Deep Space 3 Metrology System
A metrology subsystem on board the Deep Space 3, a separated interferometer mission, is used to determine stellar fringe delay jitter, delay rate, and intial delay.
Deep↗
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NASA Lyndon B. Johnson Space Center's Metrology Program
Since the establishment in 1962 of the NASA-JSC Metrology Program, the Reference Standards Laboratory has successfully accomplished its goal and objectives. An on-going laboratory surveillance program, established for insuring a continuing validation of the measurements required at the center, is shown to remain at the forefront of modern technology through its involvement in activities such as the NBS sponsored Measurement Assurance Programs and the utilization of an Automatic Calibration System.
Suraci, J. M.↗
Precision machining technology and metrology for AXAF study
The optical surfaces for the Advanced X-ray Astrophysical Facility (AXAF), was studied. The applicability of precision machining technology to the manufacture of the AXAF objective mirrors and the proposed and alternative methods for manufacturing and testing; (1) the AXAF technology mirrors and (2) the AXAF high resolution mirror assembly were reviewed. Surface shape and smoothness metrology for grazing incidence X-ray surfaces and the feasibility of applying heterodyne surface profilometry to nonflat surfaces were investigated. Three sets of scattering flats with known surface profiles and microtopographic character produced by precision machining and polished precision machine surfaces were analyzed.
Sanger, G. M.↗
Advanced flow-polishing and surface metrology of the SO56 X Ray Telescope
The surface finishing of X ray grazing incidence optics is a most demanding area of optical processing, both in terms of metrology and application of optical finishing techniques. An existing optical mirror was processed using a new removal technique that uses a jet of finely dispersed and extremely small particles that impact a surface, which under the correct conditions, produces an ultrasmooth surface, especially on aspheric curvatures. The surfaces of the SO56 mirror are tapered conical shapes that have a continuously changing radius with the primary mirror having a parabolic shape and the secondary mirror a hyperbolic shape. An optical ray trace that was conducted of a telescope used the measured parameters from the existing substrates to set up the prescription for the optical layout. The optimization indicated a wavefront performance of 0.10 A at 0.633 micron.
Source record↗
Metrology: Measurement Assurance Program Guidelines
The 5300.4 series of NASA Handbooks for Reliability and Quality Assurance Programs have provisions for the establishment and utilization of a documented metrology system to control measurement processes and to provide objective evidence of quality conformance. The intent of these provisions is to assure consistency and conformance to specifications and tolerances of equipment, systems, materials, and processes procured and/or used by NASA, its international partners, contractors, subcontractors, and suppliers. This Measurement Assurance Program (MAP) guideline has the specific objectives to: (1) ensure the quality of measurements made within NASA programs; (2) establish realistic measurement process uncertainties; (3) maintain continuous control over the measurement processes; and (4) ensure measurement compatibility among NASA facilities. The publication addresses MAP methods as applied within and among NASA installations and serves as a guide to: control measurement processes at the local level (one facility); conduct measurement assurance programs in which a number of field installations are joint participants; and conduct measurement integrity (round robin) experiments in which a number of field installations participate to assess the overall quality of particular measurement processes at a point in time.
Eicke, W. G.↗
Optical Metrology for the Filter Set for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS)
The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) will employ a wide variety of spectral filtration components including narrow band, medium band, wide band, and far ultraviolet (FUV) long pass filters, spatially- variable filters (ramp filters), VIS/IR polarizers, NUV polarizers, FUV prisms, and a grism. These components are spread across ACS's Wide Field, High Resolution, and Solar Blind channels which provide diffraction-limited imaging of astronomical targets using aberration-correcting optics which remove most aberrations from HST's Optical Telescope Assembly (OTA). In order for ACS to be truly advanced, these filters must push the state-of-the-art in performance in a number of key areas at the same time. Important requirements which these filters must meet include outstanding transmitted wavefront, high transmittance, uniform transmittance across each filter, spectrally structure-free bandpasses, exceptionally high out of band rejection, and a high degree of parfocality. These constitute a very stringent set of requirements indeed, especially for filters which are up to 90 mm in diameter. The development of optical metrology stations used to demonstrate that each ACS filter will meet its design specifications is discussed. Of particular note are specially-designed spectral transmissometers and interferometers.
Leviton, Douglas B.↗
NGST OTA Optical Metrology Instrumentation and Conceptual Approaches
An Integrated Product Team (IPT) was formed to develop a detailed concept for optical test methodology for testing of the NGST individual primary, secondary and tertiary mirrors and the full telescope system on the ground. Optical testing is a significant cost driver therefore the testing has to understood in detailed fashion early. A brief summary of the preliminary metrology test plan at the mirror component and telescope system level is presented.
Keski-Kuha, R.↗
Metrology of Optical Beam Expander for Space Readiness Coherent Lidar Experiment (SPARCLE)
Stringent requirements of the SPARCLE telescope demanded testing of its individual elements through each step of fabrication, and complete metrology of the integrated telescope both at Helium-Neon and the operational two micron wavelengths.
Kester, Thomas J.↗
Metrology and Alignment of Light Weight Grazing Incidence X-Ray Mirrors
Metrology and alignment of light weight X-ray optics have been a challenge for two reasons: (1) that the intrinsic mirror quality and distortions caused by handling can not be easily separated, and (2) the diffraction limits of the visible light become a severe problem at the order of one arc-minute. Traditional methods of using a normal incident pencil or small parallel beam which monitors a tiny fraction of the mirror in question at a given time can not adequately monitor those distortions. We are developing a normal incidence setup that monitors a large fraction, if not the whole, of the mirror at any given time. It will allow us to align thin X-ray mirrors to-an accuracy of a few arc seconds or to a limit dominated by the mirror intrinsic quality.
Zhang, William↗
Radius of Curvature Measurements: An Independent Look at Accuracy Using Novel Optical Metrology
The AMSD (Advanced Mirror System Demonstrator) program mirror specifications include the ability to manufacture the mirror to a radius of curvature of 10 m +/- 1 mm and to control its radius at 30K to the same specification. Therefore, it is necessary for the Government Team to be able to measure mirror radius of curvature to an accuracy of better than 0.5 mm. This presentation discusses a novel optical metrology system for measuring radius of curvature.
Taylor, Bryon↗
Fabrication and Metrology of High-Precision Foil Mirror Mounting Elements
During the period of this Cooperative Agreement, MIT (Massachusetts Institute of Technology) developed advanced methods for applying silicon microstructures for the precision assembly of foil x-ray optics in support of the Constellation-X Spectroscopy X-ray Telescope (SXT) development effort at Goddard Space Flight Center (GSFC). MIT developed improved methods for fabricating and characterizing the precision silicon micro-combs. MIT also developed and characterized assembly tools and several types of metrology tools in order to characterize and reduce the errors associated with precision assembly of foil optics. Results of this effort were published and presented to the scientific community and the GSFC SXT team. A bibliography of papers and presentations is offered.
Schattenburg, Mark L.↗
A Precision Metrology System for the Hubble Space Telescope Wide Field Camera 3 Instrument
The Wide Field Camera 3 (WFC3) instrument for the Hubble Space Telescope (HST) will replace the current Wide Field and Planetary Camera 2 (WFPC2). By providing higher throughput and sensitivity than WFPC2, and operating from the near-IR to the near-UV, WFC3 will once again bring the performance of HST above that from ground-based observatories. Crucial to the integration of the WFC3 optical bench is a pair of 2-axis cathetometers used to view targets which cannot be seen by other means when the bench is loaded into its enclosure. The setup and calibration of these cathetometers is described, along with results from a comparison of the cathetometer system with other metrology techniques.
Toland, Ronald W.↗
A Precision Metrology System for the Hubble Space Telescope Wide Field Camera 3 Instrument
The Wide Field Camera 3 (WFC3) instrument for the Hubble Space Telescope (HST) will replace the current Wide Field and Planetary Camera 2 (WFPC2). By providing higher throughput and sensitivity than WFPC2, and operating from the near-IR to the near-UV, WFC3 will once again bring the pefiormance of HST above that from ground-based observatories. Crucial to the integration of the WFC3 optical bench is a pair of 2-axis cathetometers used to view targets which cannot be seen by other means when the bench is loaded into its enclosure. The setup and calibration of these cathetometers is described, along with results from a comparison of the cathetometer system with other metrology techniques. Finally, the use of the cathetometers on the flight optical bench and measurement results are given.
Toland, Ronald W.↗
Metrology Evaluation of Superfinished Gears Completed
Gears, bearings, and similar mechanical elements transmit loads through the surfaces that are in contact with one another. Thus, the fatigue lives of gears can be improved by providing smoother tooth surfaces. At the NASA Lewis Research Center, we completed a metrology evaluation of one method for making gears with a highly polished, mirrorlike surface. The polished gears were measured carefully. The measurement data showed that the polishing process did, indeed, reduce the surface roughness but did not change the overall tooth shape in any harmful way. This work was done as a partnership of NASA, the U.S. Army, and the University of Wales. NASA provided conventionally ground gear specimens and has begun testing to determine the fatigue lives of the superfinished gears. Under contract, the University of Wales superfinished the gears and inspected them before and after the superfinishing operation. The U.S. Army European Research Office provided the funds and procured the contract with the University of Wales.
Krantz, Timothy L.↗
Metrology for the Development of High Energy X-Ray Optics
We are developing grazing incidence x-ray optics for a balloon-borne hard-x-ray telescope (HERO). The instrument will have 200 sq cm effective collecting area at 40 keV and an angular resolution goal of 15 arcsec. The HERO mirror shells are fabricated using electroform-nickel replication off super-polished cylindrical mandrels. The angular resolution goal puts stringent requirements on the quality of x-ray mirrors and, hence, on mandrel quality. We used metrology in an iterative approach to monitor and refine the x- ray mirror fabrication process. Comparison of surface figure and microroughness measurements of the mandrel and the shells will be presented together with results from x-ray tests.
Gubarev, Mikhail↗
Formation metrology and control for large separated optics space telescopes
In this paper we present formation flying performance analysis initial results for a representative large space telescope composed of separated optical elements [Mett 02]. A virtual-structure construct (an equivalent rigid body) is created by unique metrology and control that combines both centralized and decentralized methods. The formation may be in orbit at GEO for super-resolution Earth observation, as in the case of Figure 1, or it may be in an Earth-trailing orbit for astrophysics, Figure 2. Extended applications are envisioned for exo-solar planet interferometric imaging by a formation of very large separated optics telescopes, Figure 3. Space telescopes, with such large apertures and f/10 to f/100 optics, are not feasible if connected by massive metering structures. Instead, the new virtual-structure paradigm of information and control connectivity between the formation elements provides the necessary spatial rigidity and alignment precision for the telescope.
formation flying virtual-structure telescopes↗
Tunable Diode Laser (TDL) Development for Trace Gas Spectroscopy and Metrology Systems
The current status of tunable diode lasers (TDLs) for spectroscopy and metrology systems is reviewed.
Trace Gas Spectroscopy tunable diode lasers(TDLs) ↗
OSI Metrology Gauges
OSI requires a metrology system to measure the three dimensional baseline vector between any two of its siderostats and the distance from the beam combiner to the baseline end points.
Gursel, Y.↗