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M S Traweek

Publications and source records attributed to M S Traweek.

4 recordsLinked to original sources

Overview of the Environmental Control and Life Support System (ECLSS) testing at MSFC.

Previously, almost all water used by the crew during space flight has been transported from earth or generated inflight as a by-product of fuel cells. Additionally, this water has been stored and used for relatively short periods. To achieve the United States' commitment to a permanent manned presence in space, more innovative techniques are demanded. Over 20,000 pounds of water and large quantities of air would have to be transported to the International Space Station (ISS) every 90 days with a corresponding amount of waste returned to earth, for an eight-person crew. This approach results in prohibitive logistics costs, and necessitates near complete recovery and recycling of water. The potential hazards associated with long-term reuse of reclaimed water and revitalized air resulted in the recognition that additional characterization of closed-loop systems and products is essential. Integrated physical/chemical systems have been designed, assembled, and operated to provide air and potable water meeting ISS quality specifications. The purpose of the Environmental Control and Life Support System (ECLSS) test program at NASA's Marshall Space Flight Center (MSFC) is to conduct testing related to the performance of the ISS and its Environmental Control components. The ECLSS Test Program encompasses the Water Recovery Test (WRT), the Integrated Air Revitalization Test (IART), and Life Testing, which permits ECLSS design evaluation. These subsystems revitalize air and reclaim waste waters representative of those to be generated on-orbit. This article provides an overview of MSFC's ECLSS testing. Specific tests include: the Stage 10 Water Recovery Test; the Contaminant Injection Test; the Four-Bed Molecular Sieve Performance Enhancement Test; and Life Testing.

Air Conditioning↗

The use of exercise testing in children to evaluate abnormalities of pacemaker function not apparent at rest.

The purpose of this study was to evaluate the use of exercise testing in identifying abnormalities of pacemaker function and in confirming set parameters not apparent at rest in children with implanted atrial synchronous physiologic pacemakers. Maximal exercise tests were performed on 24 children (15 boys, 9 girls) from 4.5 to 18 years of age (median = 15) with physiologic pacemakers. The lower rate limit was observed before or following testing in 19 of 24 cases. In each case this correlated with the set lower rate limit. The upper rate limit was reached in 10 of 24 cases and was found to be lower than that programmed in one case in which a long atrial refractory period had limited the upper rate limit. Six children reached the maximum upper rate limit to which their pacemaker could be programmed. No abnormalities of atrial capture or ventricular capture occurred during exercise testing. Ventricular sensing was normal in each case. Atrial sensing was observed to be normal in 15 of the 24 cases. Two patients had decreased atrial sensing with exercise. Reversion to the "noise rate" due to myopotential inhibition was found in seven other cases. Subsequent tests on two of these children showed normal sensing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗