Dr. Philip T. C. Chen Profile

Dr. Philip T. C. Chen

at NASA Goddard Space Flight Ctr

SPIE Involvement:

Conference Program Committee | Conference Chair | Author | Editor

Publications (17)

PROCEEDINGS ARTICLE | July 22, 2016

The Neutron star Interior Composition Explorer (NICER): design and development

Proc. SPIE. 9905, Space Telescopes and Instrumentation 2016: Ultraviolet to Gamma Ray

KEYWORDS: Electronics, Aerospace engineering, Sensors, Calibration, X-rays, X-rays, Silicon, Microcontrollers, Analog electronics, X-ray detectors, Signal detection

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PROCEEDINGS ARTICLE | July 29, 2014

The neutron star interior composition explorer (NICER): mission definition

Proc. SPIE. 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray

KEYWORDS: Actuators, X-ray optics, Electronics, Sun, Stars, Sensors, X-rays, Space operations, X-ray detectors, Global Positioning System

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PROCEEDINGS ARTICLE | September 7, 2006

Contamination control of space-based laser instruments

Proc. SPIE. 6291, Optical Systems Degradation, Contamination, and Stray Light: Effects, Measurements, and Control II

KEYWORDS: Contamination, LIDAR, Laser induced damage, Laser applications, Laser development, Semiconductor lasers, Space operations, Pulsed laser operation, Contamination control, Space based lasers

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PROCEEDINGS ARTICLE | July 7, 2006

The Space Infrared Interferometric Telescope (SPIRIT): mission study results

Proc. SPIE. 6265, Space Telescopes and Instrumentation I: Optical, Infrared, and Millimeter

KEYWORDS: Telescopes, Stars, Sensors, Space telescopes, Spatial resolution, Planets, Infrared telescopes, Galactic astronomy, James Webb Space Telescope, Planetary systems

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SPIE Conference Volume | October 15, 2004

Optical Systems Degradation, Contamination, and Stray Light: Effects, Measurements, and Control

PROCEEDINGS ARTICLE | February 11, 2003

The COR1 inner coronagraph for STEREO-SECCHI

Proc. SPIE. 4853, Innovative Telescopes and Instrumentation for Solar Astrophysics

KEYWORDS: Sun, Imaging systems, Sensors, Calibration, Light scattering, Coronagraphy, Objectives, Charge-coupled devices, Space operations, Stray light

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PROCEEDINGS ARTICLE | September 11, 2002

Return flux experiment REFLEX: spacecraft self-contamination

Proc. SPIE. 4774, Optical System Contamination: Effects, Measurements, and Control VII

KEYWORDS: Contamination, Data modeling, Sensors, Argon, Spectroscopy, Molecules, Gases, Krypton, Space operations, Signal detection

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SPIE Conference Volume | September 11, 2002

Optical System Contamination: Effects, Measurements, and Control VII

SPIE Conference Volume | September 20, 2000

Optical Systems Contamination and Degradation II: Effects, Measurements, and Control

PROCEEDINGS ARTICLE | September 20, 2000

New contamination engineering technology for active on-orbit surface cleaning

Proc. SPIE. 4096, Optical Systems Contamination and Degradation II: Effects, Measurements, and Control

KEYWORDS: Telescopes, Mirrors, Carbon dioxide, Contamination, Sensors, Satellites, Particles, Space telescopes, Space operations, Atmospheric particles

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SPIE Conference Volume | October 25, 1999

Rough Surface Scattering and Contamination

PROCEEDINGS ARTICLE | October 27, 1998

Atomic oxygen erosion of a graphite coating on a TQCM onboard the Return Flux Experiment (REFLEX)

Proc. SPIE. 3427, Optical Systems Contamination and Degradation

KEYWORDS: Carbon, Contamination, Sensors, Ultraviolet radiation, Coating, Adaptive optics, Control systems, Oxygen, Earth's atmosphere, Space operations

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SPIE Conference Volume | October 27, 1998

Optical Systems Contamination and Degradation

PROCEEDINGS ARTICLE | November 11, 1996

Investigation of molecular angular distribution and its influence on contaminant transmission

Proc. SPIE. 2864, Optical System Contamination V, and Stray Light and System Optimization

KEYWORDS: Roads, Contamination, Data modeling, Reflection, Sensors, Molecules, Computer simulations, Monte Carlo methods, Contamination analysis, Virtual colonoscopy

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PROCEEDINGS ARTICLE | November 11, 1996

Incorporation of molecular adsorbers into future Hubble Space Telescope instruments

Proc. SPIE. 2864, Optical System Contamination V, and Stray Light and System Optimization

KEYWORDS: Observatories, Electronics, Zeolites, Contamination, Particles, Space operations, Assembly equipment, Contamination control, Hubble Space Telescope, Molecular electronics

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PROCEEDINGS ARTICLE | October 19, 1994

Verification of molecular contaminant and atomic oxygen modeling for the Environmental Verification Experiment for the Explorer Platform (EVEEP)

Proc. SPIE. 2261, Optical System Contamination: Effects, Measurements, and Control IV

KEYWORDS: Contamination, Sun, Data modeling, Ultraviolet radiation, Crystals, Adaptive optics, Oxygen, Space telescopes, Radiation effects, Space operations

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PROCEEDINGS ARTICLE | November 1, 1990

Surface accommodation of molecular contaminants

Proc. SPIE. 1329, Optical System Contamination: Effects, Measurement, Control II

KEYWORDS: Contamination, Molecules, Receivers, Control systems, Solids, Adsorption, Data centers, Space operations, Contamination control, Temperature metrology

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The transport of molecules, under vacuum conditions, from a source surface to a receiving surface is of major concern from the perspective of spacecraft contamination control. The transport phenomena involved is a complex mechanism comprising the physical characteristics of each surface, the properties of contaminant species participating, and the temperatures of both surfaces. Because of both the complex nature and the limited data available to describe such a phenomena, contamination modeling usually requires that a highly simplified engineering approach be undertaken. One area where this is particularly true is in the representation of the surface accommodation of incident molecules. When a molecule in the gas phase collides with the surface of a receiver it can either "stick" to that surface or be scattered away. Molecules accommodated by this surface become thermally equilibrated to the receiver temperature while the material that is not accommodated retains its original energy and undergoes specular reflection. The ratio of this thermally accommodated mass to the total incident mass is known as the "accommodation" or "sticking" coefficient. Most of the current theory and experimental work performed to date has been restricted to the accommodation coefficients of the rare gases in contact with metal surfaces3'10"1. UnfortUnately, the results generated by these studies cannot be made very useful to spacecraft contamination engineers who are predominantly interested in environments where contaminants are typically limited only to water and long-chain hydrocarbons. Because of this deficiency most current spacecraft contamination analyses are forced to rely on general mathematical expressions that consider the sticking coefficient to be only a direct function of the temperature gradient between the emitting and receiving surfaces. The major shortcoming of the simplified method presently in use is that it may provide an inadequate representation of the actual molecular transport occurring between surfaces. The purpose of this paper is, therefore, to study the nature of the transport mechanisms involved in the adsorption of high molecular weight gases on typical spacecraft surfaces, the overall concept of the sticking coefficient, and the quantitative and qualitative theory involved. In addition, this paper will examine some of the existing molecular accommodation data as it relates to spacecraft applications, as well as present new experimental data gathered by the Contamination Control Section of the Goddard Space Flight Center (GSFC). All this information will then be correlated and used to verify the accuracy of the most common sticking coefficient equations in use by contamination analyses.

Showing 5 of 17 publications

Conference Committee Involvement (6)

Optical System Contamination: Effects, Measurements and Control IX

15 August 2006 | San Diego, California, United States

Optical System Contamination: Effects, Measurements, and Control VIII

2 August 2004 | Denver, Colorado, United States

Optical System Contamination: Effects, Measurements and Control VII

10 July 2002 | Seattle, WA, United States

Optical Systems Contamination and Degradation II: Effects, Measurements, and Control

2 August 2000 | San Diego, CA, United States

Rough Surface Scattering and Contamination

21 July 1999 | Denver, CO, United States

Showing 5 of 6 published special sections

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