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Lawrence, G. F.

Publications and source records attributed to Lawrence, G. F..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Orbital and cloud cover sampling analyses for space lidar missions

The sampling capabilities of an orbital lidar mission are evaluated. Spatial and temporal sampling data from a lidar spacecraft orbit simulation are combined with global, statistical cloud cover data to yield a quantification of lidar measurement opportunities for both partly cloudy and mostly overcast viewing conditions. The optimum launch time (month and local hour) is determined to maximize lidar measurement opportunities for specified cloud cover conditions. Results indicate that the time of year selected for the lidar mission is very important in maximizing acceptable data return, whereas the effect of launch time of day on mission optimization is generally not as strong as the seasonal effect.

Lawrence, G. F.↗
NASA NTRS1980

Mission analysis for earth atmospheric measurements using a Shuttle-Spacelab lidar system

Orbital characteristics and launch conditions of a spaceborne lidar system proposed for a Shuttle Spacelab mission are analyzed. Mission design tradeoffs between instrument fields of view, resolutions, orbit groundtrack repetition parameters (Q), and orbital altitudes are shown. In the multi-experiment application of the Spacelab-lidar system, where scene illumination is the key mission parameter for the performance of the lidar instrument, results indicate that selected daytime or nighttime coverage can be programmed into Spacelab lidar missions by a judicious selection of Shuttle launch time. In addition to controlling the location of nighttime measurements, results indicate that, by the proper selection of Shuttle launch time, the magnitude and variability of solar lighting angles can be optimized to fit the requirements of the Spacelab lidar experiments.

Lawrence, G. F.↗
NASA NTRS1979

Mission analysis for earth atmospheric measurements using solar occultation experiments on Shuttle Spacelabs

The maximum geographical coverage of solar occultation experiments for various Shuttle-Spacelab mission concepts is defined and an analysis that includes trade-offs between parameters such as launch time, season, orbital inclination and altitude is presented as well as the mission design data for the Spacelab-3 flight. The effects of orbital ranges from 220 to 600 km on geographical coverage are examined with inclinations up to 97 deg for sun-synchronous orbit. Results show that the widest band of latitude coverage in the tropics and the temperate zones can be achieved with a mid-inclined (i.e., 57 deg) orbit and a mid-morning or late-night launch time.

Harrison, E. F.↗
NASA NTRS1975

Mission analysis for satellite measurements of stratospheric constituents by solar occultation

Orbital characteristics and launch vehicle requirements for a solar occultation experiment measuring atmospheric constituents, such as aerosols or ozone, during the Nimbus-G and Applications Explorer Missions are analyzed. The experiment to be flown is basically a sun photometer which measures the spectral attenuation of solar radiation by the earth's atmosphere during spacecraft sunrise and sunset, yielding two aerosol and/or ozone stratospheric profiles per orbit. The tangent latitudes and longitudes as well as frequency of these measurements are analyzed for various spacecraft orbits to define maximum geographical coverage capability. Results indicate that a 50 deg inclined orbit for Applications Explorer provides latitude coverage from approximately 70 deg north to 70 deg south every 2-1/2 weeks. A high-moon, sun-synchronous orbit with an inclination of 99 deg for Nimbus-G will provide for coverage of occultation measurements at high latitudes near the polar regions (i.e., 64 to 80 deg north and south). The solar pointing requirements of the experiment in terms of yaw and pitch angles are also defined.

Harrison, E. F.↗