Exploring Planets with Directed Aerial Robot Explorers

Global Aerospace Corporation (GAC) is developing a revolutionary system architecture for exploration of planetary atmospheres and surfaces from atmospheric altitudes. The work is supported by the NASA Institute for Advanced Concepts (NIAC). The innovative system architecture relies upon the use of Directed Aerial Robot Explorers (DAREs), which essentially are long-duration-flight autonomous balloons with trajectory control capabilities that can deploy swarms of miniature probes over multiple target areas. Balloon guidance capabilities will offer unprecedented opportunities in high-resolution, targeted observations of both atmospheric and surface phenomena. Multifunctional microprobes will be deployed from the balloons once over the target areas, and perform a multitude of functions, such as atmospheric profiling or surface exploration, relaying data back to the balloons or an orbiter. This architecture will enable low-cost, low-energy, long-term global exploration of planetary atmospheres and surfaces. This paper focuses on a conceptual analysis of the DARE architecture capabilities and science applications for Venus, Titan and Jupiter. Preliminary simulations with simplified atmospheric models show that a relatively small trajectory control wing can enable global coverage of the atmospheres of Venus and Titan by a single balloon over a 100-day mission. This presents unique opportunities for global in situ sampling of the atmospheric composition and dynamics, atmospheric profiling over multiple sites with small dropsondes and targeted deployment of surface microprobes. At Jupiter, path guidance capabilities of the DARE platforms permits targeting localized regions of interest, such as "hot spots" or the Great Red Spot. A single DARE platform at Jupiter can sample major types of the atmospheric flows (zones and belts) over a 100-day mission. Observations by deployable probes would reveal if the differences exist in radiative, dynamic and compositional environments at these sites

Selected test results from the LiFeBatt iron phosphate Li-ion battery.

In this paper the performance of the LiFeBatt Li-ion cell was measured using a number of tests including capacity measurements, capacity as a function of temperature, ohmic resistance, spectral impedance, high power partial state of charge (PSOC) pulsed cycling, pulse power measurements, and an over-charge/voltage abuse test. The goal of this work was to evaluate the performance of the iron phosphate Li-ion battery technology for utility applications requiring frequent charges and discharges, such as voltage support, frequency regulation, and wind farm energy smoothing. Test results have indicated that the LiFeBatt battery technology can function up to a 10C{sub 1} discharge rate with minimal energy loss compared to the 1 h discharge rate (1C). The utility PSOC cycle test at up to the 4C{sub 1} pulse rate completed 8,394 PSOC pulsed cycles with a gradual loss in capacity of 10 to 15% depending on how the capacity loss is calculated. The majority of the capacity loss occurred during the initial 2,000 cycles, so it is projected that the LiFeBatt should PSOC cycle well beyond 8,394 cycles with less than 20% capacity loss. The DC ohmic resistance and AC spectral impedance measurements also indicate that there were only very small changes after cycling. Finally, at a 1C charge rate, the over charge/voltage abuse test resulted in the cell venting electrolyte at 110 C after 30 minutes and then open-circuiting at 120 C with no sparks, fire, or voltage across the cell

BNCT filter design studies for the ORNL Tower Shielding Facility

Boron Neutron Capture Therapy (BNCT) in the United States has entered into a new phase with the initiation of clinical trials using neutron sources at the Brookhaven National Laboratory and the Massachusetts Institute of Technology. If these trials are successful at demonstrating the efficacy of BNCT as a viable treatment for glioblastoma multiforme, then there will be an immediate demand for several additional neutron sources in order to treat the several thousand patients currently diagnosed with glioblastomas in the U.S. each year. However, the requirements for an acceptable neutron source for BNCT are rather severe in terms of the need to provide a sufficient number of epithermal neutrons to a patient-accessible location in a reasonable time with minimal thermal-neutron, fast- neutron, and gamma-ray background. A recent study of potential neutron sources at Oak Ridge National Laboratory (ORNL) has been completed, which concludes that the Tower Shielding Facility (TSF), also appears very well suited for BNCT. The light-water-cooled reactor is contained in an aluminum pressure vessel and located in a large concrete `bunker` referred to as the Big Beam Shield (BBS). The BBS contains a 77-cm-diameter beam collimator, which permits access to a broad beam neutron flux exceeding 4 x 10[sup ll] Cm[sup -2]s[sup- 1] at the operational power of 1 MW. The collimated beam emerges horizontally onto an unenclosed test pad area on which shield mockups were assembled. The appropriate beam filter and collimator system can be easily constructed in the expansive area previously used for the large shield mockups. Additional engineering of the beam shutter mechanism and the construction of treatment support facilities will be needed but can be easily accommodated on the remote dedicated site. The filter design analysis is provided

Mars Exploration with Directed Aerial Robot Explorers

Global Aerospace Corporation (GAC) is developing a revolutionary system architecture for exploration of planetary atmospheres and surfaces from atmospheric altitudes. The work is supported by the NASA Institute for Advanced Concepts (NIAC). The innovative system architecture relies upon the use of Directed Aerial Robot Explorers (DAREs), which essentially are long‐duration‐flight autonomous balloons with trajectory control capabilities that can deploy swarms of miniature probes over multiple target areas. Balloon guidance capabilities will offer unprecedented opportunities in high‐resolution, targeted observations of both atmospheric and surface phenomena. Multifunctional microprobes will be deployed from the balloons when over the target areas, and perform a multitude of functions, such as atmospheric profiling or surface exploration, relaying data back to the balloons or an orbiter. This architecture will enable low‐cost, low‐energy, long‐term global exploration of planetary atmospheres and surfaces. A conceptual analysis of DARE capabilities and science applications for Mars is presented. Initial results of simulations indicate that a relatively small trajectory control wing can significantly change planetary balloon flight paths, especially during summer seasons in Polar Regions. This opens new possibilities for high‐resolution observations of crustal magnetic anomalies, polar layered terrain, polar clouds, dust storms at the edges of the Polar caps and of seasonal variability of volatiles in the atmosphere

Liquid Metal Reactor Program: JASPER US/DOE/PNC Shielding Research Program : Technical progress report, April 1-May 31, 1987

This progress report details activities on the JASPER Shielding Program for the time period of April 1, 1987 through May 31, 1987

BUGLE-96: A revised multigroup cross section library for LWR applications based on ENDF/B-VI Release 3

A revised multigroup cross-section library based ON ENDF/B-VI Release 3 has been produced for light water reactor shielding and reactor pressure vessel dosimetry applications. This new broad-group library, which is designated BUGLE-96, represents an improvement over the BUGLE-93 library released in February 1994 and is expected to replace te BUGLE-93 data. The cross-section processing methodology is the same as that used for producing BUGLE-93 and is consistent with ANSI/ANS 6.1.2. As an added feature, cross-section sets having upscatter data for four thermal neutron groups are included in the BUGLE-96 package available from the Radiation Shielding Information Center. The upscattering data should improve the application of this library to the calculation of more accurate thermal fluences, although more computer time will be required. The incorporation of feedback from users has resulted in a data library that addresses a wider spectrum of user needs

Liquid Metal Reactor Program: JASPER USDOE/PNC Shielding Research Program: Technical progress report, August 1-September 30, 1986

This report details activities on the JASPER Shielding Program for the time period of August 1, 1986 through September 30, 1986. This report contains the measurements in phases VI and VII, a graphite benchmark study and an alternate loop type shield design study for the Liquid Metal Reactor (LMR), respectively. This report also includes the results of analyses for phases I, II, III, V, and VI

Specifications for the JASPER Program attenuation experiment

An integral shielding experiment has been designed to investigate neutron penetration through benchmark and representative mockups of the radial shield designs for advanced sodium-cooled reactor concepts. The experiment will be performed in FY 1986 at the ORNL Tower Shielding Facility to study neutron penetration through various combinations of graphite, boron carbide, and steel configurations using representative near-core and sodium-pool source spectra. Detailed configuration descriptions and measurement specifications for the experiment are included

Models of the SL9 Impacts II. Radiative-hydrodynamic Modeling of the Plume Splashback

We model the plume "splashback" phase of the SL9 collisions with Jupiter using the ZEUS-3D hydrodynamic code. We modified the Zeus code to include gray radiative transport, and we present validation tests. We couple the infalling mass and momentum fluxes of SL9 plume material (from paper I) to a jovian atmospheric model. A strong and complex shock structure results. The modeled shock temperatures agree well with observations, and the structure and evolution of the modeled shocks account for the appearance of high excitation molecular line emission after the peak of the continuum light curve. The splashback region cools by radial expansion as well as by radiation. The morphology of our synthetic continuum light curves agree with observations over a broad wavelength range (0.9 to 12 microns). A feature of our ballistic plume is a shell of mass at the highest velocities, which we term the "vanguard". Portions of the vanguard ejected on shallow trajectories produce a lateral shock front, whose initial expansion accounts for the "third precursors" seen in the 2-micron light curves of the larger impacts, and for hot methane emission at early times. Continued propagation of this lateral shock approximately reproduces the radii, propagation speed, and centroid positions of the large rings observed at 3-4 microns by McGregor et al. The portion of the vanguard ejected closer to the vertical falls back with high z-component velocities just after maximum light, producing CO emission and the "flare" seen at 0.9 microns. The model also produces secondary maxima ("bounces") whose amplitudes and periods are in agreement with observations.Comment: 13 pages, 9 figures (figs 3 and 4 in color), accepted for Ap.J. latex, version including full figures at: http://oobleck.tn.cornell.edu/jh/ast/papers/slplume2-20.ps.g