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David W Dunham

Yale University, Astronomy, Alumnus

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Dr. Dunham is the Chief Mission Design Engineer at KinetX Aerospace. He got his Ph.D. in celestial mechanics from Yale University in 1971. For many years, he was Robert Farquhar’s right-hand man, playing major roles in the trajectory design for pioneering missions, including ISEE-3, the first libration-point mission and first to a comet

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Vrije Universiteit Brussel

Ministero dell'Istruzione, dell'Università e della Ricerca (M.I.U.R.)

University of Tunis El Manar

Armando Marques-Guedes

UNL - New University of Lisbon

Mariafelicia De Laurentis

Università degli Studi di Napoli "Federico II"

Higher Colleges of Technology

University of Castilla-La Mancha

Tata Institute of Fundamental Research

Sergey A Khaibrakhmanov

Saint-Petersburg State University

Jesus Milton R.S.

Jain University

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Papers by David W Dunham

Solar diameter measurements from eclipses as a solar variability proxy

Proceedings of the International Astronomical Union, 2015

The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations ar... more The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations are obtained near both the northern and southern limits of the eclipse path, in principle, the angular diameter of the Sun can be measured. Concerted efforts have been made to obtain contact timings from locations near total solar eclipse path edges since the mid 19th century, and Edmund Halley organized a rather successful first effort in 1715. Members of IOTA have been making increasingly sophisticated observations of the Baily's bead phenomena near central solar eclipse path edges since 1970.

Geodetic Applications of Grazing Occultations

Highlights of Astronomy, 1971

Angular diameters of stars to be occulted by minor planets

VizieR Online Data Catalog: XZ Catalog of Zodiacal Stars (XZ80N) (Dunham+ 1995)

Vizier Online Data Catalog, Feb 1, 1995

Occultations of Zubenelgenubi by the orbits of the satellites of Uranus

Contingency study for the third international Sun-Earth Explorer (ISEE-3) satellite

Lunar occultation of ISEE-3

Occultations of Astrographic Catalog stars by (46) Hestia

Libration Point Missions, 1978 – 2002

Libration Point Orbits and Applications, 2003

This paper summarizes the six missions to the vicinity of libration points that have been flown u... more This paper summarizes the six missions to the vicinity of libration points that have been flown up to the time of this conference in June 2002. The first libration-point mission, the third International Sun-Earth Explorer (ISEE-3), is emphasized because it laid the groundwork for so many later missions, most of which are covered more thoroughly in other papers given at this conference. First, the authors present some basic properties of libration-point orbits, and some history of their development for early missions. Only brief information is given here; details can be found in the references.

The Angular Diameter of TX Piscium

Monthly Notices of the Royal Astronomical Society, 1975

The Dimensions of (6) Hebe as a Result of Occultation Observations

Revista mexicana de astronomía y astrofísica

From visual observations of the occultation of the star gamma Ceti by the minor planet (6) Hebe w... more

Upcoming planetary occultations

Lunar occultation angular diameter measurements

The Astronomical Journal, 1980

Precise measurement of asteroid sizes and shapes from occultations

The observational techniques (including photoelectric observations, television recordings, and vi... more The observational techniques (including photoelectric observations, television recordings, and visual timings) used to measure asteroid dimensions from occultations of stars by asteroids are discussed together with the methods of analysis appropriate to occultation data. Results are presented on the determinations of asteroid diameter, density, and internal structure measures learned from occultations of 36 asteroids. Prospects for continued effective applications of the occultation technique to asteroid studies are discussed.

Trajectories for spacecraft encounters with comet Honda-Mrkos-Pajdušáková in 1996

Acta Astronautica, 1990

ABSTRACT

Ground-Based Observations Of Lunar Meteoritic Phenomena

Earth, Moon, and Planets, 2003

The occurrence and visibility of meteoroid impacts on the moon as seen from the earth were little... more The occurrence and visibility of meteoroid impacts on the moon as seen from the earth were little more than speculation prior to November 1999. The best evidence of present-day impact activity came from the seismic experiments left on the Moon during the Apollo era. Past systematic attempts at earth-based observations to document lunar impacts revealed nothing conclusive. However, during the Leonid storms of 1999 and 2001, lunar impact events were for the first time confirmed by multiple independent observers. A total of 15 meteoritic impact flash events have been verified during these storms, with an additional 12 unconfirmed but likely events awaiting confirmation. Estimates of the mass of these meteoroids range from less than one gram for the faintest flashes to more than 10 kg for the brightest observed flash. The fraction of visible light to total energy produced by these events, a quantity known as luminous efficiency, averages about 0.001 for the established events. The confirmation of lunar meteoritic events on the Moon opens a new avenue in lunar and planetary research, one which could help bridge the gap between atmospheric sampling of the smallest components of meteoroid streams and interplanetary debris to the larger scale objects accessible to ground-based telescopes.

The CONTOUR discovery mission

1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999

Over a six-year period, CONTOUR will fly within 100 kilometers of three comet nuclei: Encke in 20... more Over a six-year period, CONTOUR will fly within 100 kilometers of three comet nuclei: Encke in 2003, Schwassmann-Wachmann-3 in 2006, and finally d'Arrest in 2008. CONTOUR will take images, make spectral maps, and analyze dust and gas. The payload includes fixed and tracking imagers that will provide high-resolution images and spectral maps. CONTOUR uses several innovative techniques for performing deep space missions at low cost. These include an indirect launch strategy, unanended hibernation, and an innovative mission and spacecraft design. This paper compares the CONTOUR design and development approach with other recent programs and identifies challenges CONTOUR will face ih this era of faster, cheaper, and better. 1. 2. 3. 4.

Supporting a Deep Space Gateway with Free-Return Earth-Moon Periodic Orbits

Introduction: Earth-Moon periodic/cycler orbits constantly travel between the Earth and Moon via ... more Introduction: Earth-Moon periodic/cycler orbits constantly travel between the Earth and Moon via freereturn, figure-8 circumlunar segments. Such cycler orbits can host a space station that can be utilized in a flexible manner with regard to providing support (e.g., propellant, crew supplies, robotic spacecraft, etc.) to other stations/nodes near or on the Moon, to near-Earth asteroids and Mars. If an Earth-Moon cycling station acts a propellant depot, then the braking delta-V (ΔV) needed to enter lunar orbit, land on the lunar surface, and ascend back to lunar orbit to eventually reach the Earth can be provided by the cycling station thus minimizing the mass needed for human launches. Propellant can also be transported to and from lunar orbit (including a deep space gateway station at/near and Earth-Moon Lagrange point) via Earth-Moon cycling trajectories. Figure-8 cyclers can also provide abort-friendly trajectory plans for crew to execute in case of an emergency. Connections to an...

Small Satellite Rendezvous and Characterization of Asteroid 99942 Apophis

The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low-cost c... more The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low-cost characterization mission to the asteroid 99942 Apophis that leverage small spacecraft architectures and technologies. The mission goals were to perform physical characterization and improve the orbital model. The MAAT mission uses a small spacecraft free flyer and a bi-propellant transfer stage that can be incorporated as a secondary payload on Evolved Expendable Launch Vehicles (EELVs), Atlas V or Delta IV launches. Using the innovative secondary architecture allows the system to be launched on numerous GTO or LTO opportunities such as NASA science missions or commercial communication satellites. The trajectory takes advantage of the reduced Delta-V requirement during the 20122015 time frame, with a large flexible launch opportunity, from January to November 2012 and heliocentric injection occurs in April 2013. Primary communications use the traditional Deep Space Network (DSN) with a se...

Precise astrometry and diameters of asteroids from occultations – a data set of observations and their interpretation

Monthly Notices of the Royal Astronomical Society, 2020

Occultations of stars by asteroids have been observed since 1961, increasing from a very small nu... more Occultations of stars by asteroids have been observed since 1961, increasing from a very small number to now over 500 annually. We have created and regularly maintain a growing data set of more than 5000 observed asteroidal occultations. The data set includes the raw observations, astrometry at the 1 mas level based on centre of mass or figure (not illumination), where possible the asteroid’s diameter to 5 km or better, and fits to shape models, the separation and diameters of asteroidal satellites, and double star discoveries with typical separations being in the tens of mas or less. The data set is published at NASA’s Planetary Data System and is regularly updated. We provide here an overview of the data set, discuss the issues associated with determining the astrometry and diameters, and give examples of what can be derived from the data set. We also compare the occultation diameters of asteroids with the diameters measured by the satellites NEOWISE, AKARI AcuA, and IRAS, and sho...

Solar diameter measurements from eclipses as a solar variability proxy

Proceedings of the International Astronomical Union, 2015

The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations ar... more The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations are obtained near both the northern and southern limits of the eclipse path, in principle, the angular diameter of the Sun can be measured. Concerted efforts have been made to obtain contact timings from locations near total solar eclipse path edges since the mid 19th century, and Edmund Halley organized a rather successful first effort in 1715. Members of IOTA have been making increasingly sophisticated observations of the Baily's bead phenomena near central solar eclipse path edges since 1970.

Geodetic Applications of Grazing Occultations

Highlights of Astronomy, 1971

Angular diameters of stars to be occulted by minor planets

VizieR Online Data Catalog: XZ Catalog of Zodiacal Stars (XZ80N) (Dunham+ 1995)

Vizier Online Data Catalog, Feb 1, 1995

Occultations of Zubenelgenubi by the orbits of the satellites of Uranus

Contingency study for the third international Sun-Earth Explorer (ISEE-3) satellite

Lunar occultation of ISEE-3

Occultations of Astrographic Catalog stars by (46) Hestia

Libration Point Missions, 1978 – 2002

Libration Point Orbits and Applications, 2003

This paper summarizes the six missions to the vicinity of libration points that have been flown u... more This paper summarizes the six missions to the vicinity of libration points that have been flown up to the time of this conference in June 2002. The first libration-point mission, the third International Sun-Earth Explorer (ISEE-3), is emphasized because it laid the groundwork for so many later missions, most of which are covered more thoroughly in other papers given at this conference. First, the authors present some basic properties of libration-point orbits, and some history of their development for early missions. Only brief information is given here; details can be found in the references.

The Angular Diameter of TX Piscium

Monthly Notices of the Royal Astronomical Society, 1975

The Dimensions of (6) Hebe as a Result of Occultation Observations

Revista mexicana de astronomía y astrofísica

From visual observations of the occultation of the star gamma Ceti by the minor planet (6) Hebe w... more

Upcoming planetary occultations

Lunar occultation angular diameter measurements

The Astronomical Journal, 1980

Precise measurement of asteroid sizes and shapes from occultations

The observational techniques (including photoelectric observations, television recordings, and vi... more The observational techniques (including photoelectric observations, television recordings, and visual timings) used to measure asteroid dimensions from occultations of stars by asteroids are discussed together with the methods of analysis appropriate to occultation data. Results are presented on the determinations of asteroid diameter, density, and internal structure measures learned from occultations of 36 asteroids. Prospects for continued effective applications of the occultation technique to asteroid studies are discussed.

Trajectories for spacecraft encounters with comet Honda-Mrkos-Pajdušáková in 1996

Acta Astronautica, 1990

ABSTRACT

Ground-Based Observations Of Lunar Meteoritic Phenomena

Earth, Moon, and Planets, 2003

The occurrence and visibility of meteoroid impacts on the moon as seen from the earth were little... more The occurrence and visibility of meteoroid impacts on the moon as seen from the earth were little more than speculation prior to November 1999. The best evidence of present-day impact activity came from the seismic experiments left on the Moon during the Apollo era. Past systematic attempts at earth-based observations to document lunar impacts revealed nothing conclusive. However, during the Leonid storms of 1999 and 2001, lunar impact events were for the first time confirmed by multiple independent observers. A total of 15 meteoritic impact flash events have been verified during these storms, with an additional 12 unconfirmed but likely events awaiting confirmation. Estimates of the mass of these meteoroids range from less than one gram for the faintest flashes to more than 10 kg for the brightest observed flash. The fraction of visible light to total energy produced by these events, a quantity known as luminous efficiency, averages about 0.001 for the established events. The confirmation of lunar meteoritic events on the Moon opens a new avenue in lunar and planetary research, one which could help bridge the gap between atmospheric sampling of the smallest components of meteoroid streams and interplanetary debris to the larger scale objects accessible to ground-based telescopes.

The CONTOUR discovery mission

1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999

Over a six-year period, CONTOUR will fly within 100 kilometers of three comet nuclei: Encke in 20... more Over a six-year period, CONTOUR will fly within 100 kilometers of three comet nuclei: Encke in 2003, Schwassmann-Wachmann-3 in 2006, and finally d'Arrest in 2008. CONTOUR will take images, make spectral maps, and analyze dust and gas. The payload includes fixed and tracking imagers that will provide high-resolution images and spectral maps. CONTOUR uses several innovative techniques for performing deep space missions at low cost. These include an indirect launch strategy, unanended hibernation, and an innovative mission and spacecraft design. This paper compares the CONTOUR design and development approach with other recent programs and identifies challenges CONTOUR will face ih this era of faster, cheaper, and better. 1. 2. 3. 4.

Supporting a Deep Space Gateway with Free-Return Earth-Moon Periodic Orbits

Introduction: Earth-Moon periodic/cycler orbits constantly travel between the Earth and Moon via ... more Introduction: Earth-Moon periodic/cycler orbits constantly travel between the Earth and Moon via freereturn, figure-8 circumlunar segments. Such cycler orbits can host a space station that can be utilized in a flexible manner with regard to providing support (e.g., propellant, crew supplies, robotic spacecraft, etc.) to other stations/nodes near or on the Moon, to near-Earth asteroids and Mars. If an Earth-Moon cycling station acts a propellant depot, then the braking delta-V (ΔV) needed to enter lunar orbit, land on the lunar surface, and ascend back to lunar orbit to eventually reach the Earth can be provided by the cycling station thus minimizing the mass needed for human launches. Propellant can also be transported to and from lunar orbit (including a deep space gateway station at/near and Earth-Moon Lagrange point) via Earth-Moon cycling trajectories. Figure-8 cyclers can also provide abort-friendly trajectory plans for crew to execute in case of an emergency. Connections to an...

Small Satellite Rendezvous and Characterization of Asteroid 99942 Apophis

The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low-cost c... more The Measurement and Analysis of Apophis Trajectory (MAAT) concept study investigated a low-cost characterization mission to the asteroid 99942 Apophis that leverage small spacecraft architectures and technologies. The mission goals were to perform physical characterization and improve the orbital model. The MAAT mission uses a small spacecraft free flyer and a bi-propellant transfer stage that can be incorporated as a secondary payload on Evolved Expendable Launch Vehicles (EELVs), Atlas V or Delta IV launches. Using the innovative secondary architecture allows the system to be launched on numerous GTO or LTO opportunities such as NASA science missions or commercial communication satellites. The trajectory takes advantage of the reduced Delta-V requirement during the 20122015 time frame, with a large flexible launch opportunity, from January to November 2012 and heliocentric injection occurs in April 2013. Primary communications use the traditional Deep Space Network (DSN) with a se...

Precise astrometry and diameters of asteroids from occultations – a data set of observations and their interpretation

Monthly Notices of the Royal Astronomical Society, 2020

Occultations of stars by asteroids have been observed since 1961, increasing from a very small nu... more Occultations of stars by asteroids have been observed since 1961, increasing from a very small number to now over 500 annually. We have created and regularly maintain a growing data set of more than 5000 observed asteroidal occultations. The data set includes the raw observations, astrometry at the 1 mas level based on centre of mass or figure (not illumination), where possible the asteroid’s diameter to 5 km or better, and fits to shape models, the separation and diameters of asteroidal satellites, and double star discoveries with typical separations being in the tens of mas or less. The data set is published at NASA’s Planetary Data System and is regularly updated. We provide here an overview of the data set, discuss the issues associated with determining the astrometry and diameters, and give examples of what can be derived from the data set. We also compare the occultation diameters of asteroids with the diameters measured by the satellites NEOWISE, AKARI AcuA, and IRAS, and sho...