Dennis Charles Evans

Evans Engineering; Independent Consultant, Principle Optical Engineer.

Has forty years of successful technical participation, leadership, and management of short and long range science and engineering development and applications programs. Engineering development and science research in space sciences, systems engineering, and technical management, are the primary fields of experience.

Has experience with project management, product development, systems engineering, computer applications, science research, and engineering development and application. The experience includes: engineering, science, and management of satellite and sounding rockets systems for stellar, planetary, and solar research; photometry and spectrophotometry from the extreme ultraviolet through centimeter microwave; photographic instrument design; computer applications systems implementation and programming; hardware and software evaluation and specification; robotic systems; relativity; non-Euclidean geometries; philosophy; religion-theory of God; and cosmology - theory of creation.

Has experience including instrument optics, optical design, optical system engineering, optical engineering, stray light analysis, stray light modeling, system engineering, development and definition of instrument system specifications, requirements reviews, interface definition, tolerance budgeting, and study report integration, final formatting, and presentation. Is considered a national authority on stray light control and analysis.

Has experience using state-of-the-art sophisticated commercially available optical design and analysis software in order to perform optimization (using and developing design merit functions), sensitivity and tolerance analysis. Specific sequential ray trace application programs used are GOALS, ACCOS, SYNOPSYS, Code-V, and ZEMAX. Has written own ray tracing software, Ray Trace Language (RTL) which has been used in place of Code-V for 3D development of optical designs. Has used ASAP (Advanced Systems Analysis Program) for generalized non-sequential ray tracing, scattering, diffraction, ghost, and radiometric evaluation of optical instruments. Has developed techniques for working with optical system using AutoCAD and provides translation capability between optical design software and AutoCAD, Pro/E and I-DEAS CAD systems. Has used APART (Arizona’s Program of Analysis of Radiative Transfer), a deterministic radiative transfer stray light analysis program that includes diffraction characterization.


College course work included:

Professional Experience

1982-Present: Evans Optical, System, Design, & Software Engineering, Independent Consultant

Since 1993 approximately 50 tasks for 30 different projects have been supported. Most support is related to satellite instruments with optics, but ground based and airborne instruments are included. The tasks include proposal studies, system engineering, optical system engineering, optical design, optical engineering, stray light analysis, stray light modeling, photometric analysis, and integration support. Support of these tasks has required knowledge and application of state-of-the-art concepts in detectors, lightweight optics, adaptive optics, electro-optical mechanisms, and the latest optical fabrication techniques.

Several of the projects listed below have been studies in the Goddard Space Flight Center Instrument Synthesis & Analysis Laboratory (ISAL). In that lab instrument concepts are developed by instrument development teams using the latest concepts in optical physics and optical technology in order to increase the scope and range of instruments while reducing their mass and cost. The ISAL is a laboratory environment where a matrixed team of engineers and scientists is assembled to produce an end-to-end instrument concept, generally (but not always) using optical (electromagnetic spectrum) sensors for remote terrestrial or astronomical observations. The ISAL work has been supported on contract as a principle optical engineer, a very senior position requiring rapid independent design and development in a continuously fluctuating team environment. Rapid development and presentation of customer reports are a product of the ISAL environment. Optical science and systems engineering reports and presentations have been provided. One of the ISAL tasks (AGSI) resulted in formal engineering publications that were presented at a national conference for Remote Sensing.   <Link to ISAL Typical Tasks>

Project: ...............Support provided

AGD ..................Advanced Grating Design – testing of new modifications of ZEMAX for elliptical and optically fabricated holographic gratings.

AGSI .................Earth observing advanced weather satellite design study - optical design, stray light design - 3-axis stabilized.

GATES ..............Earth observing advanced weather satellite design study - optical design, stray light design - satellite attitude scanning.

Ana Lani ............X-Ray Sky Mapping, 9 telescope cluster, stray light control.

CHyMERA .......Environmental pollution imager - refractive instrument optical evaluation and thermal sensitivity analysis.

CIRCE ..............Confusion-limited InfraRed Cosmic Explorer - Stray light design for proposal.

CIRS .................Planetary fly-by stray light baffle evaluation and recommendations.

COR-1 ..............Coronagraph stray light suppression study.

FUSE ................Stray light baffle consulting.

GALEX ........... .Design review support for optical mounting problems.

GOES ................Stray light analysis, image analysis, photometric studies, calibration, design review support.

GPM ..................Global Precipitation Measurement-Synthetic Thinned Aperture Radiometer – systems engineering evaluation, ground track, and microwave waveguide/antenna fabrication source investigation.

HST STIS ..........Instrument stray light evaluation and miscellaneous baffle design recommendation

IRAC .................Infrared Array Camera optical design studies and stray light analysis, image analysis, photometric analysis, 3D ASAP modeling, APART analysis, GSE optical and photometric analysis, Integration image analysis, ghost image analysis.

IRIS & Astro-F.. Proposal variants of IRAC.

IRMOS ..............TI-Digital Mirror Device micro-mirror array optical modeling for ground based instrument for NGST related instrument.

JMEX ................Jupiter Magnetospheric Explorer, Sun Shade Design, Stray Light Suppression Baffle Design and work with tolerance analysis for focus drive mechanisms specification.

Kronos ..............Optical re-packaging study.

L2-Sounder .......Earth limb sounder from L2 orbit - optical evaluation.

MAP .................Star tracker baffle review and sun shield design change recommendations.

MLL .................Ocean Mixed Layer Lidar optical design and performance evaluation.

MODIS ............Instrument calibration study - design of equipment for in-situ calibration of integrated instrument.

NICI ................Stray light performance evaluation and baffle design for the Near Infrared Coronagraphic Imager for the GEMINI North Telescope in Hawaii.

NGST MIR ......Instrument design evaluation support, Stray light studies.

NIRCam ..........Stray Light baffle design for a proposed NGST instrument.

ORBVIEW ......Photometric performance and stray light performance instrument evaluation.

REDAII ...........Optical design support for combined Earth Sciences - NGST test satellite.

Resource 21 .....Photometric performance and stray light proposal support for earth resources imaging satellite.

Solar Stereo .....Coronagraph stray light suppression design.

SDO ...............Solar Dynamics Observatory – assessment of optical performance of candidate instruments, including imagers, spectrographs, magnetographs, and coronagraphs.

TOMS ............Stray light evaluation and design review support.

WFC-3 ...........Photometric analysis and stray light design studies.

WIRE .............APART stray light analysis support, Design change recommendations.

Some tasks in more detail:

Evaluated the detailed stray light suppression design of the Wide-field Infrared Explorer (WIRE) instrument designed for a Pegasus launched mission. Created 3D AutoCAD models for perspective image rendering of views from critical design points. Reviewed APART program input decks for consistency with mechanical design. By implementing recommended changes in baffle design, stray light was reduced from above that specified (not expected to work properly) to a couple of orders-of-magnitude below the design specification.

Participated in a "tiger team" evaluation of stray light problems associated with the Earth Sensor Assembly on the Geostationary Observational Environmental Satellite. Using AutoCAD and Autovision to find multiple reflection paths and non-sequential ray tracing to verify angular and path sequences.

Optical design and analysis was completed for a reflective optical system as a candidate to be used by the Smithsonian Astrophysical Observatory on the Space Infrared Telescope for imaging on Infrared Array Cameras. The reflective and refractive optical systems include filters and a grism (diffraction grating/prism element). Optimization, diffraction and wavefront error analysis was performed. Optical modeling found the sources of ghost images and spurious reflections. Point source images of GSE optics were modeled for study during flight integration.

Radiometric calibration consultation to Goddard Space Flight Center, Optics Branch, for studying the performance of the Geostationary Observational Environmental Satellite - Imager and Sounder Instruments. Participated in calibration of the star sense instrument channels, including primary stellar calibration measurements at Palomar Observatory and elsewhere.

Provided stray light suppression evaluation and review of the design of the Near Infrared Camera - Multi-Object Spectrograph and the Space Telescope Imaging Spectrograph, two second generation instruments for the Hubble Space Telescope. This task involved 3D drawing analysis of fabrication concept models in AutoCAD. Grism and echelle spectrograph designs were reviewed for applicable performance. There were severe weight problems encountered because of the wide spectral range of observation desired.

Provided consultation and advice concerning the stray light analysis and stray light suppression in the Composite Infrared Spectrometer on the Cassini mission to Saturn and for the Total Ozone Mapping Satellite.

Developed the Ray Trace Language (RTL) optical design code for personal computers in APL for PC machines and in FORTH for Apple machines. Consulting provided for stray light evaluation of infrared satellite imaging system; for proposal development in computer sciences, optical systems, and artificial intelligence; echelle spectrograph optical design, and optical system modification for a CCD linear array, high data rate microdensitometer.

1988-1993 Advanced Technology & Research Corporation, Manager, Instruments Systems Division.

Provided management and technical support for robotic and space-related task order contracts. Tasks included vision processing, robot explosive ordnance disposal, optical and stray light instrument design, conceptual design and evaluation of space flight instruments (ultraviolet, visible, and infrared), space flight information management systems, acquisition and control systems. Tasks have included: the fabrication of a full scale operational mock-up of the Space Shuttle Remote Manipulator System arm; optical and electronic design of the Infrared Array Camera instrument for the Space Infrared Telescope Facility; stray light testing of the Geostationary Observational Environmental Satellite Imager and Sounder instruments; stray light evaluation of the Total Ozone Mapping Spectrometer; and stray light analysis of the Composite Infrared Spectrometer for observing the rings of Saturn.

1986 - 1989 Space Exploration & Development Corporation, President.

SEDC was a business development corporation for providing support for astronaut mission specialist and professional engineering training, as well as training for "space tourists", and operation of space-related theme park activities. Acquisition of a Florida site at Space Center Executive Airport was unsuccessful.

1984 - 1988 Sachs/Freeman Associates, Inc. (SFA, Inc.), Director of Space Sciences.

In charge of computer science and space science research. Project Manager for operation of Goddard Space Flight Center Visitor Information Centers. Performed stray light measurement for the Diffuse Infrared Background Experiment optical module. Designed and implemented full scale, operational mock-up of Space Shuttle Remote Manipulator System arm - capable of handling 1,000 pounds at 60-foot extension.

1964 - 1984 Goddard Space Flight Center, Senior Systems Engineer

Performed reviews and analysis of the Solar Optical Telescope Facility and scientific instruments to be based on that Space Shuttle facility. Electro-optical system performance, including stray light suppression design and analysis was the main area of emphasis. The position is attached to the Electro-Optical Systems Section, Instrument Systems Branch of the Instruments Division. (1981-1984)

Instrument Systems Engineer for the Cosmic Background Explorer - Led a multidisciplinary team of Systems Engineers for the Far Infrared Absolute Spectrometer, Diffuse Infrared Background Experiment, and Differential Microwave Radiometer (DMR) instruments. While working in this position, also a Participating Scientist in the COBE mission. The DMR instruments have discovered small fluctuations in the cosmic background. (1980-1981)

Scientific Instrument Manager for the International Ultraviolet Explorer (IUE) launched on January 26, 1978 and operational for almost 19 years until it was retired from operation on September 30, 1996. Participated in optical design, stray light baffle design, stray light testing, assembly, ground and orbital testing of the IUE as well as management of Instrument activities. Collocated with the Projects Directorate while attached to the Laboratory for Optical Astronomy. Managed a matrix organization of 168 engineers and technicians - a $38 million segment of a 600-man, $100 million project, while in operation the most widely used observatory in the history of mankind. During the project was also responsible for procurements, procurement tracking, schedule and trend analysis and control, developing analyzing and modifying project schedules, and budget control. Result: Surpassed duration goal of 3 years. Performance goal of 30-minute observation sequence exceeded by factor of 48 - not limited by stray sunlight. Received Presidential Award for Design Excellence in 1988. (1974-1980)

Head, Instrumentation Section, Observational Astronomy Branch, Laboratory for Optical Astronomy. Responsibilities included all aspects of management and scientific participation in the Laboratory sounding rocket planetary and stellar observing program, including optical design, development, assembly, test, launch, data reduction, and laboratory support of numerous sounding rocket payloads. Section now forms core of Shuttle payload development activity for SpaceLab. Specified and purchased the first decentralized computer system for the Laboratory for Optical Astronomy and Solar Physics image processing and payload calibration facility. This position required exercise of a wide range of scientific, engineering, and administrative skills. (1971-1974)

Senior Staff Scientist in the Astronomy Systems Branch of the Laboratory for Optical Astronomy. Research in planetary astronomy included ultraviolet spectroscopy of Venus, Mars, and Jupiter. Discovered low surface pressure on Mars. Participated in absolute photometry related to the calibration of the Orbiting Astronomical Observatory Project. (1964-1971)

1961 - 1963 Douglas Aircraft Company, Santa Monica, California

Science Staff Member of the Advance Space Research Section, Planetary Meteorology Group - Participated in infrared observations of Venus from DC-8 aircraft and planning for airborne solar eclipse observations.

Honors And Professional Affiliations

Scientific And Technical Publications And Reports:

These reports have been published as industrial/government technical reports, published in national and international technical and scientific journals. Some of the publications have been presented at national and international meetings. Oral presentations have been made related to all the references.

Advanced Geosynchronous Studies Imager: AGSI Study Report (1999) Section 3.1 Optics, Del Jenstrom, Study Manager, GSFC, NASA, November 1999

"Advanced Geosynchronous Studies Imager: An ‘all reflective’, off-center, off-axis, off-center, focal telescope for Earth Observation." (1999) Proceedings of SPIE, Earth Observing Systems, William L. Barnes, Chair/Editor, Denver CO, 18-20 July 1999, Volume 3750-4, pp 11-22.

"Final Report of the GOES Sounder SN04 IR Responsivity Changes Review Team to the NASA GSFC GOES Project Office", Emil Dusio (ed.), ITT Aerospace/Communications Division, Fort Wayne, Indiana, April 3, 1995

"Telescope Stray Light Design" section of Infrared Array Camera, ASTRO-F Feasibility Study, NASA, Goddard Space Flight Center, IRAC-701-001, Giovanni Fazio, Harvey Moseley, Lois Workman, eds., January 1995

"Test Plan: Star Sense/Solar Stray Light Test (GOES S/N02 Instruments)" (1992) ATR:310:DCE/dce-92-013

"Development of an Abrasive Waterjet Cutting Robot for Explosive Ordnance Disposal", Co-Authors: Robert A. Weber, Frank W. Kearny, Mark D. Ginsberg, Azizollah Abrisahamian, US Army Construction Engineering Research Laboratory (1-800-USA-CERL) Technical Report M-90/17, June 1990.

"Infrared Array Camera - Baseline Optical Design," Technical Review, NASA, Goddard Space Flight Center, Contract NAS5-29412, Task 49, February 1990

"Creation, Faith, and Four Dimensions," Northeastern Christian Junior College, Science Day, April 13, 1985

"APART/PADE Analytical Evaluation of the Diffuse Infrared Background Experiment for NASA's Cosmic Background Explorer," Co-author: R.P. Breault, Breault Research Organization, Inc. Society for Photo-optical Instrumentation Engineers Proceedings, Vol. 511, August 19-24, 1984.

"Principles of Stray Light Suppression and Conceptual Application to the Design of the Diffuse Infrared Background Experiment for NASA's Cosmic Background Explorer," Generation, Measurement, and Control of Stray Radiation, III: Society for Photo-Optical Instrumentation Engineers Proceedings, Vol. 384, 1983.

"Optical Design of the Diffuse Infrared Background Experiment for NASA's Cosmic Background Explorer," Instrumentation for Astronomy IV: Society for Photo Optical Instrumentation Engineers Proceedings, Volume 331, 1982, with M.S. Miller, H. Moseley, and U. Ludwig.

Instrument Definition for the Diffuse Infrared Background Experiment (DIRBE), on the Cosmic Background Explorer (COBE), co-author and participating scientist, Goddard Space Flight Center, Greenbelt, MD, June 1979, Revised Oct. 1979.

"IUE Observations of Solar System Objects," Co-Authors: A.L. Lane, E. Hamick, et al., Nature, Vol. 275, October 1978.

"In-Flight Performance of the IUE," Co-authors: A. Boggess, R.C. Bohlin, et al., Nature, Vol. 275, October 1978.

"The IUE Spacecraft and Instrumentation," Co-authors: A. Boggess, F.A. Carr, D.C. Evans, et al., Nature, Vol. 275, October 1978.

System Design Report for the International Ultraviolet Explorer (IUE), Volume 1, Scientific Instrument, Scientific Instrument Manager, NASA Goddard Space Flight Center, Greenbelt, MD, August 1976.

"Absolute Ultraviolet Spectrophotometry of Alpha Canis Majoris, Gamma Orionis, Kappa Orionis, and Alpha Leonis," in A.D. Code, ed. The Scientific Results of the Orbiting Astronomical Observatory (OAO-2), NASA SP-310, Washington, DC, 1972.

"Ultraviolet Planetary Observations through 1968," Appendix 1, and co-author of "Report of the Planetary Astronomy Panel," in R.O. Doyle, ed. A Long Range Program in Space Astronomy, NASA SP-213, Washington, DC, 1969.

"Daytime Rocket Photographs of Stars and Airglow," Co-author: L. Dunkelman, Science, Vol. 164, No. 3886, June 20, 1969

"Star Sightings from Manned Spacecraft," Co-author: L. Dunkelman, Astronomical Journal, Vol. 72, No. 795, 1967.

"Evidence for a High Level Stratospheric Dust Layer from Satellite Twilight Color Photographs," Co-authors: C.L. Mateer, L. Dunkelman and J.V. Dave, Transactions of the American Geophysical Union, Vol. 48, No. 104, 1967.

"Ultraviolet Reflectivity of Venus and Jupiter," (GSFC X-613-66-172), Space Research, Vol. 7, Proceedings of COSPAR, May 1966.

"Observed Ultraviolet Reflectivity of Mars," Science, Vol. 149, No. 3687, p. 969-972, August 1965.

"Model Atmospheres for the Planet Mars," Co-author: P.E. Wasko, AIAA Paper 64-67, Jan. 20-22, 1964 AIAA Journal, (A64-12926) also Douglas Aircraft Co., Inc., Report SM 44552, August 1963.

An Airborne Infrared Radiometer Experiment to Detect Water Vapor on Venus, Douglas Aircraft Co., Inc. Report SM-42977, Santa Monica, CA (N63-22939), April 1963.

Physical Properties of the Planet Venus, Douglas Aircraft Co., Inc., Report SM-41586, Santa Monica, CA, July 1962 (N62-16253)


U.S. Serial Number 07/094,583; Filed September 9, 1987. Mass Relocation Inertia Controller - A low cost attitude control system for Spartan Class free flyer satellites.

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