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The feasibility of employing thin-film heat-flux gages was studied as a method of defining boundary layer characteristics at supersonic speeds in a high speed blowdown wind tunnel. Flow visualization techniques (using oil) were employed. Tabulated data (computer printouts), a test facility description, and photographs of test equipment are given.
Determination of aerial camera shutter and aperture settings to produce consistently high-quality aerial photographs is a task complicated by numerous variables. Presented in this article are brief discussions of each variable and specific data which may be used for the systematic control of each. The variables discussed include sunlight, aircraft altitude, subject and season, film speed, and optical system. Data which may be used as a base reference are included, and encompass two sets of sensitometric specifications for two film-chemistry processes along with camera-aircraft parameters, which have been established and used to produce good exposures. Information contained here may be used to design and implement an exposure-determination system for aerial photography.
In order to develop an experiment which would provide previously unknown information at the projected new launch period, a decision was made to modify the S-027 experiment to allow detection of lower energies which had previously not been mapped. The modification basically required that the static counters be replaced with a thin film entrance window gas flow counter which would allow detection of X-ray energies as low as 150 ev. The new experiment designated S-150 was designed to detect X-ray energies over a spectrum of 150 ev to 10 Kev. Photographs of the S-150 experiment are shown. Basically the same signal detection and processing techniques were used on the S-150 experiment as were used on the S-027. For economic reasons much of the S-027 subassembly hardware was used on the new experiment. The main design changes were in the signal detection system and the high energy veto system.
A relatively simple and reasonably accurate dry-surface coating method for visualization of the separation line on a bluff body was devised and successfully tested. This technique is based on the color reaction of a dry film containing a pH indicator with an appropriate gas released in the body wake. The dry-surface coating method is effective at any Reynolds number and for both incident laminar and turbulent flows. It further supplies a colorful permanent of consistently good photographic quality of the separation line. The effectiveness and accuracy of this technique were tested in visualizing the separation angle on a circular cylinder in both laminar and turbulent crossflows at subcritical Reynolds numbers. Separation angles revealed by the visualization were within + or - 4 percent of their counterparts deduced from the mean wall pressure distribution.
The flow field produced by a low aspect ratio wing (AR = 3.0) with a partial span leading edge droop was investigated in a series of low speed wind tunnel tests (Reynolds number based on 17.8 cm chord = 560,000). Photographs were obtained of surface oil flow patterns over an angle of attack range of alpha = 0 to 29 deg. Flow field surveys of the partially stalled wing at alpha = 25 deg were completed using a hot-wire probe, a split-film probe and a Conrad probe. The flow field survey data was presented using a color video display. The data indicated regions of apparent reversed flow in the separation region behind the wing and indicated the general cross-sectional shape of the separated wake flow.
The Synoptic Terrain Photography Experiment (S-5) was successfully conducted during the Gemini V mission, the second of the Gemini flights on which it was carried. This report summarizes briefly the methods and results of the experiment. Interpretation of the many excellent pictures obtained is in progress, and a full report is not possible at this time; instead, representative pictures will be presented and described. The purpose of the experiment was to obtain a large number of high-quality color photographs of selected land areas from geologic and geographic study. Southern Mexico, eastern Africa, and Australia were given high priority, but it was stressed that good pictures of any cloud-free land area would be useful. The same camera (Hasselblad 500 C) and film (Ektachrome MS) used on the Gemini III and IV missions were carried on the Gemini V flight.
A strain transducer system and process for making the same is disclosed. A beryllium copper ring having four strain gages is electrically connected in Wheatstone bridge fashion to the output instrumentation. Tabs are bonded to a balloon or like surface with strain on the surface causing bending of a ring which provides an electrical signal through the gages proportional to the surface strain. A photographic pattern of a one half ring segment as placed on a sheet of beryllium copper for chem-mill etch formation is illustrated.
Evaluation of photographic and thermal infrared imagery acquired at an altitude of 11,500 ft above ground level (in southwestern South Dakota) on Oct. 15, 1970, June 30, 1971, and Aug. 2, 1971, for use in mapping range sites and soils. A density slicing system was used to enhance film optical density differences associated with range sites and soils. The range site boundaries in native rangeland areas were found to be delineated best by a density slicing analysis of color infrared film obtained in August 1971. The range site maps produced by density slicing were superior to existing range inventory maps. The density slicing analysis of color infrared film from the August 1971 flight was best for locating soil boundaries in rangeland areas. To adequately map soils in rangeland areas, data based on density slicing used in conjunction with slope gradient information derived from stereoscopic analyses provided more detailed and accurate information than is presently available from range site and soil maps of the area.
The paper discusses the impact of various Space Shuttle mission parameters on the efficient and meaningful utilization of the large format camera (LFC) as a photographic acquisition system. Some of the LFC's vital statistics and its mounting within the Orbiter payload are described. LFC characteristics and mounting dictate certain mission parameters. The controlling parameters are orbit inclinations, launch time of year, launch time of day, orbital altitude, mission duration, overlap selection, film capacity, and climatological prediction. A mission case is evaluated relative to controlling parameters and geographical area(s) of interest.
The author has identified the following significant results. Digital analysis of LANDSAT CCT's indicated that two discrete spectral background zones occurred among the five soil zone. K-CLASS classification of corn revealed that accuracy increased when two background zones were used, compared to the classification of corn stratified by five soil zones. Selectively varying film type developer and development time produces higher contract in reprocessed imagery. Interpretation of rangeland and cropped land data from 1968 aerial photography and 1976 LANDSAT imagery indicated losses in rangeland habitat. Thermal imagery was useful in locating potential sources of sub-surface water and geothermal energy, estimating evapotranspiration, and inventorying the land.
The author has identified the following significant results. Preliminary analysis of the capabilities of ERTS-1 data in land use mapping and change detection has revealed that Level 1 land use mapping can be performed and that in some cases land use changes can be identified. Land use interpretation was accomplished with the aid of a film projection viewer and the I2S additive color viewer. By varying the filters and illumination of each spectral band it was possible to better distinguish urban areas and transportation routes. Also it enabled the toning down of signatures such as cropland and forests which on many color infrared composite photographs were washed out with strong red tints. It appears that ERTS-1 imagery is useful not only for Level 1 mapping at scales of 1:250,000 or smaller, but also for monitoring agricultural changes and locating areas of construction, when such land uses approach an area of approximately two hectares.
Positive correlation exists between reflectance of water and the water quality parameter of turbidity. This relationship holds for all times for a particular waste. At particular times other parameters such as suspended solids correlate to turbidity and can also be mapped. To analyze aerial photos properly to obtain water reflectance, a standard reflectance panel is needed somewhere in the frame. For this study color and color-infrared film are used and analyzed with a color microdensitometer which, with certain modifications, is also used to analyze reflectance of water samples. Noise in the analysis includes bottom effects, reflection from the air-water interface, and path luminance, but these can all be dealt with by proper techniques.
The activities of the Photographic Technology Division, and particularly the Photo Science Office, the Precision Processing Laboratory, and the Motion Picture Laboratory, in connection with the scientific photography of the Apollo 16 manned space mission are documented. Described are the preflight activities involved in establishing a standard process for each of the flight films, the manned in which flight films were handled upon arrival at the Manned Spacecraft Center in Houston, Texas, and how the flight films were processed and duplicated. The tone reproduction method of duplication is described. The specific sensitometric and chemical process controls are not included.
A photographic flight was made over the James River on May 17, 1977. The data show that, in general, James River water has very high sunlight reflectance. In the Bailey Bay area this reflectance is drastically reduced. Also shown is a technique for normalizing off-axis variations in radiance film exposure from camera falloff and uneven sunlight conditions to the nadir value. After data normalization, a spectral analysis is performed that identifies Bailey Creek water in James River water. The spectral results when compared with laboratory spectrometer data indicate that reflectance from James River water is dominated by suspended matter, while the substance most likely responsible for reduced reflectance in Bailey Creek water is dissolved organic carbon.
A pool boiling apparatus was mounted on a counterweighted platform which could be dropped a distance of nine feet. By varying the size of the counterweight, the effective gravity field on the equipment was adjusted between zero and unity. A study of boiling burnout in water indicated that a variation in the critical heat flux according to the one quarter power of gravity was reasonable. A consideration of the transient burnout process was necessary in order to properly interpret the data. A photographic study of nucleate boiling showed how the velocity of freely rising vapor bubbles decreased as gravity was reduced. The bubble diameters at the time of breakoff from the heated surface were found to vary inversely as gravity to the 1/3.5 power. Motion pictures were taken to illustrate both nucleate and film boiling in the low gravity range.
The author has identified the following significant results. Using the 12S Digicol color additive viewer and eight color classification map has been produced of a portion of the study area. Channel 3 of the MSS produced the best map. Enlargements of the MSS data have been accomplished by using the Data Analysis Station. The attached film recorder has three color guns which are capable of placing 2400 square elements across a 9 inch film. It has been found that by repeating ERTS element 9 times and each scan line 13 times that a map of a scale approximately 1:62,000 can be produced as a color negative film strip. This can be contact printed to produce a color map of the scale. As yet this procedure does not correct for image skew caused by rotation which is believed to be the major source of distortion and blockiness in the image. However, the final product which has not undergone any photographic enlargement is superior to photographically enlarged maps of the same scale.
In late 1973, NASA plans to launch a three-man experimental space station, the Skylab Workshop. Technical specifications regarding the instrumental facilities of the space station are presented, giving attention to the multispectral photographic facility, the IR spectrometer, the multispectral scanner, the L-band radiometer, and the S-193 sensor. The S-193 sensor will provide data applicable to studying varying ocean surfaces, wave conditions, sea and lake ice, ocean clouds, weather prediction, and soil types. All data from the sensors will be recorded on film and analog magnetic tape for return at the end of each manned period of Skylab.
A magnetic monopole traversing a dielectric medium at a velocity greater than the phase velocity of light in that medium, will give rise to Cerenkov radiation with the electric field tangent to the cone generated by the photon wave propagation vector, and the magnetic field normal to that surface. This is the opposite polarization to that encountered with an electric charge. It is proposed that either by inserting a linearly polarizing layer between the radiator and the photographic emulsion, or by selecting a linearly polarizing material as the radiator, one could directly observe the field polarization by examining the photographic image and thus uniquely identify a magnetic monopole. The ability of the detector is further enhanced by the index of refraction dependence of the Cerenkov output from a magnetic monopole.