space exploration. The "Space Mirror," 42 1/2 feet high by 50 feet wide, illuminates the names of the fallen astronauts cut through the monument's black granite surface. The Memorial Mirror is accessible through the KSC Visitor Complex.

Transition Metal Switchable Mirror

ScienceCinema

None

2017-12-09

The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft.

Transition Metal Switchable Mirror

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-08-21

The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft.

Age-Specific Effects of Mirror-Muscle Activity on Cross-Limb Adaptations Under Mirror and Non-Mirror Visual Feedback Conditions.

PubMed

Reissig, Paola; Stöckel, Tino; Garry, Michael I; Summers, Jeffery J; Hinder, Mark R

2015-01-01

Cross-limb transfer (CLT) describes the observation of bilateral performance gains due to unilateral motor practice. Previous research has suggested that CLT may be reduced, or absent, in older adults, possibly due to age-related structural and functional brain changes. Based on research showing increases in CLT due to the provision of mirror visual feedback (MVF) during task execution in young adults, our study aimed to investigate whether MVF can facilitate CLT in older adults, who are known to be more reliant on visual feedback for accurate motor performance. Participants (N = 53) engaged in a short-term training regime (300 movements) involving a ballistic finger task using their dominant hand, while being provided with either visual feedback of their active limb, or a mirror reflection of their active limb (superimposed over the quiescent limb). Performance in both limbs was examined before, during and following the unilateral training. Furthermore, we measured corticospinal excitability (using TMS) at these time points, and assessed muscle activity bilaterally during the task via EMG; these parameters were used to investigate the mechanisms mediating and predicting CLT. Training resulted in significant bilateral performance gains that did not differ as a result of age or visual feedback (both p > 0.1). Training also elicited bilateral increases in corticospinal excitability (p < 0.05). For younger adults, CLT was significantly predicted by performance gains in the trained hand (β = 0.47), whereas for older adults it was significantly predicted by mirror activity in the untrained hand during training (β = 0.60). The present study suggests that older adults are capable of exhibiting CLT to a similar degree to younger adults. The prominent role of mirror activity in the untrained hand for CLT in older adults indicates that bilateral cortical activity during unilateral motor tasks is a compensatory mechanism. In this particular task, MVF did not facilitate the

Lifetime Prediction for Degradation of Solar Mirrors using Step-Stress Accelerated Testing (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, J.; Elmore, R.; Kennedy, C.

This research is to illustrate the use of statistical inference techniques in order to quantify the uncertainty surrounding reliability estimates in a step-stress accelerated degradation testing (SSADT) scenario. SSADT can be used when a researcher is faced with a resource-constrained environment, e.g., limits on chamber time or on the number of units to test. We apply the SSADT methodology to a degradation experiment involving concentrated solar power (CSP) mirrors and compare the results to a more traditional multiple accelerated testing paradigm. Specifically, our work includes: (1) designing a durability testing plan for solar mirrors (3M's new improved silvered acrylic "Solarmore » Reflector Film (SFM) 1100") through the ultra-accelerated weathering system (UAWS), (2) defining degradation paths of optical performance based on the SSADT model which is accelerated by high UV-radiant exposure, and (3) developing service lifetime prediction models for solar mirrors using advanced statistical inference. We use the method of least squares to estimate the model parameters and this serves as the basis for the statistical inference in SSADT. Several quantities of interest can be estimated from this procedure, e.g., mean-time-to-failure (MTTF) and warranty time. The methods allow for the estimation of quantities that may be of interest to the domain scientists.« less

Self-Balancing, Optical-Center-Pivot, Fast-Steering Mirror

NASA Technical Reports Server (NTRS)

Moore, James D.; Carson, Johnathan W.

2011-01-01

A complete, self-contained fast-steering- mirror (FSM) mechanism is reported consisting of a housing, a mirror and mirror-mounting cell, three PZT (piezoelectric) actuators, and a counterbalance mass. Basically, it is a comparatively stiff, two-axis (tip-tilt), self-balanced FSM. The present invention requires only three (or three pairs for flight redundancy) actuators. If a PZT actuator degrades, the inherent balance remains, and compensation for degraded stroke is made by simply increasing the voltage to the PZT. Prior designs typically do not pivot at the mirror optical center, creating unacceptable beam shear.

Replicate Wolter-I x-ray mirrors

NASA Technical Reports Server (NTRS)

Engelhaupt, D. E.; Rood, R.; Fawcett, S.; Griffith, C.; Khanijow, R.

1994-01-01

Cylindrical (hyperbolic - parabolic Wolter I) mirrors have been electroformed from nickel over an electroless nickel-phosphorous (NiP) plated aluminum mandrel in support of the NASA AXAF-S x-ray spectrometer program. The electroless nickel was diamond turned and polished to achieve a surface finish of 10 angstroms rms or better. Gold was then plated on the nickel alloy after an electrochemical passivation step. Next a heavy layer of pure nickel was plated one millimeter thick with controlled stress at zero using a commercial PID program to form the actual mirror. This shell was removed from the NiP alloy coated mandrel by cryogenic cooling and contraction of the aluminum to release the mirror. It is required that the gold not adhere well to the NiP but all other plated coatings must exhibit good adherence. Four mirrors were fabricated from two mandrels prepared by this method. The area of each part is 0.7 square meters (7.5 square feet).

Numerical modeling of electroactive polymer mirrors for space applications

NASA Technical Reports Server (NTRS)

Bao, X.; Bar-Cohen, Y.; Chang, Z.; Sherrit, S.

2003-01-01

A controllable mirror made of single-layer EAP mirror is proposed in this paper. An analytical solution of required voltage distribution for forming a parabolic mirror from a planar film is presented.