Dr. George R. Gladstone Profile

Dr. George R. Gladstone

Institute Scientist at Southwest Research Institute

SPIE Involvement:

Author

Publications (34)

Proceedings Article | 21 August 2024 Presentation + Paper

Results of the JUICE ultraviolet spectrograph near-Earth commissioning

Michael Davis, G. Randall Gladstone, Thomas Greathouse, Philippa Molyneux, Kurt Retherford, Sue Ferrell, Maarten Versteeg, Steven Persyn

Proceedings Volume 13093, 1309305 (2024) https://doi.org/10.1117/12.3020022

KEYWORDS: Ultraviolet radiation, Sensors, Space operations, Stars, Calibration, Spectrographs, Microchannel plates

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We present the results of the JUpiter ICy moons Explorer ultraviolet spectrograph (JUICE-UVS) near-earth commissioning performed between June 14th and 25th 2023. JUICE-UVS is a modest power (9 W), compact ultraviolet spectrograph that is the fifth in a series of six such spectrographs designed and built by Southwest Research Institute for ESA and NASA missions. JUICE-UVS includes several innovations in detector, electronics, optics, and software. These innovations include an atomic-layer deposition (ALD) coating on the detector microchannel plates to minimize gain sag as photons are detected during the mission, electronic components able to withstand the harsh Jovian radiation environment, low-scatter optics to minimize the “wings” of the detected interplanetary Lyman-alpha emission, and a programmable histogram data collection mode that maximizes science return while minimizing stored and telemetered data volume. JUICE-UVS also features a high-spatial resolution observation mode, where a small (1/4 the width of nominal) aperture swings into place at the aperture stop and sharpens the instrument focus. Near-earth commissioning activities included measurements of detector dark noise, optimizing detector HV level via observations of the interplanetary Lyman-alpha, and a “sky-spin” observation over the JUICE-UVS 7.5°-long slit while the spacecraft rolled about the high-gain antenna (a “great circle” swath 7.5° wide). Dark rates matched those measured on the ground (approximately 5 Hz/cm²). HV levels were nominal for the operational temperature (approximately 0°C). Observations with the high-spatial resolution aperture confirmed the sharpened focus when compared to nominal observations. The “sky-spin” observation passed through the galactic plane, allowing for the identification of many known UV-bright stars. These stars provide a rough estimate of instrument effective area that will be refined after JUICE passes >2 AU from the sun, enabling 3-axis stabilized pointed observations.

Proceedings Article | 5 October 2023 Presentation + Paper

Post-delivery calibration of the JUICE ultraviolet spectrograph (JUICE-UVS)

Michael Davis, Maarten Versteeg, G. Randall Gladstone, Sue Ferrell, Philippa Molyneux, Steven Persyn, Kurt Retherford

Proceedings Volume 12678, 126780X (2023) https://doi.org/10.1117/12.2675923

KEYWORDS: Ultraviolet radiation, Space operations, Microchannel plates, Vacuum, Histograms, Calibration, Spectrographs, Equipment, Light sources and illumination

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Proceedings Article | 31 August 2022 Poster + Paper

Europa clipper ultraviolet spectrograph: ground calibration results

Michael Davis, Kurt Retherford, Philippa Molyneux, G. Randall Gladstone, Noel Eloriaga, Rohini Giles, Thomas Greathouse, Ujjwal Raut, Todd Veach, Sue Ferrell, Maarten Versteeg, Matthew Freeman, Kristian Persson

Proceedings Volume 12181, 1218138 (2022) https://doi.org/10.1117/12.2630530

KEYWORDS: Calibration, Sensors, Ultraviolet radiation, Spatial resolution, Spectrographs, Microchannel plates, Point spread functions, Aluminum, Spectral resolution

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Proceedings Article | 31 August 2022 Poster + Presentation + Paper

An ultraviolet stellar catalog for occultation measurements, planetary illumination modeling, and spectral sky map analyses

Michael Velez, Kurt Retherford, Vincent Hue, Joshua Kammer, G. Randall Gladstone, Michael Davis, Thomas Greathouse, Tracy Becker, Philippa Molyneux, Shawn Brooks, Ujjwal Raut, Andrew Steffl, Maarten Versteeg

Proceedings Volume 12181, 1218133 (2022) https://doi.org/10.1117/12.2630352

KEYWORDS: Ultraviolet radiation, Stars, Data modeling, Jupiter, Spectrographs, Atmospheric modeling, Spectral models, Reflectivity, Pluto, Oxygen

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SPIE Journal Paper | 19 November 2021

Updated radiometric and wavelength calibration of the Juno ultraviolet spectrograph

Vincent Hue, Rohini Giles, George Gladstone, Thomas Greathouse, Michael Davis, Joshua Kammer, Maarten Versteeg

JATIS, Vol. 7, Issue 04, 044003, (November 2021) https://doi.org/10.1117/12.10.1117/1.JATIS.7.4.044003

KEYWORDS: Calibration, Ultraviolet radiation, Sensors, Spectrographs, Neon, Argon, Stars, Aluminum, Mirrors, Jupiter

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Proceedings Article | 24 August 2021 Presentation + Paper

TRL6 testing of a curved borosilicate glass microchannel plate far-UV detector assembly for spaceflight

Michael Davis, Oswald H. Siegmund, G. Randall Gladstone, Adrian Martin, Kurt Retherford, John Vallerga

Proceedings Volume 11821, 118210A (2021) https://doi.org/10.1117/12.2594177

KEYWORDS: Sensors, Microchannel plates, Electronics, Quantum efficiency, Borosilicate glass, Resistance, Spectrographs, Far ultraviolet

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Proceedings Article | 24 August 2021 Presentation + Paper

NExtUP: the Normal-incidence Extreme Ultraviolet Photometer

Jeremy Drake, Peter Cheimets, Cecilia Garraffo, Bradford Wargelin, Allison Youngblood, Vinay Kashyap, Paola Testa, David Caldwell, James Mason, Brian Fleming, Kevin France, Scott Wolk, Oswald Siegmund, Tommi Koskinen, Julian Alvarado-Gomez, Maria Mercedes Lopez-Morales, Guillaume Gronoff, Jay Bookbinder, Martin Barstow, David Windt, Randy Gladstone, Christopher Loghry, Rix Yarbrough

Proceedings Volume 11821, 1182108 (2021) https://doi.org/10.1117/12.2594408

KEYWORDS: Extreme ultraviolet, Stars, Sensors, Microchannel plates, Space operations, Photons, Multilayers, Planets, Exoplanets, Mirrors

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Proceedings Article | 11 June 2021 Open Access

The JUICE ultraviolet spectrograph: a next-generation compact UVS for ESA’s JUICE mission

Michael Davis, G. Randall Gladstone, Kurt Retherford, Steven Persyn

Proceedings Volume 11852, 1185226 (2021) https://doi.org/10.1117/12.2599357

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Proceedings Article | 13 December 2020 Presentation + Paper

Ground calibration results of the JUICE ultraviolet spectrograph

Michael Davis, G. Randall Gladstone, Rohini Giles, Thomas Greathouse, Philippa Molyneux, Ujjwal Raut, Kurt Retherford, Sue Baldor, Maarten Versteeg, Matthew Freeman, Kristian Persson, Steven Persyn

Proceedings Volume 11444, 1144404 (2020) https://doi.org/10.1117/12.2562986

KEYWORDS: Ultraviolet radiation, Spectrographs, Calibration, Spectral calibration, Jupiter, Spatial resolution, Atomic layer deposition, Spectral resolution, Microchannel plates, Sensors

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Proceedings Article | 9 September 2019 Presentation + Paper

High-resolution aperture shape analysis for the JUICE and Europa ultraviolet spectrographs

Michael Davis, Steven Osterman, G. Randall Gladstone, Kurt Retherford

Proceedings Volume 11118, 1111819 (2019) https://doi.org/10.1117/12.2529668

KEYWORDS: Spatial resolution, Sensors, Spectrographs, Point spread functions, Ultraviolet radiation, Convolution, Electronics, Image resolution, Shape analysis

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Proceedings Article | 9 September 2019 Paper

Bench and thermal vacuum testing of the JUICE-UVS microchannel plate detector system

Michael Davis, Oswald H. Siegmund, G. Randall Gladstone, Adrian Martin, Philippa Molyneux, Kurt Retherford, Todd Veach, John Vallerga

Proceedings Volume 11118, 111180Q (2019) https://doi.org/10.1117/12.2529649

KEYWORDS: Sensors, Microchannel plates, Electronics, Spectrographs, Atomic layer deposition, Coating, Quantum efficiency

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SPIE Journal Paper | 20 May 2019

Planning operations in Jupiter’s high-radiation environment: optimization strategies from Juno-ultraviolet spectrograph

Joshua Kammer, Vincent Hue, Thomas Greathouse, G. Randall Gladstone, Michael Davis, Maarten Versteeg

JATIS, Vol. 5, Issue 02, 027001, (May 2019) https://doi.org/10.1117/12.10.1117/1.JATIS.5.2.027001

KEYWORDS: Space operations, Jupiter, Sensors, Data acquisition, Radiation effects, Spectrographs, Ultraviolet radiation, Auroras, Data storage, Microchannel plates

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Proceedings Article | 19 September 2018 Presentation + Paper

Europa Ultraviolet Spectrograph: contamination transport modeling to predict mission performance

Genevieve Devaud, Russell Schweickart, Brandon Walther, Michael Davis, U. Raut, G. Randall Gladstone, Kurt Retherford

Proceedings Volume 10748, 107480B (2018) https://doi.org/10.1117/12.2320331

KEYWORDS: Electronics, Ultraviolet radiation, Microchannel plates, Contamination, Space operations, Molecules, Diffusion, Spectrographs, Performance modeling, Thermal modeling

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Proceedings Article | 6 July 2018 Presentation + Paper

Stray and scattered light properties of the Juno ultraviolet spectrograph

Michael Davis, G. Randall Gladstone, Thomas Greathouse, Vincent Hue, Maarten Versteeg

Proceedings Volume 10699, 106990J (2018) https://doi.org/10.1117/12.2312141

KEYWORDS: Light scattering, Sensors, Space operations, Mirrors, Ultraviolet radiation, Stray light, Spectrographs, Jupiter, Scatter measurement

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Proceedings Article | 6 July 2018 Paper

Planning operations in Jupiter's high-radiation environment: optimization strategies from Juno-UVS

Joshua Kammer, Vincent Hue, Thomas Greathouse, G. Randall Gladstone, Michael Davis, Maarten Versteeg

Proceedings Volume 10699, 106993A (2018) https://doi.org/10.1117/12.2312261

KEYWORDS: Jupiter, Space operations, Sensors, Radiation effects, Data acquisition, Auroras, Electrons, Data storage, Electronics, Mirrors

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Proceedings Article | 6 July 2018 Paper

Performance and design of MgF2 + Au coatings on aluminum mirrors: enabling far-ultraviolet solar occultation measurements for Europa-UVS

Ujjwal Raut, Preston Karnes, Kurt Retherford, Michael Davis, G. R. Gladstone, Thomas Greathouse, Brandon Walther, Elizabeth Czajka

Proceedings Volume 10699, 106992Z (2018) https://doi.org/10.1117/12.2312928

KEYWORDS: Mirrors, Magnesium fluoride, Gold, Aluminum, Sensors, Photons, Reflectivity, Sun, Optical coatings, Exosphere

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Proceedings Article | 6 July 2018 Paper

In-flight characterization and calibration of the Juno-Ultraviolet Spectrograph (Juno-UVS)

V. Hue, J. Kammer, G. Gladstone, T. Greathouse, M. Davis, B. Bonfond, M. Versteeg, D. Grodent, J.-C. Gérard, S. Bolton, S. Levin

Proceedings Volume 10699, 1069931 (2018) https://doi.org/10.1117/12.2311563

KEYWORDS: Stars, Ultraviolet radiation, Calibration, Sensors, Spectrographs, Jupiter, Mirrors, Microchannel plates, Databases, Photons

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The Juno mission is a NASA New Frontiers mission, orbiting Jupiter since 4 July 2016 and placed on a 53-day period, highly elliptical, polar orbit. The Ultraviolet Spectrograph onboard Juno (Juno-UVS) is a photoncounting imaging spectrograph, designed to cover the 68-210 nm spectral range.¹ This range includes the H₂ bands and the Lyman series produced in Jupiter’s far-ultraviolet (FUV) auroras. The purpose of Juno-UVS is to study Jupiter’s auroras from the unique vantage point above both poles allowed by Juno’s orbit, and to provide a wider auroral context for the in-situ particle and field instruments on Juno. Because of the 2 rpm spin of Juno, UVS nominally observes 7.5°x360° swaths of the sky during each spin of the spacecraft. The spatial resolutions along the slit and across the slit, i.e. in the spin direction, are respectively 0.16° and 0.2° , while the filled-slit spectral resolution is ∼1.3 nm.² UVS borrows heavily from previous instruments led by Southwest Research Institute (New-Horizons and Rosetta Alices, LRO-LAMP), major improvements are: (i) an extensive radiation shielding; (ii) a scan mirror which allows targeting specific auroral features; and (iii) an improved cross-delay line readout scheme of the microchannel plate (MCP) detector. The ability offered by the scan mirror combined with Juno’s spin allows UVS access to half of the sky during every spacecraft rotation. This pointing flexibility, combined with the changing spin-axis of the spacecraft since launch, has allowed UVS to map 99 % of the sky in the 68-210 nm range. This paper describes the substantial number of spectra that have been used to monitor the health of the instrument over the course of the mission. More than 5800 spectra of mainly O, A, and B spectral-type stars in the V-magnitude range of ∼0-7 have been extracted to date. Selected stars among this list are used to calibrate the UVS instrument. This paper describes how previous spectral databases from the International Ultraviolet Explorer have been refined and adapted for UVS’ calibration purposes, in combination with observations from the Hubble Space Telescope. The retrieved effective area of the instrument peaks around 0.28 at ∼125 nm, with uncertainties lower than 10%.

Proceedings Article | 27 July 2016 Paper

MeV-level electron and gamma ray sensitivites of modern far ultraviolet sensitive microchannel plate detectors

Michael Davis, Thomas Greathouse, Chathan Cooke, Ryan Blase, G. Randall Gladstone, Kurt Retherford

Proceedings Volume 9915, 99152B (2016) https://doi.org/10.1117/12.2232755

KEYWORDS: Jupiter, Sensors, Microchannel plates, Gamma radiation, Ultraviolet radiation, Spectrographs, Particles, Photons, Silica, Electronics

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Proceedings Article | 24 August 2015 Paper

Solar glint suppression in compact planetary ultraviolet spectrographs

Michael Davis, Jason Cook, Cesare Grava, Thomas Greathouse, G. Randall Gladstone, Kurt Retherford

Proceedings Volume 9601, 96010P (2015) https://doi.org/10.1117/12.2187105

KEYWORDS: Sensors, Mirrors, Light scattering, Space operations, Stray light, Ultraviolet radiation, Spectrographs, Reflectivity, Lamps, Diffraction gratings

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Proceedings Article | 25 July 2014 Paper

Improved ground calibration results from Southwest Research Institute Ultraviolet Radiometric Calibration Facility (UV-RCF)

Michael Davis, Thomas Greathouse, G. Randall Gladstone, Kurt Retherford, David Slater, S. Alan Stern, Maarten Versteeg

Proceedings Volume 9144, 914433 (2014) https://doi.org/10.1117/12.2057043

KEYWORDS: Calibration, Ultraviolet radiation, Spectrographs, Sensors, Lamps, Photodiodes, Mirrors, Diodes, Monochromators, Silicon

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Proceedings Article | 24 July 2014 Paper

Improved resolution in wide-field ultraviolet astronomical imaging

Michael Davis, Thomas Greathouse, G. Randall Gladstone

Proceedings Volume 9144, 914404 (2014) https://doi.org/10.1117/12.2057020

KEYWORDS: Imaging systems, Mirrors, Sensors, Spatial resolution, Extreme ultraviolet, Ultraviolet radiation, Off axis mirrors, Image resolution, Astronomical imaging, Confocal microscopy

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Proceedings Article | 26 September 2013 Paper

Performance results from in-flight commissioning of the Juno Ultraviolet Spectrograph (Juno-UVS)

T. Greathouse, G. Gladstone, M. Davis, D. Slater, M. Versteeg, K. Persson, B. Walther, G. Winters, S. Persyn, J. Eterno

Proceedings Volume 8859, 88590T (2013) https://doi.org/10.1117/12.2024537

KEYWORDS: Mirrors, Ultraviolet radiation, Sensors, Space operations, Stars, Calibration, Spectrographs, Jupiter, Atmospheric particles, Microchannel plates

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Proceedings Article | 26 September 2013 Paper

An improved wide-field camera for imaging Earth's plasmasphere at 30.4 nm

Michael Davis, G. Randall Gladstone, Jerry Goldstein, Bill Sandel, Thomas Greathouse, Kurt Retherford, Gregory Winters

Proceedings Volume 8859, 88590U (2013) https://doi.org/10.1117/12.2024440

KEYWORDS: Extreme ultraviolet, Imaging systems, Sensors, Mirrors, Cameras, Head, Reflectivity, Multilayers, Coating, Solar processes

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Proceedings Article | 26 September 2013 Paper

Radiometric calibration of the SwRI ultraviolet reflectance chamber (SwURC) far-ultraviolet reflectometer

Preston Karnes, Kurt Retherford, Gregory Winters, Eric Bassett, Stephen Escobedo, Edward Patrick, Amanda Richter, Michael Davis, Paul Miles, Joel Parker, G. Randall Gladstone, Thomas Greathouse, Eric Schindhelm, Lori Feaga, S. Alan Stern

Proceedings Volume 8859, 88590R (2013) https://doi.org/10.1117/12.2024460

KEYWORDS: Sensors, Reflectivity, Ultraviolet radiation, Lamps, Calibration, Monochromators, Reflectometry, Data acquisition, Halogens, Control systems

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Proceedings Article | 15 October 2012 Paper

The Southwest Research Institute ultraviolet reflectance chamber (SwURC): a far ultraviolet reflectometer

Gregory Winters, Kurt Retherford, Michael Davis, Stephen Escobedo, Eric Bassett, Edward Patrick, Maggie Nagengast, Matthew Fairbanks, Paul Miles, Joel Parker, G. Randall Gladstone, David Slater, S. Alan Stern

Proceedings Volume 8495, 84950N (2012) https://doi.org/10.1117/12.930184

KEYWORDS: Sensors, Ultraviolet radiation, Reflectivity, Monochromators, Mirrors, Reflectometry, Data acquisition, Lamps, Calibration, Signal detection

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Proceedings Article | 15 September 2011 Paper

Commissioning and in-flight calibration results of the Lunar Reconnaissance Orbiter's Lyman Alpha Mapping Project (LRO/LAMP) UV imaging spectrograph

Michael Davis, G. Randall Gladstone, Maarten Versteeg, Thomas Greathouse, S. Alan Stern, Joel Wm. Parker, Andrew Steffl, Kurt Retherford, David Slater

Proceedings Volume 8146, 814603 (2011) https://doi.org/10.1117/12.894282

KEYWORDS: Calibration, Lamps, Sensors, Point spread functions, Ultraviolet radiation, Reconnaissance, Spectrographs, Space operations, Stars, Extreme ultraviolet

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Proceedings Article | 14 September 2011 Paper

Radiometric performance results of the Juno ultraviolet spectrograph (Juno-UVS)

Michael Davis, G. Randall Gladstone, Thomas Greathouse, David Slater, Maarten Versteeg, Kristian Persson, Gregory Winters, Steven Persyn, John Eterno

Proceedings Volume 8146, 814604 (2011) https://doi.org/10.1117/12.894274

KEYWORDS: Sensors, Ultraviolet radiation, Calibration, Spectrographs, Argon, Space operations, Electronics, Aluminum, Point spread functions, Mirrors

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Proceedings Article | 11 September 2009 Paper

Radiometric performance results of the Lunar Reconnaissance Orbiter's Lyman Alpha Mapping Project (LRO/LAMP) UV imaging spectrograph

Michael Davis, David Slater, G. Randall Gladstone, S. Alan Stern, Thomas Greathouse, Kurt Retherford, Maarten Versteeg, Ronald Black

Proceedings Volume 7441, 744110 (2009) https://doi.org/10.1117/12.826068

KEYWORDS: Lamps, Sensors, Calibration, Ultraviolet radiation, Argon, Point spread functions, Spectrographs, Space operations, Reconnaissance, Microchannel plates

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Proceedings Article | 11 September 2009 Paper

SwRI's Alice line of ultraviolet spectrographs

Kurt Retherford, S. Alan Stern, David Slater, G. Randall Gladstone, Michael Davis, J. Parker, Maarten Versteeg, A. Steffl, Thomas Greathouse, N. Cunningham

Proceedings Volume 7441, 744111 (2009) https://doi.org/10.1117/12.826192

KEYWORDS: Ultraviolet radiation, Sensors, Spectrographs, Lamps, Airglow, Jupiter, Pluto, Mirrors, Comets, Microchannel plates

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Proceedings Article | 22 September 2005 Paper

ALICE: the ultraviolet imaging spectrograph aboard the New Horizons Pluto mission spacecraft

S. Alan Stern, John Scherrer, David Slater, G. Gladstone, Greg Dirks, John Stone, Michael Davis, Marteen Versteeg, O. Siegmund

Proceedings Volume 5906, 590618 (2005) https://doi.org/10.1117/12.613128

KEYWORDS: Sensors, Electronics, Microchannel plates, Pluto, Space operations, System on a chip, Airglow, Spectrographs, Ultraviolet radiation, Data acquisition

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Proceedings Article | 22 September 2005 Paper

LAMP: The Lyman Alpha Mapping Project aboard the NASA Lunar Reconnaissance Orbiter mission

G. Randall Gladstone, S. Alan Stern, Kurt Retherford, Ron Black, John Scherrer, David Slater, John Stone, Paul Feldman, Dana Crider

Proceedings Volume 5906, 59061A (2005) https://doi.org/10.1117/12.617778

KEYWORDS: Lamps, Sensors, Ultraviolet radiation, Microchannel plates, Spectrographs, Electronics, Data acquisition, Reconnaissance, Signal to noise ratio, Light sources

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Proceedings Article | 7 July 1993 Paper

Oxygen imager (OXI) for magnetospheric imagery applications

Supriya Chakrabarti, Daniel Cotton, Timothy Cook, G. Gladstone

Proceedings Volume 2008, (1993) https://doi.org/10.1117/12.147635

KEYWORDS: Ions, Airglow, Mirrors, Sensors, Imaging systems, Auroras, Magnetosphere, Extreme ultraviolet, Oxygen, Coating

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Proceedings Article | 7 July 1993 Paper

High-latitude ion transport and energetic explorer (HI-LITE): a mission to investigate ion outflow from the high-latitude ionosphere

Mark Smith, Federico Herrero, Michael Hesse, Daniel Baker, Peter Bochsler, Peter Wurz, Hans Balsiger, Supriya Chakrabarti, Gary Erickson, Daniel Cotton, Thomas Stephen, Claude Jamar, Jean-Claude Gerard, Stephen Fuselier, Arthur Ghielmetti, Stephen Mende, William Peterson, Edward Shelley, Richard Vondrak, Dennis Gallagher, Thomas Moore, Craig Pollock, Roger Arnoldy, Michael Lockwood, Randy Gladstone

Proceedings Volume 2008, (1993) https://doi.org/10.1117/12.147643

KEYWORDS: Ions, Space operations, Plasma, Wind energy, Magnetosphere, Solar processes, In situ metrology, Convection, Chemical species, Spectroscopy

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