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NASA NTRS1974

Pulmonary function evaluation during and following Skylab space flights

Previous experience during the Apollo postflight exercise testing indicated no major changes in pulmonary function. Although pulmonary function has been studied in detail following exposure to hypoxic and hyperoxic environments, few studies have dealt with normoxic environments at reduced total pressure as encountered during the Skylab missions. Forced vital capacity was measured during the preflight and postflight periods of the Skylab 2 mission. Initial in-flight measurements of vital capacity were obtained during the last two weeks of the second manned mission (Skylab 3). Comprehensive pulmonary function screening was accomplished during the Skylab 4 mission. The primary measurements made during Skylab 4 testing included residual volume determination, closing volume, vital capacity, and forced vital capacity and its derivatives. In addition, comprehensive in-flight vital capacity measurements were made during the Skylab 4 mission. Vital capacity was decreased slightly during flight in all Skylab 4 crewmen. No major preflight to postflight changes were observed in the other parameters.

Sawin, C. F.↗

NASA NTRS1975

Flight Performance of Skylab Attitude and Pointing Control System

In 1967 a paper at the AIAA Guidance, Control and Flight Dynamics Conference in Huntsville, Ala. presented for the first time the prot)osed SKYLAB Attitude and Pointing Control System (APCS) The system requirements, Apollo Telescope Mount (ATM) configuration, control philosophy, and operational modes were presented and the APCS described. The Initial mission and system design requirements changed during the period of time before the SKYLAB was launched. This paper will review the Initial and final APCS requirements and goals and their relationship. The actual flight mission (and Its alterations during the flight) and known achieved APCS performance will then be presented. SKYLAB was a tremendous success in furthering man's scientific knowledge; but perhaps SKYLAB will be remembered more for the anomalies and the efforts undertaken to solve them. On May 14, 1973, the unmanned SKYLAB Orbital Workshop (OWS) was launched from Cape Kennedy. Serious hardware failures began to occur during ascent through the atmosphere and their spectre continued to haunt both the astronauts and their ground based support team. Nor were these the only surprises affecting the design and operation of the APCS. Mission requirements for pointing to various stellar targets and to nadir for earth resources experiments were added after the hardware was designed. The chance appearance of comet Kohoutek during the SKYLAB operational life-time caused NASA to add comet observation to the mission requirements and to adjust the time when the third crew would man the SKYLAB. The development of new procedures and software for the opportunity to observe this visitor to our solar system is described.

Chubb, W. B.↗

NASA NTRS1973

Convection effects on Skylab experiments M551, M552, and M553, phase C report

This report described an analysis of Skylab Experiments M551 (Metals Melting), M552 (Exothermic Brazing), and M553 (Sphere Forming). The primary objective is the study of convection in the molten metals and their attendant solidification theory. Particular attention is given to clarifying the effects of reduced gravity on molten metal flow and solidification. Based on an analysis of physical forces and solidification theory expected for ground-based and Skylab processing, low-g variations were predicted for each experiment. A comparison was then made with the Skylab results available to date. Both metallurgical analyses of other investigators and movies of ground-based and Skylab samples were utilized. Several low-g variations in Skylab processed materials were successfully predicted based on expected variations in physical forces and fluid convection. The same analysis also successfully predicted several features in the Skylab-processed materials which were identical to terrestrially-processed materials. These results are summarized in the conclusion section for each experiment.

Bourgeois, S. V.↗

NASA NTRS1974

Results of Skylab medical experiment M171: Metabolic activity

The experiment was conducted to establish whether man's ability to perform mechanical work would be progressively altered as a result of exposure to the weightless environment of space flight. The Skylab crewmen exercised on a bicycle ergometer at workloads approximating 25, 50, and 75 percent of their maximum aerobic capacity. The physiological parameters monitored were respiratory gas exchange, blood pressure, and vectorcardiogram/heart rate. The results of these tests indicate that the crewmen had no significant decrement in their responses to exercise during their exposure to zero gravity. The results of the third manned Skylab mission (Skylab 4) are presented and a comparison is made of the overall results obtained from the three successively longer Skylab manned missions. The Skylab 4 crewmembers' 84-day in-flight responses to exercise were no worse and were probably better than the responses of the crewmen on the first two Skylab missions. Indications that exercise was an important contributing factor in maintaining this response are discussed.

Michel, E. L.↗

NASA NTRS1975

Detectability of geothermal areas using Skylab X-5 data

The results are presented of a study which was undertaken to determine if data from a single near-noon pass of Skylab could be used to detect geothermal areas. The size and temperature requirements for a geothermally heated area to be seen by Skylab S-192 MSS X-5 thermal sensor were calculated. This sensor obtained thermal data with the highest spatial resolution of any nonmilitary satellite system. Only very large hot areas could be expected to be unambiguously recognized with a single data set from this instrument. The study area chosen was The Geysers geothermal field in Sonoma County, California, the only geothermal area of significant size scanned by Skylab. Unfortunately, 95% of the Skylab thermal channel data was acquired within 3 hours of local noon. For The Geysers area only daytime X-5 data were available. An analysis of the thermal channel data (10.2 to 12.5 um) revealed that ground temperatures determined by Skylab were normally distributed. No anomalous hot spots were apparent. Computer enhancement techniques were used to delineate the hottest 100 and 300 ground areas (pixel, 75 m by 75 m) within the study region. It was found that the Skylab MSS with the X-5 thermal detector does not have sufficient spatial resolution to locate unambiguously from daytime data any but the largest and hottest convectively created geothermal features, which in general are prominent enough to have been previously recognized.

Siegal, B. S.↗

NASA NTRS1975

Evaluation of Skylab data for land use mapping

Skylab multispectral scanner data, digitized Skylab color IR photography, digitized Skylab black and white multiband photography, and Earth Resources Technology Satellite (ERTS) multispectral scanner data collected within a twenty-four hour time period over an area in south-central Indiana near Bloomington on June 9 and 10, 1973, were compared in a machine-aided land use analysis of the area. The overall classification performance results, obtained with nine land use classes were 87% correct classification using the 'best' 4 channels of the Skylab multispectral scanner, 80% for the channels on the Skylab multispectra scanner, which are spectrally comparable to the ERTS multispectral scanner, 88% for the ERTS multispectral scanner, 83% for the digitized color IR photography, and 76% for the digitized black and white multiband photography. The results indicate that the Skylab multispectral scanner may yield even higher classification accuracies when a noise filtered multispectral scanner data set becomes available in the near future.

Biehl, L. L.↗

NASA NTRS1973

Skylab systems flight performance - An interim report

An unmanned Skylab space station was launched on May 14, 1973. The space station was inserted into a near-circular earth orbit of approximately 435 kilometers altitude. Initial difficulties with Skylab are reported together with the steps taken to overcome these difficulties. The first crew made its rendezvous with Skylab on May 25. A Skylab description is given and a systems overview is presented. Skylab attitude requirements are discussed together with details of attitude control, the communications network, scientific investigations, student experiments, earth resources studies, weather studies, solar observations, biomedical investigations, technology investigations, crew mobility and effectiveness investigations, habitability assessments, and a comet observation.

Belew, L. F.↗

NASA NTRS1974

Skylab Medical Data Center and Archives

The founding of the Skylab medical data center and archives as a central area to house medical data from space flights is described. Skylab program strip charts, various daily reports and summaries, experiment reports and logs, status report on Skylab data quality, raw data digital tapes, processed data microfilm, and other Skylab documents are housed in the data center. In addition, this memorandum describes how the data center acted as a central point for the coordination of preflight and postflight baseline data and how it served as coordinator for all data processing through computation and analysis. Also described is a catalog identifying Skylab medical experiments and all related data currently archived in the data center.

Spross, F. R.↗

NASA NTRS1975

Evaluation of the suitability of Skylab data for the purpose of petroleum exploration

The author has identified the following significant results. Comparisons of the various photographic bands of Skylab imagery indicate that, overall, standard color (particularly S190B) is the most valuable for geological purposes. Detailed examination of all bands indicates that as with ERTS imagery each band contains useful information that is unique to it. The results of geological interpretations based on ERTS and Skylab imagery are strikingly similar. It appears that more information can be extracted from a single Skylab overpass than a single ERTS overpass, but that with repeated passes the lower resolution ERTS imagery may yield information comparable to that contained in S190B imagery. Comparison of Skylab photography to high altitude aircraft photography suggests that there are distinct advantages to using Skylab imagery for regional geologic interpretations. This is primarily because of the synoptic view provided by the space acquired imagery allows and encourages integration of regional geologic features.

Collins, R. J.↗

NASA NTRS1975

The detection of geothermal areas from Skylab thermal data

Skylab-4 X-5 thermal data of the geysers area was analyzed to determine the feasibility of using midday Skylab images to detect geothermal areas. The hottest ground areas indicated on the Skylab image corresponded to south-facing barren or sparsely vegetated slopes. A geothermal area approximately 15 by 30 m coincided with one of the hottest areas indicated by Skylab. This area could not be unambiguously distinguished from the other areas which are believed to be hotter than their surroundings as a result of their topography, and micrometeorological conditions. A simple modification of a previous thermal model was performed and the predicted temperatures for the hottest slopes using representative values was in general agreement with the observed data. It is concluded that data from a single midday Skylab pass cannot be used to locate geothermal areas.

Siegal, B. S.↗

NASA NTRS1975

Skylab mobile laboratory

The Skylab mobile laboratory was designed to provide the capability to obtain necessary data on the Skylab crewmen 30 days before lift-off, within 1 hour after recovery, and until preflight physiological baselines were reattained. The mobile laboratory complex consisted of six laboratories that supported cardiovascular, metabolic, nutrition and endocrinology, operational medicine, blood, and microbiology experiments; a utility package; and two shipping containers. The objectives and equipment requirements of the Skylab mobile laboratory and the data acquisition systems are discussed along with processes such as permanently mounting equipment in the individual laboratories and methods of testing and transporting the units. The operational performance, in terms of amounts of data collected, and the concept of mobile laboratories for medical and scientific experiments are evaluated. The Skylab mobile laboratory succeeded in facilitating the data collection and sample preservation associated with the three Skylab manned flights.

Primeaux, G. R.↗

NASA NTRS1974

System safety as applied to Skylab

Procedural and organizational guidelines used in accordance with NASA safety policy for the Skylab missions are outlined. The basic areas examined in the safety program for Skylab were the crew interface, extra-vehicular activity (EVA), energy sources, spacecraft interface, and hardware complexity. Fire prevention was a primary goal, with firefighting as backup. Studies of the vectorcardiogram and sleep monitoring experiments exemplify special efforts to prevent fire and shock. The final fire control study included material review, fire detection capability, and fire extinguishing capability. Contractors had major responsibility for system safety. Failure mode and effects analysis (FMEA) and equipment criticality categories are outlined. Redundancy was provided on systems that were critical to crew survival (category I). The five key checkpoints in Skylab hardware development are explained. Skylab rescue capability was demonstrated by preparations to rescue the Skylab 3 crew after their spacecraft developed attitude control problems.

Kleinknecht, K. S.↗

NASA NTRS1974

Susceptibility to motion sickness among Skylab astronauts

The mechanisms causing susceptibility to motion sickness in zero gravity are not well understood. Preflight and postflight motion sickness susceptibility tests conducted on the three Skylab crews are described. Under operational conditions, the first Skylab crew experienced no motion sickness, while the other two crews did. Susceptibility was greater in the Skylab workshop than in the command module. Weightlessness in itself is a unique motion environment. Changes occur in nonrigid body parts and in the response of macular receptors in the otolith organs. Tests in parabolic flight, where zero gravity is the only significant factor in motion sickness susceptibility, indicate that some people need to adapt to weightlessness and others do not. A comparison of all US and Soviet manned missions indicates that a headward shift of fluid on transition to zero gravity is not a predisposing factor in motion sickness. Under certain conditions after adaptation susceptibility was lower in the Skylab workshop than on the ground. The anti-motion sickness drugs used in Skylab are judged effective for prevention and treatment.

Graybiel, A.↗

NASA NTRS1975

Evaluation of Skylab earth laser beacon imagery

During the Skylab 3 and 4 missions the Skylab spacecraft was illuminated by a low power argon ion and dye laser. The earth laser beacon was studied visually by the astronauts. In addition, they collected 35 mm hand-held color photographs of the beacons. Photographs are shown that were obtained on Skylab 3 and Skylab 4. The imagery collected during the Skylab mission was analyzed to evaluate the utility of beacon lasers as terrestial 'artificial stars' for space navigation. The analyses of the imagery revealed two unusual features of the earth laser beacon: (1) The beacon, even though of a low power (approximately 1 watt), is considerably brighter than any other terrain feature and is readily visible on imagery at a distance in excess of 1500 km (900 miles). (2) Another feature of the beacon is its large size. The typical beacon extends over about 5 resolution areas with a characteristic dimension of about 200 m.

Piech, K. R.↗

NASA NTRS1975

Computer-aided analysis of Skylab multispectral scanner data in mountainous terrain for land use, forestry, water resource, and geologic applications

The author has identified the following significant results. One of the most significant results of this Skylab research involved the geometric correction and overlay of the Skylab multispectral scanner data with the LANDSAT multispectral scanner data, and also with a set of topographic data, including elevation, slope, and aspect. The Skylab S192 multispectral scanner data had distinct differences in noise level of the data in the various wavelength bands. Results of the temporal evaluation of the SL-2 and SL-3 photography were found to be particularly important for proper interpretation of the computer-aided analysis of the SL-2 and SL-3 multispectral scanner data. There was a quality problem involving the ringing effect introduced by digital filtering. The modified clustering technique was found valuable when working with multispectral scanner data involving many wavelength bands and covering large geographic areas. Analysis of the SL-2 scanner data involved classification of major cover types and also forest cover types. Comparison of the results obtained wth Skylab MSS data and LANDSAT MSS data indicated that the improved spectral resolution of the Skylab scanner system enabled a higher classification accuracy to be obtained for forest cover types, although the classification performance for major cover types was not significantly different.

Hoffer, R. M.↗

NASA NTRS1975

Utilizing Skylab data in on-going resources management programs in the state of Ohio

The author has identified the following significant results. The use of Skylab imagery for total area woodland surveys was found to be more accurate and cheaper than conventional surveys using aerial photo-plot techniques. Machine-aided (primarily density slicing) analyses of Skylab 190A and 190B color and infrared color photography demonstrated the feasibility of using such data for differentiating major timber classes including pines, hardwoods, mixed, cut, and brushland providing such analyses are made at scales of 1:24,000 and larger. Manual and machine-assisted image analysis indicated that spectral and spatial capabilities of Skylab EREP photography are adequate to distinguish most parameters of current, coal surface mining concern associated with: (1) active mining, (2) orphan lands, (3) reclaimed lands, and (4) active reclamation. Excellent results were achieved when comparing Skylab and aerial photographic interpretations of detailed surface mining features. Skylab photographs when combined with other data bases (e.g., census, agricultural land productivity, and transportation networks), provide a comprehensive, meaningful, and integrated view of major elements involved in the urbanization/encroachment process.

Baldridge, P. E.↗

NASA NTRS1976

Lineaments on Skylab photographs: Detection, mapping, and hydrologic significance in central Tennessee

The author has identified the following significant results. Lineaments were detected on Skylab photographs by stereo viewing, projection viewing, and composite viewing. Sixty-nine percent more lineaments were found by stereo viewing than by projection, but segments of projection lineaments are longer; total length of lineaments found by these two methods is nearly the same. Most Skylab lineaments consist of topographic depression: stream channel alinements, straight valley walls, elongated swales, and belts where sinkholes are abundant. Most of the remainder are vegetation alinements. Lineaments are most common in dissected areas having a thin soil cover. Results of test drilling show: (1) the median yield of test wells on Skylab lineaments is about six times the median yield of all existing wells; (2) three out of seven wells on Skylab lineaments yield more than 6.3 1/s (110 gal/min): (3) low yields are possible on lineaments as well as in other favorable locations; and (4) the largest well yields can be obtained at well locations of Skylab lineaments that also are favorably located with respect to topography and geologic structure, and are in the vicinity of wells with large yields.

Moore, G. K.↗

NASA NTRS1977

Radiological protection and medical dosimetry for the Skylab crewmen

Dosimetry results for Skylab crewmembers show that the Skylab 4 crewmen received the highest dose equivalents but remained well within the established limits for Skylab missions below the threshold of significant clinical effects. These dose equivalents apply specificially to long term effects such as general life shortening, increased neoplasm incidence, and cataract production. A Skylab crewman could fly a mission comparable to one 84-day Skylab 4 mission per year for 50 years before exceeding these career limits.

Bailey, J. V.↗