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Head, J.

Publications and source records attributed to Head, J..

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Selecting and Certifying a Landing Site for Moonrise in South Pole-Aitken Basin

MoonRise is a New Frontiers mission concept to land in the South Pole-Aitken (SPA) basin, collect samples, and return the samples to Earth for detailed mineral, chemical, petrologic, geochronologic, and physical properties analyses to address science questions relevant to the early evolution of the Solar System and the Moon. Science associated with this mission concept is described elsewhere; here we discuss selection of sites within SPA to address science objectives using recent scientific studies (orbital spectroscopy, gravity, topography), and the use of new data (LRO) to certify safe landing sites for a robotic sample return mission such as MoonRise.

Jolliff, B.↗
NASA NTRS1994

First Galileo image of asteroid 243 Ida

The second spacecraft encounter with an asteroid has yielded an unprecedentedly high resolution portrait of 243 Ida. On 28 Aug. 1993, Galileo obtained an extensive data set on this small member of the Koronis family. Most of the data recorded on the tape recorder will be returned to Earth in spring 1994. A five-frame mosaic of Ida was acquired with good illumination geometry a few minutes before closest approach; it has a resolution of 31 to 38 m/pixel amd was played back during Sept. 1993. Preliminary analyses of this single view of Ida are summarized.

Chapman, C. R.↗
NASA NTRS1994

Maximizing the Scientific Return of Low Cost Planetary Missions Using Solar Electric Propulsion(abstract)

After many years of development, solar electric propulsion is now a practical low cost alternative for many planetary missions. In response to the recent Discovery AO, we and a number of colleagues have examined the scientific return from a missioon to map the Moon and then rendezvous with a small body. In planning this mission, we found that solar electric propulsion was quite affordable under the Discovery guidelines, that many targets could be reached more rapidly with solar electric propulsion than chemical propulsion, that a large number of planetary bodies were accessible with modest propulsion systems, and that such missions were quite adaptable, with generous launch windows which minimized mission risks. Moreover, solar electric propulsion is ideally suited for large payloads requiring a large amount of power.

solar electric propulsion low cost missions ion th↗
NASA NTRS1992

Galileo encounter with 951 Gaspra - First pictures of an asteroid

Galileo images of Gaspra reveal it to be an irregularly shaped object (19 by 12 by 11 kilometers) that appears to have been created by a catastrophic collisional disruption of a precursor parent body. The cratering age of the surface is about 200 million years. Subtle albedo and color variations appear to correlate with morphological features: brighter materials are associated with craters especially along the crests of ridges, have a stronger 1-micrometer absorption, and may represent freshly excavated mafic materials; darker materials exhibiting a significantly weaker 1-micrometer absorption appear concentrated in interridge areas. One explanation of these patterns is that Gaspra is covered with a thin regolith and that some of this material has migrated downslope in some areas.

Belton, M. J. S.↗
NASA NTRS1991

Orientale and South Pole-Aitken basins on the Moon: Preliminary Galileo imaging results

During the Earth-Moon flyby the Galileo Solid State Imaging System obtained new information on the landscape and physical geology of the Moon. Multicolor Galileo images of the Moon reveal variations in color properties of the lunar surface. Using returned lunar samples as a key, the color differences can be interpreted in terms of variations in the mineral makeup of the lunar rocks and soil. The combined results of Apollo landings and multicolor images from Galileo allow extrapolation of surface composition to areas distant from the landing sites, including the far side invisible from Earth.

Head, J.↗
NASA NTRS1984

RAMIS DBMS Update

Highlights of a round table discussion of end-user computing, IBM strategies, fourth generation languages, and directions for software innovation are presented as well as observations from an in-depth study of 271 organizations. The RAMIS data base management system is evaluated according to 10 defining criteria for a fourth-generation language: result-oriented programming; common language/demand level adaptability; application extension; user/machine insulation; work station environment; comprehensive software toolkit; integrating perspective on computing and data resources; end user data base capability; accessible dictionaries; and user assistance/facility coordination.

Head, J.↗
NASA NTRS1983

RAMIS

A description is given of experience with the RAMIS data base management system. Examples are given of tasks where the user friendly aspects of the system facilitated quick handling of inquiries.

Head, J.↗