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Miller, L. J.

Publications and source records attributed to Miller, L. J..

15 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

The International Space Station human life sciences experiment implementation process

The selection, definition, and development phases of a Life Sciences flight research experiment has been consistent throughout the past decade. The implementation process, however, has changed significantly within the past two years. This change is driven primarily by the shift from highly integrated, dedicated research missions on platforms with well defined processes to self contained experiments with stand alone operations on platforms which are being concurrently designed. For experiments manifested on the International Space Station (ISS) and/or on short duration missions, the more modular, streamlined, and independent the individual experiment is, the more likely it is to be successfully implemented before the ISS assembly is completed. During the assembly phase of the ISS, science operations are lower in priority than the construction of the station. After the station has been completed, it is expected that more resources will be available to perform research. The complexity of implementing investigations increases with the logistics needed to perform the experiment. Examples of logistics issues include- hardware unique to the experiment; large up and down mass and volume needs; access to crew and hardware during the ascent or descent phases; maintenance of hardware and supplies with a limited shelf life,- baseline data collection schedules with lengthy sessions or sessions close to the launch or landing; onboard stowage availability, particularly cold stowage; and extensive training where highly proficient skills must be maintained. As the ISS processes become better defined, experiment implementation will meet new challenges due to distributed management, on-orbit resource sharing, and adjustments to crew availability pre- and post-increment. c 2001. Elsevier Science Ltd. All rights reserved.

Research↗
NASA NTRS1998

Pulsing Inertial Oscillation, Supercell Storms, and Surface Mesonetwork Data

The pulsing inertial oscillation (PIO) model is a nonlinear, time-dependent, translating vortex solution of the inviscid, compressible fluid dynamic equations in the middle troposphere. The translation of this vortex during a pulse is strikingly similar to that of a supercell storm -- a rotating thunderstorm that can generate tornadoes and hail. Two studies were performed to test the hypothesis that some supercell storms are manifestations of a PIO pulse. The first study applied the model to an intense interior draft whose buoyancy was bounded by a temperature excess of +/- 12 K. The peak updraft speed achieved was 41.5 m/ s and the peak Rossby number was 92.9. The study also pointed to an advanced concept for attaining higher values. The second study applied the PIO model to a supercell storm as a whole and succeeded in replicating its bulk properties, such as mesocyclonic circulation, net mass and moisture influxes, and time track. This study also identified a critical feature of the PIO model that could be tested against storm data: The average vertical draft is downward before the turn in the storm track and upward afterwards. In the conventional theory, the average vertical draft is upward from storm inception until dissipation. These differing draft predictions were compared with the best available data, which are surface mesonetwork data. These data were found to support the PIO model. However, surface data alone are not conclusive, and further measurements are warranted.

Costen, R. C.↗
NASA NTRS1994

Low Cost Uplink Concepts

In order to minimize the cost of developing sequences of commands for small, low cost missions, a cost effective set of uplink tools used in conjunction with an appropriate ground system architecture (including a multi-mission operations facility) must be utilized.

ground system architecture generic uplink process ↗
NASA NTRS1993

First radar echoes from cumulus clouds

In attempting to use centimeter-wavelength radars to investigate the early stage of precipitation formation in clouds, 'mantle echoes' are rediscovered and shown to come mostly from scattering by small-scale variations in refractive index, a Bragg kind of scattering mechanism. This limits the usefulness of single-wavelength radar for studies of hydrometeor growth, according to data on summer cumulus clouds in North Dakota, Hawaii, and Florida, to values of reflectivity factor above about 10 dBZe with 10-cm radar, 0 dBZe with 5-cm radar, and -10 dBZe with 3-cm radar. These are limits at or above which the backscattered radar signal from the kinds of clouds observed can be assumed to be almost entirely from hydrometeors or (rarely) other particulate material such as insects. Dual-wavelength radar data can provide the desired information about hydrometeors at very low reflectivity levels if assumptions can be made about the inhomogeneities responsible for the Bragg scattering. The Bragg scattering signal itself probably will be a useful way to probe inhomogeneities one-half the radar wavelength in scale for studying cloud entrainment and mixing processes. However, this use is possible only before scattering from hydrometeors dominates the radar return.

Knight, Charles A.↗
NASA NTRS1988

Voyager flight engineering preparations for Neptune encounter

Voyager 2 will make the first close observations of the planet Neptune, during the period from June 1 to October 1,1989. A number of flight engineering activities are being conducted in preparation for the encounter. This paper discusses the most significant of these activities: new image motion compensation techniques, attitude control system changes, new exposure capabilities, new data handling capabilities, radiation protection measures, and new navigation methods. In addition, the process of performing late sequence updates is discussed. An overview of the Neptune mission is also presented.

Miller, L. J.↗
NASA NTRS1987

Antenna Technology Shuttle Experiment (ATSE)

Numerous space applications of the future will require mesh deployable antennas of 15 m in diameter or greater for frequencies up to 20 GHz. These applications include mobile communications satellites, orbiting very long baseline interferometry (VLBI) astrophysics missions, and Earth remote sensing missions. A Lockheed wrap rip antennas was used as the test article. The experiments covered a broad range of structural, control, and RF discipline objectives, which is fulfilled in total, would greatly reduce the risk of employing these antenna systems in future space applications. It was concluded that a flight experiment of a relatively large mesh deployable reflector is achievable with no major technological or cost drivers. The test articles and the instrumentation are all within the state of the art and in most cases rely on proven flight hardware. Every effort was made to design the experiments for low cost.

Freeland, R. E.↗
NASA NTRS1983

Navigation of the Galileo mission

An overview of the navigation of the Galileo mission is given. Predicted navigation performance for the various mission phases is discussed with particular emphasis given to the tour phase. Orbit determination strategies and resulting accuracies are discussed for various data types. In particular, the results of combining a new Very Long Baseline Interferometry (VLBI) data type called Differential One-Way Range (DOR) with conventional radio and optical data types are presented. Maneuver strategy results include the effects of maneuver placement and various targeting methods on propellant consumption and delivery accuracy. Emphasis is placed on new results obtained using asymptote and split targeting.

Miller, L. J.↗
NASA NTRS1980

Cooperative convective precipitation experiment

The experiment strives to improve understanding of the physics of convective precipitation. Major emphasis is placed on obtaining a good description of the whole convective precipitation system. A framework is presented within which single, significant, tractable problems are investigated.

Miller, L. J.↗
NASA NTRS1978

Mini-BRU/BIPS foil bearing development

The analysis revealed the failure agent to be a combination of poor teflon coating adhesion, a decrease in bearing sway space and, possibly, lack of flushing flow through the bearing. A change in Teflon coating vendors provided substantially improved coating quality and surface finish. The sway space was increased and the cooling bleed flow was adjusted to flush the bearing. These changes were included in a test conducted in the WHL from 6 April to 22 May 1978 which resulted in the completion of 1006.9 hours of operation at temperature and load. Post-test inspection revealed the bearings to be in excellent condition and capable of completing a much longer test.

Dobler, F. X.↗
NASA NTRS1978

Galileo satellite tour maneuver strategies

In January of 1982 the United States will launch Galileo, the first space mission designed to perform an intensive tour of the Galilean satellites of Jupiter. This paper discusses the results of preliminary maneuver strategy studies for typical interplanetary and orbital phases of the Galileo mission. These studies include the effects of maneuver placement and various linear control algorithms on propellant consumption as determined by Monte Carlo analysis. Estimates of total propellant required for various probabilities of mission success are also given.

Miller, L. J.↗
NASA NTRS1978

Seasat land experiments

An overview of the Seasat land experiments is presented. The potential roles for active microwave imaging systems on board satellites were reviewed with particular emphasis on the Seasat Synthetic Aperture Radar (SAR). Recommendations were made concerning the type of experiments that could most profitably be conducted over land with the Seasat SAR system capabilities available.

Estes, J. E.↗
NASA NTRS1977

Voyager navigation strategy and accuracy

The paper presents the results of the prelaunch navigation studies conducted for the Mariner spacecraft launched toward encounters with the giant planets. The navigation system and the strategy for using this system are described. The requirements on the navigation system demanded by the goals of the project are mentioned, and the predicted navigational capability relative to each of the requirements is discussed. Baseline navigation results for three possible trajectories are analyzed.

Jones, J. B.↗
NASA NTRS1970

New hyperthermal thermosetting heterocyclic polymers

Polyimidazopyrrolone polymers, formed by the condensation of aromatic dianhydrides with aromatic tetraamines in various solvents, form moldings that resist degradation in air and retain great strength at 400 to 700 degrees F. The resins have good insulating properties, are easy to mold, and make good protective coatings.

Bilow, N.↗