108 research outputs found

    Occupant Protection during Orion Crew Exploration Vehicle Landings

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    The constellation program is evaluating current vehicle design capabilities for nominal water landings and contingency land landings of the Orion Crew Exploration vehicle. The Orion Landing Strategy tiger team was formed to lead the technical effort for which associated activities include the current vehicle design, susceptibility to roll control and tip over, reviewing methods for assessing occupant injury during ascent / aborts /landings, developing an alternate seat/attenuation design solution which improves occupant protection and operability, and testing the seat/attenuation system designs to ensure valid results. The EVA physiology, systems and Performance (EPSP) project is leading the effort under the authority of the Tiger Team Steering committee to develop, verify, validate and accredit biodynamics models using a variety of crash and injury databases including NASCAR, Indy Car and military aircraft. The validated biodynamics models will be used by the Constellation program to evaluate a variety of vehicle, seat and restraint designs in the context of multiple nominal and off-nominal landing scenarios. The models will be used in conjunction with Acceptable Injury Risk definitions to provide new occupant protection requirements for the Constellation Program

    Biosensors for EVA: Muscle Oxygen and pH During Walking, Running and Simulated Reduced Gravity

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    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO2 on the leg during cycling. Our NSBRI-funded project is looking to extend this methodology to examine activities which more appropriately represent EVA activities, such as walking and running and to better understand factors that determine the metabolic cost of exercise in both normal and lunar gravity. Our 4 year project specifically addresses risk: ExMC 4.18: Lack of adequate biomedical monitoring capability for Constellation EVA Suits and EPSP risk: Risk of compromised EVA performance and crew health due to inadequate EVA suit systems

    Science Operations for the 2008 NASA Lunar Analog Field Test at Black Point Lava Flow, Arizona

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    Surface science operations on the Moon will require merging lessons from Apollo with new operation concepts that exploit the Constellation Lunar Architecture. Prototypes of lunar vehicles and robots are already under development and will change the way we conduct science operations compared to Apollo. To prepare for future surface operations on the Moon, NASA, along with several supporting agencies and institutions, conducted a high-fidelity lunar mission simulation with prototypes of the small pressurized rover (SPR) and unpressurized rover (UPR) (Fig. 1) at Black Point lava flow (Fig. 2), 40 km north of Flagstaff, Arizona from Oct. 19-31, 2008. This field test was primarily intended to evaluate and compare the surface mobility afforded by unpressurized and pressurized rovers, the latter critically depending on the innovative suit-port concept for efficient egress and ingress. The UPR vehicle transports two astronauts who remain in their EVA suits at all times, whereas the SPR concept enables astronauts to remain in a pressurized shirt-sleeve environment during long translations and while making contextual observations and enables rapid (less than or equal to 10 minutes) transfer to and from the surface via suit-ports. A team of field geologists provided realistic science scenarios for the simulations and served as crew members, field observers, and operators of a science backroom. Here, we present a description of the science team s operations and lessons learned

    Design, Fabrication, and Testing of Silicon-integrated Li-ion Secondary Micro Batteries with Interdigital Electrodes

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    This paper reports the design, fabrication, and testing of silicon-integrated lithium ion secondary micro batteries with a side-by-side electrode setup. Cavities separated by narrow silicon spacers served as containments for two interdigitally arranged electrodes and were etched into -Si by wet chemical etching. The etched silicon battery containments were passivated by a layer of SiOx/SixNy. Al current collectors were applied by sputtering and back etching. A volumetric micro dispenser served to fill the cavities with slurries of the active materials - lithium cobalt manganese oxide (Liy(Ni1/2Co1/5Mn3/10)O2) as the cathode and lithium titanate (Li4Ti5O12) as the anode material. Filling with electrolyte, encapsulation, and electrochemical characterization of the finished cells took place in an Ar-filled glove box. The fabricated batteries with IDE show considerably lower impedances than cells with single side by side electrodes and are capable of constant current loads up to 10 C. A linear capacity loss rate of <0.1% per cycle was observed over 30 full cycles at 0.2C

    Overview of ASDEX Upgrade Results

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    Overview of ASDEX Upgrade results

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    Recent results from the ASDEX Upgrade experimental campaigns 2001 and 2002 are presented. An improved understanding of energy and particle transport emerges in terms of a 'critical gradient' model for the temperature gradients. Coupling this to particle diffusion explains most of the observed behaviour of the density profiles, in particular, the finding that strong central heating reduces the tendency for density profile peaking. Internal transport barriers (ITBs) with electron and ion temperatures in excess of 20 keV (but not simultaneously) have been achieved. By shaping the plasma, a regime with small type II edge localized modes (ELMs) has been established. Here, the maximum power deposited on the target plates was greatly reduced at constant average power. Also, an increase of the ELM frequency by injection of shallow pellets was demonstrated. ELM free operation is possible in the quiescent H-mode regime previously found in DIII-D which has also been established on ASDEX Upgrade. Regarding stability, a regime with benign neoclassical tearing modes (NTMs) was found. During electron cyclotron current drive (ECCD) stabilization of NTMs, βN could be increased well above the usual onset level without a reappearance of the NTM. Electron cyclotron resonance heating and ECCD have also been used to control the sawtooth repetition frequency at a moderate fraction of the total heating power. The inner wall of the ASDEX Upgrade vessel has increasingly been covered with tungsten without causing detrimental effects on the plasma performance. Regarding scenario integration, a scenario with a large fraction of noninductively driven current (≥50%), but without ITB has been established. It combines improved confinement (τE/τITER98 ≈ 1.2) and stability (βN ≤ 3.5) at high Greenwald fraction (ne/nGW ≈ 0.85) in steady state and with type II ELMy edge and would offer the possibility for long pulses with high fusion power at reduced current in ITER
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