ALBERT

Description: The Jet Propulsion Laboratory is developing a new imaging interferometer that has double the efficiency of conventional interferometers and only a fraction of the mass and volume. The project is being funded as part of the Defense Advanced Research Projects Agency (DARPA) Photonic Wavelength And Spatial Signal Processing program (PWASSSP).

Description: Pneumothorax is commonly seen in trauma patients; the diagnosis is usually confirmed by radiography. Use of ultrasound for this purpose, in environments such as space flight and remote terrestrial areas where radiographic capabilities are absent, is being investigated by NASA. In this study, the ability of ultrasound to assess the magnitude of pneumothorax in a porcine model was evaluated. Sonography was performed on anesthetized pigs (avg. wt. 50 kg) in both ground-based laboratory (n = 5) and micro gravity conditions (0 g) aboard the KC-135 aircraft during parabolic flight (n = 4). Aliquots of air (50-1 OOcc) were introduced into the chest through a catheter to simulate pneumothorax. Results were video-recorded and digitized for later interpretation by radiologists. Several distinct sonographic patterns of partial lung sliding were noted, including the combination of a sliding zone with a still zone, and a "segmented" sliding zone. These "partial lung sliding" patterns exclude massive pneumothorax manifested by a complete separation of the lung from the parietal pleura. In 0 g, the sonographic picture was more diverse; 1 g differences between posterior and anterior aspects were diminished. CONCLUSIONS: Modest pneumothorax can be inferred by the ultrasound sign of "partial lung sliding". This finding, which increases the negative predictive value of thoracic ultrasound, may be attributed to intermittent pleural contact, small air spaces, or alterations in pleural lubricant. Further studies of these phenomena are warranted.

Description: NASA is investigating high power, high specific impulse propulsion technologies that could enable ambitious flights such as multi-body rendezvous missions, outer planet orbiters and interstellar precursor missions. The requirements for these missions are much more demanding than those for state-of-the-art solar-powered ion propulsion applications. The purpose of the NEXIS program is to develop advanced ion thruster technologies that satisfy the requirements for high power, high specific impulse operation, high efficiency and long thruster life. The nominal design point for the NEXIS thruster is 20 kWe at a specific impulse of 7500 s with an efficiency over 78% and a xenon throughput capability of greater than 2000 kg. These performance and throughput goals will be achieved by applying a combination of advanced technologies including a large discharge chamber, erosion resistant carbon-carbon grids, an advanced reservoir hollow cathode and techniques for increasing propellant efficiency such as grid masking and accelerator grid aperture diameter tailoring. This paper provides an overview of the challenges associated with these requirements and how they are being addressed in the NEXIS program.

Description: BACKGROUND: As a medical emergency that can affect even well-screened, healthy individuals, peritonitis developing during a long-duration space exploration mission may dictate deviation from traditional clinical practice due to the absence of otherwise indicated surgical capabilities. Medical management can treat many intra-abdominal processes, but treatment failures are inevitable. In these circumstances, percutaneous aspiration under sonographic guidance could provide a "rescue" strategy. Hypothesis: Sonographically guided percutaneous aspiration of intra-peritoneal fluid can be performed in microgravity. METHODS: Investigations were conducted in the microgravity environment of NASA's KC-135 research aircraft (0 G). The subjects were anesthetized female Yorkshire pigs weighing 50 kg. The procedures were rehearsed in a terrestrial animal lab (1 G). Colored saline (500 mL) was introduced through an intra-peritoneal catheter during flight. A high-definition ultrasound system (HDI-5000, ATL, Bothell, WA) was used to guide a 16-gauge needle into the peritoneal cavity to aspirate fluid. RESULTS: Intra-peritoneal fluid collections were easily identified, distinct from surrounding viscera, and on occasion became more obvious during weightless conditions. Subjectively, with adequate restraint of the subject and operators, the procedure was no more demanding than during the 1-G rehearsals. CONCLUSIONS: Sonographically guided percutaneous aspiration of intra-peritoneal fluid collections is feasible in weightlessness. Treatment of intra-abdominal inflammatory conditions in spaceflight might rely on pharmacological options, backed by sonographically guided percutaneous aspiration for the "rescue" of treatment failures. While this risk mitigation strategy cannot guarantee success, it may be the most practical option given severe resource limitations.

Description: The addition of a comprehensive wave investigation to the Jupiter Icy Moons Orbiter (JIMO) science payload will provide a broad range of information on the icy moons of Jupiter including the detection of subsurface liquid oceans; mapping of their ionospheres; their interaction with the magnetospheric environment; and on the Jovian magnetosphere. These measurements are obtained through the use of both passive and active (sounding) means over broad frequency ranges. The frequency range of interest extends from less than 1 Hz to 40 MHz for passive measurements, from approximately 1 kHz to a few MHz for magnetospheric and ionospheric sounding, and between 1 and approximately 10 MHz for subsurface radar sounding. An instrument to detect subsurface radar sounding, magnetospheric interactions, and ionospheric sounding is discussed.

Description: The purpose of this research is to develop, test and calibrate a prototype portable device that will measure human metabolic activity; namely time resolved measurements of gas temperature, pressure and flow-rate, and oxygen and carbon dioxide partial pressure during inhalation and exhalation.

Description: This paper discusses the development and design of an experimental test cell for ground-based testing to provide requirements for the Spaceflight Holography Investigation in a Virtual Apparatus (SHIVA) experiment. Ground-based testing of a hardware breadboard set-up is being conducted at Marshall Space Flight Center in Huntsville, Alabama. SHIVA objectives are to test and validate new solutions of the general equation of motion of a particle in a fluid, including particle-particle interaction, wall effects, motion at higher Reynolds Number, and a motion and dissolution of a crystal moving in a fluid. These objectives will be achieved by recording a large number of holograms of particle motion in the International Space Station (ISS) glove box under controlled conditions, extracting the precise three- dimensional position of all the particles as a function of time, and examining the effects of all parameters on the motion of the particles. This paper will describe the mechanistic approach to enabling the SHIVA experiment to be performed in a ISS glove box in microgravity. Because the particles are very small, surface tension becomes a major consideration in designing the mechanical method to meet the experiments objectives in microgravity, To keep a particle or particles in the center of the test cell long enough to perform and record the experiment and to preclude contribution to particle motion, requires avoiding any initial velocity in particle placement. A Particle Injection Mechanism (PIM) designed for microgravity has been devised and tested to enable SHIVA imaging. Also, a test cell capture mechanism, to secure the test cell during vibration on a specially designed shaker table for the SHIVA experiment will be described. Concepts for flight design are also presented.

Description: Basic research on advanced plasma-based propulsion systems is routinely focused on plasmadynamics, performance, and efficiency aspects while relegating the development of critical enabling technologies, such as flight-weight magnets, to follow-on development work. Unfortunately, the low technology readiness levels (TRLs) associated with critical enabling technologies tend to be perceived as an indicator of high technical risk, and this, in turn, hampers the acceptance of advanced system architectures for flight development. Consequently, there is growing recognition that applied research on the critical enabling technologies needs to be conducted hand in hand with basic research activities. The development of flight-weight magnet technology, for example, is one area of applied research having broad crosscutting applications to a number of advanced propulsion system architectures. Therefore, NASA Marshall Space Flight Center, Louisiana State University (LSU), and the National High Magnetic Field Laboratory (NHMFL) have initiated an applied research project aimed at advancing the TRL of flight-weight magnets. This Technical Publication reports on the group's initial effort to demonstrate the feasibility of cryogenic high-purity aluminum magnet technology and describes the design, construction, and testing of a 6-in-diameter by 12-in-long aluminum solenoid magnet. The coil was constructed in the machine shop of the Department of Physics and Astronomy at LSU and testing was conducted in NHMFL facilities at Florida State University and at Los Alamos National Laboratory. The solenoid magnet was first wound, reinforced, potted in high thermal conductivity epoxy, and bench tested in the LSU laboratories. A cryogenic container for operation at 77 K was also constructed and mated to the solenoid. The coil was then taken to NHMFL facilities in Tallahassee, FL. where its magnetoresistance was measured in a 77 K environment under steady magnetic fields as high as 10 T. In addition, the temperature dependence of the coil's resistance was measured from 77 to 300 K. Following this series of tests, the coil was transported to NHMFL facilities in Los Alamos, NM, and pulsed to 2 T using an existing capacitor bank pulse generator. The coil was completely successful in producing the desired field without damage to the windings.

Description: The High resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC 11) will use almost identical versions of an ion-implanted silicon bolometer array developed at the National Aeronautics and Space Administration's Goddard Space Flight Center (GSFC). The GSFC "Pop-Up" Detectors (PUD's) use a unique folding technique to enable a 12 x 32-element close-packed array of bolometers with a filling factor greater than 95 percent. A kinematic Kevlar(Registered Trademark) suspension system isolates the 200 mK bolometers from the helium bath temperature, and GSFC - developed silicon bridge chips make electrical connection to the bolometers, while maintaining thermal isolation. The JFET preamps operate at 120 K. Providing good thermal heat sinking for these, and keeping their conduction and radiation from reaching the nearby bolometers, is one of the principal design challenges encountered. Another interesting challenge is the preparation of the silicon bolometers. They are manufactured in 32-element, planar rows using Micro Electro Mechanical Systems (MEMS) semiconductor etching techniques, and then cut and folded onto a ceramic bar. Optical alignment using specialized jigs ensures their uniformity and correct placement. The rows are then stacked to create the 12 x 32-element array. Engineering results from the first light run of SHARC II at the CalTech Submillimeter Observatory (CSO) are presented.

Description: When astronauts return to Earth and stand, their heart rates may speed inordinately, their blood pressures may fall, and some may experience frank syncope. We studied brief autonomic and haemodynamic transients provoked by graded Valsalva manoeuvres in astronauts on Earth and in space, and tested the hypothesis that exposure to microgravity impairs sympathetic as well as vagal baroreflex responses. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, respiration and peroneal nerve muscle sympathetic activity in four healthy male astronauts (aged 38-44 years) before, during and after the 16 day Neurolab space shuttle mission. Astronauts performed two 15 s Valsalva manoeuvres at each pressure, 15 and 30 mmHg, in random order. Although no astronaut experienced presyncope after the mission, microgravity provoked major changes. For example, the average systolic pressure reduction during 30 mmHg straining was 27 mmHg pre-flight and 49 mmHg in flight. Increases in muscle sympathetic nerve activity during straining were also much greater in space than on Earth. For example, mean normalized sympathetic activity increased 445% during 30 mmHg straining on earth and 792% in space. However, sympathetic baroreflex gain, taken as the integrated sympathetic response divided by the maximum diastolic pressure reduction during straining, was the same in space and on Earth. In contrast, vagal baroreflex gain, particularly during arterial pressure reductions, was diminished in space. This and earlier research suggest that exposure of healthy humans to microgravity augments arterial pressure and sympathetic responses to Valsalva straining and differentially reduces vagal, but not sympathetic baroreflex gain.