- API data.nasa.gov | Last Updated 2018-07-20T08:06:51.000Z
<p>Observations of energetic neutral atoms (ENAs) provide the only way to observe solar energetic particles (SEPs) where they are accelerated. The one observation of solar ENAs to date had low sensitivity, a high energy threshold, and no imaging information. The Solar Energetic Neutral-atom Imaging Coronagraph (SENIC) instrument concept combines large detector area, a low energy threshold, and high angular resolution. The key design challenge for this concept was to minimize the level of stray light illuminating the detectors.<br /> </p> <p>Measurements of energetic neutral atoms (ENAs) are a new tool to improve our understanding of energy release and particle acceleration in solar eruptive events. Due to limitations of past observations, even the most basic questions remain unanswered about the acceleration of solar energetic particles (SEPs) by shocks driven by coronal mass ejections (CMEs). ENAs provide the only way to observe SEPs where they are accelerated. The one observation of solar ENAs to date had low sensitivity, a high energy threshold, and no imaging information. The Solar Energetic Neutral-atom Imaging Coronagraph (SENIC) instrument concept is designed to observe ENAs from <~20 keV to a few hundred keV with a spectral resolution as good as 1 keV and image them from 2 R_sun to 40 R_sun with a spatial resolution of 0.1 R_sun. Since ENAs cannot be imaged with focusing optics, this concept uses an indirect imaging technique similar to the one successfully used on RHESSI. Thus, the SENIC instrument concept combines large detector area, a low energy threshold, and high angular resolution.<br /> </p>
- API data.nasa.gov | Last Updated 2018-07-19T07:28:36.000Z
A heliogyro spacecraft is a specific type of solar sail that generates thrust from the reflection of solar photons. The proposed research for this fellowship will address the limitations of current analytic models and control designs for a heliogyro spacecraft to develop practical solutions. The first objective is to derive new equations of motion for the essential blade dynamics. The reduced order model for a heliogyro spacecraft will include multiple degrees of freedom, coupled dynamics, solar radiation pressure loading and torque source boundary conditions, all of which are lacking from the current analytic models. The second objective is to develop a root control system that effectively damps the structural modes of a heliogyro spacecraft. The final objective is to determine the blade behavior during initial spin-up of the spacecraft and blade deployment. The main methods used to accomplish these research objectives will include classical control theory in conjunction with impedance control and a thorough understanding of the blade dynamics. The heliogyro spacecraft modeling will begin with simplified linear assumptions. The coupling and nonlinearities will be added incrementally to the model. The propellant-free heliogyro is a long-duration sustainable spacecraft whose maneuverability allows it to attain previously inaccessible orbits for traditional spacecraft. Continuing research in practical heliogyro control will significantly advance the TRL of this innovative design, in turn lowering the cost of existing missions and opening up exciting new mission possibilities.
- API data.nasa.gov | Last Updated 2018-07-19T07:30:17.000Z
Mars planetary surface access is one of NASA's biggest technical challenges involving advanced entry, descent, and landing (EDL) technologies and methods. This NASA Innovative Advanced Concept (NIAC) project intends to solve one of the top challenges for landing large payloads and humans on Mars by using advanced atmospheric In-Situ Resource Utilization (ISRU) methods that have never been tried or studied before. The proposed Mars Molniya Orbit Atmospheric Resource Mining concept mission architecture will make Mars travel routine and affordable for cargo and crew, therefore enabling the expansion of human civilization to Mars.
- API data.nasa.gov | Last Updated 2018-09-07T17:39:46.000Z
<p>Future astrophysics missions require efficient, low-temperature cryocoolers to cool advanced instruments or serve as the upper stage cooler for sub-Kelvin refrigerators. Potential astrophysics missions include Lynx, the Origin Space Telescope, and the Superconducting Gravity Gradiometer. Cooling loads for these missions are up to 300 mW at temperatures of 4 to 10 K, with additional loads at higher temperatures for other subsystems. Due to low jitter requirements, a cryocooler with very low vibration is needed for many missions. In addition, a multi-stage cooler, capable of providing refrigeration at more than one temperature simultaneously, can provide the greatest system efficiency with the lowest mass. Turbo-Brayton cryocoolers have space heritage and are ideal for these missions due to negligible vibration emittance and high efficiency at low temperatures. The primary limitation in implementing Brayton cryocoolers at temperatures below 10 K has been the development of high efficiency turbines. On the proposed program, Creare plans to leverage recent developments in gas bearing technology and low-temperature alternators to realize a high-efficiency, low-temperature turbine. On the Phase I project, we will perform a proof-of-concept demonstration of the turbine technology at temperatures down to 4 K. On the Phase II project, we will build and demonstrate an advanced low-temperature turbine at temperatures of 4 to 10 K.</p>
- API data.nasa.gov | Last Updated 2018-07-19T07:43:40.000Z
The semiconductor material InAlAs has the potential to improve upon current space photovoltaics in a number of ways. InAlAsSb lattice-matched to InP would operate as the top cell in a triple-junction design with an AM0 efficiency of 37.1%, a cell-level mass specific power >1000 W/kg, and panel-level mass specific power of 662 W/kg. Development of InAlAs for engineered substrates would result in a lattice-matched triple-junction cell with a 1-sun AM1.5 efficiency of 40.4%. Additionally, InAlAs lattice-matched to InP has the appropriate bandgap for operation in low-intensity low-temperature conditions. Development of these proposed photovoltaic cells is particularly warranted since the InP materials system is known to be exceptionally radiation tolerant, which is ideal for space operation. Furthermore, lattice-matched cells are lighter and more mechanically stable than their metamorphic counterparts. The technology proposed in this application would increase capability and durability for missions needing onboard power or electric propulsion, and would also correspond to technology gains for terrestrial concentrator photovoltaic systems. The materials proposed in this study have undergone little to no development. Development of these materials would occur via semiconductor growth methods of metal organic vapor phase epitaxy or molecular beam epitaxy. Growth conditions such as temperature, gaseous precursors, and gas ratios can be adjusted to target desired material properties. This research would initially focus on materials development. Once the desired material are grown, they can then be fabricated in complete photovoltaic cells and tested for radiation and temperature tolerance which are important considerations for space applications.
- API data.nasa.gov | Last Updated 2018-07-20T07:23:36.000Z
Accurate measurement of atmospheric parameters with high resolution needs advanced lasers. In this SBIR program we propose to develop innovative Q-switched high power 2-micron fiber laser with pulse energy greater than 10mJ, repetition rate of 10Hz to 1KHz, and pulse duration of 200ns using innovative highly efficient Tm-doped glass fiber. This new fiber laser will be an all-fiber laser system consisting of actively Q-switched fiber laser and fiber amplifiers. This proposed all-fiber laser system is compact, highly efficient, robust and highly reliable, which is especially suited for NASA's application where operating environment is always extremely rough. In Phase I we will design and fabricate Tm-doped glasses, design and fabricate single mode and double cladding single mode Tm-doped fibers, and demonstrate Q-switched single frequency 2-micron fiber laser and amplifiers.
- API data.nasa.gov | Last Updated 2018-07-19T08:48:46.000Z
<p>Frequent, short-term crew exposure to elevated CO2 levels combined with other physiological impacts of microgravity may lead to a number of detrimental effects, including loss of vision. This technology project seeks to develop a prototype of a real-time location system integrated with a CO2 sensor to monitor and correlate space-time-CO2 concentration with physical symptoms and functional evaluations of impairment. The CO2 sensor will be integrated with a low-power ultra-wideband (UWB) communication system with location-tracking capability. Although the initial development is oriented to the measurement of CO2, the system concept can easily be adapted to accommodate other types of sensors. <p/><p>Recent findings indicate that frequent, short-term crew exposure to elevated CO2 levels combined with other physiological impacts of microgravity may lead to a number of detrimental effects, including loss of vision. To evaluate the risks associated with transient elevated CO2 levels and design effective countermeasures, doctors must have access to frequent CO2 measurements in the immediate vicinity of individual crew members along with simultaneous measurements of their location in the space environment. To achieve this goal, a small, low-power, wearable system that integrates an accurate CO2 sensor with an ultra-wideband (UWB) radio capable of real-time location estimation and data communication is proposed. This system would be worn by crew members and would automatically gather and transmit sampled sensor data tagged with real-time, high-resolution location information. Under the current proposed effort, a breadboard prototype of such a system will be developed. Although the initial effort is targeted to CO2 monitoring, the concept is applicable to other types of sensors. For the initial effort, existing EV Modular Instrumentation System (MIS) Wireless Sensor Network (WSN) hardware will be leveraged to integrate a low-power CO2 sensor with a commercially available UWB radio system with ranging capability. In addition, potential for integration of this system with EV's Electronic-textile System for the Evaluation of Wearable Technology (E-SEWT) will be evaluated.</p>
- API data.nasa.gov | Last Updated 2018-07-19T11:19:09.000Z
We propose to develop and commercialize a new type of low-stress iridium (Ir) X-ray mirror coating technology that can be used for the construction of high-resolution X-ray telescopes comprising thin-shell mirror substrates, such as the Soft X-ray Telescope (SXT) currently being developed for the Constellation-X mission. The urgent need for low-stress Ir coating technology is driven by the current limitations on telescope angular resolution resulting from substrate distortions caused by conventional reflective Ir coatings that have high stress. In particular, we have measured film stresses in excess of 3 GPa in the case of 30 nm Ir films deposited by conventional magnetron sputtering techniques. The distortions in thin glass mirror shells (such as those suitable for the Constellation-X SXT) resulting from these extremely large coating stresses presently make the largest contribution to the SXT telescope imaging error budget, of order 10 arcsec or more. Consequently, it will be difficult, if not impossible, to meet the imaging requirements of Constellation-X, or other future high-resolution X-ray missions, unless high-quality Ir coatings having significantly lower stresses can be developed. The development of such coatings is precisely the aim of our proposal.
- API data.nasa.gov | Last Updated 2018-08-02T15:25:23.000Z
Our mission archetype is exploration of hazardous, non-planar terrain, such as Martian caves or icy crevasses on Europa. Clusters of SPEARS sensors will be used to gather scientific measurements over a wide area. The major objective of this study is to demonstrate general feasibility of the concept and to make inroads in a few crucial technology bottlenecks. Experimentation with an early terrestrial prototype will demonstrate viability of core ideas and assist in evangelism. We will leverage existing test facilities, like our planetary roverscape, to provide great value relative to funding level. Lastly, analysis of SPEARS architecture in the context of possible future missions will ground this work for NASA relevance. A study in projectile payload selection will be performed, considering environmental and optical sensors. Strategies for anchoring, localization, and comms will be surveyed. Various thrust modalities (e.g. compressed gas vs. mechanical) for the launcher system will also be compared. Most critically, several automated multi-sensor data fusion techniques providing image stabilization, panoramic stitching, and 3D mapping (several of which this team has pioneered) will be evaluated and demonstrated. This will be accomplished by the construction of a basic terrestrial proof-of-concept system comprised of a CO2 projectile launcher and 2-3 example projectiles such as a camera, illuminator, and radio beacon. Existing algorithms and software will be built upon to demonstrate processing techniques, and extensions implemented to meet observed challenges will directly advance the state of the art.
- API data.nasa.gov | Last Updated 2018-07-20T06:59:23.000Z
We propose an improved cathode based on our novel theory of the role of scandium oxide in enhancing emission in tungsten impregnate cathodes. Recent results have demonstrated the efficacy of nano-particle scandium oxide, but a detailed theory on mechanism has been lacking. Our theory explains published data and point to an optimized cathode which we here propose to build and test at our facility. The cathode is the performance limiting component in high frequency linear beam amplifiers such as traveling wave tubes and klystrons. Bandwidth, data rates, numbers of channels, frequency and output power requirements are going up. The performance of linear beam amplifiers is acutely limited by the cathode limitations. Scandate cathodes offer a way to increase emission from current limits of about 10 A/cm2 to about 50 A/cm2.