- API data.nasa.gov | Last Updated 2018-07-20T07:17:16.000Z
The investigation of the coating friction as a function of time is important to monitor the ball bearing heath. Despite the importance of the subject mater, there is a crucial lack of information in the literature about coating life and friction force in ball bearings as coating wear of progressively increases. Here we propose to develop a strategic space vehicle health monitoring system that will identify potential and/or imminent lubrication problems, analyze these parameters in real time, and provide direct input so that these problems are mitigated prior to failure. We will set up a lab experiment environment with a universal microtribometer and acoustic emission sensors measuring the signals associated with wear and the changes that tend to occur as a function of time. Friction force and acoustic signal will be measured with respect to the bearing condition. To capture the dynamic nature of friction evolution, we propose to extract the temporal transient features from the sensing data and develop Hidden Markov Models with four distinct states associated with four operation conditions of the ball bearing. Our system uniquely combine both physics-based and stochastic models for the online diagnosis.
- API data.nasa.gov | Last Updated 2018-07-19T07:32:14.000Z
A trajectory design tool is sought to leverage chaos and nonlinear dynamics present in multi-body gravitational fields to design ultra-low energy transfer trajectories, with applications to continuously thrusting spacecraft. Specifically invariant manifolds associated with liberation points will be leveraged in an algorithm to generate initial solutions which will be fed into higher fidelity optimization tools. The tool will be used in a case study to design an interplanetary transfer trajectory for a CubeSat using solar electric propulsion. By combining the inherent efficiency of solar electric propulsion, with the fuel savings available through invariant manifold trajectory design, it is expected the required fuel will be cut significantly, as compared to spacecraft using chemical rockets and Hohmann transfers. The research will contribute to the proliferation of new in-space propulsion systems by providing a simulation-based design tool specifically targeted at such systems. Thus the research answers the call of TABS sections 2.4, In-Space Propulsion Supporting Technology, and 11.18 Simulation Based Systems Engineering. Furthermore, as the algorithm is computationally improved, the trajectory software may be implemented onboard spacecraft, enabling online trajectory design and optimization. Therefore the research meets the call of TABS section 4.5, Autonomy. Finally, ultra-low energy trajectories can be used to cheaply send scouting spacecraft for precursor missions. CubeSat missions, enabled by the proposed research, could serve to study and map human exploration destinations prior to human arrival. Thus the proposed research meets the calls for Destination, Reconnaissance and Mapping, as in section 7.1.1, as well as Modeling, Simulations and Destination Characterization, as in section 7.6.1.
- API data.nasa.gov | Last Updated 2018-07-19T02:46:54.000Z
Galileo Orbiter Magnetometer (MAG) calibrated high-resolution data from the Earth-2 flyby in spacecraft, GSE, and GSM coordinates. These data cover the interval 1992-11-03 to 1992-12-19.
- API data.nasa.gov | Last Updated 2018-07-19T09:16:33.000Z
Munro offer an innovatiive, intelligent, fully integrated hardware and software cockpit system solution for handling many General Aviation (GA) and UAV emergencies so as to minimize NextGen ATM disruption while saving lives. This ADS-B-ER system will provide GA airplanes and UAVs automated -ER trajectories to the nearest suitable airport avoiding terrain/obstacles, hazardous weather and restricted airspace.
- API data.nasa.gov | Last Updated 2018-07-19T15:57:23.000Z
JEM Engineering proved the technical feasibility of the FlexScan array?a very low-cost, highly-efficient, wideband phased array antenna?in Phase I, and stands ready to develop it into a fully-functional, flight-qualifiable prototype in Phase II. JEM developed an S-Band (2.0-2.3 GHz) antenna array design appropriate for the stratospheric balloon application through requirements definition, modeling, and performance predictions. The critical technology for this array is an electrically-controlled Variable Delay Line (VDL), used to provide true time-delay for beamsteering. VDLs were designed, built and tested, and shown to have excellent performance. The VDLs were tested over 2.4 million cycles without degradation, indicating good life, especially for the balloon application. A 4-port linear beamformer was built, and used to validate the beamformer concept. The objective of the proposed 24-month Phase II effort is to develop, prototype, and demonstrate a flight-qualifiable FlexScan phased array that achieves the bandwidth, antenna gain, and scan range required for a balloon-borne TDRSS data link in S-band, while meeting environmental requirements. Upon completion of Phase II, the FlexScan array will be ready to commercialize for the balloon-borne application, with other NASA and non-NASA commercial applications soon to follow.
Generating Autoclave-Level Mechanical Properties with Out-of-Autoclave Thermoplastic Placement of Large Composite Aerospace Structures, Phase Idata.nasa.gov | Last Updated 2018-07-19T13:25:16.000Z
Out-of-autoclave thermoplastic tape/tow placement (TP-ATP) is nearing commercialization but suffers a moderate gap in mechanical properties compared with laminates fabricated via thermoset autoclave processing. Out-of-autoclave thermoplastic processing significantly lowers composite aerospace part costs, but the property gap must be closed. This STTR program, endorsed herein by Boeing and Cytec Engineered Materials, will remedy the mechanical property shortfall and enable large composite aerospace structure important to NASA to be manufactured without an autoclave. Accudyne is teaming with University of Delaware -- Center for Composite Materials to apply their state-of-the-art TP-ATP process/property models to elucidate the physical mechanisms affecting microstructural quality that cause the property gap. Models will be applied to the NASA LaRC TP-ATP deposition head to optimize the head configuration and machine operating parameters, and the control systems for full mechanical properties. Laminates will be manufactured to demonstrate the property improvements. The process, head, and equipment changes will be upgraded on the NASA-LaRC thermoplastic tape head. In Phase 2, process/head modeling will be extended through laminate fabrication and testing, and a component of interest to NASA will be fabricated demonstrating the improved "autoclave level" mechanical performance.
- API data.nasa.gov | Last Updated 2018-07-19T05:24:08.000Z
This dataset is comprised of asteroid flux data measured in 26 filters using the McCord dual beam photometer, and covering the range 0.32 - 1.08 microns for 285 numbered asteroids, as published in Chapman & Gaffey (1979b) and McFadden, et al. (1984).
- API data.nasa.gov | Last Updated 2018-07-19T12:43:08.000Z
Space-based imaging sensors are important for NASA's mission in both performing scientific measurements and producing literature and documentary cinema. The recent proliferation of high-definition capture devices and displays (HDTV) provide the general public with first-hand human experiences hundreds miles above sea level in brilliant detail. The recent IMAX film "Hubble," which features one of the final space shuttle missions to repair the orbital telescope, is a prime example. The core of current space-based video capture devices consist of digital imaging sensors. Unfortunately, the harsh conditions of space limit the lifespan of all the imaging sensors, in addition to other electronics. Consequently, NASA is seeking innovative technologies for space-based applications to extend the operational life of these systems to three years or more. In this SBIR project, we propose to investigate robust image reconstruction based on novel signal processing techniques in the vein of compressed sensing (CS) to mitigate pixel damage to the point that is imperceptible by the human eye. Specifically, this proposal is a response to the solicitation for radiation-hardened programmable encoding technology as an identified mid-term NASA solution. CS is a recently introduced novel framework that goes against the traditional data acquisition paradigm. CS demonstrates that a sparse, or compressible, signal can be acquired using a low rate acquisition process that projects the signal onto a small set of vectors incoherent with the sparsity basis. This approach is divided into encoder and decoder stages. We propose performing the encoding in-line with acquisition using a low-SWaP, radiation-tolerant FPGA. The robust reconstruction will occur back on Earth where high-performance GPU-accelerated workstations can be used. A benefit of our solution is that it does not require a modification to the original imaging system.
Automated Manufacture of Damage Detecting, Self-Healing Composite Cryogenic Pressure Vessels, Phase Idata.nasa.gov | Last Updated 2018-07-19T09:30:20.000Z
During Phase I, Aurora Flight Sciences and the University of Massachusetts Lowell propose to demonstrate the feasibility of enhancing a commercially available out-of-autoclave (OOA) carbon prepreg material system (e.g. IM7/5320) via embedded structural health monitoring (SHM) and self-healing capabilities, which can be manufactured by an automated fiber placement (AFP) machine. This proposed "smart" material will ultimately enable the cost-effective manufacture of large, lightweight core-stiffened composite cryogenic pressure vessels. Carbon nanotubes (CNTs) will be transferred either directly onto the prepreg, or onto adhesive film plies that are subsequently laminated with the prepreg material. Electrical conductivity measurements via the CNTs will provide embedded SHM capabilities, while localized Joule heating will accelerate self-healing polymerization reactions. The CNT-enhanced prepreg will also serve as a carrier layer to embed well-dispersed self-healing micro-/nano-capsules within the polymer matrix and which will allow for self-healing of microcracks resulting from impact damage and thermal cycling. Self-healing efficiency will be characterized via mechanical testing. This smart material will ultimately be produced in spools of half-inch wide unidirectional prepreg slit tape, and laid down using Aurora's 7-axis, 16-spool automated fiber placement (AFP) machine. Trade studies will be performed on the AFP machine to determine the optimal processing parameters for laying down the smart material. The targeted demonstrator structure, a "smart" cryogenic pressure vessel, will detect microcracks caused by incident impact damage and rapidly repair the damage in situ.
- API data.nasa.gov | Last Updated 2018-07-19T09:51:31.000Z
In the Phase I program, Busek Co. Inc. tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high flow iodine feed system, and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200-600V was demonstrated. Testing has shown that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering slightly higher thrust to power (T/P). Plume current was also measured at a variety of operating conditions. Preliminary design work for a new thruster to be built in Phase II was also completed. In Phase II a complete iodine fueled system will be developed including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW. However, it can be deeply throttled as well as clustered to much higher power levels. The technology can also be scaled to >100 kW per thruster to support MW-class missions. The target thruster efficiency for the full scale system is 65% at high Isp (~3000 s) and 60% at high thrust (Isp~2000 s). These projections are based on Phase I testing and prior testing of higher power thrusters. Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. High purity iodine is available commercially in large quantities at much lower cost than xenon. Iodine stores at 2 to 3 times greater density than xenon and at approximately one thousandth of the pressure and may be stored in low mass, low cost propellant tanks instead. Passive, long term storage of a fully fueled system is feasible including storage in conformal tanks which may be used to shield internal components against some types of space radiation.