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Results for “STS-50 Shuttle Project”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Self-organizing map (SOM) of space acceleration measurement system (SAMS) data

In this paper, space acceleration measurement system (SAMS) data have been classified using self-organizing map (SOM) networks without any supervision; i.e., no a priori knowledge is assumed regarding input patterns belonging to a certain class. Input patterns are created on the basis of power spectral densities of SAMS data. Results for SAMS data from STS-50 and STS-57 missions are presented. Following issues are discussed in details: impact of number of neurons, global ordering of SOM weight vectors, effectiveness of a SOM in data classification, and effects of shifting time windows in the generation of input patterns. The concept of 'cascade of SOM networks' is also developed and tested. It has been found that a SOM network can successfully classify SAMS data obtained during STS-50 and STS-57 missions.

STS-57 Shuttle Project↗
NASA NTRS1994

Cell proliferation inhibition in reduced gravity

Extended durations of spaceflight have been shown to be deleterious on an organismic level; however, mechanisms underlying cellular sensitivity to the gravitational environment remain to be elucidated. The majority of the gravitational studies to date indicates that cell regulatory pathways may be influenced by their gravitational environment. Still, few cell biology experiments have been performed in space flight and even fewer experiments have been repeated on subsequent flights. With flight opportunities on STS-50, 54, and 57, Sf9 cells were flown in the BioServe Fluids Processing Apparatus and cell proliferation was measured with and without exposure to a cell regulatory sialoglycopeptide (CeReS) inhibitor. Results from these flights indicate that the Sf9 cells grew comparable to ground controls, that the CeReS inhibitor bound to its specific receptor, and that its signal transduction cascade was not gravity sensitive.

STS-54 Shuttle Project↗
NASA NTRS1999

Unsupervised classification of Space Acceleration Measurement System (SAMS) data using ART2-A

The Space Acceleration Measurement System (SAMS) has been developed by NASA to monitor the microgravity acceleration environment aboard the space shuttle. The amount of data collected by a SAMS unit during a shuttle mission is in the several gigabytes range. Adaptive Resonance Theory 2-A (ART2-A), an unsupervised neural network, has been used to cluster these data and to develop cause and effect relationships among disturbances and the acceleration environment. Using input patterns formed on the basis of power spectral densities (psd), data collected from two missions, STS-050 and STS-057, have been clustered.

STS-57 Shuttle Project↗
NASA NTRS1994

Development of the brine shrimp Artemia is accelerated during spaceflight

Developmentally arrested brine shrimp cysts have been reactivated during orbital spaceflight on two different Space Shuttle missions (STS-50 and STS-54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rates or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye development, but the observation was not statistically significant. However, in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant difference in degree of flight to control development was found. By as early as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine shrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage.

Flight Experiment↗
NASA NTRS1994

Extended duration orbiter medical project countermeasure to reduce post space flight orthostatic intolerance (LBNP) (STS-50/USML-1)

During the STS-50/USML-1 mission and five other Shuttle flights, decompression of the legs and lower abdomen ('lower body negative pressure,' LBNP) was used: (1) to apply a standardized stress to the cardiovascular system, to document the loss of orthostatic function during an extended period in weightlessness, and (2) to test its efficacy as a treatment which may be used to protect astronauts from gravitationally-induced fainting during and after reentry on Space Shuttle flights. The loss of orthostatic tolerance (as determined by LBNP) occured even earlier than indicated by similar testing on Skylab (1973-1974). The treatment was shown to be effective in reversing some of the effects of extended weightlessness on the cardiovascular system for at least one day after treatment.

Charles, John B.↗
NASA NTRS1994

Extended duration orbiter medical project variability of blood pressure and heart rate (STS-50/USML-1)

Decreases in arterial baroreflex function after space flight may be related to changes in blood pressure and heart rate patterns during flight. Ambulatory blood pressure and heart rate were measured for 24 hours, in fourteen astronauts on two occasions before flight, two to three occasions in flight, and 2 days after landing on Shuttle missions lasting 4 to 14 days. Blood pressure and heart rate were recorded every 20minutes during awake periods and every 30 minutes during sleep. In pre- and postflight studies, the 24-hour ambulatory measurements were followed by studies of carotid baroreceptor-cardiac reflex responses. Carotid baroreceptors were stimulated using a sequence of neck pressure and suction from +40 to -65 mmHg.

Fritsch-Yelle, Janice M.↗
NASA NTRS1994

The Portable Dynamic Fundus Instrument: Uses in telemedicine and research

For years ophthalmic photographs have been used to track the progression of many ocular diseases such as macular degeneration and glaucoma as well as the ocular manifestations of diabetes, hypertension, and hypoxia. In 1987 a project was initiated at the Johnson Space Center (JSC) to develop a means of monitoring retinal vascular caliber and intracranial pressure during space flight. To conduct telemedicine during space flight operations, retinal images would require real-time transmissions from space. Film-based images would not be useful during in-flight operations. Video technology is beneficial in flight because the images may be acquired, recorded, and transmitted to the ground for rapid computer digital image processing and analysis. The computer analysis techniques developed for this project detected vessel caliber changes as small as 3 percent. In the field of telemedicine, the Portable Dynamic Fundus Instrument demonstrates the concept and utility of a small, self-contained video funduscope. It was used to record retinal images during the Gulf War and to transmit retinal images from the Space Shuttle Columbia during STS-50. There are plans to utilize this device to provide a mobile ophthalmic screening service in rural Texas. In the fall of 1993 a medical team in Boulder, Colorado, will transmit real-time images of the retina during remote consultation and diagnosis. The research applications of this device include the capability of operating in remote locations or small, confined test areas. There has been interest shown utilizing retinal imaging during high-G centrifuge tests, high-altitude chamber tests, and aircraft flight tests. A new design plan has been developed to incorporate the video instrumentation into face-mounted goggle. This design would eliminate head restraint devices, thus allowing full maneuverability to the subjects. Further development of software programs will broaden the application of the Portable Dynamic Fundus Instrument in telemedicine and medical research.

Hunter, Norwood↗
NASA NTRS1999

Preliminary Results of the Third Test Series of Nonmetal Material Flammability Evaluation In SKOROST Apparatus on the Space Station Mir

The work has been done according to the US/Russian Joint Project "Experimental Evaluation of the Material Flammability in Microgravity" a continued combustion study in the SKOROST test apparatus on the OS Mir. The objective of the project was to evaluate the flammability and flame-spread rate for the selected polymer materials in low velocity flow in microgravity. Lately, the issue of nonmetal material combustion in microgravity has become of great importance, based on the necessity to develop the fire safety system for the new International Space Station (ISS). Lack of buoyant flow in microgravity reduces oxygen transfer into the combustion zone, which leads to flame extinction when the flow velocity is less than the limiting flow velocity V(sub lim) for the material. The ISS FGB fire-safety system was developed based on this phenomenon. The existence of minimum flow velocity V(sub lim) to sustain fire for the selected materials was determined both theoretically and experimentally. In the latter, it is shown that, even for thermally thin nonmetal materials with a very low oxygen index C(sub lim) of 12.5% (paper sheets with the thickness of 0.1 mm), a limiting flow velocity V(sub lim) exists at oxygen concentration Co(sub OX) = 17-21%, and is about 1.0 - 0.1 cm/sec. This might be explained by the relative increase in thermal losses due to radiation from the surface and from the gaseous phase. In the second series of experiments in Skorost apparatus on Orbital Station Mir the existence of the limiting flow velocity V(sub lim) for combustion was confirmed for PMMA and glass-epoxy composite strip samples 2 mm thick at oxygen concentration C(sub OX) = 21.5%. It was concluded that V(sub lim) depends on C(sub OX) for the PMMA sample with a low oxygen index of 15.5%, the limiting flow velocity V(sub lim) was less than 0.5 cm/sec, and for the glass-epoxy composite sample with a high oxygen index of 19%, the limiting flow velocity V(sub lim) was higher than 15 cm/sec. As of now only those materials that maintain their integrity during combustion were investigated. The materials that disintegrate when burning present more danger for fire safety because the flame can spread farther with the parts of the structure, ejected melt drops, et cetera. Materials such as polyethylene are of great interest since they form a lengthy melt zone during the combustion in normal gravity. This melt zone generates drops of liquids that promote faster flame spread compared to usual combustion. The preliminary results of polyethylene insulation flammability evaluation in microgravity are shown in the NASA Wire Insulation Flammability (WIF) experiment during Space Shuttle flight STS-50. A lot of interesting data was collected during the WIF test program. However, one of the most important results was that, in microgravity, the extinction of the polyethylene occurred almost immediately when the flow of relatively low oxygen concentration (C(sub OX)=21%) was stopped. The purpose of the work reported here is to expand the existing data base on material flammability in microgravity and to conduct the third series of the space experiment using Skorost apparatus on Orbiatl Station Mir with melting polymers, which might increase the probability of fire and its propagation in ventilated microgravity environment of orbiting spacecraft.

Ivanov, A. V.↗
NASA NTRS1994

Abrogation of TNF-mediated cytotoxicity by space flight involves protein kinase C

Experiments conducted on STS-50 indicated that space flight significantly inhibited tumor necrosis factor (TNF)-mediated killing of LM929 cells compared to ground controls. In ground-based studies, activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate (PMA) also inhibited TNF-mediated killing of LM929 cells. Therefore, we used PKC inhibitors to determine if the inhibitory effects of spaceflight on TNF-mediated cytotoxicity involved the activation of PKC. In experiments conducted onboard space shuttle mission STS-54, we saw that in the presence of the protein kinase C inhibitors H7 and H8, TNF-mediated cytotoxicity was restored to levels of those observed in the ground controls. Subsequent experiments done during the STS-57 mission tested the dose response of two protein kinase inhibitors, H7 and HA1004. We again saw that killing was restored in a dose-dependent manner, with inhibitor concentrations known to inhibit PKC being most effective. These data suggest that space flight ameliorates the action of TNF by affecting PKC in target cells.

STS-54 Shuttle Project↗