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Holland, W.

Publications and source records attributed to Holland, W..

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

The Path to Interferometry in Space

For over two decades, astronomers have considered the possibilities for interferometry in space. The first of these missions was the Space Interferometry Mission (SIM), but that was followed by missions for studying exoplanets (e.g Terrestrial Planet Finder, Darwin), and then far-infrared interferometers (e.g. the Space Infrared Interferometric Telescope, the Far-Infrared Interferometer). Unfortunately, following the cancellation of SIM, the future for space-based interferometry has been in doubt, and the interferometric community needs to reevaluate the path forward. While interferometers have strong potential for scientific discovery, there are technological developments still needed, and continued maturation of techniques is important for advocacy to the broader astronomical community. We review the status of several concepts for space-based interferometry, and look for possible synergies between missions oriented towards different science goals.

Rinehart, S. A.↗
NASA NTRS1999

Information Flow in the Launch Vehicle Design/Analysis Process

This paper describes the results of a team effort aimed at defining the information flow between disciplines at the Marshall Space Flight Center (MSFC) engaged in the design of space launch vehicles. The information flow is modeled at a first level and is described using three types of templates: an N x N diagram, discipline flow diagrams, and discipline task descriptions. It is intended to provide engineers with an understanding of the connections between what they do and where it fits in the overall design process of the project. It is also intended to provide design managers with a better understanding of information flow in the launch vehicle design cycle.

Humphries, W. R., Sr.↗
NASA NTRS1999

The Dust and Gas Content of a Disk Around Young Star HR 4796A

We have used the James Clerk Maxwell Telescope (JCMT) in Hawaii to search at submillimeter wavelengths for continuum emission from dust, and spectral line emission from carbon monoxide (CO) gas, in the neighborhood of HR 4796A.

astrophysics planets formation extraterrestrial pl↗
NASA NTRS1981

Unigrid methods for boundary value problems with nonrectangular domains

Boundary value problems with nonrectangular domains were solved with unigrid methods. Unigrid was developed, its relationship to multigrid is described and some simple theory is presented. Its use is illustrated with a North Atlantic basin oceanographic model problem. It is demonstrated how unigrid (and, hence, multigrid) can be used efficiently with vector computers on problems with irregular domains.

Holland, W.↗
NASA NTRS1974

SSME/side loads analysis for flight configuration, revision A

This document describes the dynamic loads analysis accomplished for the Space Shuttle Main Engine (SSME) considering the side load excitation associated with transient flow separation on the engine bell during ground ignition. The results contained herein pertain only to the flight configuration. A Monte Carlo procedure was employed to select the input variables describing the side load excitation and the loads were statistically combined. This revision includes an active thrust vector control system representation and updated orbiter thrust structure stiffness characteristics. No future revisions are planned but may be necessary as system definition and input parameters change.

Holland, W.↗