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Underwater Communications is very much an experimental science because of the complex medium - the water - and its unpredictable propagation properties, thus mandating experiments to validate theory. The medium is particularly challenging for the transmission of acoustic and optical signals. Thus, the true performance of a transmitter/receiver system can be(More)
The sampling capability of Tenax-TA tubes, used in the National Aeronautics and Space Administration's solid sorbent air sampler to trap and concentrate contaminants from air aboard spacecraft, was improved by incorporating two sorbents within the tubes. Existing tubes containing only Tenax-TA allowed highly volatile compounds to "break through" during(More)
Introduction: A new method to evaluate the long-term collision probabilities between orbiting objects has been developed. It is designed to work with any orbital evolution model to estimate the collision probabilities of a system (asteroids, comets, Kuiper Belt objects, or planetesimals) as the system evolves in time. Contrary to Öpik's classical method(More)
A number of statistical tools have been developed over the years for assessing the risk of reentering objects to human populations. These tools make use of the characteristics (e.g., mass, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more(More)
Biological particulates collected on air filters during shuttle missions (STS-40 and STS-42) were identified using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). A method was developed for identifying the atmospheric particles and their sources through the analysis of standard materials and the selection of "marker" compounds specific to the(More)
Degradation of air quality in the Space Shuttle environment through chemical contamination and high solid-particulate levels may affect crew performance and health. A comprehensive study of the Shuttle atmosphere was undertaken during the STS-40 (Spacelab Space Life Sciences 1) and STS-42 (Spacelab International Microgravity Laboratory 1) missions to(More)
Four satellite fragmentation events were recorded during the second quarter of 2005, including the breakups of two Proton Block DM auxiliary motors, becoming the 32 nd and 33 rd events for this class overall. The first recent event, on 23 April 2005, involved an ullage motor used by the fourth stage of a Russian Proton launch vehicle for the Cosmos 2224(More)
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