Mr. J. Allen Crane Profile

J. Allen Crane

Mechanical Systems Engineer at NASA Goddard Space Flight Ctr

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Publications (6)

Proceedings Article | 19 September 2016 Presentation + Paper

Advanced topographic laser altimeter system (ATLAS) receiver telescope assembly (RTA) and transmitter alignment and test

John Hagopian, Matthew Bolcar, John Chambers, Allen Crane, Bente Eegholm, Tyler Evans, Samuel Hetherington, Eric Mentzell, Patrick Thompson, Luis Ramos-Izquierdo, David Vaughnn

Proceedings Volume 9972, 997207 (2016) https://doi.org/10.1117/12.2240241

KEYWORDS: Space telescopes, Telescopes, Optical fibers, Receivers, Transmitters, Diffractive optical elements, Collimators, Wavefronts, Mirrors, Interferometers

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The sole instrument on NASA’s ICESat-2 spacecraft shown in Figure 1 will be the Advanced Topographic Laser Altimeter System (ATLAS)¹. The ATLAS is a Light Detection and Ranging (LIDAR) instrument; it measures the time of flight of the six transmitted laser beams to the Earth and back to determine altitude for geospatial mapping of global ice. The ATLAS laser beam is split into 6 main beams by a Diffractive Optical Element (DOE) that are reflected off of the earth and imaged by an 800 mm diameter Receiver Telescope Assembly (RTA). The RTA is composed of a 2-mirror telescope and Aft Optics Assembly (AOA) that collects and focuses the light from the 6 probe beams into 6 science fibers. Each fiber optic has a field of view on the earth that subtends 83 micro Radians. The light collected by each fiber is detected by a photomultiplier and timing related to a master clock to determine time of flight and therefore distance. The collection of the light from the 6 laser spots projected to the ground allows for dense cross track sampling to provide for slope measurements of ice fields. NASA LIDAR instruments typically utilize telescopes that are not diffraction limited since they function as a light collector rather than imaging function. The more challenging requirements of the ATLAS instrument require better performance of the telescope at the ¼ wave level to provide for improved sampling and signal to noise. NASA Goddard Space Flight Center (GSFC) contracted the build of the telescope to General Dynamics (GD). GD fabricated and tested the flight and flight spare telescope and then integrated the government supplied AOA for testing of the RTA before and after vibration qualification. The RTA was then delivered to GSFC for independent verification and testing over expected thermal vacuum conditions. The testing at GSFC included a measurement of the RTA wavefront error and encircled energy in several orientations to determine the expected zero gravity figure, encircled energy, back focal length and plate scale. In addition, the science fibers had to be aligned to within 10 micro Radians of the projected laser spots to provide adequate margin for operations on-orbit. This paper summarizes the independent testing and alignment of the fibers performed at the GSFC.

Proceedings Article | 2 September 2008 Paper

Verification of the James Webb Space Telescope Integrated Science Instrument Module cryogenic structural alignment requirements via photogrammetry

Maria Nowak, Paul Cleveland, Allen Crane, Pamela Davila, Acey Herrera, Jason Hylan, Andrew Liehr, James Marsh, Raymond Ohl, Kevin Redman, Henry Sampler, Joseph Stock, Greg Wenzel, Robert Woodruff, Philip Young

Proceedings Volume 7068, 70680Q (2008) https://doi.org/10.1117/12.798791

KEYWORDS: Cameras, Cryogenics, Photogrammetry, James Webb Space Telescope, Distortion, Error analysis, Metrology, Calibration, Received signal strength, Optical alignment

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Proceedings Article | 1 October 2007 Paper

Photogrammetric metrology for the James Webb Space Telescope integrated science instrument module

Maria Nowak, Allen Crane, Pamela Davila, William Eichhorn, James Gill, Acey Herrera, Michael Hill, Jason Hylan, Mark Jetten, James Marsh, Raymond Ohl, Robert Quigley, Kevin Redman, Henry Sampler, Geraldine Wright, Philip Young

Proceedings Volume 6692, 66920P (2007) https://doi.org/10.1117/12.733896

KEYWORDS: Photogrammetry, Nondestructive evaluation, Cameras, Metrology, James Webb Space Telescope, Cryogenics, Temperature metrology, Optical alignment, Space telescopes, Interfaces

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Proceedings Article | 17 September 2007 Paper

Cryogenic system for interferometric measurement of dimensional changes at 40 K: design and performance

Peter Blake, Franklin Miller, Tim Zukowski, Edgar Canavan, Allen Crane, Tim Madison, David Miller

Proceedings Volume 6692, 669207 (2007) https://doi.org/10.1117/12.741002

KEYWORDS: Interferometers, Mirrors, Distortion, Composites, Cryogenics, Interferometry, Sapphire, Metrology, Thermal modeling, Aerospace engineering

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Proceedings Article | 22 December 2003 Paper

Wilkinson Microwave Anisotropy Probe scientific instrument metrology

J. Allen Crane, Acey Herrera, Neil Dahya, Henry Sampler, Pete Mule, Mike Hill, Carlos Aviado, Dean Osgood, Alex Bereczky

Proceedings Volume 5180, (2003) https://doi.org/10.1117/12.506267

KEYWORDS: Reflectors, Staring arrays, Metrology, Microwave radiation, Optical alignment, Space operations, Cameras, Waveguides, Photogrammetry, Autocollimation

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The Wilkinson Microwave Anisotropy Probe (WMAP) measures anisotropy or temperature differences in the Cosmic Microwave Background (CMB) radiation with high angular resolution and sensitivity, yielding unprecedented accuracy. To achieve this measurement, WMAP’s back-to-back Gregorian telescopes focus microwave radiation into 20 feed horns connected to 10 differential microwave radiometers. Proper alignment of the telescope reflectors, feed horns, and radiometers at flight temperatures was essential to the mission success. This paper will present the WMAP instrument metrology requirements and associated challenges, discuss the opto-mechanical tooling utilized to accomplish these objectives, and then give an overview of the metrology effort. The WMAP instrument integration effort included the following key metrology tasks: alignment and clocking of 20 microwave feed horns and mating microwave differencing assemblies within a focal plane assembly; alignment of a pair of primary and secondary reflectors composing back-to-back Gregorian telescopes; and the placement of the focal plane assembly and reflector system relative to each other, and as a unit on the spacecraft. WMAP environmental test metrology efforts included: reflector and truss thermal stability at 80 K; reflector and feed horn position verification at 90 K, and pre and post vibration and acoustic test reflector and feed horn position verification. The WMAP instrument integration and test objectives required the use of a photogrammetric camera, a laser tracker, a portable coordinate measuring machine (PCMM), and theodolites utilizing an electronic theodolite metrology system (ETMS) and autocollimation. The synergy of these metrology systems facilitated the successful characterization of the WMAP scientific instrument mechanical performance data at room temperature and flight temperatures, and correlation of the data to the analytical model. WMAP was launched on July 1, 2001, and flight data has confirmed the proper on-orbit instrument alignment was achieved.

Proceedings Article | 16 November 2000 Paper

Alignment measurements of the Microwave Anisotropy Probe (MAP) instrument in a thermal/vacuum chamber using photogrammetry

Michael Hill, Acey Herrera, J. Allen Crane, Edward Packard, Carlos Aviado, Henry Sampler

Proceedings Volume 4131, (2000) https://doi.org/10.1117/12.406549

KEYWORDS: Cameras, Microwave radiation, Reflectors, Staring arrays, Temperature metrology, Imaging systems, Helium, Anisotropy, Telescopes, Photogrammetry

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