Science.gov

Sample records for earth reentry breakup

  1. Inadvertent Earth Reentry Breakup Analysis for the New Horizons Mission

    NASA Technical Reports Server (NTRS)

    Ling, Lisa M.; Salama, Ahmed; Ivanov, Mark; McRonald, Angus

    2007-01-01

    The New Horizons (NH) spacecraft was launched in January 2006 aboard an Atlas V launch vehicle, in a mission to explore Pluto, its moons, and other bodies in the Kuiper Belt. The NH spacecraft is powered by a Radioisotope Thermoelectric Generator (RTG) which encases multiple General Purpose Heat Source (GPHS) modules. Thus, a pre-launch vehicle breakup analysis for an inadvertent atmospheric reentry in the event of a launch failure was required to assess aerospace nuclear safety and for launch contingency planning. This paper addresses potential accidental Earth reentries analyzed at the Jet Propulsion Laboratory (JPL) which may arise during the ascent to parking orbit, resulting in a suborbital reentry, as well as a departure from parking orbit, resulting in an orbital reentry.

  2. A methodology of MSL breakup analysis for Earth accidental reentry and its application to breakup analysis for Mars off-nominal entry

    NASA Technical Reports Server (NTRS)

    Salama, Ahmed; Ling, Lisa

    2005-01-01

    Vehicle breakup analysis has been performed for missions that may carry nuclear fuel for heating or power purposes to assess nuclear safety in case of launch failure leading to atmospheric reentry. Also, failure scenarios exist which could lead to breakup during Entry / Descent / Landing (EDL) at Mars due to off-nominal entries, with implications for planetary protection requirements. Since the Mars Science Laboratory (MSL) spacecraft may include a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), an analysis of breakup in case of launch failure is required. Also, breakup during Mars EDL due to off-nominal entries could release the RTG heat source that has implications for planetary protection requirements. This paper presents a methodology of MSL breakup analysis for launch failure with application to Mars off-nominal entry.

  3. Reentry Breakup Recorder: An Innovative Device for Collecting Data during Breakup of Reentering Objects

    NASA Astrophysics Data System (ADS)

    Ailor, W. H.; Weaver, M. A.

    2012-01-01

    More than 40 large, human-made, uncontrolled objects reenter the earth's atmosphere every year, and some fraction of the mass of each object survives to impact the ground or water. Some of these surviving objects are sizable and potentially hazardous. Recognizing this fact, space agencies are developing regulations and standards to limit ground hazards. Unfortunately, detailed information on how objects respond to the severe heating and loads environment is not available due to the difficulty in recording and broadcasting data during reentry and breakup. The Reentry Breakup Recorder (REBR) was developed using a different paradigm - rather than broadcasting data during the breakup event, record the data and broadcast it after the reentry has effectively ended, but before the data recorder actually impacts the Earth's surface. The paper describes how this approach minimizes the weight of the recording device and the overall cost of data recovery. The first flight tests of the REBR device were conducted in 2011; a REBR was inside the Japanese HTV2 and the European ATV-2 vehicles when they were deorbited into the Pacific Ocean. The paper presents a summary of the results of those tests and gives an overview of how future versions of REBR will revolutionize our understanding of reentry breakup and might be used to prototype "black box" systems for space transportation vehicles.

  4. ISS Update: ATV-3 ReEntry Breakup Recorder

    NASA Video Gallery

    ISS Update Commentator Pat Ryan talks with Dr. William Ailor, Principal Investigator for the ReEntry Breakup Recorder (REBR) for The Aerospace Corporation. Ailor talks about capturing data as Europ...

  5. Radioactive satellites - Intact reentry and breakup by debris impact

    NASA Technical Reports Server (NTRS)

    Anz-Meador, P. D.; Potter, A. E., Jr.

    1991-01-01

    There is a substantial mass of radioactive material in nuclear reactors or radioisotope thermal generators (RTGs) in orbit about the earth. This paper examines the reentry of intact nuclear fuel cores and RTGs and the fragmentation and subsequent radioactive debris cloud deposition and evolution resulting from the impact of orbital debris upon an orbiting reactor, fuel core, or RTG. To assess the intact reentry, decay rates and a predicted decay date using historical and projected orbital decay data, are estimated. The current NASA debris environment model is utilized to estimate impact rates and debris cloud evolution of a fragmentation event. Results of these analyses are compared and concepts are tendered which would tend to minimize the radiological debris hazard to personnel and structures both on the earth's surface and in low earth orbit.

  6. Reentry analysis for low Earth orbiting spacecraft

    NASA Astrophysics Data System (ADS)

    Newman, Lauri Kraft; Folta, David C.; Ross, Brian P.; Bouslog, Stanley A.

    As a result of recent National Aeronautics and Space Administration (NASA) Management Instruction (NMI), NASA spacecraft programs must limit orbital debris by design and/or by operational procedures. To fulfill this requirement, spacecraft may be required to be removed from their operational orbit after mission completion. Spacecraft disposal by atmospheric reentry is a means to accomplish this task. To assess the risk to man, an analysis must be done to determine which parts of the spacecraft are likely to survive a reentry of the Earth's atmosphere and where those parts will land. These issues are currently being examined for the Earth Observing System (EOS-AM1). The Johnson Space Center (JSC) Aeroscience Branch, supported by the Lockheed Engineering and Sciences Co., has developed a tool which permits the analysis of the thermal effects of reentry on individual spacecraft components to determine which components are expected to survive reentry. This paper presents an examination of the burnup and reentry of EOS-AM1 and describes a method for other spacecraft to use in analyzing similar reentry issues.

  7. Supercontinent Breakup and the Deep Earth

    NASA Astrophysics Data System (ADS)

    Torsvik, T. H.

    2014-12-01

    As many as five supercontinents have been proposed and the deep Earth probably holds the key to understand their breakup. The African and Pacific large low shear-wave velocity provinces (LLSVPs) have been stable for the entire Phanerozoic and possibly much longer. Their edges are the dominant source of deep plumes which travel from the base of the mantle to the surface where episodic large igneous province (LIP) activity has punctuated plate tectonics by creating and modifying plate boundaries. Pangea, the best-documented supercontinent, formed at the end of the Carboniferous (320 Ma) by fusing Gondwana and Laurussia. The Panjal Traps (289 Ma) probably assisted in an early Pangea breakup phase (opening of the Neotethys) but the most important phase of breakup started when the Central Atlantic Ocean opened at around 195 Ma. Perhaps not coincidentally, the region where the Atlantic spreading started was preceded by the emplacement of the Central Atlantic Magmatic Province (201 Ma), one of the largest LIPs. The Karoo LIP (183 Ma) heralded the Jurassic breakup of Pangea (separation of East and West Gondwana) whereas Paraná-Etendeka LIP activity (134 Ma) preceded South Atlantic break-up by a few million years. The North Atlantic realm experienced prolonged Late Palaeozoic to Cenozoic extension and sedimentary basin formation but the final Early Eocene break-up occurred shortly after a massive episode of volcanism and LIP formation (North Atlantic Igneous Province, 62 Ma) as in most Pangea breakup examples. All LIPs assisting Pangea breakup were sourced by plumes from the margin of the African LLSVP.

  8. Reentry analysis

    SciTech Connect

    Biehl, F.A.

    1984-05-01

    This paper presents the criteria, previous nuclear experience in space, analysis techniques, and possible breakup enhancement devices applicable to an acceptable SP-100 reentry from space. Reactor operation in nuclear-safe orbit will minimize the radiological risk; the remaining safeguards criteria need to be defined. A simple analytical point mass reentry technique and a more comprehensive analysis method that considers vehicle dynamics and orbit insertion malfunctions are presented. Vehicle trajectory, attitude, and possible breakup enhancement devices will be integrated in the simulation as required to ensure an adequate representation of the reentry process.

  9. A Genesis breakup and burnup analysis in off-nominal Earth return and atmospheric entry

    NASA Technical Reports Server (NTRS)

    Salama, Ahmed; Ling, Lisa; McRonald, Angus

    2005-01-01

    The Genesis project conducted a detailed breakup/burnup analysis before the Earth return to determine if any spacecraft component could survive and reach the ground intact in case of an off-nominal entry. In addition, an independent JPL team was chartered with the responsibility of analyzing several definitive breakup scenarios to verify the official project analysis. This paper presents the analysis and results of this independent team.

  10. Effects of atmospheric breakup on crater field formation. [on earth

    NASA Technical Reports Server (NTRS)

    Passey, Q. R.; Melosh, H. J.

    1980-01-01

    This paper investigates the physics of meteoroid breakup in the atmosphere and its implications for the observed features of strewn fields. There are several effects which cause dispersion of the meteoroid fragments: gravity, differential lift of the fragments, bow shock interaction just after breakup, centripetal separation by a rotating meteroid, and possibly a dynamical transverse separation resulting from the crushing deceleration in the atmosphere. Of these, it is shown that gravity alone can produce the common pattern in which the largest crater occurs at the downrange end of the scatter ellipse. The average lift-to-drag ratio of the tumbling fragments must be less than about 0.001, otherwise small fragments would produce small craters downrange of the main crater, and this is not generally observed. The cross-range dispersion is probably due to the combined effects of bow shock interaction, crushing deceleration, and possibly spinning of the meteoroid. A number of terrestrial strewn fields are discussed in the light of these ideas, which are formulated quantitatively for a range of meteoroid velocities, entry angles, and crushing strengths. It is found that when the crater size exceeds about 1 km, the separation between the fragments upon landing is a fraction of their own diameter, so that the crater formed by such a fragmented meteoroid is almost indistinguishable from that formed by a solid body of the same total mass and velocity.

  11. Snowball Earth ocean chemistry driven by extensive ridge volcanism during Rodinia breakup

    NASA Astrophysics Data System (ADS)

    Gernon, T. M.; Hincks, T. K.; Tyrrell, T.; Rohling, E. J.; Palmer, M. R.

    2016-03-01

    During Neoproterozoic Snowball Earth glaciations, the oceans gained massive amounts of alkalinity, culminating in the deposition of massive cap carbonates on deglaciation. Changes in terrestrial runoff associated with both breakup of the Rodinia supercontinent and deglaciation can explain some, but not all of the requisite changes in ocean chemistry. Submarine volcanism along shallow ridges formed during supercontinent breakup results in the formation of large volumes of glassy hyaloclastite, which readily alters to palagonite. Here we estimate fluxes of calcium, magnesium, phosphorus, silica and bicarbonate associated with these shallow-ridge processes, and argue that extensive submarine volcanism during the breakup of Rodinia made an important contribution to changes in ocean chemistry during Snowball Earth glaciations. We use Monte Carlo simulations to show that widespread hyaloclastite alteration under near-global sea-ice cover could lead to Ca2+ and Mg2+ supersaturation over the course of the glaciation that is sufficient to explain the volume of cap carbonates deposited. Furthermore, our conservative estimates of phosphorus release are sufficient to explain the observed P:Fe ratios in sedimentary iron formations from this time. This large phosphorus release may have fuelled primary productivity, which in turn would have contributed to atmospheric O2 rises that followed Snowball Earth episodes.

  12. An Analysis of Recent Major Breakups in he Low Earth Orbit Region

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Anz-Meador, P. D.

    2010-01-01

    Of the 190 known satellite breakups between 1961 and 2006, only one generated more than 500 cataloged fragments. The event was the explosion of the Pegasus Hydrazine Auxiliary Propulsion System in 1996, adding 713 fragments to the U.S. Satellite Catalog. Since the beginning of 2007; however, the near-Earth environment has been subjected to several major breakups, including the Fengyun-1C anti-satellite test and the explosion of Briz-M in 2007, the unusual breakup of Cosmos 2421 in 2008, and the collision between Iridium 33 and Cosmos 2251 in 2009. Combined, these events added more than 5000 large (> or equal 10 cm) fragments to the environment. Detailed analysis of the radar cross section measurements and orbit histories of the fragments from these major events reveals several unusual characteristics in their size and area-to-mass ratio distributions. The characteristics could be related to the material composition of the parent vehicles, the nature of the breakup, and the composition and physical property of the fragments. In addition, the majority of these fragments are expected to remain in orbit for at least decades. Their long-term impact to the environment is analyzed using the NASA orbital debris evolutionary model, LEGEND. Descriptions of these analyses and a summary are included in this paper.

  13. The reentry to Earth as a valuable option at the end-of-life of Libration Point Orbit missions

    NASA Astrophysics Data System (ADS)

    Alessi, Elisa Maria

    2015-06-01

    Nowadays the mission design must comprise the implementation of end-of-life disposal solutions to preserve the space environment and for the sustainability of the project as a whole. In this work, the Earth's reentry is presented as a disposal strategy that it is worth investigating also for Libration Point Orbit missions. Following a recent ESA study, the analysis is performed first in the Circular Restricted Three-Body Problem, and then considering a high-fidelity model. The test cases selected are Herschel, SOHO and Gaia. Attention is paid not only to the Δv -budget, but also to the reentry angle, the time of flight and the regions on the surface of the Earth involved. A review on the known cases of hypervelocity reentries and the corresponding physics is given in order to find a reasonable approach to avoid dangerous fragmentations at low altitudes.

  14. Atmospheric breakup of a small comet in the Earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Teterev, A. V.; Misychenko, N. I.; Rudak, L. V.; Romanov, G. S.; Smetannikov, A. S.; Nemchinov, I. V.

    1993-01-01

    The aerodynamic stresses can lead to the deformation and even to destruction of the meteoroids during their flight through the atmosphere. The pressure at the blunt nose of the cosmic body moving at very high speed through the dense layers of the atmosphere may be much larger than the tensile or the compressive strength of the body. So the usage of the hydrodynamics theory is validated. The estimates show that the transverse velocity of the substance of the body U is of the order of (rho(sub a)/rho(sub o))(sup 1/2)V where V is the velocity of the body and rho(sub o) is its density, rho(sub a) is the density of the atmosphere. The separation of the fragments is larger than the diameter of the body D if D is less than D(sub c) = 2H(square root of rho(sub a)/rho(sub o)), where H is the characteristic scale of the atmosphere. For an icy body one obtains U = 1/30(V) and critical diameter D(sub C) = 500 m. The process of the disintegration of the body is still not fully understood and so one can use the numerical simulation to investigate it. Such simulations where conducted for the Venusian atmosphere and the gaseous equation of state of the body was used. For the Earth atmosphere for the velocity V = 50 km/s the pressure at the blunt nose of the body is 25 kbar, and is of the order of bulk modulus of compressibility of the water or ice. The realistic EOS of water in tabular form was used. It was assumed that the initial shape of the body was spherical and the initial diameter D(sub o) of the body is 200 m and so it is smaller than the critical diameter D(sub C). The initial kinetic energy of the icy body is equivalent to the energy of the explosion 1200 Mt of TNT. The results of the simulation of the deformation of the body during its vertical flight through the atmosphere and during its impact into the ocean are presented.

  15. Assessment of the consequences of the Fengyun-1C breakup in low Earth orbit

    NASA Astrophysics Data System (ADS)

    Pardini, Carmen

    On 11 January 2007, the 880 kg (958 kg at launch) weather spacecraft Fengyun-1C, launched on 10 May 1999 into a sun-synchronous orbit with a CZ-4B booster from the Taiyuan Satellite Launch Center, was destroyed over central China as a result of the first successful Chinese anti-satellite weapon test. It was carried out with a direct ascent interception with a kinetic energy kill vehicle launched by an SC-19 missile, fired from a mobile ground platform close to the Xichang Satellite Launch Center. While the technical details of the test, probably the third attempt, and the characteristics of the weapon used remain shrouded in secrecy, the intentional breakup of the aging weather spacecraft, fully functional until 2005, produced a huge amount of debris in one of the orbital regimes already most affected by past fragmentation events. At present, the US Space Surveillance Network has identified about 2600 objects, typically larger than 10 cm, but the fragments larger than 1 cm may be more than 100,000. After two decades of substantial international progress in the field of orbital debris mitigation, in order to preserve the low Earth and geosynchronous environments for future space missions, the Fengyun-1C destruction represented a serious turnabout. In fact, it abruptly increased by approximately 20% the number of cataloged debris in orbit. To give a rough idea of the impact of this single event on the circumterrestrial environment, it is sufficient to realize that about 15 years of global space activity - including failures and accidental breakups - had been needed to increase, by a comparable amount, the number of cataloged debris in orbit to the level observed before the Chinese anti-satellite test. The purpose of this presentation is to assess the impact of the debris cloud generated by the Fengyun-1C breakup on the low Earth environment. The anti-satellite test was carried out at an altitude of about 863 km, spreading the cataloged fragments between 200 and 4000

  16. Reentry response of the lightweight radioisotope heater unit resulting from a Cassini Venus-Venus-Earth-Jupiter gravity assist maneuver accident

    SciTech Connect

    1996-12-01

    Reentry analyses consisting of ablation response, thermal response and thermal stress response have been conducted on the Lightweight Radioisotope Heater Unit (LWRHU) for Cassini/Venus-Venus-Earth-Jupiter-Gravity-Assist (VVEJGA) reentry conditions. Sequential ablation analyses of the LWRHU aeroshell, and the fuel pellet have been conducted in reentry regimes where the aeroshell has been deemed to fail. The failure criterion for ablation is generally assumed to be recession corresponding to 75% and 100% of the wall thickness. The 75% recession failure criteria allows for uncertainties that result mainly because of the high energies involved in the VVEJGA reentries compared to orbital decay reentries. Risk evaluations should consider the fact that for shallow flight paths the unit may disassemble at high-altitude as a result of ablation or may remain intact with a clad that had been molten. Within the limitations of the methodologies and assumptions of the analyses, the results indicate that: (1) For a side-on stable LWRHU reentry, aeroshell ablation failures occur for all reentry angles. (2)For a side-on spinning LWRHU reentry, aeroshell ablation failures are minimal. (3) For the tumbling LWRHU reentry, the aeroshell survives for most angles. (4) For the thermostructural analyses, using both a 1% and 5% allowable strain, all reentry angles and orientations examined resulted in small localized failures, but aeroshell breach is not predicted for any case. The analyses included in this report concentrate on VVEJGA reentry scenarios. Analyses reported previously have demonstrated that the LWRHU has adequate design margin to survive reentry from orbital decay scenarios and most injection scenarios at speeds up to escape speeds. The exception is a narrow range of flight path angles that produce multiple skip trajectories which may have excessive ablation.

  17. Planet Earth Set to Broil: Thermal Radiation from Chicxulub Ejecta Reentry

    NASA Astrophysics Data System (ADS)

    Goldin, T. J.; Melosh, H. J.

    2009-03-01

    We model the thermal radiation transfer due to the atmospheric reentry of hypervelocity Chicxulub impact ejecta. Self-shielding of downward radiation by the spherules limits the magnitude and duration of the thermal pulse at the Earth’s surface.

  18. Astronaut Thermal Exposure: Re-Entry After Low Earth Orbit Rescue Mission

    NASA Technical Reports Server (NTRS)

    Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Son, Chang; Bue, Grant

    2009-01-01

    The STS-125 mission, launched May 11, 2009, is the final servicing mission to the Hubble Space Telescope. The repair mission's EVA tasks are described, including: installing a new wide field camera; installing the Cosmic Origins Spectrograph; repairing the Space Telescope Imaging Spectrograph; installing a new outer blanket layer; adding a Soft Capture and Rendezvous System for eventual controlled deorbit in about 2014; replacing the 'A' side Science Instrument Command and Data Handling module; repairing the Advanced Camera for surveys; and, replacing the rate sensor unit gyroscopes, fine guidance sensors and 3 batteries. Additionally, the Shuttle crew cabin thermal environment is described. A CFD model of per person CO2 demonstrates a discrepancy between crew breathing volume and general mid-deck levels of CO2. A follow-on CFD analysis of the mid-deck temperature distribution is provided. Procedural and engineering mitigation plans are presented to counteract thermal exposure upon reentry to the Earth atmosphere. Some of the procedures include: full cold soak the night prior to deorbit; modifying deck stowage to reduce interference with air flow; and early securing of avionics post-landing to reduce cabin thermal load prior to hatch opening. Engineering mitigation activities include modifying the location of the aft starboard ICUs, eliminating the X3 stack and eliminating ICU exhaust air directed onto astronauts; improved engineering data of ICU performance; and, verifying the adequacy of mid-deck temperature control using CFD models in addition to lumped parameter models. Post-mitigation CFD models of mid-deck temperature profiles and distribution are provided.

  19. Reentry response of the light weight radioisotope heater unit resulting from a Venus-Earth-Earth Gravity Assist maneuver accident

    SciTech Connect

    Hagan, J.C.

    1988-10-01

    Reentry analyses consisting of ablation response, thermal response and thermal stress response have been conducted on the Light Weight Radioisotope Heater Unit for Galileo/VEEGA reentry conditions. Sequential ablation analyses of the LWRHU aeroshell, the fuel clad, and the fuel pellet have been conducted in reentry regimes where the aeroshell has been deemed to fail. The failure criterion for ablation is assumed to be recession corresponding to 50% of the wall thickness (the design criterion recommended in the DOE Overall Safety Manual). Although the analyses have been carried far beyond this limit (as presented and discussed herein), JHU/APL endorses the position that failure may occur at the time that this recession is achieved or at lower altitudes within the heat pulse considering the uncertainties in the aerodynamic, thermodynamic, and thermo-structural analyses and modeling. These uncertainties result mainly because of the high energies involved in the VEEGA reentries compared to orbital decay reentries. Risk evaluations should consider the fact that for shallow flight paths the unit may disassemble at high-altitude as a result of ablation or may remain intact until it impacts with a clad that had been molten. 80 refs., 46 figs., 16 tabs.

  20. Effect of simulated Earth reentry exposure on mechanical properties of several oxide dispersion strengthened and superalloy sheet materials

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1977-01-01

    The effects of simulated multiple reentry into the earth's atmosphere on the mechanical properties of several high temperature metallic sheet materials were evaluated. The materials included five tin-gage (nominally 0.025- or 0.037-cm) oxide dispersion strengthened (ODS) alloys and two thin-gage (nominally 0.037-cm) superalloys. Multiple reentry conditions were simulated through cyclic Plasma Arc Tunnel (PAT) exposure. PAT exposure generally consisted of 100 cycles of 600 second duration at 1255, 1366, or 1477 K in a Mach 4.6 airstream with an impact pressure of nominally 800 N/m2. PAT exposure generally produced a uniform oxide scale, oxide pits or intergranular oxidation, Kirkendall porosity, and alloy depletion zones except for the aluminum-containing ODS alloys. Only a uniform oxide scale was formed on the aluminum-containing ODS alloys. PAT exposure did not significantly affect the mechanical properties of the thin-gage (nominally 0.025- or 0.037-cm) alloys evaluated. Thus it appears that the microstructural changes produced by Plasma Arc Tunnel exposure has little influence on mechanical properties.

  1. Comparison of ORSAT and SCARAB Reentry Analysis Tools for a Generic Satellite Test Case

    NASA Technical Reports Server (NTRS)

    Kelley, Robert L.; Hill, Nicole M.; Rochelle, W. C.; Johnson, Nicholas L.; Lips, T.

    2010-01-01

    Reentry analysis is essential to understanding the consequences of the full life cycle of a spacecraft. Since reentry is a key factor in spacecraft development, NASA and ESA have separately developed tools to assess the survivability of objects during reentry. Criteria such as debris casualty area and impact energy are particularly important to understanding the risks posed to people on Earth. Therefore, NASA and ESA have undertaken a series of comparison studies of their respective reentry codes for verification and improvements in accuracy. The NASA Object Reentry Survival Analysis Tool (ORSAT) and the ESA Spacecraft Atmospheric Reentry and Aerothermal Breakup (SCARAB) reentry analysis tools serve as standard codes for reentry survivability assessment of satellites. These programs predict whether an object will demise during reentry and calculate the debris casualty area of objects determined to survive, establishing the reentry risk posed to the Earth's population by surviving debris. A series of test cases have been studied for comparison and the most recent uses "Testsat," a conceptual satellite composed of generic parts, defined to use numerous simple shapes and various materials for a better comparison of the predictions of these two codes. This study is an improvement on the others in this series because of increased consistency in modeling techniques and variables. The overall comparison demonstrated that the two codes arrive at similar results. Either most objects modeled resulted in close agreement between the two codes, or if the difference was significant, the variance could be explained as a case of semantics in the model definitions. This paper presents the main results of ORSAT and SCARAB for the Testsat case and discusses the sources of any discovered differences. Discussion of the results of previous comparisons is made for a summary of differences between the codes and lessons learned from this series of tests.

  2. 14 CFR 435.7 - Payload reentry determination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... transport a payload to Earth on a reentry vehicle unless the proposed payload is exempt from payload...

  3. 14 CFR 435.7 - Payload reentry determination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... transport a payload to Earth on a reentry vehicle unless the proposed payload is exempt from payload...

  4. 14 CFR 435.7 - Payload reentry determination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... transport a payload to Earth on a reentry vehicle unless the proposed payload is exempt from payload...

  5. 14 CFR 435.7 - Payload reentry determination.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... transport a payload to Earth on a reentry vehicle unless the proposed payload is exempt from payload...

  6. Risk Assessment for Destructive Re-Entry

    NASA Astrophysics Data System (ADS)

    Lips, T.; Koppenwallner, G.; Bianchi, L.; Klinkrad, H.

    2009-03-01

    From 2007 to 2008, Hypersonic Technology Göttingen (HTG) worked on a study called Risk Assessment for Destructive Re-entry (RADR). The main purposes of this study were to identify and to quantify the inherent uncertainties of re-entry analysis tools, and to provide possible risk mitigation measures. For these purposes, three basic risk scenarios were specified: a 1-ton-class satellite without propulsion for uncontrolled re-entry, a 6-ton-class satellite with propulsion and the capability to perform a controlled re-entry, and a 1-ton-class launcher upper stage re-entering uncontrolled. Based on the identified uncertainty parameters, variation analyses were conducted for these scenarios with the two ESA tools for re-entry analysis SCARAB (Spacecraft Atmospheric Reentry and Aerothermal Breakup) and SESAM (Spacecraft Entry Survival Analysis Module). This paper describes the major results of the RADR study.

  7. Reentry Experiment SAT-X

    NASA Astrophysics Data System (ADS)

    Woods, Maurice; Kuhns, Casey; Honda, Motoaki; Shiely, Robert; Adamson, Aaron; Aken, Jordan; Walch, Robert; Galovich, Cynthia; Semak, Matthew

    2011-10-01

    The challenge of reentering the Earth's atmosphere is not new. For years, NASA has successfully designed vessels that have endured the harsh process of reentry. However, in most cases, this is made possible only through the act of over-engineering; designing to withstand conditions far beyond what is expected to be encountered. Though this method has been effective, there would be benefit in knowing more precisely what to expect upon atmospheric reentry. The University of Northern Colorado Reentry Experiment SAT-X project, launched from Wallops Island, Virginia on July 21, 2011, was designed to shed light on the reentry process by collecting motion data for a capsule ejected from a rocket. Moreover, a secondary objective was to test the capability of the prototype capsule to serve as a platform for future reentry experiments. The mission and preliminary results from the launch will be described.

  8. UARS Re-Entry Prediction and Analysis

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene G.; Johnson, N. L.

    2012-01-01

    The National Aeronautics and Space Administration (NASA) deployed the Upper Atmosphere Research Satellite (UARS) from the Space Shuttle payload bay during the STS-48 mission in September, 1991. The 5700 kg satellite was decommissioned in December, 2005 and was maneuvered into a lower altitude orbit to shorten its on-orbit lifetime to reduce the probability of a debris producing accidental collision. The satellite reentered the Earth s atmosphere over the Pacific Ocean on September 24, 2011. Analysis by NASA s Orbital Debris Program Office using the ORSAT software predicted that approximately two dozen fragments from UARS would survive reentry to reach the ground. This presentation will discuss the reentry predictions made in the days prior to the reentry and compare the UARS reentry with other historical reentries. It will also present the results of the ORSAT analysis showing predicted surviving reentry objects

  9. Novel Hybrid Ablative/Ceramic Layered Composite for Earth Re-entry Thermal Protection: Microstructural and Mechanical Performance

    NASA Astrophysics Data System (ADS)

    Triantou, K.; Mergia, K.; Marinou, A.; Vekinis, G.; Barcena, J.; Florez, S.; Perez, B.; Pinaud, G.; Bouilly, J.-M.; Fischer, W. P. P.

    2015-04-01

    In view of spacecraft re-entry applications into planetary atmospheres, hybrid thermal protection systems based on layered composites of ablative materials and ceramic matrix composites are investigated. Joints of ASTERM™ lightweight ablative material with Cf/SiC (SICARBON™) were fabricated using commercial high temperature inorganic adhesives. Sound joints without defects are produced and very good bonding of the adhesive with both base materials is observed. Mechanical shear tests under ambient conditions and in liquid nitrogen show that mechanical failure always takes place inside the ablative material with no decohesion of the interface of the adhesive layer with the bonded materials. Surface treatment of the ablative surface prior to bonding enhances both the shear strength and the ultimate shear strain by up to about 60%.

  10. Re-entry vehicle dynamics

    NASA Astrophysics Data System (ADS)

    Regan, F. J.

    The present book has the objective to provide the practicing engineer with a senior-level introduction to the dynamics of reentry vehicles. A description is provided of an atmospheric model, and the earth's form and gravity field are examined, taking into account basic atmospheric relationships, the development of an analytic atmospheric model, a simple atmospheric model for closed-form solutions, the geocentric position vector, the deviation of the vertical, the earth's radius, and a computer program for calculating the gravitational acceleration. Force equations are considered along with aspects of Keplerian motion, reentry body particle mechanics, moment equations, axis transformations, a flowfield description, moment equations in a constant density atmosphere, boost trajectories, angular motion during the Keplerian phase, angular motion during reentry, and the inverse method. Attention is also given to first-order linear differential equations with variable coefficients, ring laser gyros and pendulous accelerometers, the calculation of the real roots of a polynomial, quaternions.

  11. The Breakup

    ERIC Educational Resources Information Center

    Lum, Lydia

    2011-01-01

    This article reports on the breakup between Texas Southmost College (TSC) and the upper-division University of Texas at Brownsville (UTB). The split marks the official end of an unusual 20-year partnership between TSC and the University of Texas System that, for the first time, ushered four-year university education into overwhelmingly Latino…

  12. Pico Reentry Probes: Affordable Options for Reentry Measurements and Testing

    NASA Technical Reports Server (NTRS)

    Ailor, William H.; Kapoor, Vinod B.; Allen, Gay A., Jr.; Venkatapathy, Ethiraj; Arnold, James O.; Rasky, Daniel J.

    2005-01-01

    It is generally very costly to perform in-space and atmospheric entry experiments. This paper presents a new platform - the Pico Reentry Probe (PREP) - that we believe will make targeted flight-tests and planetary atmospheric probe science missions considerably more affordable. Small, lightweight, self-contained, it is designed as a "launch and forget" system, suitable for experiments that require no ongoing communication with the ground. It contains a data recorder, battery, transmitter, and user-customized instrumentation. Data recorded during reentry or space operations is returned at end-of-mission via transmission to Iridium satellites (in the case of earth-based operations) or a similar orbiting communication system for planetary missions. This paper discusses possible applications of this concept for Earth and Martian atmospheric entry science. Two well-known heritage aerodynamic shapes are considered as candidates for PREP: the shape developed for the Planetary Atmospheric Experiment Test (PAET) and that for the Deep Space II Mars Probe.

  13. 14 CFR 435.35 - Acceptable reentry risk for reentry of a reentry vehicle.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Acceptable reentry risk for reentry of a reentry vehicle. 435.35 Section 435.35 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Safety...

  14. 14 CFR 435.35 - Acceptable reentry risk for reentry of a reentry vehicle.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... reentry vehicle. 435.35 Section 435.35 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Safety Review and Approval for Reentry of a Reentry Vehicle §...

  15. 14 CFR 435.35 - Acceptable reentry risk for reentry of a reentry vehicle.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... reentry vehicle. 435.35 Section 435.35 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Safety Review and Approval for Reentry of a Reentry Vehicle §...

  16. 14 CFR 435.35 - Acceptable reentry risk for reentry of a reentry vehicle.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... reentry vehicle. 435.35 Section 435.35 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Safety Review and Approval for Reentry of a Reentry Vehicle §...

  17. 14 CFR 435.35 - Acceptable reentry risk for reentry of a reentry vehicle.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... reentry vehicle. 435.35 Section 435.35 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Safety Review and Approval for Reentry of a Reentry Vehicle §...

  18. Reentry safety for the Topaz II Space Reactor: Issues and analyses

    SciTech Connect

    Connell, L.W.; Trost, L.C.

    1994-03-01

    This report documents the reentry safety analyses conducted for the TOPAZ II Nuclear Electric Propulsion Space Test Program (NEPSTP). Scoping calculations were performed on the reentry aerothermal breakup and ground footprint of reactor core debris. The calculations were used to assess the risks associated with radiologically cold reentry accidents and to determine if constraints should be placed on the core configuration for such accidents. Three risk factors were considered: inadvertent criticality upon reentry impact, atmospheric dispersal of U-235 fuel, and the Special Nuclear Material Safeguards risks. Results indicate that the risks associated with cold reentry are very low regardless of the core configuration. Core configuration constraints were therefore not established for radiologically cold reentry accidents.

  19. System specification for the reusable reentry satellite

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The RRS design shall provide a relatively inexpensive method of access to micro and fractional gravity space environments for an extended period of time, with eventual intact recovery on the surface of the Earth. This specification establishes the performance, design, development, and test requirements for the Reusable Reentry Satellite (RRS) system.

  20. Analysis of reentry survivability of UARS spacecraft

    NASA Astrophysics Data System (ADS)

    Rochelle, W. C.; Marichalar, J. J.; Johnson, N. L.

    2004-01-01

    An analysis of reentry survivability of the NASA Goddard space flight center (GSFC) upper atmosphere research satellite (UARS) was performed by Lockheed Martin space operations (LMSO), Houston, TX. The objective of this study was to use the NASA Lyndon B. Johnson space center (JSC)/LMSO object reentry survival analysis tool (ORSAT) to investigate reentry, breakup, demise, and impact of approximately 160 specific components of the UARS. This paper contains descriptions of the UARS spacecraft as modeled by ORSAT, method of approach (including assumptions), and results obtained. The analysis showed that about 150 component types, including the parent body, will demise, and 12 types (26 counting multiple components) will survive. The components that survive produce a debris casualty area of 22 m 2, a surviving mass of 532 kg, a casualty risk of 1:2800, and a debris footprint length of nearly 800 km. The 22 m 2 debris casualty area reflects the results of a parametric assessment; otherwise the casualty area would have been larger.

  1. Analysis of Reentry Survivability for UARS Spacecraft

    NASA Astrophysics Data System (ADS)

    Rochelle, W.; Marichalar, J.; Johnson, N.

    The NASA Goddard Space Flight Center (GSFC) Upper Atmosphere Research Satellite (UARS), which was launched September 12, 1991 by the Space Shuttle STS-48, will be decommissioned in 2002-2003. It is currently planned to allow the spacecraft to reenter in an orbital decay mode. An analysis of reentry survivability of the UARS in this orbital decay mode was performed by Lockheed Martin Space Operations (LMSO), Houston, TX. The objective of this study was to use the NASA Johnson Space Center (JSC)/LMSO Object Reentry Survival Analysis Tool (ORSAT) to investigate reentry, breakup, demise, and impact of over 160 UARS components. The ORSAT code contains six general models of operation, including trajectory, atmosphere, aerodynamics, aeroheating, thermal, and debris casualty/ground impact risk. Objects are computed to demise in the code at the altitude at which the object's absorbed heat (defined as net heat rate integrated over time multiplied by surface area) becomes greater than the material heat of ablation. An updated version of ORSAT (Version 5.5) was used in this UARS analysis. This version enables objects to be evaluated in which parameters such as initial surface temperature, oxidation efficiency, mode of tumbling, breakup altitude, or other factors can be varied in a single object reentry simulation. The survivability factor (ratio of total absorbed heat on the object to its material heat of ablation) can be plotted as a function of some of these parameters. This information was used to make good engineering decisions of whether a borderline object (at the knee of the demise altitude/downrange plot) would demise or survive. This paper contains descriptions of the UARS spacecraft as modeled by ORSAT, method of approach (including assumptions), and results obtained. Plots showing such component reentry profiles as altitude, velocity, ballistic coefficient, heating rate, absorbed heat, surface temperature, and demise altitude are included. The analysis showed that

  2. Surviving Atmospheric Spacecraft Breakup

    NASA Technical Reports Server (NTRS)

    Szewczyk, Nathaniel J.; Conley, Catharine A.

    2003-01-01

    In essence, to survival a spacecraft breakup an animal must not experience a lethal event. Much as with surviving aircraft breakup, dissipation of lethal forces via breakup of the craft around the organism is likely to greatly increase the odds of survival. As spacecraft can travel higher and faster than aircraft, it is often assumed that spacecraft breakup is not a survivable event. Similarly, the belief that aircraft breakup or crashes are not survivable events is still prevalent in the general population. As those of us involved in search and rescue know, it is possible to survive both aircraft breakup and crashes. Here we make the first report of an animal, C. elegans, surviving atmospheric breakup of the spacecraft supporting it and discuss both the lethal events these animals had to escape and the implications implied for search and rescue following spacecraft breakup.

  3. Estimation of decayed satellite reentry trajectories

    NASA Astrophysics Data System (ADS)

    Barker, R. H., Jr.

    1981-12-01

    A technique was developed for estimation of decayed Earth satellite reentry trajectories to provide impact locations for debris search requirements. The technique used a linearized differential-corrector as an extension of existing orbit estimation methods. The reentry observations consisted of angular, infrared measurements from orbital sensors. An eight dimension state vector was used with components for position, velocity, a ballistic parameter, and the scale height from an isothermal density model. Simulated data runs identified the uncertain dynamics of the true reentry process as the most significant impact on estimator performance. The uncertain dynamics pose significant problems for standard model compensation methods such as adaptive pseudo-noise compensation or more sophisticated techniques such as statistical linearization or higher order filters. The adaptive determination of an 'ad hoc' scalar fading memory parameter was used to modify the estimator-computed state covariance matrix. The bias in the state estimates were well within the variance from this modified covariance matrix.

  4. JHU/APL Breakup Analysis Tool (APLbat) for the New Horizons Radiological Contingency

    NASA Astrophysics Data System (ADS)

    Lear, Matthew; McGrath, Brian; Takashima, Naruhisa; Heyler, Gene

    2007-01-01

    The New Horizons spacecraft will be the first to study Pluto and its largest moon Charon. It launched on 19 January 2006 and will encounter Pluto in 2015. The long duration of the flight, the great distance from the Sun, and the low temperatures in the Pluto-Kuiper Belt necessitate the use of a Radioisotope Thermoelectric Generator (RTG) for heating and electricity. RTGs provide heat and electricity through the radioactive decay of plutonium dioxide (PuO2) fuel pellets. The pellets are contained in protective shells called the General Purpose Heat Source (GPHS) modules. As the New Horizons Pluto-Kuiper Belt mission-implementing organization. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) was responsible for determining the Earth impact footprint of the GPHS modules in the event of an orbital or suborbital re-entry accident during launch. The JHU/APL-developed computer program, APL Breakup Analysis Tool (APLbat), takes estimates of uncertainty in the initial vehicle (spacecraft) position and motion and, using a design-of-experiments approach and a six-degree-of-freedom dynamics model, simulates the continued motion of the vehicle, predicts its breakup as it re-enters the atmosphere, and produces a most probable elliptical Earth impact footprint for the GPHS modules.

  5. Satellite Breakup Risk Mitigation

    NASA Technical Reports Server (NTRS)

    Leleux, Darrin P.; Smith, Jason T.

    2006-01-01

    Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.

  6. Spacecraft destruction during re-entry - latest results and development of the SCARAB software system

    NASA Astrophysics Data System (ADS)

    Lips, T.; Fritsche, B.; Koppenwallner, G.; Klinkrad, H.

    2004-01-01

    The calculation of destructive re-entries and the prediction of the related ground risk potential due to fragment objects reaching the ground have become of high interest in the past years. This was also evident during the re-entry of the MIR space station in 2001. In 1995, under ESA contract, HTG started an international cooperation with other companies and institutes to develop the SCARAB software system (Spacecraft Atmospheric Re-Entry and Aerothermal Break-Up). SCARAB is a quasi-deterministic tool, modeling a re-entry object down to sub-system level. The resulting aerodynamic parameters and mass distribution allow calculating a realistic 6D re-entry trajectory. Geometry and mass are continuously updated during calculation. Multi-level fragmentations due to different destruction processes are considered. The SCARAB software has been applied to several projects, namely ATV (ESA), ROSAT (Germany), Ariane-5 (ESA) and BeppoSAX (Italy). The practical application of SCARAB to project work has been demonstrated. In addition SCARAB has been compared with NASA's ORSAT code. It has also been verified with experimental data gained from re-entry vehicles, break-up observations and wind-tunnel tests. SCARAB is now on the way to become the European standard software for re-entry destruction analysis.

  7. Surviving atmospheric spacecraft breakup

    NASA Technical Reports Server (NTRS)

    Szewczyk, Nathaniel J.; McLamb, William

    2005-01-01

    Spacecraft travel higher and faster than aircraft, making breakup potentially less survivable. As with aircraft breakup, the dissipation of lethal forces via spacecraft breakup around an organism is likely to greatly increase the odds of survival. By employing a knowledge of space and aviation physiology, comparative physiology, and search-and-rescue techniques, we were able to correctly predict and execute the recovery of live animals following the breakup of the space shuttle Columbia. In this study, we make what is, to our knowledge, the first report of an animal, Caenorhabditis elegans, surviving the atmospheric breakup of the spacecraft that was supporting it and discuss both the lethal events these animals had to escape and the implications for search and rescue following spacecraft breakup.

  8. Atmospheric reentry of the in-core thermionic SP-100 reactor system

    NASA Technical Reports Server (NTRS)

    Stamatelatos, M. G.; Barsell, A. W.; Harris, P. A.; Francisco, J.

    1987-01-01

    Presumed end-of-life atmospheric reentry of the GA SP-100 system was studied to assess dispersal feasibility and associated hazards. Reentry was studied by sequential use of an orbital trajectory and a heat analysis computer program. Two heating models were used. The first model assumed a thermal equilibrium condition between the stagnation point aerodynamic heating and the radiative cooling of the skin material surface. The second model allowed for infinite conductivity of the skin material. Four reentering configurations were studied representing stages of increased SP-100 breakup: (1) radiator, shield and reactor, (2) shield and reactor, (3) reactor with control drums, and (4) reactor without control drums. Each reentering configuration was started from a circular orbit at 116 km having an inertial velocity near Mach 25. The assumed failing criterion was the attainment of melting temperature of a critical system component. The reentry analysis revealed breakup of the vessel in the neighborhood of 61 km altitude and scattering of the fuel elements. Subsequent breakup of the fuel elements was not predicted. Oxidation of the niobium skin material was calculated to cause an increase in surface temperature of less than ten percent. The concept of thermite analogs for enhancing reactor reentry dispersal was assessed and found to be feasible in principle. A conservative worst-case hazards analysis was performed for radioactive and nonradioactive toxic SP-100 materials assumed to be dispersed during end-of-life reentry. The hazards associated with this phase of the SP-100 mission were calculated to be insignificant.

  9. Reentry trajectories and their optimization by an evolution algorithm

    NASA Astrophysics Data System (ADS)

    Bade, A.; Voegt, S.; Axmann, J. K.; Rex, D.

    The descent of a winged space vehicle from an orbit and the following re-entry into denser atmospheric layers is a rather complex physical process. To get insight into some of the fundamental phenomena, as a first step, the re-entry of simple shaped bodies has to be simulated. In order to improve the understanding of the physics, in this paper, a stepwise approach is presented: re-entry of balls, of capsules and of winged vehicles. For the re-entry of winged space vehicles, the equations of motion are not formulated in Keplerian elements but in earth-oriented coordinate systems, with the help of spherical polar coordinates in the most general form. They include thrust and aerodynamic forces (in three components). The atmosphere is regarded as fixed with the rotating oblate earth. This set of differential equations is solved by numerical integration. The influence of the angle of attack and of the bank angle upon the re-entry trajectory is discussed, also with respect to constraints (e.g., surface temperature). In all practical applications, various optimization problems arise, e.g. if for a required lateral range the heat load for the vehicle has to be minimized. The Institute of Space Technology and Reactor Technology has developed a method based on the evolution strategy, which will shortly be described here. Optimal re-entry trajectories for a preliminary configuration similar to HORUS are presented.

  10. Flight Performance of the Inflatable Reentry Vehicle Experiment 3

    NASA Technical Reports Server (NTRS)

    Dillman, Robert; DiNonno, John; Bodkin, Richard; Gsell, Valerie; Miller, Nathanael; Olds, Aaron; Bruce, Walter

    2013-01-01

    The Inflatable Reentry Vehicle Experiment 3 (IRVE-3) launched July 23, 2012, from NASA Wallops Flight Facility (WFF) on a Black Brant XI suborbital sounding rocket and successfully performed its mission, demonstrating the survivability of a hypersonic inflatable aerodynamic decelerator (HIAD) in the reentry heating environment and also illustrating the effect of an offset center of gravity on the HIAD's lift-to-drag ratio. IRVE-3 was a follow-on to 2009's IRVE-II mission, which demonstrated exo-atmospheric inflation, reentry survivability - without significant heating - and the aerodynamic stability of a HIAD down to subsonic flight conditions. NASA Langley Research Center is leading the development of HIAD technology for use on future interplanetary and Earth reentry missions.

  11. Reusable Reentry Satellite (RRS): Configuration trade study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The overall Reusable Reentry Satellite (RRS) Phase B Study objective is to design a relatively inexpensive satellite to access space for extended periods of time, with eventual recovery of experiments on Earth. The expected principal use for such a system is research on the effects of variable gravity (0-1.5 g) and radiation on small animals, plants, lower life forms, tissue samples, and materials processes. The RRS will be capable of: (1) being launched by a variety of expendable launch vehicles; (2) operating in low earth orbit as a free flying unmanned laboratory; and (3) executing independent atmospheric reentry and soft landing. The RRS will be designed to be refurbished and reused up to three times a year for a period of 10 years. The information provided in this report describes the process involved in the evolution of the RRS overall configuration. This process considered reentry aerodynamics, aerothermodynamics, internal equipment layout, and vehicle mass properties. This report delineates the baseline design decisions that were used to initiate the RRS design effort. As a result, there will be deviations between this report and the RRS Final Report. In those instances, the RRS Final Report shall be considered to be the definitive reference.

  12. Shadowgraph Images of Re-entry Vehicles

    NASA Technical Reports Server (NTRS)

    1960-01-01

    These four shadowgraph images represent early re-entry vehicle concepts. A shadowgraph is a process that makes visible the disturbances that occur in a fluid flow at high velocity, in which light passing through a flowing fluid is refracted by the density gradients in the fluid resulting in bright and dark areas on a screen placed behind the fluid.H. Julian Allen pioneered and developed the Blunt Body Theory which made possible the heat shield designs that were embodied in the Mercury, Gemini and Apollo space capsules, enabling astronauts to survive the firey re-entry into Earth's atmosphere. A blunt body produces a shockwave in front of the vehicle--visible in the photo--that actually shields the vehicle from excessive heating. As a result, blunt body vehicles can stay cooler than pointy, low drag vehicles.

  13. Analysis of reentry into the White Sands Missile Range (WSMR) for the LifeSat mission

    NASA Technical Reports Server (NTRS)

    Hametz, M.; Roszman, L.; Snow, F.; Cooley, J.

    1993-01-01

    This study investigates the reentry of the LifeSat vehicles into the WSMR. The LifeSat mission consists of two reusable reentry satellites, each carrying a removable payload module, which scientists will use to study long-term effects of microgravity, Van Allen belt radiation, and galactic cosmic rays on living organisms. A series of missions is planned for both low-Earth circular orbits and highly elliptic orbits. To recover the payload module with the specimens intact, a soft parachute landing and recovery at the WSMR is planned. This analysis examines operational issues surrounding the reentry scenario to assess the feasibility of the reentry.

  14. Atmospheric breakup of meteoroids

    NASA Astrophysics Data System (ADS)

    El-Dasher, Bassem; Swift, Damian; Remington, Bruce; Mulford, Roberta; Milathianaki, Despina; Chen, Laura; Eakins, Daniel

    2013-06-01

    When meteoroids enter a planetary atmosphere, breakup is governed by the Rayleigh-Taylor instability, mitigated by the strength of the meteoritic material. Particle sizes in the breakup cascade depend on the perturbation length scales exhibiting growth. The physics of meteoroid entry is thus related closely to experiments where strength at high pressure is inferred from the Rayleigh-Taylor growth of perturbations. There are significant discrepancies between predicted and observed breakup altitudes of meteoroids, which in turn reduce the accuracy of assessments of the impact threat from asteroids. Simulations, validated by laboratory experiments of instability growth, can play a role in understanding the breakup of meteoroids and thus the threat from asteroids. Continuum dynamics simulations provide more rigorous stress distribution than are usually used in breakup analyses, and can be used to calibrate compact expressions describing the breakup conditions. We have measured the strength of samples from Fe-rich meteorites using indentation and shock-loading experiments, and found them to be significantly stronger than was previously realized. This, together with the more accurate stress analysis, removes the altitude discrepancy for Fe-rich meteorites. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  15. Spacecraft destruction during re-entry - latest results and developments of the SCARAB software system

    NASA Astrophysics Data System (ADS)

    Lips, T.; Fritsche, B.; Koppenwallner, G.; Klinkrad, H.

    Not only since the re-entry of the MIR space station in 2001 the calculation of destructive re-entry and the prediction of ground risk potential due to space debris objects reaching the ground have become of high interest. Already in 1995 HTG started in an international cooperation with other companies and institutes under ESA contract the development of the SCARAB software system (SpaceCraft Atmospheric Re-entry and Aerothermal Break-up). SCARAB is a deterministic tool. The re-entry object is completely modelled down to sub-system level. The resulting aerodynamic parameters and mass distribution allow calculating a realistic 6D re-entry trajectory. Geometry and mass are continuously updated during calculation. Multi-level fragmentations due to different destruction processes are considered. The SCARAB software has been applied to several projects, namely ATV (Europe), ROSAT (Germany), Ariane-5 (Europe) and BeppoSAX (Italy). The practical application of SCARAB to project work has been demonstrated. In addition SCARAB has been tested against the NASA ORSAT code. It has also been verified with experimental data gained from re-entry vehicles, break-up observations and wind-tunnel tests. SCARAB is now on the way to become the European standard software for re-entry destruction analysis. This paper will give an overview of the latest results of applications of the software and a description of the interactive development process to fit the different needs of each project. The key features of planned future releases will be presented.

  16. Description of Jet Breakup

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  17. GOCE Re-Entry Campaign

    NASA Astrophysics Data System (ADS)

    Bastida, B.; Flohrer, T.; Lemmens, S.; Krag, H.

    2015-03-01

    Every year ESA, through the Space Debris Office, participates to an Inter-Agency Space Debris Coordination Committee (IADC) Re-entry Test Campaign.. For the campaign of 2013, ESA’s proposal to select GOCE's re-entry was accepted. The campaign opened on the 21st October 2013 after fuel depletion of the drag-compensating ion propulsion. GOCE was expected to enter into a phase of attitude-controlled fine-pointing mode (FPM) until the attitude controllers would be unable to cope with the atmospheric torques and then the satellite would enter in a phase of fully uncontrolled flight. In this paper, we present the evolution of ESA’s daily predictions on the re-entry epoch using different sources of orbital information. The uncertainties on the spacecraft operability (i.e. the physical limits of the attitude controller) led to a non-standard re-entry scenario were different attitudes had to be considered (instead of the commonly assumed random tumbling mode case that is used whenever no information on the physical properties of a re-entering object is available). A daily assessment of the status, in coordination with the flight control team, was required and implied a continuous update on the predicted failure point of the attitude controller. This in turn imposed the need for considering an asymmetric re-entry window. These operation-bound uncertainties were simulated to predict the attitude evolution after failure at different altitudes and their effects evaluated to be taken into account for the re-entry predictions. We present ESA’s re-entry prediction activities for GOCE, internally, and within the IADC, and address specific technical aspects and challenges for re-entry predictions, which are related to the expected and occurred attitude of GOCE during the final re-entry phase.

  18. Re-entry Experiment Launch

    NASA Video Gallery

    On August 10, 2009, NASA successfully launched the Inflatable Re-entry Vehicle Experiment (IRVE) and proved that spacecraft can use inflatable heat shields to reduce speed and provide protection du...

  19. Coulomb Breakup Problem

    SciTech Connect

    Kadyrov, A. S.; Bray, I.; Stelbovics, A. T.; Mukhamedzhanov, A. M.

    2008-12-05

    We formulate scattering theory in the framework of a surface-integral approach utilizing analytically known asymptotic forms of the three-body wave functions. This formulation is valid for both short-range and Coulombic potentials. The post and prior forms of the breakup amplitude are derived without any reference to renormalization procedures.

  20. RITD - Re-entry: Inflatable Technology Development in Russian Collaboration

    NASA Astrophysics Data System (ADS)

    Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Arruego, I.; Schmidt, W.; Haukka, H.; Finchenko, V.; Martynov, M.; Ostresko, B.; Ponomarenko, A.; Kazakovtsev, V.; Martin, S.; Siili, T.

    2014-04-01

    A new generation of inflatable Entry, Descent and Landing System (EDLS) for Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth's atmosphere is studied by the EU/RITD [1] project. Project focuses on the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry.

  1. Modeling of drop breakup in the bag breakup regime

    NASA Astrophysics Data System (ADS)

    Wang, C.; Chang, S.; Wu, H.; Xu, J.

    2014-04-01

    Several analytic models for predicting the drop deformation and breakup have been developed over the last three decades, but modeling drop breakup in the bag-type regime is less reported. In this Letter, a breakup model has been proposed to predict the drop deformation length and breakup time in the bag-type breakup regime in a more accurate manner. In the present model, the drop deformation which is approximately as the displacement of the centre of mass (c. m.) along the axis located at the centre of the drop, and the movement of c. m. is obtained by solving the pressure balance equation. The effects of the drop deformation on the drop external aerodynamic force are considered in this model. Drop breakup occurs when the deformation length reaches the maximum value and the maximum deformation length is a function of Weber number. The performance and applicability of the proposed breakup model are tested against the published experimental data.

  2. Application of the V-Gamma map to vehicle breakup analysis

    NASA Technical Reports Server (NTRS)

    Salama, Ahmed; McRonald, Angus; Ahmadi, Reza; LIng, Lisa; Accad, Elie; Kim, Alex

    2003-01-01

    The V-Gamma map consists of all possible pairs of speed and flight path angle at atmospheric entry interface for accidental Earth reentries resulting from steady misaligned burns, incomplete burns, or no burn.

  3. 14 CFR 435.3 - Types of reentry licenses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... authorizes a licensee to reenter one model or type of reentry vehicle, other than an RLV, to a reentry...

  4. 14 CFR 435.9 - Issuance of a reentry license.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... reentry license authorizes a licensee to reenter a reentry vehicle and payload, if any, in accordance...

  5. 14 CFR 435.9 - Issuance of a reentry license.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... reentry license authorizes a licensee to reenter a reentry vehicle and payload, if any, in accordance...

  6. 14 CFR 435.3 - Types of reentry licenses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... authorizes a licensee to reenter one model or type of reentry vehicle, other than an RLV, to a reentry...

  7. 14 CFR 435.3 - Types of reentry licenses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... authorizes a licensee to reenter one model or type of reentry vehicle, other than an RLV, to a reentry...

  8. 14 CFR 435.9 - Issuance of a reentry license.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... reentry license authorizes a licensee to reenter a reentry vehicle and payload, if any, in accordance...

  9. 14 CFR 435.3 - Types of reentry licenses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... authorizes a licensee to reenter one model or type of reentry vehicle, other than an RLV, to a reentry...

  10. 14 CFR 435.9 - Issuance of a reentry license.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV... reentry license authorizes a licensee to reenter a reentry vehicle and payload, if any, in accordance...

  11. The problem of space nuclear power sources collisions with artificial space objects in near-earth orbits

    NASA Astrophysics Data System (ADS)

    Gafarov, Albert A.

    1993-01-01

    Practically all space objects with onboard nuclear power sources stay in earth satellite orbits with an orbital lifetime long enough to reduce their radioactivity to levels presenting no danger for the Earth population. One of the reasons for orbit lifetime reduction can be collisions with other space objects in near-earth orbits. The possible consequence of collisions can be partial, or even complete, destruction of the spacecraft with an onboard nuclear power source; as well as delivery of additional impulse both to the spacecraft and its fragments. It is shown that collisions in orbit do not cause increase of radiation hazard for the Earth population if there is aerodynamic breakup of nuclear power sources into fragments of safe sizes during atmospheric reentry.

  12. Lunar Return Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Wall Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Tran, Van T.; Bowles, Jeff

    2007-01-01

    Thermostructural analysis was performed on generic crew exploration vehicle (GCEV) heat shielded wall structures subjected to reentry heating rates based on five potential lunar return reentry trajectories. The GCEV windward outer wall is fabricated with a graphite/epoxy composite honeycomb sandwich panel and the inner wall with an aluminum honeycomb sandwich panel. The outer wall is protected with an ablative Avcoat-5026-39H/CG thermal protection system (TPS). A virtual ablation method (a graphical approximation) developed earlier was further extended, and was used to estimate the ablation periods, ablation heat loads, and the TPS recession layer depths. It was found that up to 83 95 percent of the total reentry heat load was dissipated in the TPS ablation process, leaving a small amount (3-15 percent) of the remaining total reentry heat load to heat the virgin TPS and maintain the TPS surface at the ablation temperature, 1,200 F. The GCEV stagnation point TPS recession layer depths were estimated to be in the range of 0.280-0.910 in, and the allowable minimum stagnation point TPS thicknesses that could maintain the substructural composite sandwich wall at the limit temperature of 300 F were found to be in the range of 0.767-1.538 in. Based on results from the present analyses, the lunar return abort ballistic reentry was found to be quite attractive because it required less TPS weight than the lunar return direct, the lunar return skipping, or the low Earth orbit guided reentry, and only 11.6 percent more TPS weight than the low Earth orbit ballistic reentry that will encounter a considerable weight penalty to obtain the Earth orbit. The analysis also showed that the TPS weight required for the lunar return skipping reentry was much more than the TPS weight necessary for any of the other reentry trajectories considered.

  13. An Analysis of Ablation-Shield Requirements for Manned Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Roberts, Leonard

    1960-01-01

    The problem of sublimation of material and accumulation of heat in an ablation shield is analyzed and the results are applied to the reentry of manned vehicles into the earth's atmosphere. The parameters which control the amount of sublimation and the temperature distribution within the ablation shield are determined and presented in a manner useful for engineering calculation. It is shown that the total mass loss from the shield during reentry and the insulation requirements may be given very simply in terms of the maximum deceleration of the vehicle or the total reentry time.

  14. Simulated Reentry Heating by Torching

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    2008-01-01

    The two first order reentry heating parameters are peak heating flux (W/square cm) and peak heat load (kJ/square cm). Peak heating flux (and deceleration, gs) is higher for a ballistic reentry and peak heat load is higher for a lifting reentry. Manned vehicle reentries are generally lifting reentries at nominal 1-5 gs so that personnel will not be crushed by high deceleration force. A few off-nominal manned reentries have experienced 8 or more gs with corresponding high heating flux (but below nominal heat load). The Shuttle Orbiter reentries provide about an order of magnitude difference in peak heating flux at mid-bottom (TPS tiles, approximately 6 W/square cm or 5 BTU/square ft - sec) and leading edge (RCC, approximately 60 W/square cm or 50 BTU/square ft- sec). Orion lunar return and Mars sample lander are of the same order of magnitude as orbiter leading edge peak heat loads. Flight temperature measurements are available for some orbiter TPS tile and RCC locations. Return-to-Flight on-orbit tile-repair-candidate-material-heating performance was evaluated by matching propane torch heating of candidate-materials temperatures at several depths to orbiter TPS tile flight-temperatures. Char and ash characteristics, heat expansion, and temperature histories at several depths of the cure-in-place ablator were some of the TPS repair material performance characteristics measured. The final char surface was above the initial surface for the primary candidate (silicone based) material, in contrast to a receded surface for the Apollo-type ablative heat shield material. Candidate TPS materials for Orion CEV (LEO and lunar return), and for Mars sample lander (MSL) are now being evaluated. Torching of a candidate ablator material, PICA, was performed to match the ablation experienced by the STARDUST PICA heat shield. Torching showed that the carbon fiberform skeleton in a sample of PICA was inhomogeneous in that sample, and allowed measurements (of the clumps and voids) of

  15. Simulated Reentry Heating by Torching

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    2008-01-01

    The two first order reentry heating parameters are peak heating flux (W/cm2) and peak heat load (kJ/cm2). Peak heating flux (and deceleration, gs) is higher for a ballistic reentry and peak heat load is higher for a lifting reentry. Manned vehicle reentries are generally lifting reentries at nominal 1-5 gs so that personnel will not be crushed by high deceleration force. A few off-nominal manned reentries have experienced 8 or more gs with corresponding high heating flux (but below nominal heat load). The Shuttle Orbiter reentries provide about an order of magnitude difference in peak heating flux at mid-bottom (TPS tiles, approximately 6 W/cm2 or 5 BTU/ft2- sec) and leading edge (RCC, approximately 60 W/cm2 or 50 BTU/ft2- sec). Orion lunar return and Mars sample lander are of the same order of magnitude as orbiter leading edge peak heat loads. Flight temperature measurements are available for some orbiter TPS tile and RCC locations. Return-to-Flight on-orbit tile-repair-candidate-material-heating performance was evaluated by matching propane torch heating of candidate-materials temperatures at several depths to orbiter TPS tile flight-temperatures. Char and ash characteristics, heat expansion, and temperature histories at several depths of the cure-in-place ablator were some of the TPS repair material performance characteristics measured. The final char surface was above the initial surface for the primary candidate (silicone based) material, in contrast to a receded surface for the Apollo-type ablative heat shield material. Candidate TPS materials for Orion CEV (LEO and lunar return), and for Mars sample lander are now being evaluated. Torching of a candidate ablator material, PICA, was performed to match the ablation experienced by the STARDUST PICA heat shield. Torching showed that the carbon fiberform skeleton in a sample of PICA was inhomogeneous in that sample, and allowed measurements (of the clumps and voids) of the inhomogeneity. Additional reentry

  16. Trajectory Design and Control for the Compton Gamma Ray Observatory Re-Entry

    NASA Technical Reports Server (NTRS)

    Hoge, Susan; Vaughn, Frank J., Jr.

    2001-01-01

    The Compton Gamma Ray Observatory (CGRO) controlled re-entry operation was successfully conducted in June of 2000. The surviving parts of the spacecraft landed in the Pacific Ocean within the nominal impact target zone. The design of the maneuvers to control the trajectory to accomplish this re-entry presented several challenges. These challenges included the timing and duration of the maneuvers, propellant management, post-maneuver state determination, collision avoidance with other spacecraft, accounting for the break-up of the spacecraft into several pieces with a wide range of ballistic coefficients, and ensuring that the impact footprint would remain within the desired impact target zone in the event of contingencies. This paper presents the initial re-entry trajectory design and traces the evolution of that design into the maneuver sequence used for the re-entry. The paper also discusses the spacecraft systems and operational constraints imposed on the trajectory design and the required modifications to the initial design based on those constraints. Data from the reentry operation are also presented.

  17. Trajectory Design and Control for the Compton Gamma Ray Observatory Re-Entry

    NASA Technical Reports Server (NTRS)

    Hoge, Susan; Vaughn, Frank; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    The Compton Gamma Ray Observatory (CGRO) controlled re-entry operation was successfully conducted in June of 2000. The surviving parts of the spacecraft landed in the Pacific Ocean within the predicted footprint. The design of the maneuvers to control the trajectory to accomplish this re-entry presented several challenges. These challenges included timing and duration of the maneuvers, fuel management, post maneuver position knowledge, collision avoidance with other spacecraft, accounting for the break-up of the spacecraft into several pieces with a wide range of ballistic coefficients, and ensuring that the impact footprint would remain within the desired landing area in the event of contingencies. This paper presents the initial re-entry trajectory design and the evolution of the design into the maneuver sequence used for the re-entry. The paper discusses the constraints on the trajectory design, the modifications made to the initial design and the reasons behind these modifications. Data from the re-entry operation are presented.

  18. An auroral breakup mechanism

    NASA Technical Reports Server (NTRS)

    Maggs, J. E.

    1973-01-01

    A purely growing electrostatic drift instability driven by the electron temperature gradient at the inner edge of the plasma sheet can grow for large enough values of the temperature gradient. The parallel electric field associated with the instability is localized near the magnetic equator. The growth of the drift instability leads to enhanced whistler noise and increased electron pitch angle diffusion. If the current limit is exceeded in the ionosphere while the parallel electric field of the drift instability exists along the field line, rapid electron precipitation (the auroral breakup) can result.

  19. Understanding Columbia's Reentry Problems

    NASA Technical Reports Server (NTRS)

    Paul, Thomas

    2006-01-01

    Soon after the Space Shuttle Columbia accident occurred last year, a group of CFD analysts from NASA centers and private industry was organized to help determine the cause of the accident. This group was under the direction of the Applied Aeroscience and CFD Branch of the Aeroscience and Flight Mechanics Division at the Johnson Space Center. For external flow simulations, noncommercia2 CFD codes that specialize in hypersonic or high Mach number flows were used. These tools were used to determine heating rates, pressures, and temperatures for a large number of vehicle damage scenarios. Lockheed Martin Space Operations was called upon to provide CFD support in the area of internal flows within the shuttle wing cavity, and for these simulations, FLUENT 6.1 was chosen. Two large-scale, simplified models were m to understand the flow patterns once a breach of the internal wing cavity was initiated. The results were primarily used to visualize flow patterns within the wing cavity. The first CFD model included the entire lee wing without the wheel well cavity. The purpose of the first model, which did not include the reinforced carbon-carbon (RCC) cavity along the wing leading edge, was to visualize the flow field within the wing cavity immediately after the leading edge spar breach, This model assumed that the flow coming into the wing cavity was normal to the spar. It included all of the primary vents that allow for flow between the main cavities of the wing. A six-inch diameter hole was modeled in the spar at the approximate location where the spar breach was judged to have occurred, which was between RCC panels 8 and 9. The results of the modeling showed that at this location, the high temperature, high velocity gas stream entering the wing cavity impinged on the outboard wheel well cavity. Instrumentation in the Shuttle wheel well cavity registered abnormal temperatures during reentry, so the FLUENT results helped support the conclusion of the accident investigation

  20. History of satellite break-ups in space

    NASA Technical Reports Server (NTRS)

    Gabbard, J.

    1985-01-01

    By 28 June 1961 the 1st Aerospace Control Squadron had cataloged 115 Earth orbiting satellites from data supplied by a rather diverse collection of radar and optical sensors. On 29 June 1961, the Able Star rocket of the 1961 Omicron launch exploded causing a quantum jump in the number of Earth orbiting objects. Since that time there have been 69 Earth orbiting satellites break up in space whose debris remained in orbit long enough for orbital elements to be developed. A list of the 69 breakups is provided. The debris from some of the lower altitude breakups has all decayed. Among the 69 breakups, 44 have cataloged debris remaining in orbit. As of 1 July 1982, the size of the cataloged orbiting population was exactly 4700. Forty-nine percent of these objects are fragments of the forty-four breakups. For each breakup the various orbits of its debris represent a family of orbits that are related in characteristics due to their common impulse launch. A few examples are shown of how the families are oriented in space.

  1. Statistical Issues for Uncontrolled Reentry Hazards

    NASA Technical Reports Server (NTRS)

    Matney, Mark

    2008-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering objects to human populations. These tools make use of the characteristics (e.g., mass, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of the analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. This inevitably involves assumptions that simplify the problem and make it tractable, but it is often difficult to test the accuracy and applicability of these assumptions. This paper looks at a number of these theoretical assumptions, examining the mathematical basis for the hazard calculations, and outlining the conditions under which the simplifying assumptions hold. In addition, this paper will also outline some new tools for assessing ground hazard risk in useful ways. Also, this study is able to make use of a database of known uncontrolled reentry locations measured by the United States Department of Defense. By using data from objects that were in orbit more than 30 days before reentry, sufficient time is allowed for the orbital parameters to be randomized in the way the models are designed to compute. The predicted ground footprint distributions of these objects are based on the theory that their orbits behave basically like simple Kepler orbits. However, there are a number of factors - including the effects of gravitational harmonics, the effects of the Earth's equatorial bulge on the atmosphere, and the rotation of the Earth and atmosphere - that could cause them to diverge from simple Kepler orbit behavior and change the ground footprints. The measured latitude and longitude

  2. Reentry Vehicle Flight Controls Design Guidelines: Dynamic Inversion

    NASA Technical Reports Server (NTRS)

    Ito, Daigoro; Georgie, Jennifer; Valasek, John; Ward, Donald T.

    2002-01-01

    This report addresses issues in developing a flight control design for vehicles operating across a broad flight regime and with highly nonlinear physical descriptions of motion. Specifically it addresses the need for reentry vehicles that could operate through reentry from space to controlled touchdown on Earth. The latter part of controlled descent is achieved by parachute or paraglider - or by all automatic or a human-controlled landing similar to that of the Orbiter. Since this report addresses the specific needs of human-carrying (not necessarily piloted) reentry vehicles, it deals with highly nonlinear equations of motion, and then-generated control systems must be robust across a very wide range of physics. Thus, this report deals almost exclusively with some form of dynamic inversion (DI). Two vital aspects of control theory - noninteracting control laws and the transformation of nonlinear systems into equivalent linear systems - are embodied in DI. Though there is no doubt that the mathematical tools and underlying theory are widely available, there are open issues as to the practicality of using DI as the only or primary design approach for reentry articles. This report provides a set of guidelines that can be used to determine the practical usefulness of the technique.

  3. Test Cases for Reentry Survivability Modeling

    NASA Astrophysics Data System (ADS)

    Ailor, W.; Hallman, W.; Steckel, G.; Weaver, M.

    2012-01-01

    One approved approach for minimizing the long-term hazards posed by space debris is to reenter space hardware into the atmosphere at end-of-mission or to place hardware in an orbit with a relatively short lifetime. Selection of a short lifetime orbit vice a deorbited reentry into a safe area depends on predictions of the hazards posed by random reentry of the object. If the object is left in orbit, what is the casualty expectation associated with its eventual reentry? Clearly, having high confidence in reentry hazard prediction tools is important to this decision-making process and the final choice can have significant mission and cost impacts. This paper describes a set of test cases that can be used to validate reentry hazard models. The test cases were assembled from reentry cases where "known" and tracked objects reentered the atmosphere and debris from the reentries was subsequently found on the ground and was analyzed. The test cases include best estimates of the state, mass properties, and physical description of each object prior to reentry, the wind profile through which the debris fell (for one case), and the impact location and physical description of each surviving object. The report also summarizes results of metallurgical analyses conducted on surviving debris, which places limits on the maximum temperatures reached during reentry. Details on a specific reentry are included as an example.

  4. Current reduction in a pseudo-breakup event: THEMIS observations

    NASA Astrophysics Data System (ADS)

    Yao, Z. H.; Pu, Z. Y.; Owen, C. J.; Fu, S. Y.; Chu, X. N.; Liu, J.; Angelopoulos, V.; Rae, I. J.; Yue, C.; Zhou, X.-Z.; Zong, Q.-G.; Cao, X.; Shi, Q. Q.; Forsyth, C.; Du, A. M.

    2014-10-01

    Pseudo-breakup events are thought to be generated by the same physical processes as substorms. This paper reports on the cross-tail current reduction in an isolated pseudo-breakup observed by three of the THEMIS probes (THEMIS A (THA), THEMIS D (THD), and THEMIS E (THE)) on 22 March 2010. During this pseudo-breakup, several localized auroral intensifications were seen by ground-based observatories. Using the unique spatial configuration of the three THEMIS probes, we have estimated the inertial and diamagnetic currents in the near-Earth plasma sheet associated with flow braking and diversion. We found the diamagnetic current to be the major contributor to the current reduction in this pseudo-breakup event. During flow braking, the plasma pressure was reinforced, and a weak electrojet and an auroral intensification appeared. After flow braking/diversion, the electrojet was enhanced, and a new auroral intensification was seen. The peak current intensity of the electrojet estimated from ground-based magnetometers, ~0.7 × 105 A, was about 1 order of magnitude lower than that in a typical substorm. We suggest that this pseudo-breakup event involved two dynamical processes: a current-reduction associated with plasma compression ahead of the earthward flow and a current-disruption related to the flow braking/diversion. Both processes are closely connected to the fundamental interaction between fast flows, the near-Earth ambient plasma, and the magnetic field.

  5. Incarceration, Prisoner Reentry, and Communities.

    PubMed

    Morenoff, Jeffrey D; Harding, David J

    2014-07-01

    Since the mid-1970s the United States has experienced an enormous rise in incarceration and accompanying increases in returning prisoners and in post-release community correctional supervision. Poor urban communities are disproportionately impacted by these phenomena. This review focuses on two complementary questions regarding incarceration, prisoner reentry, and communities:(1) whether and how mass incarceration has affected the social and economic structure of American communities, and (2) how residential neighborhoods affect the social and economic reintegration of returning prisoners. These two questions can be seen as part of a dynamic process involving a pernicious "feedback" loop, in which mass incarceration undermines the structure and social organization of some communities, thus creating more criminogenic environments for returning prisoners and further diminishing their prospects for successful reentry and reintegration. PMID:25400321

  6. Incarceration, Prisoner Reentry, and Communities

    PubMed Central

    Morenoff, Jeffrey D.; Harding, David J.

    2014-01-01

    Since the mid-1970s the United States has experienced an enormous rise in incarceration and accompanying increases in returning prisoners and in post-release community correctional supervision. Poor urban communities are disproportionately impacted by these phenomena. This review focuses on two complementary questions regarding incarceration, prisoner reentry, and communities:(1) whether and how mass incarceration has affected the social and economic structure of American communities, and (2) how residential neighborhoods affect the social and economic reintegration of returning prisoners. These two questions can be seen as part of a dynamic process involving a pernicious “feedback” loop, in which mass incarceration undermines the structure and social organization of some communities, thus creating more criminogenic environments for returning prisoners and further diminishing their prospects for successful reentry and reintegration. PMID:25400321

  7. Preventing re-entry to foster care.

    PubMed

    Carnochan, Sarah; Rizik-Baer, Daniel; Austin, Michael J

    2013-01-01

    Re-entry to foster care generally refers to circumstances in which children who have been discharged from foster care to be reunified with their family of origin, adopted, or provided kinship guardianship are returned to foster care. In the context of the federal performance measurement system, re-entry refers specifically to a return to foster care following an unsuccessful reunification. The federal Children and Family Services Review measures re-entry to foster care with a single indicator, called the permanency of reunification indicator, one of four indicators comprising the reunification composite measure. This review focuses on research related to the re-entry indicator, including the characteristics of children, caregivers and families, as well as case and child welfare services that are associated with a higher or lower risk of re-entry to foster care. Promising post-reunification services designed to prevent re-entry to foster care are described. PMID:23705650

  8. Genesis Reentry Observations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Suggs, R. M.; Swift, W. R.

    2005-01-01

    The Genesis spacecraft reentry represented a unique opportunity to observe a "calibrated meteor" from northern Nevada. Knowing its speed, mass, composition, and precise trajectory made it a good subject to test some of the algorithms used to determine meteoroid mass from observed brightness. It was also a good test of an inexpensive set of cameras that could be deployed to observe future shuttle reentries. The utility of consumer-grade video cameras was evident during the STS-107 accident investigation, and the Genesis reentry gave us the opportunity to specify and test commercially available cameras that could be used during future reentries. This Technical Memorandum describes the video observations and their analysis, compares the results with a simple photometric model, describes the forward scatter radar experiment, and lists lessons learned from the expedition and implications for the Stardust reentry in January 2006 as well as future shuttle reentries.

  9. Reentry survival analysis of tumbling metallic hollow cylinder

    NASA Astrophysics Data System (ADS)

    Sim, Hyung-seok; Kim, Kyu-hong

    2011-09-01

    The survival of orbital debris reentering the Earth's atmosphere is considered. The numerical approach of NASA's Object Reentry Survival Analysis Tool (ORSAT) is reviewed, and a new equation accounting for reradiation heat loss of hollow cylindrical objects is presented. Based on these, a code called Survivability Analysis Program for Atmospheric Reentry (SAPAR) has been developed, and the new equation for reradiation heat loss is validated. Using this equation in conjunction with the formulation used in ORSAT, a comparative case study on the Delta-II second stage cylindrical tank is given, demonstrating that the analysis using the proposed equation is in good agreement with the actual recovered object when a practical value for thermal emissivity is used. A detailed explanation of the revised formulation is given, and additional simulation results are presented. Finally, discussions are made to address the applicability of the proposed equation to be incorporated in future survival analyses of orbital debris.

  10. Optimum reentry trajectories of a lifting vehicle

    NASA Technical Reports Server (NTRS)

    Chern, J. S.; Vinh, N. X.

    1980-01-01

    Research results are presented of an investigation of the optimum maneuvers of advanced shuttle type spacecraft during reentry. The equations are formulated by means of modified Chapman variables resulting in a general set of equations for flight analysis which are exact for reentry and for flight in a vacuum. Four planar flight typical optimum manuevers are investigated. For three-dimensional flight the optimum trajectory for maximum cross range is discussed in detail. Techniques for calculating reentry footprints are presented.

  11. 75 FR 75621 - Office of Commercial Space Transportation; Waiver of Autonomous Reentry Restriction for a Reentry...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-06

    ... Commercial Space Transportation Reusable Launch Vehicle and Reentry Licensing Regulations, 64 FR 19626, 19645... the Federal Aviation Administration (FAA) by Space Exploration Technologies Corp. (SpaceX): A petition... initiation of reentry in the absence of active human control. Reentry NPRM, 64 FR at 19645. The FAA...

  12. PREDICTION OF AGRICULTURAL WORKER SAFETY REENTRY TIMES FOR ORGANOPHOSPHATE INSECTICIDES

    EPA Science Inventory

    Concepts and current methods of determining worker safety reentry times are reviewed. Comparison of human monitoring studies, factors in a worker reentry episode and exposure estimation methods illustrate the advantages of estimation methods. Research needs for worker reentry tim...

  13. Heat source reentry vehicle design study

    NASA Technical Reports Server (NTRS)

    Ryan, R. L.

    1971-01-01

    The design details are presented of a flight-type heat source reentry vehicle and heat exchanger compatible with the isotope Brayton power conversion system. The reference reentry vehicle and heat exchanger were modified, orbital and superorbital capability was assessed, and a complete set of detail design layout drawings were provided.

  14. Attracting Reentry Women to Engineering and Technology.

    ERIC Educational Resources Information Center

    American Society for Engineering Education, Washington, DC.

    Three papers on attracting reentry women to engineering and technology are presented. The first paper, "Encouraging Older Women as Engineering Students," discusses the opportunities, the problems, and suggested actions for women pursuing engineering careers. The second paper, "Industrial Programs for Reentry Opportunities for Women as Engineers,"…

  15. Guiding Principles for Physician Reentry Programs

    ERIC Educational Resources Information Center

    Kenagy, Gretchen P.; Schneidman, Barbara S.; Barzansky, Barbara; Dalton, Claudette; Sirio, Carl A.; Skochelak, Susan E.

    2011-01-01

    Physician reentry is defined by the American Medical Association (AMA) as: "A return to clinical practice in the discipline in which one has been trained or certified following an extended period of clinical inactivity not resulting from discipline or impairment." Physician reentry programs are creating an avenue for physicians who have left…

  16. Earth

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The following aspects of the planet Earth are discussed: plate tectonics, the interior of the planet, the formation of the Earth, and the evolution of the atmosphere and hydrosphere. The Earth's crust, mantle, and core are examined along with the bulk composition of the planet.

  17. Near Term Effects from Satellite Break-Ups on Manned Space Activities

    NASA Technical Reports Server (NTRS)

    Theall, J. R.; Matney, M. J.

    2000-01-01

    Since 1961, almost 160 satellite break-ups have occurred on-orbit, and have been the major contributor to the growth of the orbital debris population. When a satellite breaks up, the debris exists in a relatively concentrated form, orbiting in a loose cloud with the parent body until orbital perturbations disperse the cloud into the average background. Manned space activities, which usually take place in low Earth orbit at altitudes less than 500 km, have been continuous for the past I I years while Mir was inhabited and promise to be again continuous when the International Space Station becomes permanently manned. This paper surveys historical breakups over the last I I years to determine the number that affect altitudes lower than 500 km. Selected breakup are analyzed using NASA's Satellite Breakup Risk Assessment Model (SBRAM) to determine the specific short term risk from those breakups to manned missions.

  18. GOCE SSTI GNSS Receiver Re-Entry Phase Analysis

    NASA Astrophysics Data System (ADS)

    Zin, A.; Zago, S.; Scaciga, L.; Marradi, L.; Floberghagen, R.; Fehringer, M.; Bigazzi, A.; Piccolo, A.; Luini, L.

    2015-03-01

    Gravity field and Ocean Circulation Explorer (GOCE) was an ESA Earth Explorer mission dedicated to the measure of the Earth Gravity field. The Spacecraft has been launched in 2009 and the re-entry in atmosphere happened at the end of 2013 [1]. The mean orbit altitude was set to 260 km to maximize the ultra-sensitive accelerometers on board. GOCE was equipped with two main payloads: the Electrostatic Gravity Gradiometer (EGG), a set of six 3-axis accelerometers able to measure the gravity field with unrivalled precision and then to produce the most accurate shape of the ‘geoid’ and two GPS receivers (nominal and redundant), used as a Satellite-to-Satellite Tracking Instrument (SSTI) to geolocate the gradiometer measurements and to measure the long wavelength components of the gravity field with an accuracy never reached before. Previous analyses have shown that the Precise Orbit Determination (POD) of the GOCE satellite, derived by processing the dual-frequency SSTI data (carrier phases and pseudoranges) are at the “state-of-art” of the GPS based POD: kinematic Orbits Average of daily 3D-RMS is 2,06 cm [2]. In most cases the overall accuracy is better than 2 cm 3D RMS. Moreover, the “almost continuous” [2] 1 Hz data availability from the SSTI receiver is unique and allows for a time series of kinematic positions with only 0.5% of missing epochs [2]. In October 2013 GOCE mission was concluded and in November the GOCE spacecraft re-entered in the atmosphere. During the re-entry phase the two SSTI receivers have been switched on simultaneously in order to maximize the data availability. In summer 2013, the SSTI firmware was tailored in order to sustain additional dynamic error (tracking loops robustness), expected during the re-entry phase. The SW was uploaded on SSTI-B (and purposely not on SSTI-A). Therefore this was an unique opportunity to compare a “standard” receiver behaviour (SSTI-A) with an improved one (SSTI-B) in the challenging reentry phase

  19. The cometary breakup hypothesis re-examined

    NASA Astrophysics Data System (ADS)

    La Violette, P. A.

    1987-02-01

    The theory that a Chiron-like progenitor of both Comet Encke and the Tunguska cosmic body may have fragmented beginning around 22,000 years BP and that debris from this breakup was responsible for producing the high heavy metal concentrations observed in the Late Wisconin stage polar ice is shown to be incorrectly founded. This paper reexamines the geochemical comparison which Clube and Napier (1984) make between the composition of the Tunguska cosmic body and elemental abundances previously reported for a sample of Sn-rich dust retrieved from the Wisconsin section of the Camp Century ice core. No evidence is found that would link these two sources to a common origin. Thus the hypothesis that a cometary breakup was responsible for modulating the earth's climate and perpetuating the last ice age is unfounded. On the other hand, evidence is presented indicating that debris from the Tunguska explosion may be present in a firm layer at Dome C, East Antarctica. Analysis of the geochemical data for this stratum leads to an estimate of 10 to the 6th to 10 to the 7th t for the mass of the Tunguska body, in approximate agreement with previous determinations.

  20. Thermal Protection Materials for Reentry Applications

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia M.; Stackpoole, Mairead; Gusman, Mike; Loehman, Ron; Kotula, Paul; Ellerby, Donald; Arnold, James; Wercinski, Paul; Reuthers, James; Kontinos, Dean

    2001-01-01

    Thermal protection materials and systems (IRS) are used to protect spacecraft during reentry into Earth's atmosphere or entry into planetary atmospheres. As such, these materials are subject to severe environments with high heat fluxes and rapid heating. Catalytic effects can increase the temperatures substantially. These materials are also subject to impact damage from micrometeorites or other debris during ascent, orbit, and descent, and thus must be able to withstand damage and to function following damage. Thermal protection materials and coatings used in reusable launch vehicles will be reviewed, including the needs and directions for new materials to enable new missions that require faster turnaround and much greater reusability. The role of ablative materials for use in high heat flux environments, especially for non-reusable applications and upcoming planetary missions, will be discussed. New thermal protection system materials may enable the use of sharp nose caps and leading edges on future reusable space transportation vehicles. Vehicles employing this new technology would have significant increases in maneuverability and out-of-orbit cross range compared to current vehicles, leading to increased mission safety in the event of the need to abort during ascent or from orbit. Ultrahigh temperature ceramics, a family of materials based on HfB2 and ZrB2 with SiC, will be discussed. The development, mechanical and thermal properties, and uses of these materials will be reviewed.

  1. Reentry thermal protection from Pioneer F RTG insulation material

    NASA Technical Reports Server (NTRS)

    Vorreiter, J. W.

    1972-01-01

    Ablation tests were performed on the insulation material used in the Pioneer F radioisotope thermoelectric generator (RTG) in the Ames Arc-Heated Planetary-Gas Wind Tunnel. Test results indicate that the material, trade name Min-K 1301, should experience little ablation for heat transfer rates below 40 BTU/sq ft-sec. If the current design were to be changed so that the various pieces of Min-K were fastened or interlocked together the total amount of heat delivered to the RTG heat source during an earth orbital decay reentry would be reduced by at least 22.7%.

  2. 14 CFR 435.3 - Types of reentry licenses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Types of reentry licenses. 435.3 Section 435.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.3 Types of reentry licenses....

  3. Follow-up investigations of GPHS motion during heat pulse intervals of reentries from gravity-assist trajectories

    SciTech Connect

    Sharbaugh, R.C.

    1992-03-23

    Motion studies of the General Purpose Heat Source Module, GPHS, which were conducted in the heat pulse intervals associated with entries from earth gravity assist trajectories. The APL six-degree-of-freedom reentry program designated TMAGRA6C was used. The objectives of the studies were to (1) determine whether the GPHS module entering the earth's atmosphere from an earth-gravity-assist trajectory has a preferred orientation during the heat pulse of reentry, (2) determine the effect of magnus force on the roll rate and angle of attack of the GPHS during an EGA entry, (3) determine the effect of the magnitude of pitch and roll damping on the GPHS motion.

  4. Reusable Reentry Satellite (RRS) system design study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) is intended to provide investigators in several biological disciplines with a relatively inexpensive method to access space for up to 60 days with eventual recovery on Earth. The RRS will permit totally intact, relatively soft, recovery of the vehicle, system refurbishment, and reflight with new and varied payloads. The RRS is to be capable of three reflights per year over a 10-year program lifetime. The RRS vehicle will have a large and readily accessible volume near the vehicle center of gravity for the Payload Module (PM) containing the experiment hardware. The vehicle is configured to permit the experimenter late access to the PM prior to launch and rapid access following recovery. The RRS will operate in one of two modes: (1) as a free-flying spacecraft in orbit, and will be allowed to drift in attitude to provide an acceleration environment of less than 10(exp -5) g. the acceleration environment during orbital trim maneuvers will be less than 10(exp -3) g; and (2) as an artificial gravity system which spins at controlled rates to provide an artificial gravity of up to 1.5 Earth g. The RRS system will be designed to be rugged, easily maintained, and economically refurbishable for the next flight. Some systems may be designed to be replaced rather than refurbished, if cost effective and capable of meeting the specified turnaround time. The minimum time between recovery and reflight will be approximately 60 days. The PMs will be designed to be relatively autonomous, with experiments that require few commands and limited telemetry. Mass data storage will be accommodated in the PM. The hardware development and implementation phase is currently expected to start in 1991 with a first launch in late 1993.

  5. STS-30 deorbit and reentry ground track

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Rockwell International (RI) supplied artist concept titled 'STS-30 Deorbit and Reentry Track' shows Atlantis, Orbiter Vehicle (OV) 104, deorbit and reentry ground track. Ground track and map portray OV-104's deorbit over Madagascar, atmospheric reentry maneuvers, approach to the California coast, and landing at Edwards Air Force Base (EAFB), California. the transport trailer of the Payload Environmental Transportation System (PETS). Magellan, destined for unprecedented studies of Venusian topographic features, will be deployed by the crew of NASA's STS-30 mission in April 1989. View provided by KSC with alternate number KSC-88PC-1086.

  6. Fusion and Breakup of Weakly Bound Nuclei

    SciTech Connect

    Gomes, P. R. S.; Lubian, J.; Padron, I.; Crema, E.; Chamon, L. C.; Hussein, M. S.; Canto, L. F.

    2006-08-14

    We discuss the influence of the breakup process of weakly bound nuclei on the fusion cross section. The complete fusion for heavy targets is found to be suppressed due to the incomplete fusion following the breakup, whereas this effect is negligible for light targets. The total fusion cross sections for stable projectiles are not affected by the breakup process, whereas it is suppressed for halo projectiles. The non capture breakup is the dominant process at sub-barrier energies.

  7. Impacts, tillites, and the breakup of Gondwanaland

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Marshall, John R.; Aggarwal, Hans

    1993-01-01

    Mathematical analysis demonstrates that substantial impact crater deposits should have been produced during the last 2 Gy of Earth's history. Textures of impact deposits are shown to resemble textures of tillites and diamictites of Precambrian and younger ages. The calculated thickness distribution for impact crater deposits produced during 2 Gy is similar to that of tillites and diamictites of 2 Ga or younger. We suggest, therefore, that some tillites/diamictites could be of impact origin. Extensive tillite/diamictite deposits predated continental flood basalts on the interior of Gondwanaland. Significantly, other investigators have already associated impact cratering with flood basalt volcanism and continental rifting. Thus, it is proposed that the breakup of Gondwanaland could have been initiated by crustal fracturing from impacts.

  8. Atomization, drop size, and penetration for cross-stream water injection at high-altitude reentry conditions with application to the RAM C-1 and C-3 flights

    NASA Technical Reports Server (NTRS)

    Gooderum, P. B.; Bushnell, D. M.

    1972-01-01

    Atomization, drop size, and penetration data are presented for cross stream water injection at conditions simulating high altitude reentry (low Weber number, high static temperature, high Knudsen number, and low static pressure). These results are applied to the RAM C-1 and C-3 flights. Two primary breakup modes are considered, vapor pressure or flashing and aerodynamic atomization. Results are given for breakup boundaries and mean drop size for each of these atomization mechanisms. Both standard and flight orifice geometries are investigated. The data were obtained in both a static environment and in conventional aerodynamic facilities at Mach numbers of 4.5 and 8. The high temperature aspects of reentry were simulated in a Mach 5.5 cyanogen-oxygen tunnel with total temperature of 4500 K.

  9. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

    Glaese, J. R.; Kennel, H. F.

    1979-01-01

    All the available torque equilibrium attitudes (most were useless from the standpoint of lack of electrical power) and the equilibrium seeking method are presented, as well as the actual successful application during the 3 weeks prior to Skylab reentry.

  10. Re-Entry Platform for Radiation Studies

    NASA Astrophysics Data System (ADS)

    Bailet, G. B.; Bourgoing, A. B.; Magin, T. M.; Laux, C. O. L.

    2014-06-01

    Based on an emission spectrometer, the payload developed by ECP and VKI will permit through newly developed methodology to characterize the reentry plasma and some ablation behaviors including recession rate in a plug concept to be flown by 2015.

  11. Lifetime and reentry prediction for the Petite Amateur Navy Satellite (PANSAT)

    NASA Astrophysics Data System (ADS)

    Cuff, Daniel J.

    1994-06-01

    The Naval Postgraduate School (NPS) is developing a small satellite for digital communications in the amateur frequency band. The Petite Amateur Navy Satellite (PANSAT) will primarily act as an orbiting spread-spectrum communications laboratory, possesses neither an attitude control nor a propulsion system, and is designed to 'tumble' along its orbital path once it is released from the launch vehicle which is scheduled to be the space shuttle. An explanation of the many variables and assumptions affecting PANSAT is provided as insight for the lifetime and reentry predictions. Using a conservative approach, results from combining altitudes and inclinations from expected space shuttle missions, solar flux and magnetic indices from three different sources, and the use of an orbital propagator program, LIFETIME 4.1, which was developed by Aerospace Corporation, attest that the minimum 2 year lifetime requirement for PANSAT will be met by nine shuttle missions between July 1996 and December 1997. A reentry analysis concluded that PANSAT will experience sufficient aerodynamic forces to cause structural failure and breakup during atmospheric reentry.

  12. Statistical Issues for Uncontrolled Reentry Hazards - Empirical Tests of the Predicted Footprint for Uncontrolled Satellite Reentry Hazards

    NASA Astrophysics Data System (ADS)

    Matney, M.

    2012-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering objects to human populations. These tools make use of the characteristics (e.g., mass, material, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of the analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. Because this information is used in making policy and engineering decisions, it is important that these assumptions be tested using empirical data. This study uses the latest database of known uncontrolled reentry locations measured by the United States Department of Defense. The predicted ground footprint distributions of these objects are based on the theory that their orbits behave basically like simple Kepler orbits. However, there are a number of factors in the final stages of reentry - including the effects of gravitational harmonics, the effects of the Earth's equatorial bulge on the atmosphere, and the rotation of the Earth and atmosphere - that could cause them to diverge from simple Kepler orbit behavior and possibly change the probability of reentering over a given location. In this paper, the measured latitude and longitude distributions of these objects are directly compared with the predicted distributions, providing a fundamental empirical test of the model assumptions.

  13. Statistical Issues for Uncontrolled Reentry Hazards Empirical Tests of the Predicted Footprint for Uncontrolled Satellite Reentry Hazards

    NASA Technical Reports Server (NTRS)

    Matney, Mark

    2011-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering objects to human populations. These tools make use of the characteristics (e.g., mass, material, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of the analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. Because this information is used in making policy and engineering decisions, it is important that these assumptions be tested using empirical data. This study uses the latest database of known uncontrolled reentry locations measured by the United States Department of Defense. The predicted ground footprint distributions of these objects are based on the theory that their orbits behave basically like simple Kepler orbits. However, there are a number of factors in the final stages of reentry - including the effects of gravitational harmonics, the effects of the Earth s equatorial bulge on the atmosphere, and the rotation of the Earth and atmosphere - that could cause them to diverge from simple Kepler orbit behavior and possibly change the probability of reentering over a given location. In this paper, the measured latitude and longitude distributions of these objects are directly compared with the predicted distributions, providing a fundamental empirical test of the model assumptions.

  14. Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM

    NASA Technical Reports Server (NTRS)

    Jullien, Pierre

    2008-01-01

    During re-entry, spacecrafts are subjected to extreme thermal loads. On mars, they may go through dust storms. These external heat loads are leading the design of re-entry vehicles or are affecting it for spacecraft facing solid propellant jet stream. Sizing the Thermal Protection System require a good knowledge of such solicitations and means to model and reproduce them on earth. Through its work on European projects, ASTRIUM has developed the full range of competences to deal with such issues. For instance, we have designed and tested the heat-shield of the Huygens probe which landed on Titan. In particular, our plasma generators aim to reproduce a wide variety of re-entry conditions. Heat loads are generated by the huge speed of the probes. Such conditions cannot be fully reproduced. Ground tests focus on reproducing local aerothermal loads by using slower but hotter flows. Our inductive plasma torch enables to test little samples at low TRL. Amongst the arc-jets, one was design to test architecture design of ISS crew return system and others fit more severe re-entry such as sample returns or Venus re-entry. The last developments aimed in testing samples in seeded flows. First step was to design and test the seeding device. Special diagnostics characterizing the resulting flow enabled us to fit it to the requirements.

  15. GPHS motion studies for heat pulse intervals of reentries from gravity-assist trajectories. Aerospace Nuclear Safety Program

    SciTech Connect

    Lucero, E.F.; Sharbaugh, R.C.

    1990-03-01

    Motion studies of the General Purpose Heat Source Module, GPHS, were conducted in the heat pulse interval associated with entries from earth gravity assist trajectories. The APL six-degree-of-freedom reentry program designated TMAGRA6C was used. The objectives of the studies were to (1) determine the effect of ablation on GPHS motion, and (2) determine whether the GPHS module entering the earth`s atmosphere from an earth-gravity-assist trajectory has a preferred orientation during the heat pulse phase of reentry. The results are given in summary form for easy visualization of the initial conditions investigated and to provide a quick-look of the resulting motion. Detail of the motion is also given for the parameters of interest for each case studied. Selected values of initial pitch rate, roll rate, and combinations of these within the range 0{degree} to 1000{degrees}/sec were investigated for initial reentry angles of -7{degrees} (shallow) and -90{degrees} (steep) and initial angles of attack of 0{degree} (broadface to the wind) and 90{degrees}. Although the studies are not exhaustive, a sufficient number of reentry conditions (initial altitude, reentry angle, angle of attack, rotational motion) have been investigated to deduce certain trends. The results also provide information on additional reentry conditions that need to be investigated. The present results show four GPHS orientations that predominate - all with some pitch oscillations and rolling motion. These are: angles of attack, {alpha}{sub R} of 0{degree}, 30{degrees}, 90{degrees} and tumbling. It should be assumed that all these orientations are equally probable because only combinations of two initial reentry angles, {gamma}{sub 0}, and two values of {alpha}{sub R}. have been investigated. Further the probability for any given initial rate on orientation is not known.

  16. Women offenders and reentry issues.

    PubMed

    Taylor, S D

    1996-01-01

    Women parallel men in their profile of physical disease, psychosocial configuration, addictive patterns, and criminal deviance. For women offenders in particular, the prison environment reinforces a victim role that originated in childhood and adolescence. In addition, such settings discourage both emotional expression (except for aggression) and responsibility, since basic needs such as food, lodging, and clothing are provided. Incarcerated women have significant treatment issues, including the lack of social and vocational role definition, psychological dependence and psychic craving, poorly developed social skills, and conflicts in social, family, and intimate relationships. This article describes the unique psychoeducational and skills-training needs of women offenders as they adjust to community living, and outlines specific treatment interventions that have proven to effect successful patient outcomes. Case studies are used to illustrate the reentry experiences of three women offenders with distinct backgrounds. One example illustrates how a woman who had been involved in the criminal justice system for 24 years overcame her addiction and self-confidence issues. A second case study profiles an offender with three children who had experienced sexual trauma during her childhood and adult years. A third case reports on an African-American woman whose crack-cocaine addiction resulted in the birth of a drug-exposed son. The treatment model tested in all three cases emphasized the practical and often overlooked treatment issues of incarcerated women. PMID:8714337

  17. 75 FR 75619 - Waiver of Acceptable Mission Risk Restriction for Reentry and a Reentry Vehicle

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-06

    ... Vehicle and Reentry Licensing Regulations, Final Rule, 65 FR 56618 (Sep. 19, 2000). When discussing the...) (defining ``reentry'' as a purposeful act); see also 65 FR at 56624 (clarifying that, under Chapter 701.... See 49 U.S.C. at 70102(12); 65 FR at 56624. Under the above rationale, the total E c for the...

  18. A Strengths-Based Approach to Prisoner Reentry: The Fresh Start Prisoner Reentry Program.

    PubMed

    Hunter, Bronwyn A; Lanza, A Stephen; Lawlor, Mike; Dyson, William; Gordon, Derrick M

    2016-08-01

    Scholars have called for a strengths-based approach to prisoner reentry, yet there are few available program models that outline how to integrate this approach into the current reentry program landscape. The present article highlights a strengths-based prisoner reentry program that provided services to men both pre- and post-release from prison to the community in the United States. Qualitative findings from focus groups provide preliminary support for the strengths-based approach and highlight men's strengths and needs as well as challenges related to the program's implementation. The reentry program then drew from participants' reports to inform program development activities. Implications and recommendations for integrating strengths-based approaches into prisoner reentry interventions are discussed. PMID:25805715

  19. Coronas-F Orbit Monitoring and Re-Entry Prediction

    NASA Technical Reports Server (NTRS)

    Ivanov, N. M.; Kolyuka, Yu. F.; Afanasieva, T. I.; Gridchina, T. A.

    2007-01-01

    Russian scientific satellite CORONAS-F was launched on July, 31, 2001. The object was inserted in near-circular orbit with the inclination 82.5deg and a mean altitude approx. 520 km. Due to the upper atmosphere drag CORONAS-F was permanently descended and as a result on December, 6, 2005 it has finished the earth-orbital flight, having lifetime in space approx. 4.5 years. The satellite structural features and its flight attitude control led to the significant variations of its ballistic coefficient during the flight. It was a cause of some specific difficulties in the fulfillment of the ballistic and navigation support of this space vehicle flight. Besides the main mission objective CORONAS-F also has been selected by the Inter-Agency Space Debris Coordination Committee (IADC) as a target object for the next regular international re-entry test campaign on a program of surveillance and re-entry prediction for the hazard space objects within their de-orbiting phases. Spacecraft (S/C) CORONAS-F kept its working state right up to the end of the flight - down to the atmosphere entry. This fact enabled to realization of the additional research experiments, concerning with an estimation of the atmospheric density within the low earth orbits (LEO) of the artificial satellites, and made possible to continue track the S/C during final phase of its flight by means of Russian regular command & tracking system, used for it control. Thus there appeared a unique possibility of using for tracking S/C at its de-orbiting phase not only passive radar facilities, belonging to the space surveillance systems and traditionally used for support of the IADC re-entry test campaigns, but also more precise active trajectory radio-tracking facilities from the ground control complex (GCC) applied for this object. Under the corresponding decision of the Russian side such capability of additional high-precise tracking control of the CORONAS-F flight in this period of time has been implemented

  20. Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Structure

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Gong, Leslie; Quinn, Robert D.

    2007-01-01

    Comparative studies were performed on the heat-shielding characteristics of honeycomb-core sandwich panels fabricated with different materials for possible use as wall panels for the proposed crew exploration vehicle. Graphite/epoxy sandwich panel was found to outperform aluminum sandwich panel under the same geometry due to superior heat-shielding qualities and lower material density. Also, representative reentry heat-transfer analysis was performed on the windward wall structures of a generic crew exploration vehicle. The Apollo low Earth orbit reentry trajectory was used to calculate the reentry heating rates. The generic crew exploration vehicle has a graphite/epoxy composite honeycomb sandwich exterior wall and an aluminum honeycomb sandwich interior wall, and is protected with the Apollo thermal protection system ablative material. In the thermal analysis computer program used, the TPS ablation effect was not yet included; however, the results from the nonablation heat-transfer analyses were used to develop a "virtual ablation" method to estimate the ablation heat loads and the thermal protection system recession thicknesses. Depending on the severity of the heating-rate time history, the virtual ablation period was found to last for 87 to 107 seconds and the ablation heat load was estimated to be in the range of 86 to 88 percent of the total heat load for the ablation time period. The thermal protection system recession thickness was estimated to be in the range of 0.08 to 0.11 inches. For the crew exploration vehicle zero-tilt and 18-degree-tilt stagnation points, thermal protection system thicknesses of h = {0.717, 0.733} inches were found to be adequate to keep the substructural composite sandwich temperature below the limit of 300 F.

  1. 14 CFR 435.15 - Rights not conferred by reentry license.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.15 Rights not conferred by reentry license. Issuance of a reentry license...

  2. 14 CFR 435.15 - Rights not conferred by reentry license.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.15 Rights not conferred by reentry license. Issuance of a reentry license...

  3. 14 CFR 435.15 - Rights not conferred by reentry license.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.15 Rights not conferred by reentry license. Issuance of a reentry license...

  4. 14 CFR 435.15 - Rights not conferred by reentry license.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.15 Rights not conferred by reentry license. Issuance of a reentry license...

  5. GPHS motion studies for heat pulse intervals of reentries from gravity-assist trajectories. [General Purpose Heat Source Module (GPHS)

    SciTech Connect

    Lucero, E.F.; Sharbaugh, R.C.

    1990-03-01

    Motion studies of the General Purpose Heat Source Module, GPHS, were conducted in the heat pulse interval associated with entries from earth gravity assist trajectories. The APL six-degree-of-freedom reentry program designated TMAGRA6C was used. The objectives of the studies were to (1) determine the effect of ablation on GPHS motion, and (2) determine whether the GPHS module entering the earth's atmosphere from an earth-gravity-assist trajectory has a preferred orientation during the heat pulse phase of reentry. The results are given in summary form for easy visualization of the initial conditions investigated and to provide a quick-look of the resulting motion. Detail of the motion is also given for the parameters of interest for each case studied. Selected values of initial pitch rate, roll rate, and combinations of these within the range 0[degree] to 1000[degrees]/sec were investigated for initial reentry angles of -7[degrees] (shallow) and -90[degrees] (steep) and initial angles of attack of 0[degree] (broadface to the wind) and 90[degrees]. Although the studies are not exhaustive, a sufficient number of reentry conditions (initial altitude, reentry angle, angle of attack, rotational motion) have been investigated to deduce certain trends. The results also provide information on additional reentry conditions that need to be investigated. The present results show four GPHS orientations that predominate - all with some pitch oscillations and rolling motion. These are: angles of attack, [alpha][sub R] of 0[degree], 30[degrees], 90[degrees] and tumbling. It should be assumed that all these orientations are equally probable because only combinations of two initial reentry angles, [gamma][sub 0], and two values of [alpha][sub R]. have been investigated. Further the probability for any given initial rate on orientation is not known.

  6. German experiments developed for reentry missions

    NASA Astrophysics Data System (ADS)

    Auweter-Kurtz, M.; Hald, H.; Koppenwallner, G.; Speckmann, H.-D.

    1996-01-01

    For the development of reentry technology it is essential that the knowledge gained from ground test facilities and numerical methods is tested and broadened in real reentry flights. The first of such projects was the space reentry capsule EXPRESS, which was designed as a German—Japanese enterprise for both microgravity research and reentry experiments. The capsule was built by the Russian company DB Saljut as part of the Khrunichev State Research and Production Space Center and modified by DASA. The capsule was launched from Kagoshima by a Japanese M-3 SII rocket in January 1995. Due to a failure of the rocket, the nominal orbital altitude could not be reached, which led to an early reentry of the capsule in Ghana after two and a half orbits. In the stagnation region of the reentry module an experiment was planned with a fibre reinforced ceramic tile of 300 mm in diameter integrated in the ablative heat shield. This experiment, called "CETEX", was designed by the German Aerospace Research Establishment (DLR) in Stuttgart. The aim of CETEX is to qualify lightweight fibre reinforced ceramics and related structural concepts in terms of heat shield applications for space vehicles as well as to compare the erosion behaviour shown in flight experiments and ground tests. An integral part of the CETEX experiment is the PYREX experiment of the University of Stuttgart. With PYREX a pyrometer shall be qualified, which is designed for high precision temperature measurement of heat shield materials made of fibre reinforced ceramic compounds during the reentry phase of space vehicles and probes. A third German experiment, RAFLEX, projected by Hyperschall Technologie Göttingen (HTG), was also integrated in the CETEX tile. RAFLEX is designed for the measurement of dynamic and static pressures and heat transfer at various positions on the EXPRESS capsule. Two small SiC tubes are fed through the CETEX tile for the RAFLEX and RTEX experiments. RTEX is a Japanese spectroscopy

  7. Measuring Public Support for Prisoner Reentry Options.

    PubMed

    Garland, Brett; Wodahl, Eric; Cota, Lisa

    2016-09-01

    Few topics have been discussed more extensively or feverishly within correctional academic and professional circles in the past few decades than prisoner reentry. Although program and policy evaluations have been conducted, a lack of public support for prisoner reentry initiatives could undermine the sustainability of prisoner reentry as a large-scale movement. Interestingly, no multivariate, explanatory analyses of the correlates of support for prisoner reentry policies could be found in the literature. This omission is due in part to the absence of clear psychometric measures to assess support. The current study examines the data obtained from a sample of residents in a Midwestern state to determine the dimensionality of support for prisoner reentry interventions using both exploratory factor analysis (EFA) and ordinary least squares (OLS) regression. Specifically, our expectation is that the following three-factor structure will be identified: (a) support for transitional programs aimed at building skills and knowledge to handle the obstacles of the prison-to-community transitional process, (b) support for post-release transitional housing units, and (c) opposition to denying offenders housing opportunities. Our results support a three-factor model. The implications of these findings for future research are discussed. PMID:25816814

  8. 14 CFR 435.43 - Payload reentry review requirements and procedures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 435.43 Payload reentry review requirements and... shall apply to the payload reentry review conducted for a license to reenter a reentry vehicle...

  9. 14 CFR 435.43 - Payload reentry review requirements and procedures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 435.43 Payload reentry review requirements and... shall apply to the payload reentry review conducted for a license to reenter a reentry vehicle...

  10. 14 CFR 435.43 - Payload reentry review requirements and procedures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 435.43 Payload reentry review requirements and... shall apply to the payload reentry review conducted for a license to reenter a reentry vehicle...

  11. 14 CFR 435.43 - Payload reentry review requirements and procedures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 435.43 Payload reentry review requirements and... shall apply to the payload reentry review conducted for a license to reenter a reentry vehicle...

  12. Orbital debris from upper-stage breakup

    NASA Technical Reports Server (NTRS)

    Loftus, Joseph P., Jr. (Editor)

    1989-01-01

    The present conference on the effects of launch vehicle upper-stage breakup on the orbital debris scenario discusses an analysis of the SPOT 1 Ariane third stage, the explosive fragmentation of orbiting propellant tanks, albedo estimates for debris, Ariane-related debris in deep-space orbit, and the relationship of hypervelocity impacts to upper-stage breakups. Also discussed are the prospects for and the economics of the future removal of orbital debris, collision probabilities in GEO, current operational practices for Delta second stage breakup prevention, breakup-precluding modifications to the Ariane third stage, and the safing of the H-1 second stage after spacecraft separation.

  13. Application of the FADS system on the Re-entry Module

    NASA Astrophysics Data System (ADS)

    Zhen, Huang

    2016-07-01

    The aerodynamic model for Flush Air Data Sensing System (FADS) is built based on the surface pressure distribution obtained through the pressure orifices laid on specific positions of the surface,and the flight parameters,such as angle of attack,angle of side-slip,Mach number,free-stream static pressure and dynamic pressure are inferred from the aerodynamic model.The flush air data sensing system (FADS) has been used on several flight tests of aircraft and re-entry vehicle,such as,X-15,space shuttle,F-14,X-33,X-43A and so on. This paper discusses the application of the FADS on the re-entry module with blunt body to obtain high-precision aerodynamic parameters.First of all,a basic theory and operating principle of the FADS is shown.Then,the applications of the FADS on typical aircrafts and re-entry vehicles are described.Thirdly,the application mode on the re-entry module with blunt body is discussed in detail,including aerodynamic simulation,pressure distribution,trajectory reconstruction and the hardware shoule be used,such as flush air data sensing system(FADS),inertial navigation system (INS),data acquisition system,data storage system.Finally,ablunt module re-entry flight test from low earth orbit (LEO) is planned to obtain aerodynamic parameters and amend the aerodynamic model with this FADS system data.The results show that FADS system can be applied widely in re-entry module with blunt bodies.

  14. Atomic and molecular data for spacecraft re-entry plasmas

    NASA Astrophysics Data System (ADS)

    Celiberto, R.; Armenise, I.; Cacciatore, M.; Capitelli, M.; Esposito, F.; Gamallo, P.; Janev, R. K.; Laganà, A.; Laporta, V.; Laricchiuta, A.; Lombardi, A.; Rutigliano, M.; Sayós, R.; Tennyson, J.; Wadehra, J. M.

    2016-06-01

    The modeling of atmospheric gas, interacting with the space vehicles in re-entry conditions in planetary exploration missions, requires a large set of scattering data for all those elementary processes occurring in the system. A fundamental aspect of re-entry problems is represented by the strong non-equilibrium conditions met in the atmospheric plasma close to the surface of the thermal shield, where numerous interconnected relaxation processes determine the evolution of the gaseous system towards equilibrium conditions. A central role is played by the vibrational exchanges of energy, so that collisional processes involving vibrationally excited molecules assume a particular importance. In the present paper, theoretical calculations of complete sets of vibrationally state-resolved cross sections and rate coefficients are reviewed, focusing on the relevant classes of collisional processes: resonant and non-resonant electron-impact excitation of molecules, atom–diatom and molecule–molecule collisions as well as gas-surface interaction. In particular, collisional processes involving atomic and molecular species, relevant to Earth (N2, O2, NO), Mars (CO2, CO, N2) and Jupiter (H2, He) atmospheres are considered.

  15. YPF uses horizontal reentry to aid thin bed production

    SciTech Connect

    Acosta, M.R.; Leiro, F.A.; Sesano, G.S.; Hill, D.

    1997-01-01

    Reentry and horizontal drilling/completion techniques have proven themselves useful in exploiting thin beds. A pilot horizontal reentry contracted by Yacimiento Petroliferos Fiscales (YPF) for a marginal well in its Lomita Sur field resulted in decreased water coning and production rates four times greater than expected. Further horizontal reentries in this thin-bed field are planned.

  16. 14 CFR 435.13 - Transfer of a reentry license.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Transfer of a reentry license. 435.13 Section 435.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.13 Transfer of a...

  17. 14 CFR 435.13 - Transfer of a reentry license.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Transfer of a reentry license. 435.13 Section 435.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE...

  18. 14 CFR 431.59 - Issuance of payload reentry determination.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Issuance of payload reentry determination. 431.59 Section 431.59 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination...

  19. 14 CFR 435.7 - Payload reentry determination.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Payload reentry determination. 435.7 Section 435.7 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.7 Payload...

  20. 14 CFR 435.13 - Transfer of a reentry license.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Transfer of a reentry license. 435.13 Section 435.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE...

  1. 14 CFR 435.9 - Issuance of a reentry license.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Issuance of a reentry license. 435.9 Section 435.9 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.9 Issuance of a...

  2. 14 CFR 435.13 - Transfer of a reentry license.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Transfer of a reentry license. 435.13 Section 435.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE...

  3. 14 CFR 435.13 - Transfer of a reentry license.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Transfer of a reentry license. 435.13 Section 435.13 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE...

  4. 14 CFR 431.55 - Payload reentry review.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Payload reentry review. 431.55 Section 431.55 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.55 Payload...

  5. Antimisting fuel breakup and flammability

    NASA Technical Reports Server (NTRS)

    Parikh, P.; Fleeter, R.; Sarohia, V.

    1983-01-01

    The breakup behavior and flammability of antimisting turbine fuels subjected to aerodynamic shear are investigated. Fuels tested were Jet A containing 0.3% FM-9 polymer at various levels of degradation ranging from virgin AMK to neat Jet A. The misting behavior of the fuels was quantified by droplet size distribution measurements. A technique based on high resolution laser photography and digital image processing of photographic records for rapid determination of droplet size distribution was developed. The flammability of flowing droplet-air mixtures was quantified by direct measurements of temperature rise in a flame established in the wake of a continuous ignition source. The temperature rise measurements were correlated with droplet size measurements. The flame anchoring phenomenon associated with the breakup of a liquid fuel in the wake of bluff body was shown to be important in the context of a survivable crash scenario. A pass/fail criterion for flammability testing of antimisting fuels, based on this flame-anchoring phenomenon, was proposed. The role of various ignition sources and their intensity in ignition and post-ignition behavior of antimisting fuels was also investigated.

  6. Assessment of the ATV-1 Re-Entry Observation Campaign for Future Re-Entry Missions

    NASA Astrophysics Data System (ADS)

    Lips, T.; Lohle, S.; Marynowsky, T.; Rees, D.; Stenbeak-Nielsen, H. C.; Beks, M. L.; Hatton, J.

    2010-09-01

    This paper summarizes the midterm results of the currently ongoing ESA study “Assessment of the ATV-1 Reentry Observation Campaign for Future Re-entry Missions”. The primary objective of this study is to investigate the data obtained during a joint ESA/NASA airborne observation campaign of the destructive re-entry of ATV-1 Jules Verne which occurred on September 29, 2008. The presented results are focused on spectroscopic fragment characterization(material identification), frame-by-frame fragment tracking(manual and automatic) for various video recordings, 3D triangulation of the tracked fragments, and fragment propagation until complete demise or ground impact, including the actual size and location of the ATV-1 debris footprint. Fragment propagation analyses comprise also the derivation of aerodynamic fragment properties and potential delta velocities. These parameters are of high importance for the re-entry safety analysis for ATV-2 Johannes Kepler.

  7. Measuring the spectral emissivity of thermal protection materials during atmospheric reentry simulation

    NASA Technical Reports Server (NTRS)

    Marble, Elizabeth

    1996-01-01

    Hypersonic spacecraft reentering the earth's atmosphere encounter extreme heat due to atmospheric friction. Thermal Protection System (TPS) materials shield the craft from this searing heat, which can reach temperatures of 2900 F. Various thermophysical and optical properties of TPS materials are tested at the Johnson Space Center Atmospheric Reentry Materials and Structures Evaluation Facility, which has the capability to simulate critical environmental conditions associated with entry into the earth's atmosphere. Emissivity is an optical property that determines how well a material will reradiate incident heat back into the atmosphere upon reentry, thus protecting the spacecraft from the intense frictional heat. This report describes a method of measuring TPS emissivities using the SR5000 Scanning Spectroradiometer, and includes system characteristics, sample data, and operational procedures developed for arc-jet applications.

  8. The Energy Interaction Model: A promising new methodology for projecting GPHS-RTG cladding failures, release amounts & respirable release fractions for postulated pre-launch, launch, and post-reentry earth impact accidents

    NASA Astrophysics Data System (ADS)

    Coleman, James R.; Sholtis, Joseph A.; McCulloch, William H.

    1998-01-01

    Safety analyses and evaluations must be scrutable, defensible, and credible. This is particularly true when nuclear systems are involved, with their attendant potential for releases of radioactive materials (source terms) to the unrestricted environment. Analytical projections of General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) source terms, for safety analyses conducted to date, have relied upon generic data correlations using a single parameter of cladding damage, termed ``distortion.'' However, distortion is not an unequivocal measure of cladding insult, failure, or release. Furthermore, the analytical foundation, applicability, and broad use of distortion are argumentative and, thus, somewhat troublesome. In an attempt to avoid the complications associated with the use of distortion, a new methodology, referred to as the Energy Interaction Model (EIM), has been preliminarily developed. This new methodology is based upon the physical principles of energy and energy exchange during mechanical interactions. Specifically, the EIM considers the energy imparted to GPHS-RTG components (bare fueled clads, GPHS modules, and full GPHS-RTGs) when exposed to mechanical threats (blast/overpressure, shrapnel and fragment impacts, and Earth surface impacts) posed by the full range of potential accidents. Expected forms are developed for equations intended to project cladding failure probabilities, the number of cladding failures expected, release amounts, and the fraction released as respirable particles. The coefficients of the equations developed are then set to fit the GPHS-RTG test data, ensuring good agreement with the experimental database. This assured, fitted agreement with the test database, along with the foundation of the EIM in first principles, provides confidence in the model's projections beyond the available database. In summary, the newly developed EIM methodology is described and discussed. The conclusions reached are that the EIM

  9. Exclusive breakup measurements for {sup 9}Be

    SciTech Connect

    Fulton, B.R.; Cowin, R.L.; Woolliscroft, R.J.; Clarke, N.M.; Donadille, L.; Freer, M.; Leask, P.J.; Singer, S.M.; Nicoli, M.P.; Benoit, B.; Hanappe, F.; Ninane, A.; Orr, N.A.; Tillier, J.; Stuttge, L.

    2004-10-01

    The first exclusive breakup measurements for the nucleus {sup 9}Be are presented. Breakup via several discrete states is observed following scattering off {sup 12}C and {sup 208}Pb. The results support the prediction of a recent microscopic cluster calculation for a strong n+{sup 8}Be(2{sup +}) state component in the second excited state.

  10. Deformation and secondary breakup of drops

    NASA Astrophysics Data System (ADS)

    Hsiang, L.-P.; Faeth, G. M.

    1993-01-01

    Drop properties during and after secondary breakup in the bag, multimode and shear breakup regimes were observed for shock wave initiated disturbances in air at normal temperature and pressure. Test liquids included water, n-heptane, ethyl alcohol and glycerol mixtures to yield Weber numbers of 15-600. Ohnesorge numbers of 0.0025-0.039, liquid/gas density ratios of 579-985 and Reynolds numbers of 1060-15080. Measurements included pulsed shadowgraphy and double-pulsed holography to find drop sizes and velocities after breakup. Drop size distributions after breakup satisfied Simmons' universal root normal distribution in all three breakup regimes, after removing the core (or drop-forming) drop from the drop population for shear breakup. The size and velocity of the core drop after shear breakup then was correlated successfully based on the observation that the end of drop stripping corresponded to a constant Eotvos number. The relative velocities of the drop liquid were significantly reduced during secondary breakup, due both to large drag coefficients during the drop deformation stage and reduced relaxation times of smaller drops. These effects were correlated successfully based on a simplified phenomenological theory.

  11. Beam breakup in superconducting recirculating linacs

    SciTech Connect

    Joseph J. Bisognano

    1988-05-01

    The performance and operational flexibility of superconducting recirculating linacs can be limited by a variety of collective phenomena which are grouped under the name beam breakup. In this note the various beam breakup phenomena found in recirculating superconducting radio frequency linacs are described and appraised relative to beam performance.

  12. Reentry Programs for Female Scientists. Final Report.

    ERIC Educational Resources Information Center

    Lantz, Alma E.; And Others

    This is the final report of research oriented to determine the problems and successes associated with women scientists who reenter the labor force. The report deals with the assessment of the strategies used in the National Science Foundation (NSF) Career Facilitation Projects for reentry women. The evaluation focuses on the successful approaches…

  13. School Reentry Following Traumatic Brain Injury

    ERIC Educational Resources Information Center

    Deidrick, Kathleen K. M.; Farmer, Janet E.

    2005-01-01

    Successful school reentry following traumatic brain injury (TBI) is critical to recovery. Physical, cognitive, behavioral, academic, and social problems can affect a child's school performance after a TBI. However, early intervention has the potential to improve child academic outcomes and promote effective coping with any persistent changes in…

  14. Prisoner Reentry Programming: Who Recidivates and when?

    ERIC Educational Resources Information Center

    Severson, Margaret E.; Bruns, Kimberly; Veeh, Christopher; Lee, Jaehoon

    2011-01-01

    This article provides the results of a multi-year evaluation of one state's prison reentry program and its impact on the success of offender participants as measured by certain recidivism outcomes, defined here as yielding a positive urinalysis, returning to prison, and having a new conviction. Using propensity score matching, the recidivism…

  15. Reusable Reentry Satellite (RRS): Launch tradeoff study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A goal of the Phase B study is to define the launch system interfaces for the reusable reentry satellite (RRS) program. The focus of the launch tradeoff study, documented in this report, is to determine which expendable launch vehicles (ELV's) are best suited for the RRS application by understanding the impact of all viable launch systems on RRS design and operation.

  16. REENTRY OF RADON FROM MITIGATION SYSTEM OUTLETS

    EPA Science Inventory

    The paper gives results of the measurement of reentry rates for radon released at roof level and at ground level near a house, to determine whether or not exhaust is necessary above the roof. (NOTE: Some radon mitigation systems draw air with a high radon concentration from under...

  17. Structural Considerations of Inflatable Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Leonard, Robert W.; Brooks, George W.; McComb, Harvey G., Jr.

    1960-01-01

    The state of the design art for inflated structures applicable to reentry vehicles is discussed. Included are material properties, calculations of buckling and collapse loads, and calculations of deflections and vibration frequencies. A new theory for the analysis of inflated plates is presented and compared with experiment.

  18. Droplet Breakup in Expansion-contraction Microchannels.

    PubMed

    Zhu, Pingan; Kong, Tiantian; Lei, Leyan; Tian, Xiaowei; Kang, Zhanxiao; Wang, Liqiu

    2016-01-01

    We investigate the influences of expansion-contraction microchannels on droplet breakup in capillary microfluidic devices. With variations in channel dimension, local shear stresses at the injection nozzle and focusing orifice vary, significantly impacting flow behavior including droplet breakup locations and breakup modes. We observe transition of droplet breakup location from focusing orifice to injection nozzle, and three distinct types of recently-reported tip-multi-breaking modes. By balancing local shear stresses and interfacial tension effects, we determine the critical condition for breakup location transition, and characterize the tip-multi-breaking mode quantitatively. In addition, we identify the mechanism responsible for the periodic oscillation of inner fluid tip in tip-multi-breaking mode. Our results offer fundamental understanding of two-phase flow behaviors in expansion-contraction microstructures, and would benefit droplet generation, manipulation and design of microfluidic devices. PMID:26899018

  19. Droplet Breakup in Expansion-contraction Microchannels

    PubMed Central

    Zhu, Pingan; Kong, Tiantian; Lei, Leyan; Tian, Xiaowei; Kang, Zhanxiao; Wang, Liqiu

    2016-01-01

    We investigate the influences of expansion-contraction microchannels on droplet breakup in capillary microfluidic devices. With variations in channel dimension, local shear stresses at the injection nozzle and focusing orifice vary, significantly impacting flow behavior including droplet breakup locations and breakup modes. We observe transition of droplet breakup location from focusing orifice to injection nozzle, and three distinct types of recently-reported tip-multi-breaking modes. By balancing local shear stresses and interfacial tension effects, we determine the critical condition for breakup location transition, and characterize the tip-multi-breaking mode quantitatively. In addition, we identify the mechanism responsible for the periodic oscillation of inner fluid tip in tip-multi-breaking mode. Our results offer fundamental understanding of two-phase flow behaviors in expansion-contraction microstructures, and would benefit droplet generation, manipulation and design of microfluidic devices. PMID:26899018

  20. Droplet Breakup in Expansion-contraction Microchannels

    NASA Astrophysics Data System (ADS)

    Zhu, Pingan; Kong, Tiantian; Lei, Leyan; Tian, Xiaowei; Kang, Zhanxiao; Wang, Liqiu

    2016-02-01

    We investigate the influences of expansion-contraction microchannels on droplet breakup in capillary microfluidic devices. With variations in channel dimension, local shear stresses at the injection nozzle and focusing orifice vary, significantly impacting flow behavior including droplet breakup locations and breakup modes. We observe transition of droplet breakup location from focusing orifice to injection nozzle, and three distinct types of recently-reported tip-multi-breaking modes. By balancing local shear stresses and interfacial tension effects, we determine the critical condition for breakup location transition, and characterize the tip-multi-breaking mode quantitatively. In addition, we identify the mechanism responsible for the periodic oscillation of inner fluid tip in tip-multi-breaking mode. Our results offer fundamental understanding of two-phase flow behaviors in expansion-contraction microstructures, and would benefit droplet generation, manipulation and design of microfluidic devices.

  1. Characterization of the breakup of the Pegasus rocket body 1994-029B

    NASA Technical Reports Server (NTRS)

    Matney, Mark; Settecerri, Tom; Johnson, Nicholas; Stansbery, Eugene

    1997-01-01

    The breakup of a Pegasus hydrazine auxiliary propulsion system in June 1996, officially recognized as the worst satellite breakup in terms of cataloged debris, is considered. The fragmentation event is analyzed and it is discussed how these debris contribute to the current and future near earth space environment. The low altitude of the breakup and the large range of ejection velocities present concerns for other earth orbiting space vehicles, especially the Space Shuttle and the Hubble Space Telescope. In addition to orbit data collected by the U.S. Space Surveillance Network, observations were conducted with ground-based radar observatories. These observations show that the overabundance of debris is not limited to the trackable population, but also extends down to debris with sizes of less than 1 cm. Attempts to detect the debris with optical sensors were less successful.

  2. Tiny Traces of a Big Asteroid Breakup

    NASA Astrophysics Data System (ADS)

    Martel, L. M. V.

    2004-03-01

    Ancient geologic conditions in southern Sweden were ideal to preserve meteorites that fell to Earth about half a billion years ago. Researcher Birger Schmitz (working as a visiting professor at Rice University and now at the University of Lund, Sweden) and his colleagues in Goteborg, Sweden have analyzed over 40 of these rare fossil meteorites along with relict chromite grains collected from sites in a 250,000-square-kilometer area of 480-million-year-old limestone. They attribute the abundance and wide distribution of this space debris to a meteorite influx at least one hundred times more intense than the influx today. Rather than a smorgasbord of different types, cosmochemical evidence shows that the fossil meteorites are L or LL chondrites leading the team to conclude that these meteorites and chromite grains derived from a major collision in the asteroid belt. The age of the limestone is very close to the impact age of many L chondrites suggesting that this major collision was the breakup of the L chondrite parent body, possibly the largest impact in the asteroid belt in the last few billion years.

  3. The {ital Energy Interaction Model}: A promising new methodology for projecting GPHS-RTG cladding failures, release amounts & respirable release fractions for postulated pre-launch, launch, and post-reentry earth impact accidents

    SciTech Connect

    Coleman, J.R.; Sholtis, J.A. Jr.; McCulloch, W.H.

    1998-01-01

    Safety analyses and evaluations must be scrutable, defensible, and credible. This is particularly true when nuclear systems are involved, with their attendant potential for releases of radioactive materials (source terms) to the unrestricted environment. Analytical projections of General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) source terms, for safety analyses conducted to date, have relied upon generic data correlations using a single parameter of cladding damage, termed {open_quotes}distortion.{close_quotes} However, distortion is not an unequivocal measure of cladding insult, failure, or release. Furthermore, the analytical foundation, applicability, and broad use of distortion are argumentative and, thus, somewhat troublesome. In an attempt to avoid the complications associated with the use of distortion, a new methodology, referred to as the {ital Energy Interaction Model (EIM)}, has been preliminarily developed. This new methodology is based upon the physical principles of energy and energy exchange during mechanical interactions. Specifically, the {ital EIM} considers the energy imparted to GPHS-RTG components (bare fueled clads, GPHS modules, and full GPHS-RTGs) when exposed to mechanical threats (blast/overpressure, shrapnel and fragment impacts, and Earth surface impacts) posed by the full range of potential accidents. Expected forms are developed for equations intended to project cladding failure probabilities, the number of cladding failures expected, release amounts, and the fraction released as respirable particles. The coefficients of the equations developed are then set to fit the GPHS-RTG test data, ensuring good agreement with the experimental database. This assured, fitted agreement with the test database, along with the foundation of the {ital EIM} in first principles, provides confidence in the model{close_quote}s projections beyond the available database. In summary, the newly developed {ital EIM} methodology is

  4. Airborne Observation of the Hayabusa Sample Return Capsule Re-Entry

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Jenniskens, Peter M.; Cassell, Alan M.; Albers, Jim; Winterm Michael

    2011-01-01

    The Japan Aerospace Exploration Agency (JAXA) recently completed their Hayabusa asteroid exploration mission. Launched in 2003, Hayabusa made contact with, and retrieved a sample from, the near-Earth asteroid Itokawa in 2005. The sample return capsule (SRC) re-entered over the Woomera Test Range (WTR) in southern Australia on June 13, 2010, at approximately 11:21 pm local time (09:51 UTC). The SRC re-entry velocity was 12.2 km/s, making it the second-fastest Earth return velocity behind NASA s Stardust sample return capsule re-entry in 2006. From a space technology development perspective, Hayabusa s re-entry functioned as a rare flight experiment of an entry vehicle and its thermal protection system. In collaboration with the SETI Institute, NASA deployed its DC-8 airborne laboratory and a team of international researchers to Australia to observe the re-entry of the SRC. The use of an airborne platform enables observation above most clouds and weather and greatly diminishes atmospheric absorption of the optical signals. The DC-8 s flight path was engineered and flown to provide a view of the spacecraft that bracketed the heat pulse to the capsule. A suite of imaging instruments on board the DC-8 successfully recorded the luminous portion of the re-entry event. For approximately 70 seconds, the spectroscopic and radiometric instruments acquired images and spectra of the capsule, its wake, and destructive re-entry of the spacecraft bus. Figure 1 shows a perspective view of the WTR, the SRC re-entry trajectory, and the flight path of the DC-8. The SRC was jettisoned from the spacecraft bus approximately 3 hours prior to entry interface. Due to thruster failures on the spacecraft, it could not be diverted from the entry path and followed the trajectory of the SRC, where it burned up in the atmosphere between approximately 100 and 50 km altitude. Fortuitously, the separation distance between the spacecraft and SRC was sufficient to clearly resolve the SRC from the

  5. Current Status on Radiation Modeling for the Hayabusa Re-entry

    NASA Technical Reports Server (NTRS)

    Winter, Michael W.; McDaniel, Ryan D.; Chen, Yih-Kang; Liu, Yen; Saunders, David

    2011-01-01

    On June 13, 2010 the Japanese Hayabusa capsule performed its reentry into the Earths atmosphere over Australia after a seven year journey to the asteroid Itokawa. The reentry was studied by numerous imaging and spectroscopic instruments onboard NASA's DC-8 Airborne Laboratory and from three sites on the ground, in order to measure surface and plasma radiation generated by the Hayabusa Sample Return Capsule (SRC). Post flight, the flow solutions were recomputed to include the whole flow field around the capsule at 11 points along the reentry trajectory using updated trajectory information. Again, material response was taken into account to obtain most reliable surface temperature information. These data will be used to compute thermal radiation of the glowing heat shield and plasma radiation by the shock/post-shock layer system to support analysis of the experimental observation data. For this purpose, lines of sight data are being extracted from the flow field volume grids and plasma radiation will be computed using NEQAIR [4] which is a line-by-line spectroscopic code with one-dimensional transport of radiation intensity. The procedures being used were already successfully applied to the analysis of the observation of the Stardust reentry [5].

  6. Empirical Accuracies of U.S. Space Surveillance Network Reentry Predictions

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2008-01-01

    The U.S. Space Surveillance Network (SSN) issues formal satellite reentry predictions for objects which have the potential for generating debris which could pose a hazard to people or property on Earth. These prognostications, known as Tracking and Impact Prediction (TIP) messages, are nominally distributed at daily intervals beginning four days prior to the anticipated reentry and several times during the final 24 hours in orbit. The accuracy of these messages depends on the nature of the satellite s orbit, the characteristics of the space vehicle, solar activity, and many other factors. Despite the many influences on the time and the location of reentry, a useful assessment of the accuracies of TIP messages can be derived and compared with the official accuracies included with each TIP message. This paper summarizes the results of a study of numerous uncontrolled reentries of spacecraft and rocket bodies from nearly circular orbits over a span of several years. Insights are provided into the empirical accuracies and utility of SSN TIP messages.

  7. Re-Entry Survivability Risk Assessment of the Extreme Ultraviolet Explorer (EUVE)

    NASA Technical Reports Server (NTRS)

    O'Hara, Robin E.; Johnson, Nicholas L.

    2001-01-01

    A reentry analysis of the Extreme Ultraviolet Explorer (EUVE) spacecraft was performed using the Object Reentry Survival Analysis Tool (ORSAT) - Version 5.0. The analysis was done in response to a request by NASA Headquarters and Goddard Space Flight Center (GSFC) after a preliminary assessment using the NASA Johnson Space Center Debris Assessment Software (DAS) - Version 1.0 had shown that the EUVE reentry may produce a debris area greater than the limit set within the NASA Safety Standard 1740.14 guidelines. DAS predicted that an uncontrolled reentry of the EUVE spacecraft would result in a total casualty area of 12.41 sq m, which exceeds the 8 sq m limit set in the NASA standards and implies a potential human casualty risk of approximately 1 in 5300. The ORSAT model enabled a higher fidelity thermal analysis of the EUVE spacecraft, utilizing sophisticated material and thermal properties such as emissivity, heat of oxidation, thermal conductivity, and material thickness inputs, which provided a foundation for a more in depth analysis of the reentering objects. Due to the conservative nature of the DAS study, it was reasonable to run ORSAT for only the ten objects shown to survive in the original DAS analysis. The result of the ORSAT study was a reduced casualty area of only 5.95 sq m, well within NASA safety limits. With the risk to human life now acceptably low, NASA can avoid having to take mitigation measures and allow EUVE to reenter the Earth's atmosphere uncontrolled.

  8. DEBRISK, a Tool for Re-Entry Risk Analysis

    NASA Astrophysics Data System (ADS)

    Omaly, P.; Spel, M.

    2012-01-01

    An act of French parliament, adopted in 2008, imposes satellite constructors to evaluate the end-of-life operations in order to assure the risk mitigation of their satellites. One important element in this evaluation is the estimation of the mass and impact energy of the satellite debris after atmospheric re-entry. For this purpose, CNES has developed the tool DEBRISK which allows the operator to simulate the re-entry phase and to study the demise altitudes or impact energy of the individual fragments of the original satellite. DEBRISK is based on the so called object based approach. Using this approach, a breakup altitude is assumed where the satellite disintegrates due to the pressure loads. This altitude is typically around 78 km. After breakup, the satellite structure is modelled by a parent-child approach, where each child has its birth criterion. In the simplest approach the child is born after demise of the parent object. This could be the case of an object A containing an object B which is in the interior of object A and thus not exposed to the atmosphere. Each object is defined by: - its shape, attitude and dimensions, - the material along with their physical properties - the state and velocity vectors. The shape, attitude and dimensions define the aerodynamic drag of the object which is input to the 3DOF trajectory modelling. The aerodynamic mass used in the equation of motion is defined as the sum of the object's own mass and the mass of the object's offspring. A new born object inherits the state vector of the parent object. The shape, attitude and dimensions also define the heating rates experienced by the object. The heating rate is integrated in time up to the point where the melting temperature is reached. The mass of melted material is computed from the excess heat and the material properties. After each step the amount of ablated material is determined using the lumped mass approach and is peeled off from the object, updating mass and shape of the

  9. Simulation for Prediction of Entry Article Demise (SPEAD): an Analysis Tool for Spacecraft Safety Analysis and Ascent/Reentry Risk Assessment

    NASA Technical Reports Server (NTRS)

    Ling, Lisa

    2014-01-01

    For the purpose of performing safety analysis and risk assessment for a probable offnominal suborbital/orbital atmospheric reentry resulting in vehicle breakup, a synthesis of trajectory propagation coupled with thermal analysis and the evaluation of node failure is required to predict the sequence of events, the timeline, and the progressive demise of spacecraft components. To provide this capability, the Simulation for Prediction of Entry Article Demise (SPEAD) analysis tool was developed. This report discusses the capabilities, modeling, and validation of the SPEAD analysis tool. SPEAD is applicable for Earth or Mars, with the option for 3 or 6 degrees-of-freedom (DOF) trajectory propagation. The atmosphere and aerodynamics data are supplied in tables, for linear interpolation of up to 4 independent variables. The gravitation model can include up to 20 zonal harmonic coefficients. The modeling of a single motor is available and can be adapted to multiple motors. For thermal analysis, the aerodynamic radiative and free-molecular/continuum convective heating, black-body radiative cooling, conductive heat transfer between adjacent nodes, and node ablation are modeled. In a 6- DOF simulation, the local convective heating on a node is a function of Mach, angle-ofattack, and sideslip angle, and is dependent on 1) the location of the node in the spacecraft and its orientation to the flow modeled by an exposure factor, and 2) the geometries of the spacecraft and the node modeled by a heating factor and convective area. Node failure is evaluated using criteria based on melting temperature, reference heat load, g-load, or a combination of the above. The failure of a liquid propellant tank is evaluated based on burnout flux from nucleate boiling or excess internal pressure. Following a component failure, updates are made as needed to the spacecraft mass and aerodynamic properties, nodal exposure and heating factors, and nodal convective and conductive areas. This allows

  10. Landing Energy Dissipation for Manned Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    1960-01-01

    Landing Energy Dissipation for Manned Reentry Vehicles. The film shows experimental investigations to determine the landing-energy-dissipation characteristics for several types of landing gear for manned reentry vehicles. The landing vehicles are considered in two categories: those having essentially vertical-descent paths, the parachute-supported vehicles, and those having essentially horizontal paths, the lifting vehicles. The energy-dissipation devices include crushable materials such as foamed plastics and honeycomb for internal application in couch-support systems, yielding metal elements as part of the structure of capsules or as alternates for oleos in landing-gear struts, inflatable bags, braking rockets, and shaped surfaces for water impact. [Entire movie available on DVD from CASI as Doc ID 20070030945. Contact help@sti.nasa.gov

  11. Precise Orbit Determination of the GOCE Re-Entry Phase

    NASA Astrophysics Data System (ADS)

    Gini, Francesco; Otten, Michiel; Springer, Tim; Enderle, Werner; Lemmens, Stijn; Flohrer, Tim

    2015-03-01

    During the last days of the GOCE mission, after the GOCE spacecraft ran out of fuel, it slowly decayed before finally re-entering the atmosphere on the 11th November 2013. As an integrated part of the AOCS, GOCE carried a GPS receiver that was in operations during the re-entry phase. This feature provided a unique opportunity for Precise Orbit Determination (POD) analysis. As part of the activities carried out by the Navigation Support Office (HSO-GN) at ESOC, precise ephemerides of the GOCE satellite have been reconstructed for the entire re-entry phase based on the available GPS observations of the onboard LAGRANGE receiver. All the data available from the moment the thruster was switched off on the 21st of October 2013 to the last available telemetry downlink on the 10th November 2013 have been processed, for a total of 21 daily arcs. For this period a dedicated processing sequence has been defined and implemented within the ESA/ESOC NAvigation Package for Earth Observation Satellites (NAPEOS) software. The computed results show a post-fit RMS of the GPS undifferenced carrier phase residuals (ionospheric-free linear combination) between 6 and 14 mm for the first 16 days which then progressively increases up to about 80 mm for the last available days. An orbit comparison with the Precise Science Orbits (PSO) generated at the Astronomical Institute of the University of Bern (AIUB, Bern, Switzerland) shows an average difference around 9 cm for the first 8 daily arcs and progressively increasing up to 17 cm for the following days. During this reentry phase (21st of October - 10th November 2013) a substantial drop in the GOCE altitude is observed, starting from about 230 km to 130 km where the last GPS measurements were taken. During this orbital decay an increment of a factor of 100 in the aerodynamic acceleration profile is observed. In order to limit the mis-modelling of the non-gravitational forces (radiation pressure and aerodynamic effects) the newly developed

  12. Negative Emotions and Behaviors are Markers of Breakup Distress

    ERIC Educational Resources Information Center

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeanette

    2013-01-01

    Method: University students who experienced a recent romantic breakup were given several self-report measures and were then divided into high versus low breakup distress groups. Results: The high breakup distress versus the low breakup distress groups had higher scores on negative emotions scales including depression, anxiety and anger and…

  13. Intrusive Thoughts: A Primary Variable in Breakup Distress

    ERIC Educational Resources Information Center

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2013-01-01

    University students who were high versus low on breakup distress scores were given self-report measures to assess their intrusive thoughts about the romantic breakup and their somatic symptoms that followed the breakup as well as their extracurricular activities and social support that might alleviate their breakup distress. In a regression…

  14. The IADC Re-Entry Test Campaigns of EAS at PMO

    NASA Astrophysics Data System (ADS)

    Xiong, Jianning; Zhao, Changyin; Zhang, Xiaoxiang; Zhang, Wei

    2009-03-01

    In November 2008, Purple Mountain Observatory, Chinese Academy of Sciences took part in the IADC reentry test campaign 2008/1 representing China, which is called EAS.This paper presents a new reentry prediction method which estimates the reentry time. By this method 20 reentry predictions were carried out and the results were uploaded to the IADC Common and Reentry Database.

  15. Impact of tidal density variability on orbital and reentry predictions

    NASA Astrophysics Data System (ADS)

    Leonard, J. M.; Forbes, J. M.; Born, G. H.

    2012-12-01

    Since the first satellites entered Earth orbit in the late 1950's and early 1960's, the influences of solar and geomagnetic variability on the satellite drag environment have been studied, and parameterized in empirical density models with increasing sophistication. However, only within the past 5 years has the realization emerged that "troposphere weather" contributes significantly to the "space weather" of the thermosphere, especially during solar minimum conditions. Much of the attendant variability is attributable to upward-propagating solar tides excited by latent heating due to deep tropical convection, and solar radiation absorption primarily by water vapor and ozone in the stratosphere and mesosphere, respectively. We know that this tidal spectrum significantly modifies the orbital (>200 km) and reentry (60-150 km) drag environments, and that these tidal components induce longitude variability not yet emulated in empirical density models. Yet, current requirements for improvements in orbital prediction make clear that further refinements to density models are needed. In this paper, the operational consequences of longitude-dependent tides are quantitatively assessed through a series of orbital and reentry predictions. We find that in-track prediction differences incurred by tidal effects are typically of order 200 ± 100 m for satellites in 400-km circular orbits and 15 ± 10 km for satellites in 200-km circular orbits for a 24-hour prediction. For an initial 200-km circular orbit, surface impact differences of order 15° ± 15° latitude are incurred. For operational problems with similar accuracy needs, a density model that includes a climatological representation of longitude-dependent tides should significantly reduce errors due to this source.

  16. Reusable Reentry Satellite (RRS) system design study: System cost estimates document

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) program was initiated to provide life science investigators relatively inexpensive, frequent access to space for extended periods of time with eventual satellite recovery on earth. The RRS will provide an on-orbit laboratory for research on biological and material processes, be launched from a number of expendable launch vehicles, and operate in Low-Altitude Earth Orbit (LEO) as a free-flying unmanned laboratory. SAIC's design will provide independent atmospheric reentry and soft landing in the continental U.S., orbit for a maximum of 60 days, and will sustain three flights per year for 10 years. The Reusable Reentry Vehicle (RRV) will be 3-axis stabilized with artificial gravity up to 1.5g's, be rugged and easily maintainable, and have a modular design to accommodate a satellite bus and separate modular payloads (e.g., rodent module, general biological module, ESA microgravity botany facility, general botany module). The purpose of this System Cost Estimate Document is to provide a Life Cycle Cost Estimate (LCCE) for a NASA RRS Program using SAIC's RRS design. The estimate includes development, procurement, and 10 years of operations and support (O&S) costs for NASA's RRS program. The estimate does not include costs for other agencies which may track or interface with the RRS program (e.g., Air Force tracking agencies or individual RRS experimenters involved with special payload modules (PM's)). The life cycle cost estimate extends over the 10 year operation and support period FY99-2008.

  17. Study and Development of a Sub-Orbital Re-Entry Demonstrator

    NASA Astrophysics Data System (ADS)

    Savino, R.

    The Italian and European Space Agencies are supporting a research programme, developed in Campania region by a cluster of industries, research institutes and universities, on a low-cost re-entry capsule, able to return payloads from the ISS to Earth and/or to perform short-duration scientific missions in Low Earth Orbit (LEO). The ballistic capsule is characterized by a deployable, disposable "umbrella-like" heat shield that allows relatively small dimensions at launch and a sufficient exposed surface area in re-entry conditions, reducing the ballistic coefficient and leading to acceptable heat fluxes, mechanical loads and final descent velocity. ESA is supporting a preliminary study to develop a flight demonstrator of the capsule to be embarked as a secondary payload onboard a sub-orbital sounding rocket. The deployable thermal protection system concept may be applied to future science and robotic exploration mission requiring planetary entry and, possibly also to missions in the framework of Human Space flight, requiring planetary entry or re-entry. The technology offers also an interesting potential for aerobraking, aerocapture and for de-orbiting. This paper summarizes the results of these activities, which are being more and more refined as the work proceeds, including the definition and analysis of the mission scenario, the aerodynamic, aerothermodynamic, mechanical and structural analyses and the technical definition of avionics, instrumentation and main subsystems.

  18. Airborne Observation of the Hayabusa Sample Return Capsule Re-Entry

    NASA Technical Reports Server (NTRS)

    Grinstead, Jay H.; Jenniskens, Peter; Cassell, Alan M.; Albers, James; Winter, Michael W.

    2011-01-01

    NASA Ames Research Center and the SETI Institute collaborated on an effort to observe the Earth re-entry of the Japan Aerospace Exploration Agency's Hayabusa sample return capsule. Hayabusa was an asteroid exploration mission that retrieved a sample from the near-Earth asteroid Itokawa. Its sample return capsule re-entered over the Woomera Prohibited Area in southern Australia on June 13, 2010. Being only the third sample return mission following NASA's Genesis and Stardust missions, Hayabusa's return was a rare opportunity to collect aerothermal data from an atmospheric entry capsule returning at superorbital speeds. NASA deployed its DC-8 airborne laboratory and a team of international researchers to Australia for the re-entry. For approximately 70 seconds, spectroscopic and radiometric imaging instruments acquired images and spectra of the capsule, its wake, and destructive re-entry of the spacecraft bus. Once calibrated, spectra of the capsule will be interpreted to yield data for comparison with and validation of high fidelity and engineering simulation tools used for design and development of future atmospheric entry system technologies. A brief summary of the Hayabusa mission, the preflight preparations and observation mission planning, mission execution, and preliminary spectral data are documented.

  19. Electrostatic breakup in a misty plasma.

    PubMed

    Coppins, M

    2010-02-12

    A misty plasma is defined as a plasma containing small liquid droplets. In such a system, the droplets will undergo total electrostatic breakup if their charge exceeds the well-known Rayleigh limit. This imposes a minimum size on the droplets. Electrostatic breakup is a significant mechanism limiting droplet survival in a wide range of plasma applications, including plasma-enhanced chemical vapor deposition and fusion tokamaks. PMID:20366826

  20. Electrostatic Breakup in a Misty Plasma

    SciTech Connect

    Coppins, M.

    2010-02-12

    A misty plasma is defined as a plasma containing small liquid droplets. In such a system, the droplets will undergo total electrostatic breakup if their charge exceeds the well-known Rayleigh limit. This imposes a minimum size on the droplets. Electrostatic breakup is a significant mechanism limiting droplet survival in a wide range of plasma applications, including plasma-enhanced chemical vapor deposition and fusion tokamaks.

  1. EV13 Genesis Reentry Observations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.

    2006-01-01

    The Genesis spacecraft reentry represented a unique opportunity to observe a "calibrated meteor" from northern Nevada. Knowing its speed, mass, composition, and precise trajectory made it a good subject to test some of the algorithms used to determine meteoroid mass from observed brightness. It was also a good test of an inexpensive set of cameras which could be deployed to observe future shuttle reentries. The utility of consumer grade video cameras was evident during the STS-107 accident investigation and the Genesis reentry gave us the opportunity to specify and test commercially available cameras which could be used during future reentries. This report describes the video observations and their analysis, compares the results with a simple photometric model, describes the forward scatter radar experiment, and lists lessons learned from the expedition and implications for the Stardust reentry in January 2006 as well as future shuttle reentries.

  2. Relational vulnerabilities of incarcerated and reentry mothers: therapeutic implications.

    PubMed

    Few-Demo, April L; Arditti, Joyce A

    2014-11-01

    A qualitative study involving a follow-up interview with 10 incarcerated and reentry mothers in rural southwest and central Virginia was conducted to explore the influence that women's close relationships have on their reentry experiences with their families. The Vulnerability Conceptual Model (VCM) was used to sensitize an examination of how incarcerated and reentry mothers negotiate relational vulnerabilities in the context of varying situational vulnerability. Grounded theory analysis revealed three themes that characterized relational vulnerabilities. Given our focus on close relationships and the potential of the VCM to identify opportunities for resilience and vulnerability, we highlighted the influence of ambiguous and ambivalent relationships and unresolved loss and grief due to relationship dissolution or the death of a parent, sibling, child, or intimate partner in the reentry process. The data revealed two types of reentry mothers with divergent trajectories for social reintegration. Implications of these types for therapeutic treatment approaches for reentry women are discussed. PMID:23847275

  3. Air induced breakup of drops.

    NASA Astrophysics Data System (ADS)

    Han, Jaehoon; Tryggvason, Gretar

    1997-11-01

    The deformation and breakup of drops subject to both sudden and gradual acceleration is examined by axisymmetric inviscid and full numerical simulations. In the full simulations, the Navier Stokes equations are solved for the fluid inside and outside of the drop by a Front Tracking/Finite Difference Method. In the limit of small density stratification, inviscid simulations show the formation of a toroidal drop for small surface tension and the formation of skirts as the surface tension is increased. The viscous computations show a similar transition plus a RbagS break up for a relatively high surface tension, but not high enough so that the drop reaches a steady state deformation. The RbagS break up mode appears when the drop slows down due to viscous dissipation after most of its fluid has accumulated in the rim, forming a torous connected by a thin film. A RbagS is formed when the rim starts to fall faster than the film. The various break up modes, as a function of the Ohnesorge and Weber (or Eotvos) numbers as well as property ratios is discussed. Supported by AFOSR.

  4. Direct optimization method for reentry trajectory design

    NASA Astrophysics Data System (ADS)

    Jallade, S.; Huber, P.; Potti, J.; Dutruel-Lecohier, G.

    The software package called `Reentry and Atmospheric Transfer Trajectory' (RATT) was developed under ESA contract for the design of atmospheric trajectories. It includes four software TOP (Trajectory OPtimization) programs, which optimize reentry and aeroassisted transfer trajectories. 6FD and 3FD (6 and 3 degrees of freedom Flight Dynamic) are devoted to the simulation of the trajectory. SCA (Sensitivity and Covariance Analysis) performs covariance analysis on a given trajectory with respect to different uncertainties and error sources. TOP provides the optimum guidance law of a three degree of freedom reentry of aeroassisted transfer (AAOT) trajectories. Deorbit and reorbit impulses (if necessary) can be taken into account in the optimization. A wide choice of cost function is available to the user such as the integrated heat flux, or the sum of the velocity impulses, or a linear combination of both of them for trajectory and vehicle design. The crossrange and the downrange can be maximized during reentry trajectory. Path constraints are available on the load factor, the heat flux and the dynamic pressure. Results on these proposed options are presented. TOPPHY is the part of the TOP software corresponding to the definition and the computation of the optimization problemphysics. TOPPHY can interface with several optimizes with dynamic solvers: TOPOP and TROPIC using direct collocation methods and PROMIS using direct multiple shooting method. TOPOP was developed in the frame of this contract, it uses Hermite polynomials for the collocation method and the NPSOL optimizer from the NAG library. Both TROPIC and PROMIS were developed by the DLR (Deutsche Forschungsanstalt fuer Luft und Raumfahrt) and use the SLSQP optimizer. For the dynamic equation resolution, TROPIC uses a collocation method with Splines and PROMIS uses a multiple shooting method with finite differences. The three different optimizers including dynamics were tested on the reentry trajectory of the

  5. On the breakup of viscous liquid threads

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1995-01-01

    A one-dimensional model evolution equation is used to describe the nonlinear dynamics that can lead to the breakup of a cylindrical thread of Newtonian fluid when capillary forces drive the motion. The model is derived from the Stokes equations by use of rational asymptotic expansions and under a slender jet approximation. The equations are solved numerically and the jet radius is found to vanish after a finite time yielding breakup. The slender jet approximation is valid throughout the evolution leading to pinching. The model admits self-similar pinching solutions which yield symmetric shapes at breakup. These solutions are shown to be the ones selected by the initial boundary value problem, for general initial conditions. Further more, the terminal state of the model equation is shown to be identical to that predicted by a theory which looks for singular pinching solutions directly from the Stokes equations without invoking the slender jet approximation throughout the evolution. It is shown quantitatively, therefore, that the one-dimensional model gives a consistent terminal state with the jet shape being locally symmetric at breakup. The asymptotic expansion scheme is also extended to include unsteady and inerticial forces in the momentum equations to derive an evolution system modelling the breakup of Navier-Stokes jets. The model is employed in extensive simulations to compute breakup times for different initial conditions; satellite drop formation is also supported by the model and the dependence of satellite drop volumes on initial conditions is studied.

  6. Modelling the Thermal Decomposition of Carbon Fibre Materials During Re-Entry

    NASA Astrophysics Data System (ADS)

    Fritsche, B.

    2013-08-01

    The SCARAB software is a tool for calculating the motion and aerothermal destruction of spacecraft entering the Earth's atmosphere. To increase the accuracy of the re-entry simulation for spacecraft containing CFRP as wall material, the modelling of the properties of CFRP was improved. Different to the simple conventional "metallic" model with monolithic properties a sophisticated model with different zones with different properties and taking into account additional effects was developed. First a mathematical model was formulated, which was then converted to a numerical model. The numerical 1D model was tested in a testbed software, then implemented into the SCARAB software and applied to wind tunnel conditions and the re-entry of the ROSAT satellite.

  7. Effective reentry methods reduce costs and optimize production

    SciTech Connect

    Szutiak, G.; Walker, D.

    1996-10-21

    Favorable oil prices and tax incentives have spawned an increase in reentry drilling, adding new life to fields once abandoned in Canada. (The provincial government in Alberta has stimulated reentry drilling in western Canada by its tax royalty relief and incentives.) A review of four reentry projects covering 19 horizontal wells in western Canada illustrates a number of planning considerations that can save an operator money while ensuring optimization of the production. The paper recommends several standard steps in planning and executing slim hole reentries drawn from these projects.

  8. Assessment of the Breakup of the Antarctic Polar Vortex in Two New Chemistry-Climate Models

    NASA Technical Reports Server (NTRS)

    Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Li, F.; Morgenstern, O.; Braesicke, P.; Pyle, J. A.

    2010-01-01

    Successful simulation of the breakup of the Antarctic polar vortex depends on the representation of tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses the vortex breakup in two new chemistry-climate models (CCMs). The stratospheric version of the UK Chemistry and Aerosols model is able to reproduce the observed timing of the vortex breakup. Version 2 of the Goddard Earth Observing System (GEOS V2) model is typical of CCMs in that the Antarctic polar vortex breaks up too late; at 10 hPa, the mean transition to easterlies at 60 S is delayed by 12-13 days as compared with the ERA-40 and National Centers for Environmental Prediction reanalyses. The two models' skill in simulating planetary wave driving during the October-November period accounts for differences in their simulation of the vortex breakup, with GEOS V2 unable to simulate the magnitude and tilt of geopotential height anomalies in the troposphere and thus underestimating the wave driving. In the GEOS V2 CCM the delayed breakup of the Antarctic vortex biases polar temperatures and trace gas distributions in the upper stratosphere in November and December.

  9. Reentry Works: The Implementation and Effectiveness of a Serious and Violent Offender Reentry Initiative

    ERIC Educational Resources Information Center

    Bouffard, Jeffrey A.; Bergeron, Lindsey E.

    2006-01-01

    Spurred by large increases in prison populations and other recent sentencing and correctional trends, the federal government has supported the development and implementation of Serious and Violent Offender Reentry Initiatives (SVORI) nationwide. While existing research demonstrates the effectiveness of the separate components of these programs…

  10. Simulation for Prediction of Entry Article Demise (SPEAD): An Analysis Tool for Spacecraft Safety Analysis and Ascent/Reentry Risk Assessment

    NASA Technical Reports Server (NTRS)

    Ling, Lisa

    2014-01-01

    For the purpose of performing safety analysis and risk assessment for a potential off-nominal atmospheric reentry resulting in vehicle breakup, a synthesis of trajectory propagation coupled with thermal analysis and the evaluation of node failure is required to predict the sequence of events, the timeline, and the progressive demise of spacecraft components. To provide this capability, the Simulation for Prediction of Entry Article Demise (SPEAD) analysis tool was developed. The software and methodology have been validated against actual flights, telemetry data, and validated software, and safety/risk analyses were performed for various programs using SPEAD. This report discusses the capabilities, modeling, validation, and application of the SPEAD analysis tool.

  11. 14 CFR 431.61 - Incorporation of payload reentry determination in license application.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.61 Incorporation of...

  12. 14 CFR 431.61 - Incorporation of payload reentry determination in license application.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.61 Incorporation of...

  13. 14 CFR 431.57 - Information requirements for payload reentry review.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.57 Information requirements for...

  14. 14 CFR 431.61 - Incorporation of payload reentry determination in license application.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.61 Incorporation of...

  15. 14 CFR 431.61 - Incorporation of payload reentry determination in license application.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.61 Incorporation of...

  16. 14 CFR 431.57 - Information requirements for payload reentry review.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.57 Information requirements for...

  17. 14 CFR 431.57 - Information requirements for payload reentry review.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.57 Information requirements for...

  18. 14 CFR 431.57 - Information requirements for payload reentry review.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review and Determination § 431.57 Information requirements for...

  19. Kiernan reentry measurements system on Kwajalein atoll

    SciTech Connect

    Roth, K.R.; Austin, M.E.; Frediani, D.J.; Knittel, G.H.; Mrstik, A.V.

    1989-01-01

    The Kiernan Reentry Measurements System (KREMS), located on Kwajalein Atoll in the Pacific, is the United States' most sophisticated and important research and development radar site. Consisting of four one-of-a-kind instrumentation radars, KREMS has played a major role for the past 25 years in the collection of data associated with ICBM testing. Furthermore, it has served as an important space-surveillance facility that provides an early U.S. view of many Soviet and Chinese satellite launches. Finally, the system is slated to play a key role in Strategic Defense Initiative experiments.

  20. Landing Energy Dissipation for Manned Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Fisher, Loyd. L.

    1960-01-01

    The film shows experimental investigations to determine the landing-energy-dissipation characteristics for several types of landing gear for manned reentry vehicles. The landing vehicles are considered in two categories: those having essentially vertical-descent paths, the parachute-supported vehicles, and those having essentially horizontal paths, the lifting vehicles. The energy-dissipation devices include crushable materials such as foamed plastics and honeycomb for internal application in couch-support systems, yielding metal elements as part of the structure of capsules or as alternates for oleos in landing-gear struts, inflatable bags, braking rockets, and shaped surfaces for water impact.

  1. 40 CFR 161.390 - Reentry protection data requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Reentry protection data requirements. 161.390 Section 161.390 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR REGISTRATION OF ANTIMICROBIAL PESTICIDES Data Requirement Tables § 161.390 Reentry protection data requirements....

  2. Re-Entry: Managing Cross-Cultural Transitions.

    ERIC Educational Resources Information Center

    Adler, Nancy J.

    1981-01-01

    Studied the re-entry process of corporate and governmental employees (N=200) returning to Canada after working overseas. Research found re-entry into the original culture was a more difficult transition than moving to the foreign culture. Home-country managers tended to exhibit xenophobia in assessing the potential and actual effectiveness of…

  3. Gender Differences and Offender Reentry: A Review of the Literature

    ERIC Educational Resources Information Center

    Spjeldnes, Solveig; Goodkind, Sara

    2009-01-01

    Historically, men have been incarcerated at rates far greater than women. As a result, reentry and reintegration programs have focused mainly on men's needs. The Second Chance Act of 2007 authorized funding for offender reentry programs and research on special populations--including about women and parents acknowledging the importance of…

  4. 14 CFR 431.59 - Issuance of payload reentry determination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Issuance of payload reentry determination. 431.59 Section 431.59 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE...

  5. 14 CFR 431.7 - Payload and payload reentry determinations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Payload and payload reentry determinations. 431.7 Section 431.7 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) General § 431.7 Payload and payload...

  6. 14 CFR 431.59 - Issuance of payload reentry determination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Issuance of payload reentry determination. 431.59 Section 431.59 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE...

  7. 14 CFR 431.55 - Payload reentry review.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Payload reentry review. 431.55 Section 431.55 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  8. 14 CFR 431.55 - Payload reentry review.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Payload reentry review. 431.55 Section 431.55 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  9. 14 CFR 431.59 - Issuance of payload reentry determination.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Issuance of payload reentry determination. 431.59 Section 431.59 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE...

  10. 14 CFR 431.55 - Payload reentry review.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Payload reentry review. 431.55 Section 431.55 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  11. 14 CFR 431.55 - Payload reentry review.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Payload reentry review. 431.55 Section 431.55 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  12. 14 CFR 431.59 - Issuance of payload reentry determination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Issuance of payload reentry determination. 431.59 Section 431.59 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE...

  13. Reentry and Renegotiating Motherhood: Maternal Identity and Success on Parole

    ERIC Educational Resources Information Center

    Brown, Marilyn; Bloom, Barbara

    2009-01-01

    Parenting women emerging from prison on parole face numerous challenges to their successful reentry into the community. Along with finding housing, employment, and satisfying the conditions of their supervision, parenting women must also reassume their roles as mothers. This article adds to the literature on reentry by placing women's maternal…

  14. Quantifying the thermo-mechanical impact of plume arrival on continental break-up

    NASA Astrophysics Data System (ADS)

    Brune, Sascha; Popov, Anton A.; Sobolev, Stephan V.

    2013-09-01

    The arrival of a plume head at Earth's continental lithosphere is often considered to be an important factor for continental break-up. However, the impact of plume impingement on strength and duration of a rift remains unclear. In this study, we quantify the mechanical and thermal influence of a plume (i.e. lithosphere erosion) on continental break-up. To do that we apply the three-dimensional numerical code SLIM3D that features realistic elasto-visco-plastic rheology. We model the thermo-mechanical response of a segment of Earth's lithosphere that is affected both by extension as well as plume-related lithosphere erosion in order to evaluate the influence on the overall force budget. We find that lithosphere erosion leads to a moderate lithospheric strength reduction of several TN/m. In a force-limited environment, however, this strength reduction may have strong influence on the timing of continental break-up, or it may even control whether continental break-up takes place at all. Additional reduction of the lithospheric strength is likely due to the massive emplacement of dikes that follows intensive melting within the plume head.

  15. Female Arab-Muslim nursing students' reentry transitions.

    PubMed

    McDermott-Levy, Ruth

    2013-01-01

    As nursing students are increasingly studying abroad and returning to their home countries to practice, it is important to identify international nursing students' reentry transition to understand their reentry needs. Phenomenological inquiry was used to describe the reentry experience of seven Omani nurses after studying in the United States. The nurses' reentry experience was influenced by the personal and professional transformation from studying abroad and included themes of adaptation to cultural differences and service to themselves, their profession, and their nation. These nurses returned home to resume previous roles; they were changed and this required them to redefine and adapt to their roles within their families and workplace. Nurses returning from international study could benefit from a formal reentry program to assist their transition to family, community, and professional life and to enhance the nurses' contribution from their international education. PMID:23832951

  16. Analytical Predictions of Thermal Stress in the Stardust PICA Heatshield Under Reentry Flight Conditions

    NASA Technical Reports Server (NTRS)

    Squire, Thomas; Milos, Frank; Agrawal, Parul

    2009-01-01

    We performed finite element analyses on a model of the Phenolic Impregnated Carbon Ablator (PICA) heatshield from the Stardust sample return capsule (SRC) to predict the thermal stresses in the PICA material during reentry. The heatshield on the Stardust SRC was a 0.83 m sphere cone, fabricated from a single piece of 5.82 cm-thick PICA. The heatshield performed successfully during Earth reentry of the SRC in January 2006. Material response analyses of the full, axisymmetric PICA heatshield were run using the Two-Dimensional Implicit Ablation, Pyrolysis, and Thermal Response Program (TITAN). Peak surface temperatures were predicted to be 3385K, while the temperature at the PICA backface remained at the estimated initial cold-soak temperature of 278K. Surface recession and temperature distribution results from TITAN, at several points in the reentry trajectory, were mapped onto an axisymmetric finite element model of the heatshield. We used the finite element model to predict the thermal stresses in the PICA from differential thermal expansion. The predicted peak compressive stress in the PICA heatshield was 1.38 MPa. Although this level of stress exceeded the chosen design limit for compressive stresses in PICA tiles for the design of the Orion crew exploration vehicle heatshield, the Stardust heatshield exhibited no obvious mechanical failures from thermal stress. The analyses of the Stardust heatshield were used to assess and adjust the level of conservatism in the finite element analyses in support of the Orion heatshield design.

  17. TRMM Re-Entry Planning: Attitude Determination and Control During Thruster Modes

    NASA Technical Reports Server (NTRS)

    DeWeese, Keith

    2005-01-01

    The Tropical Rainfall Measuring Mission (TRMM) spacecraft has been undergoing design for a controlled re-entry to Earth. During simulation of the re-entry plan, there was evidence of errors in the attitude determination algorithms during thruster modes. These errors affected the bum efficiency, and thus planning, during re-entry. During thruster modes, the spacecraft attitude is controlled off of integrated Gyro Error Angles that were designed to closely follow the nominal spacecraft pointing frame (Tip Frame). These angles, however, were not exactly mapped to the Tip Frame from the Body Frame. Additionally, in the initial formulation of the thruster mode attitude determination algorithms, several assumptions and approximations were made to conserve processor speed. These errors became noticeable and significant when simulating bums of much longer duration (-10 times) than had been produced in flight. A solution is proposed that uses attitude determination information from a propagated extended Kalman filter that already exists in the TRMM thruster modes. This attitude information is then used to rotate the Gyro Error Angles into the Tip Frame. An error analysis is presented that compares the two formulations. The new algorithm is tested using the TRMM High-Fidelity Simulator and verified with the TRMM Software Testing and Training Facility. Simulation results for both configurations are also presented.

  18. Statistical Issues for Calculating Reentry Hazards

    NASA Technical Reports Server (NTRS)

    Bacon, John B.; Matney, Mark

    2016-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering object to human populations. These tools make use of the characteristics (e.g., mass, shape, size) of debris that are predicted by aerothermal models to survive reentry. This information, combined with information on the expected ground path of the reentry, is used to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of this analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. This inevitably involves assumptions that simplify the problem and make it tractable, but it is often difficult to test the accuracy and applicability of these assumptions. This paper builds on previous IAASS work to re-examine one of these theoretical assumptions.. This study employs empirical and theoretical information to test the assumption of a fully random decay along the argument of latitude of the final orbit, and makes recommendations how to improve the accuracy of this calculation in the future.

  19. Statistical Issues for Calculating Reentry Hazards

    NASA Technical Reports Server (NTRS)

    Matney, Mark; Bacon, John

    2016-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering object to human populations. These tools make use of the characteristics (e.g., mass, shape, size) of debris that are predicted by aerothermal models to survive reentry. This information, combined with information on the expected ground path of the reentry, is used to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of this analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. This inevitably involves assumptions that simplify the problem and make it tractable, but it is often difficult to test the accuracy and applicability of these assumptions. This paper builds on previous IAASS work to re-examine many of these theoretical assumptions, including the mathematical basis for the hazard calculations, and outlining the conditions under which the simplifying assumptions hold. This study also employs empirical and theoretical information to test these assumptions, and makes recommendations how to improve the accuracy of these calculations in the future.

  20. Orbit re-entry experiment vehicle development

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masataka; Yamawaki, Kouji; Akimoto, Toshio; Murakami, Atsushi; Inaba, Motoyuki; Kaneko, Yutaka; Shimoda, Takayuki; Ishii, Yasuo; Izumi, Tatsushi; Kawano, Isao

    1992-08-01

    An overview of the Orbital Re-entry Experiment (OREX) vehicle development, including detail design, analyses on the overall system, guidance and control, propulsion, and data acquisition systems is presented. The outline of the experiment vehicle is shown. OREX flight is analyzed and the splash down point variance ellipse is shown. Vehicle body aerodynamic characteristics were analyzed and validated by supersonic wind tunnel and dynamically balanced wind tunnel tests. Analyses on onboard equipment environmental resistance, controllability from on orbit to re-entry phases and navigation and guidance of the space plane were conducted. It was confirmed that there was no problem on the guidance and control system. Review on the propellant volume and analyses on the propulsion system performance, propulsion system heat exchanger performance, and thruster and piping system temperature were conducted and possibility of hard starting of the 150 N hydrazine thruster was noticed. RF (Radio Frequency) link analyses were conducted around Tanegashima, Ogasawara, and the splash down area and prospect of continuously acquiring good link margin for 300 seconds was obtained. Semi unitized structure of truncated cone shape with main body made of aluminum alloy, which has application record for rockets, laid with skin, stringers, and frames was employed for the structure. Data acquisition systems for tracking and operation, including those at Tanegashima, Ogasawara, Christmas, down range ship, and airplane tracking stations were studied.

  1. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

    Glaese, J. R.; Kennel, H. F.

    1980-01-01

    The method of torque equilibrium attitude control used to control the reentry of Skylab to an altitude below 150 km without the use of thruster fuel once the attitude was established is discussed. The Skylab attitude and pointing control system, which included rate gyros, sun sensors, star tracker, the Apollo telescope mount digital computer, control moment gyros and cold-gas attitude thrusters, is presented. The 12 torque equilibrium attitudes found at which aerodynamic, gravity gradient and gyroscopic torques would balance are indicated, and the three of those at which the solar power supply would be adequate for attitude control are illustrated. The equilibrium seeking method employed is then examined, and the operation and performance of the torque equilibrium attitude control system during the three weeks prior to Skylab reentry are discussed. It is concluded that the torque equilibrium attitude control method developed for Skylab was successful in performing its assigned mission, and will be valuable for the design of future, low-altitude spacecraft or tethered vehicles.

  2. Development of orbital debris spacecraft breakup models

    NASA Astrophysics Data System (ADS)

    Tedeschi, William J.; Connell, John C.; McKnight, Darren S.

    1991-08-01

    The Defense Nuclear Agency has initiated an Orbital Debris Spacecraft Breakup Modeling Program to improve the accuracy and usefulness of satellite breakup models with an emphasis on collision-induced events. Empirical, semianalytic, and complex approaches are used in the modeling. Current results from the modeling effort are presented and discussed along with data from associated hypervelocity impact test programs. It is shown that major improvements in modeling have been made but that milestones must be achieved before the models will routinely provide accurate predictions for a wide range of collision scenarios.

  3. Evaluating and Addressing Potential Hazards of Fuel Tanks Surviving Atmospheric Reentry

    NASA Technical Reports Server (NTRS)

    Kelley, Robert L.; Johnson, Nicholas L.

    2011-01-01

    In order to ensure reentering spacecraft do not pose an undue risk to the Earth's population it is important to design satellites and rocket bodies with end of life considerations in mind. In addition to considering the possible consequences of deorbiting a vehicle, consideration must also be given to the possible risks associated with a vehicle failing to become operational or reach its intended orbit. Based on recovered space debris and numerous reentry survivability analyses, fuel tanks are of particular concern in both of these considerations. Most spacecraft utilize some type of fuel tank as part of their propulsion system. These fuel tanks are most often constructed using stainless steel or titanium and are filled with potentially hazardous substances such as hydrazine and nitrogen tetroxide. For a vehicle which has reached its scheduled end of mission the contents of the tanks are typically depleted. In this scenario the use of stainless steel and titanium results in the tanks posing a risk to people and property do to the high melting point and large heat of ablation of these materials leading to likely survival of the tank during reentry. If a large portion of the fuel is not depleted prior to reentry, there is the added risk of hazardous substance being released when the tank impact the ground. This paper presents a discussion of proactive methods which have been utilized by NASA satellite projects to address the risks associated with fuel tanks reentering the atmosphere. In particular it will address the design of a demiseable fuel tank as well as the evaluation of off the shelf designs which are selected to burst during reentry.

  4. Evaluating and Addressing Potential Hazards of Fuel Tanks Surviving Atmospheric Reentry

    NASA Astrophysics Data System (ADS)

    Kelley, R. L.; Johnson, N. L.

    2012-01-01

    In order to ensure reentering spacecraft do not pose an undue risk to the Earth's population, it is important to design satellites and rocket bodies with end-of-life considerations in mind. In addition to the possible consequences of deorbiting a vehicle, consideration must be given to the possible risks associated with a vehicle failing to become operational or to reach its intended orbit. Based on recovered space debris and numerous reentry survivability analyses, fuel tanks are of particular concern in both of these considerations. Most spacecraft utilize some type of fuel tank as part of their propulsion systems. These fuel tanks are most often constructed using stainless steel or titanium and are filled with potentially hazardous substances such as hydrazine and nitrogen tetroxide. For a vehicle that has reached its scheduled end-of mission, the contents of the tanks are typically depleted. In this scenario, the likely survival of a stainless steel or titanium tank during reentry poses a risk to people and property due to the high melting point and large heat-of-ablation of these materials. If a large portion of the fuel is not depleted prior to reentry, there is the added risk of a hazardous substance being released when the tank impacts the ground. This paper presents a discussion of proactive methods that have been utilized by NASA satellite projects to address the risks associated with fuel tanks reentering the atmosphere. In particular, it will address the design of a demiseable fuel tank, as well as the evaluation of fuel tank designs, which are selected based on whether they burst during reentry.

  5. Galileo: Earth avoidance study report

    NASA Technical Reports Server (NTRS)

    Mitchell, R. T.

    1988-01-01

    The 1989 Galileo mission to Jupiter is based on a VEEGA (Venus Earth Earth-Gravity Assist) trajectory which uses two flybys of Earth and one of Venus to achieve the necessary energy and shaping to reach Jupiter. These encounters are needed because the Centaur upper stage is not now being used on this mission. Since the Galileo spacecraft uses radioisotope thermoelectric generators (RTGs) for electrical power, the question arises as to whether there is any chance of an inadvertent atmospheric entry of the spacecraft during either of the two Earth flybys. A study was performed which determined the necessary actions, in both spacecraft and trajectory design as well as in operations, to insure that the probability of such reentry is made very small, and to provide a quantitative assessment of the probability of reentry.

  6. On the driving forces of the Pangea breakup and northward drift of the Indian subcontinent

    NASA Astrophysics Data System (ADS)

    Yoshida, Masaki; Hamano, Yozo

    2015-04-01

    During the breakup of the supercontinent Pangea, the Indian subcontinent became isolated from the southern part of Pangea, called Gondwanaland, at around 130 Ma, moved northwards, and eventually collided with Eurasia to form the Himalayas at around 40-50 Ma. The reason why the Indian subcontinent moved at such a high speed of up to c. 20 cm/yr remains a controversial issue in geodynamics. Here, numerical simulation of 3-D spherical mantle convection with an Earth-like Rayleigh number is reported, considering the assembly of highly viscous continental blocks with the configuration of Pangea, to determine the geodynamic mechanisms of the Pangea breakup, the subsequent continental drift, and the high-speed northward drift of the Indian subcontinent. Our numerical simulations approximately reproduced the process of continental drift from the breakup of Pangea at 200 Ma to the present-day continental distribution. These simulations revealed that a major factor in the northward drift of the Indian subcontinent was the large-scale cold mantle downwelling that developed spontaneously in the North Tethys Ocean, attributed to the overall shape of Pangea. The strong lateral mantle flow caused by the high-temperature anomaly beneath Pangea, due to the thermal insulation effect, enhanced the acceleration of the Indian subcontinent during the early stage of the Pangea breakup. The large-scale hot upwelling plumes from the lower mantle, initially located under Africa, might have contributed to the formation of the large-scale cold mantle downwelling in the North Tethys Ocean. References: [1] Yoshida, M., Effects of various lithospheric yield stresses and different mantle-heating modes on the breakup of the Pangea supercontinent, Geophys. Res. Lett., 41(9), 3060-3067, doi:10.1002/2014GL060023, 2014. [2] Yoshida, M. and Y. Hamano, Pangea breakup and northward drift of the Indian subcontinent reproduced by a numerical model of mantle convection, Submitted to Scientific Reports, 2015

  7. An Overview of JAXA's Ground-Observation Activities for HAYABUSA Reentry

    NASA Astrophysics Data System (ADS)

    Fujita, Kazuhisa; Yamamoto, Masa-Yuki; Abe, Shinsuke; Ishihara, Yoshiaki; Iiyama, Ohmi; Kakinami, Yoshihiro; Hiramatsu, Yoshihiro; Furumoto, Muneyoshi; Takayanagi, Hiroki; Suzuki, Toshiyuki; Yanagisawa, Toshifumi; Kurosaki, Hirohisa; Shoemaker, Michael; Ueda, Masayoshi; Shiba, Yasuo; Suzuki, Masaharu

    2011-10-01

    On 2010 June 13, the HAYABUSA asteroid explorer returned to Earth and underwent a super-orbital atmospheric reentry. In order to recover the sample return capsule and to take ground-based measurements, the Japan Aerospace Exploration Agency organized a ground-observation team and performed optical tracking of the capsule, spectroscopy of the fireball, and measurements of infrasounds and shock waves generated by the fireball. In this article, an overview of the ground-based observation is presented, and an outline of the preliminary results derived from observations is reported.

  8. Magnetic field applied to thermochemical non-equilibrium reentry flows in 2D - five species

    NASA Astrophysics Data System (ADS)

    Sávio de Góes Maciel, Edisson

    2015-07-01

    In this work, a study involving magnetic field actuation over reentry flows in thermochemical non-equilibrium is performed. The Euler and Navier-Stokes equations are studied. The proposed numerical algorithm is centred and second-order accurate. The hypersonic flow around a blunt body is simulated. Three time integration methods are tested. The reactive simulations involve Earth atmosphere of five species. The work of Gaitonde is the reference to couple the fluid dynamics and Maxwell equations of electromagnetism. The results have indicated that the Maciel scheme, using the Mavriplis dissipation model, yields the best prediction of the stagnation pressure.

  9. Re-Entry Mission Analysis of the Advanced Re-entry Vehicle (ARV)

    NASA Astrophysics Data System (ADS)

    Bonetti, D.; Haya Ramos, R.; Strauch, H.; Bottacini, M.

    2011-08-01

    This paper presents the results of the DEIMOS Space S.L.U. Re-entry Mission Analysis activities obtained in the frame of the Phase A up to PRR milestone of the Advanced Re-entry Vehicle (ARV) ESA project leaded by ASTRIUM. Results presented show how the trajectory and the vehicle design are strictly related and how a feasible and robust solution can be efficiently obtained by considering since the beginning several constraints limiting the design. The process implemented combines the design of key vehicle and trajectory parameters. Once the vehicle design parameters and the conditions at the EIP are fixed, the Mission Analysis is completed by the definition of the optimal trajectory from the deorbiting to the EIP that allow the correct targeting of the EIP conditions but also a safe separation of the different modules and the correct targeting of the desired landing site.

  10. Re-Entry Mission Analysis Of The Advanced Re-Entry Vehicle (ARV)

    NASA Astrophysics Data System (ADS)

    Bonetti, Davide; Haya Ramos, Rodrigo; Strauch, Hans; Bottacini, Massimiliano

    2011-05-01

    This paper presents the results of the DEIMOS Space S.L.U. Re-entry Mission Analysis activities obtained in the frame of the Phase A up to PRR milestone of the Advanced Re-entry Vehicle (ARV) ESA project leaded by ASTRIUM. Results presented show how the trajectory and the vehicle design are strictly related and how a feasible and robust solution can be efficiently obtained by considering since the beginning several constraints limiting the design. The process implemented combines the design of key vehicle and trajectory parameters. Once the vehicle design parameters and the conditions at the EIP are fixed, the Mission Analysis is completed by the definition of the optimal trajectory from the de- orbiting to the EIP that allow the correct targeting of the EIP conditions but also a safe separation of the different modules and the correct targeting of the desired landing site.

  11. Renormalization for breakup of invariant tori

    NASA Astrophysics Data System (ADS)

    Apte, A.; Wurm, A.; Morrison, P. J.

    2005-01-01

    We present renormalization group operators for the breakup of invariant tori with winding numbers that are quadratic irrationals. We find the simple fixed points of these operators and interpret the map pairs with critical invariant tori as critical fixed points. Coordinate transformations on the space of maps relate these fixed points, and also induce conjugacies between the corresponding operators.

  12. Breakup branches of Borromean beryllium-9

    SciTech Connect

    Smith, R. Freer, M.; Wheldon, C.; Curtis, N.; Ashwood, N. I.; Barr, M.; Kokalova, Tz.; Malcolm, J. D.; Ziman, V. A.; Almaraz-Calderon, S.; Aprahamian, A.; Bucher, B.; Couder, M.; Fang, X.; Jung, F.; Lu, W.; Roberts, A.; Tan, W. P.; Copp, P.; Lesher, S. R.; and others

    2015-10-15

    The breakup reaction {sup 9}Be({sup 4}He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in {sup 9}Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in {sup 9}Be have been explored including the {sup 8}Be{sub g.s.} + n, {sup 8}Be{sub 2{sup +}} + n and {sup 5}He{sub g.s.} + {sup 4}He channels. By imposing the condition that the breakup proceeded via the {sup 8}Be ground state, clean excitation spectra for {sup 9}Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose.

  13. Computational modelling of microfluidic capillary breakup phenomena

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Sprittles, James; Oliver, Jim

    2013-11-01

    Capillary breakup phenomena occur in microfluidic flows when liquid volumes divide. The fundamental process of breakup is a key factor in the functioning of a number of microfluidic devices such as 3D-Printers or Lab-on-Chip biomedical technologies. It is well known that the conventional model of breakup is singular as pinch-off is approached, but, despite this, theoretical predictions of the global flow on the millimetre-scale appear to agree well with experimental data, at least until the topological change. However, as one approaches smaller scales, where interfacial effects become more dominant, it is likely that such unphysical singularities will influence the global dynamics of the drop formation process. In this talk we develop a computational framework based on the finite element method capable of resolving diverse spatio-temporal scales for the axisymmetric breakup of a liquid jet, so that the pinch-off dynamics can be accurately captured. As well as the conventional model, we discuss the application of the interface formation model to this problem, which allows the pinch-off to be resolved singularity-free, and has already been shown to produce improved flow predictions for related ``singular'' capillary flows.

  14. Breakup branches of Borromean beryllium-9

    NASA Astrophysics Data System (ADS)

    Smith, R.; Freer, M.; Wheldon, C.; Curtis, N.; Almaraz-Calderon, S.; Aprahamian, A.; Ashwood, N. I.; Barr, M.; Bucher, B.; Copp, P.; Couder, M.; Fang, X.; Goldring, G.; Jung, F.; Kokalova, Tz.; Lesher, S. R.; Lu, W.; Malcolm, J. D.; Roberts, A.; Tan, W. P.; Ziman, V. A.

    2015-10-01

    The breakup reaction 9Be(4He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in 9Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in 9Be have been explored including the 8Beg.s. + n, 8Be2+ + n and 5Heg.s. + 4He channels. By imposing the condition that the breakup proceeded via the 8Be ground state, clean excitation spectra for 9Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose.

  15. Projectile deformation effects in the breakup of 37Mg

    NASA Astrophysics Data System (ADS)

    Shubhchintak; Chatterjee, R.; Shyam, R.

    2016-05-01

    We study the breakup of 37Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the postform finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of 37Mg.

  16. Hayabusa Re-Entry: Trajectory Analysis and Observation Mission Design

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Winter, Michael W.; Allen, Gary A.; Grinstead, Jay H.; Antimisiaris, Manny E.; Albers, James; Jenniskens, Peter

    2011-01-01

    On June 13th, 2010, the Hayabusa sample return capsule successfully re-entered Earth s atmosphere over the Woomera Prohibited Area in southern Australia in its quest to return fragments from the asteroid 1998 SF36 Itokawa . The sample return capsule entered at a super-orbital velocity of 12.04 km/sec (inertial), making it the second fastest human-made object to traverse the atmosphere. The NASA DC-8 airborne observatory was utilized as an instrument platform to record the luminous portion of the sample return capsule re-entry (60 sec) with a variety of on-board spectroscopic imaging instruments. The predicted sample return capsule s entry state information at 200 km altitude was propagated through the atmosphere to generate aerothermodynamic and trajectory data used for initial observation flight path design and planning. The DC- 8 flight path was designed by considering safety, optimal sample return capsule viewing geometry and aircraft capabilities in concert with key aerothermodynamic events along the predicted trajectory. Subsequent entry state vector updates provided by the Deep Space Network team at NASA s Jet Propulsion Laboratory were analyzed after the planned trajectory correction maneuvers to further refine the DC-8 observation flight path. Primary and alternate observation flight paths were generated during the mission planning phase which required coordination with Australian authorities for pre-mission approval. The final observation flight path was chosen based upon trade-offs between optimal viewing requirements, ground based observer locations (to facilitate post-flight trajectory reconstruction), predicted weather in the Woomera Prohibited Area and constraints imposed by flight path filing deadlines. To facilitate sample return capsule tracking by the instrument operators, a series of two racetrack flight path patterns were performed prior to the observation leg so the instruments could be pointed towards the region in the star background where

  17. Supercontinent break-up: Causes and consequences

    NASA Astrophysics Data System (ADS)

    Li, Z. X.

    2014-12-01

    Supercontinent break-up has most commonly been linked to plume or superplume events, and/or supercontinent thermal insulation, but precise mechanisms are yet to be worked out. Even less know is if and what roles other factors may play. Key factors likely include gravitational force due to the continental superswell driven by both the lower-mantle superplume and continental thermal insulation, mental convention driven by the superplume and individual plumes atop the superplume, assisted by thermal/magmatic weakening of the supercontinent interior (both plume heat and thermal insulation heat). In addition, circum-supercontinent slab downwelling may not only drive the formation of the antipodal superplumes (thus the break-up of the supercontinent), the likely roll-back of the subduction system would also create extension within the supercontinent, facilitating supercontinent break-up. Consequences of supercontinent break-up include long-term sea-level rise, climatic changes due to changes in ocean circulation pattern and carbon cycle, and biodiversification. It has long been demonstrated that the existence of the supercontinent Pangea corresponds to a long-term sea-level drop, whereas the break-up of the supercontinent corresponds to a long-term sea-level rise (170 m higher than it is today). A recent analysis of Neoproterozoic sedimentary facies illustrates that the time of Neoproterozoic supercontinent Rodinia corresponds to a low in the percentage of deep marine facies occurrence, whereas the time of Rodinia break-up corresponds to a significantly higher percentage of deep marine facies occurrence. The long-tern sea-level drop during supercontinent times were likely caused by both plume/superplume dynamic topography and an older mean age of the oceanic crust, whereas long-tern sea-level rise during supercontinent break-up (720-580 Ma for Rodinia and Late Jurassic-Cretaceous for Pangea) likely corresponds to an younger mean age of the oceanic crust, massive plume

  18. Rising above Reality: The Voices of Reentry Black Mothers and Their Daughters

    ERIC Educational Resources Information Center

    Sealey-Ruiz, Yolanda

    2007-01-01

    This article examines the following three themes present in the educational narratives of a group of Black reentry (returning to college) mothers: (a) reentry as a response to a critical moment, (b) reentry as a strategy for coping with challenges, and (c) reentry as a practical step toward getting their daughters into college. Cursory reviews of…

  19. Reentry of radon from mitigation system outlets

    SciTech Connect

    Yuill, G.K.; Coughlin, R.J.

    1994-12-31

    Some radon mitigation systems draw air with a high radon concentration from under the basement floors of houses and exhaust it outdoors. The objective of this project was to measure the reentry rates of radon released at roof level and at ground level near a house to determine whether exhaust above the roof is necessary. This was done by using a portable mockup of a radon mitigation system exhaust, with sulfur hexafluoride (SF{sub 6}) as a tracer gas. The roof-level exhaust produced maximum indoor sulfur hexafluoride concentrations that were significantly lower than those from the ground-level exhaust. This suggests that the better radon discharge location is on the roof of a house.

  20. Entrainment instability and vertical motion as causes of stratocumulus breakup

    NASA Technical Reports Server (NTRS)

    Weaver, C. J.; Pearson, R., Jr.

    1990-01-01

    Entrainment instability is thought to be a cause of stratocumulus breakup. At the interface between the cloud and the overlying air, mixtures may form which are negatively buoyant because of cloud droplet evaporation. Quantities devised to predict breakup are obtained from aircraft observations and are tested against cloud observations from satellite. Often, the parameters indicate that breakup should occur but the clouds remain, sometimes for several days. One possible explanation for breakup is vertical motion from passing synoptic cyclones. Several cases suggest that breakup is associated with the downward vertical motion from the cold air advected behind an eastward moving cyclone.

  1. Follow-up investigations of GPHS motion during heat pulse intervals of reentries from gravity-assist trajectories. Aerospace Nuclear Safety Program

    SciTech Connect

    Sharbaugh, R.C.

    1992-03-23

    Motion studies of the General Purpose Heat Source Module, GPHS, which were conducted in the heat pulse intervals associated with entries from earth gravity assist trajectories. The APL six-degree-of-freedom reentry program designated TMAGRA6C was used. The objectives of the studies were to (1) determine whether the GPHS module entering the earth`s atmosphere from an earth-gravity-assist trajectory has a preferred orientation during the heat pulse of reentry, (2) determine the effect of magnus force on the roll rate and angle of attack of the GPHS during an EGA entry, (3) determine the effect of the magnitude of pitch and roll damping on the GPHS motion.

  2. Characterization of the 2012-044C Briz-M Upper Stage Breakup

    NASA Technical Reports Server (NTRS)

    Matney, M. J.; Hamilton, J.; Horstman, M.; Papanyan, V.

    2013-01-01

    On 6 August, 2012, Russia launched two commercial satellites aboard a Proton rocket, and attempted to place them in geosynchronous orbit using a Briz-M upper stage (2012-044C, SSN 38746). Unfortunately, the upper stage failed early in its burn and was left stranded in an elliptical orbit with a perigee in low Earth orbit (LEO). Because the stage failed with much of its fuel on board, it was deemed a significant breakup risk. These fears were confirmed when it broke up 16 October, creating a large cloud of debris with perigees below that of the International Space Station. The debris cloud was tracked by the US Space Surveillance Network (SSN), which can reliably detect and track objects down to about 10 cm in size. Because of the unusual geometry of the breakup, there was an opportunity for NASA Orbital Debris Program Office to use specialized radar assets to characterize the extent of the debris cloud in sizes smaller than the standard debris tracked by the SSN. This paper will describe the observation campaign to measure the small particle distributions of this cloud, and presents the results of the analysis of the data. We shall compare the data to the modelled size distribution, number, and shape of the cloud, and what implications this may have for future breakup debris models. We shall conclude the paper with a discussion how this measurement process can be improved for future breakups.

  3. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterizations

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Clark, S.; Fitz-Coy, N.; Huynh, T.; Opiela, J.; Polk, M.; Roebuck, B.; Rushing, R.; Sorge, M.; Werremeyer, M.

    2013-01-01

    The goal of the DebriSat project is to characterize fragments generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 s US Navy Transit satellite. There are three phases to this project: the design and fabrication of DebriSat - an engineering model representing a modern, 60-cm/50-kg class LEO satellite; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area-to-mass ratio, density, shape, material composition, optical properties, and radar cross-section distributions, will be used to supplement the DoD s and NASA s satellite breakup models to better describe the breakup outcome of a modern satellite.

  4. Characterization of the 2012-044c Briz-M Upper Stage Breakup

    NASA Technical Reports Server (NTRS)

    Matney, M. J.; Hamilton, Joseph; Papanyan, Valen

    2013-01-01

    On 6 August, 2012, Russia launched two commercial satellites aboard a Proton rocket, and attempted to place them in geosynchronous orbit using a Briz-M upper stage (2012-044C, SSN 38746). Unfortunately, the upper stage failed early in its burn and was left stranded in an elliptical orbit with a perigee in low Earth orbit (LEO). Because the stage failed with much of its fuel on board, it was deemed a significant breakup risk. These fears were confirmed when it broke up 16 October, creating a large cloud of debris with perigees below that of the International Space Station. The debris cloud was tracked by the US Space Surveillance Network (SSN), which can reliably detect and track objects down to about 10 cm in size. Because of the unusual geometry of the breakup, there was an opportunity for NASA Orbital Debris Program Office to request radar assets to characterize the extent of the debris cloud in sizes smaller than the standard debris tracked by the SSN. This paper will describe the observation campaign to measure the small particle distributions of this cloud, and presents the results of the analysis of the data. We shall compare the data to the modelled size distribution, number, and shape of the cloud, and what implications this may have for future breakup debris models. We shall conclude the paper with a discussion how this measurement process can be improved for future breakups.

  5. Empirical Tests of the Predicted Footprint for Uncontrolled Satellite Reentry Hazards

    NASA Technical Reports Server (NTRS)

    Matney, Mark

    2011-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering object to human populations. These tools make use of the characteristics (e.g., mass, material, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of the analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. Because this information is used in making policy and engineering decisions, it is important that these assumptions be tested using empirical data. This study uses the latest database of known uncontrolled reentry locations measured by the United States Department of Defense. The predicted ground footprint distributions of these objects are based on the theory that their orbits behave basically like simple Kepler orbits. However, there are a number of factors in the final stages of reentry - including the effects of gravitational harmonics, the effects of the Earth s equatorial bulge on the atmosphere, and the rotation of the Earth and atmosphere - that could cause them to diverge from simple Kepler orbit behavior and possibly change the probability of reentering over a given location. In this paper, the measured latitude and longitude distributions of these objects are directly compared with the predicted distributions, providing a fundamental empirical test of the model assumptions.

  6. Planned Flight of the Terrestrial HIAD Orbital Reentry (THOR)

    NASA Astrophysics Data System (ADS)

    Dillman, R. A.; Hughes, S. J.; DiNonno, J. M.; Bodkin, R. J.; White, J. P.; Del Corso, J. A.; Cheatwood, F. M.

    2014-06-01

    This paper discusses the mission concept for the Terrestrial HIAD Orbital Reentry (THOR), planned for flight in 2016 as a secondary payload on an orbital sciences commercial resupply mission to the International Space Station.

  7. Critical role of inhomogeneities in pacing termination of cardiac reentry

    NASA Astrophysics Data System (ADS)

    Sinha, Sitabhra; Stein, Kenneth M.; Christini, David J.

    2002-09-01

    Reentry around nonconducting ventricular scar tissue, a cause of lethal arrhythmias, is typically treated by rapid electrical stimulation from an implantable cardioverter defibrillator. However, the dynamical mechanisms of termination (success and failure) are poorly understood. To elucidate such mechanisms, we study the dynamics of pacing in one- and two-dimensional models of anatomical reentry. In a crucial realistic difference from previous studies of such systems, we have placed the pacing site away from the reentry circuit. Our model-independent results suggest that with such off-circuit pacing, the existence of inhomogeneity in the reentry circuit is essential for successful termination of tachycardia under certain conditions. Considering the critical role of such inhomogeneities may lead to more effective pacing algorithms.

  8. Reentry trajectory optimization based on a multistage pseudospectral method.

    PubMed

    Zhao, Jiang; Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

  9. Reentry Trajectory Optimization Based on a Multistage Pseudospectral Method

    PubMed Central

    Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

  10. 14 CFR 431.7 - Payload and payload reentry determinations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV... launch a payload unless the proposed payload is exempt from payload review under § 415.53 of this...

  11. 14 CFR 431.7 - Payload and payload reentry determinations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV... launch a payload unless the proposed payload is exempt from payload review under § 415.53 of this...

  12. 14 CFR 431.7 - Payload and payload reentry determinations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV... launch a payload unless the proposed payload is exempt from payload review under § 415.53 of this...

  13. 14 CFR 431.7 - Payload and payload reentry determinations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV... launch a payload unless the proposed payload is exempt from payload review under § 415.53 of this...

  14. Coupled map lattice model of jet breakup

    SciTech Connect

    Minich, R W; Schwartz, A J; Baker, E L

    2001-01-25

    An alternative approach is described to evaluate the statistical nature of the breakup of shaped charge liners. Experimental data from ductile and brittle copper jets are analyzed in terms of velocity gradient, deviation of {Delta}V from linearity, R/S analysis, and the Hurst exponent within the coupled map lattice model. One-dimensional simulations containing 600 zones of equal mass and using distinctly different force-displacement curves are generated to simulate ductile and brittle behavior. A particle separates from the stretching jet when an element of material reaches the failure criterion. A simple model of a stretching rod using brittle, semi-brittle, and ductile force-displacement curves is in agreement with the experimental results for the Hurst exponent and the phase portraits and indicates that breakup is a correlated phenomenon.

  15. Ice breakup: Observations of the acoustic signal

    NASA Astrophysics Data System (ADS)

    Waddell, S. R.; Farmer, D. M.

    1988-03-01

    We describe observations of ambient sound beneath landfast ice in the Canadian Arctic Archipelago and interpret its evolution over the period June-August in terms of ice cracking and disintegration. The data were recorded on six bands between 50 and 14,500 Hz for the period April 2 to August 7, 1986, in Dolphin and Union Strait. The frequency dependence of the attenuation of sound in water allows separation of distant and local noise sources. In conjunction with satellite imagery and meteorological data, it is shown that strong signals in the acoustic time series are associated with major breakup events. The acoustic signal can provide predictive information about ice conditions and the approach of breakup.

  16. Reusable Reentry Satellite (RRS): Telemetry, Tracking, and Command (TT/C) Coverage Tradeoff Study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) Telemetry, Tracking & Command (TT&C) Coverage Tradeoff Study described herein was performed during Part 1 of the RRS Phase B contract. This report is one of several that describes the results of various trade studies performed to arrive at a recommended design for the RRS satellite system. The overall RRS Phase B Study objective is to design a relatively inexpensive satellite to access space for extended periods of time, with eventual recovery of experiments on Earth. The RRS will be capable of: (1) being launched by a variety of expendable launch vehicles; (2) operating in low earth orbit as a free flying unmanned laboratory; and (3) executing an independent atmospheric reentry and soft landing. The RRS will be designed to be refurbished and reused up to three times a year for a period of 10 years. The expected principal use for such a system is research on the effects of variable gravity (0 to 1.5 g) and radiation on small animals, plants, lower life forms, tissue samples, and materials processes. This Summary Report provides a description of the RRS Telemetry, Tracking & Command Analysis performed to study the ground station coverage available to meet RRS requirements. Concepts were considered that used off-the-shelf technology, had generous margins of capability, and high reliability, were easily maintained, cost effective, and were compatible with existing support networks. From this study, a recommended RRS TT&C configuration will be developed.

  17. Structural Analysis and Testing of the Inflatable Re-entry Vehicle Experiment (IRVE)

    NASA Technical Reports Server (NTRS)

    Lindell, Michael C.; Hughes, Stephen J.; Dixon, Megan; Wiley, Cliff E.

    2006-01-01

    The Inflatable Re-entry Vehicle Experiment (IRVE) is a 3.0 meter, 60 degree half-angle sphere cone, inflatable aeroshell experiment designed to demonstrate various aspects of inflatable technology during Earth re-entry. IRVE will be launched on a Terrier-Improved Orion sounding rocket from NASA s Wallops Flight Facility in the fall of 2006 to an altitude of approximately 164 kilometers and re-enter the Earth s atmosphere. The experiment will demonstrate exo-atmospheric inflation, inflatable structure leak performance throughout the flight regime, structural integrity under aerodynamic pressure and associated deceleration loads, thermal protection system performance, and aerodynamic stability. Structural integrity and dynamic response of the inflatable will be monitored with photogrammetric measurements of the leeward side of the aeroshell during flight. Aerodynamic stability and drag performance will be verified with on-board inertial measurements and radar tracking from multiple ground radar stations. In addition to demonstrating inflatable technology, IRVE will help validate structural, aerothermal, and trajectory modeling and analysis techniques for the inflatable aeroshell system. This paper discusses the structural analysis and testing of the IRVE inflatable structure. Equations are presented for calculating fabric loads in sphere cone aeroshells, and finite element results are presented which validate the equations. Fabric material properties and testing are discussed along with aeroshell fabrication techniques. Stiffness and dynamics tests conducted on a small-scale development unit and a full-scale prototype unit are presented along with correlated finite element models to predict the in-flight fundamental mod

  18. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Water Landing Characteristics of a Reentry Capsule. Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions. [Entire movie available on DVD from CASI as Doc ID 20070030955. Contact help@sti.nasa.gov

  19. Breakup of Pack Ice, Antarctic Ice Shelf

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Breakup of Pack Ice along the periphery of the Antarctic Ice Shelf (53.5S, 3.0E) produced this mosaic of ice floes off the Antarctic Ice Shelf. Strong offshore winds, probably associated with strong katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filamets of sea ice, icebergs, bergy bits and growlers to flow northward into the South Atlantic Ocean. 53.5S, 3.0E

  20. Preliminary reentry safety assessment of the General Purpose Heat Source module for the Cassini mission: Aerospace Nuclear Safety Program

    SciTech Connect

    Conn, D.W.; Brenza, P.T.

    1993-04-01

    As asked by the U. S. Department of Energy/Office of Special Applications, and in support of the Environmental Impact Statement for the Cassini mission, The Johns Hopkins University/Applied Physics Laboratory (JHU/APL) has conducted preliminary one-dimensional ablation and thermal analyses of the General Purpose Heat Source (GPHS). The predicted earth entry conditions provided by the Jet Propulsion Laboratory (JPL) for a Cassini Venus-Venus-Earth-Jupiter Gravity Assist (VVEJGA) trajectory were used as initial conditions. The results of this study which constitute the initial reentry analysis assessment leading to the Cassini Updated Safety, Analysis Report (USAR) are discussed in this document.

  1. Preliminary reentry safety assessment of the General Purpose Heat Source module for the Cassini mission: Aerospace Nuclear Safety Program

    NASA Astrophysics Data System (ADS)

    Conn, D. W.; Brenza, P. T.

    1993-04-01

    As asked by the U.S. Department of Energy/Office of Special Applications, and in support of the Environmental Impact Statement for the Cassini mission, The Johns Hopkins University/Applied Physics Laboratory (JHU/APL) has conducted preliminary one dimensional ablation and thermal analyses of the General Purpose Heat Source (GPHS). The predicted earth entry conditions provided by the Jet Propulsion Laboratory (JPL) for a Cassini Venus - Venus - Earth - Jupiter gravity assist (VVEJGA) trajectory were used as initial conditions. The results of this study, which constitute the initial reentry analysis assessment leading to the Cassini Updated Safety Analysis Report (USAR), are discussed in this document.

  2. Ice multiplication by mechanical breakup and lightning

    NASA Astrophysics Data System (ADS)

    Phillips, Vaughan; Yano, Jun-Ichi

    2016-04-01

    Laboratory studies have proven the existence of several pathways for fragmentation of ice. One of these is the rime-splintering of graupel or hail in the -3 to -8 degC region (the Hallett-Mossop process). In some clouds, however, the cloud-base is too cold for this process to be active. Instead, breakup can occur by fragmentation of ice mechanically in re-bounding collisions between crystals, snow, graupel or hail. A new theoretical formulation of this mechanical breakup process of multiplication is presented for these types of ice. A numerical scheme is derived by simulation of published laboratory experiments. The role of such breakup in clouds is quantified by 3D simulations with a cloud-resolving aerosol-cloud model with emulated bin microphysics, detailed treatment of ice morphology and 7 chemical species of aerosol. Graupel-graupel collisions are predicted to produce copious numbers of ice crystals in the cold-base convective cloud simulated over Kansas. Implications for lightning from such multiplication, also simulated numerically, are discussed.

  3. Dynamics of polymeric drop breakup in microchannels

    NASA Astrophysics Data System (ADS)

    Arratia, Paulo; Gollub, Jerry; Durian, Douglas

    2006-11-01

    The dynamics of drop formation of sheared polymeric and Newtonian fluids are investigated in a 50 μm microchannel. Inverse emulsions are obtained in a cross-like geometry by impinging a continuous oil phase (with surfactant) onto either a polymeric or a Newtonian aqueous solution. The viscosity ratio between the continuous and dispersed phases is kept close to unity, and both flow rates are varied. Solutions containing small amounts (100 ppm) of flexible polymers strongly affect the filament and drop breakup processes when compared to a Newtonian solution of similar viscosity. We find that the thinning of the filament for the Newtonian case is characterized by linear decline followed by a rapid approach to breakup. The polymeric case shows an initial Newtonian-like thinning followed by a slower, elasticity- dominated thinning. Consequently, the filament breakup time and length are considerably increased for the polymeric solutions. Also, larger primary drops and beads-on-string phenomena are found for the polymer solutions.

  4. Beam Breakup Effects in Dielectric Based Accelerators

    SciTech Connect

    Schoessow, P.; Kanareykin, A.; Jing, C.; Kustov, A.; Altmark, A.; Power, J. G.; Gai, W.

    2009-01-22

    The dynamics of the beam in structure-based wakefield accelerators leads to beam stability issues not ordinarily found in other machines. In particular, the high current drive beam in an efficient wakefield accelerator loses a large fraction of its energy in the decelerator structure, resulting in physical emittance growth, increased energy spread, and the possibility of head-tail instability for an off axis beam, all of which can lead to severe reduction of beam intensity. Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators as well. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements at the AWA facility in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable. The numerical part of this research is based on a particle-Green's function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.

  5. The Beam Break-Up Numerical Simulator

    SciTech Connect

    Travish, G.A.

    1989-11-01

    Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs.

  6. Landing Energy Dissipation for Manned Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Fisher, Lloyd J., Jr.

    1960-01-01

    Analytical and experimental investigations have been made to determine the landing-energy-dissipation characteristics for several types of landing gear for manned reentry vehicles. The landing vehicles are considered in two categories: those having essentially vertical-descent paths, the parachute-supported vehicles, and those having essentially horizontal paths, the lifting vehicles. The energy-dissipation devices discussed are crushable materials such as foamed plastics and honeycomb for internal application in couch-support systems, yielding metal elements as part of the structure of capsules or as alternates for oleos in landing-gear struts, inflatable bags, braking rockets, and shaped surfaces for water impact. It appears feasible to readily evaluate landing-gear systems for internal or external application in hard-surface or water landings by using computational procedures and free-body landing techniques with dynamic models. The systems investigated have shown very interesting energy-dissipation characteristics over a considerable range of landing parameters. Acceptable gear can be developed along lines similar to those presented if stroke requirements and human-tolerance limits are considered.

  7. Asteroid breakup linked to the Great Ordovician Biodiversification Event

    NASA Astrophysics Data System (ADS)

    Schmitz, Birger; Harper, David A. T.; Peucker-Ehrenbrink, Bernhard; Stouge, Svend; Alwmark, Carl; Cronholm, Anders; Bergström, Stig M.; Tassinari, Mario; Xiaofeng, Wang

    2008-01-01

    The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval ~540Myrago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification ~470Myrago coincides with the disruption in the asteroid belt of the L-chondrite parent body-the largest documented asteroid breakup event during the past few billion years. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroids-supported by abundant Middle Ordovician fossil meteorites and impact craters-accelerated the biodiversification process.

  8. The break-up of continents and the formation of new ocean basins.

    PubMed

    Minshull, T A

    2002-12-15

    Rifted continental margins are the product of stretching, thinning and ultimate break-up of a continental plate into smaller fragments, and the rocks lying beneath them store a record of this rifting process. Earth scientists can read this record by careful sampling and with remote geophysical techniques. These experimental studies have been complemented by theoretical analyses of continental extension and associated magmatism. Some rifted margins show evidence for extensive volcanic activity and uplift during rifting; at these margins, the record of the final stages of rifting is removed by erosion and obscured by the thick volcanic cover. Other margins were underwater throughout their formation and showed rather little volcanic activity; here the ongoing deposition of sediment provides a clearer record. During the last decade, vast areas of exhumed mantle rocks have been discovered at such margins between continental and oceanic crust. This observation conflicts with the well-established idea that the mantle melts to produce new crust when it is brought close to the Earth's surface. In contrast to the steeply dipping faults commonly seen in zones of extension within continental interiors, faults with very shallow dips play a key role in the deformation immediately preceding continental break-up. Future progress in the study of continental break-up will depend on studies of pairs of margins which were once joined and on the development of computer models which can handle rigorously the complex transition from distributed continental deformation to sea-floor spreading focused at a mid-ocean ridge. PMID:12626269

  9. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  10. The Break-up and Drifting of the Continental Plates in 2D Models of Convecting Mantle

    NASA Astrophysics Data System (ADS)

    Dal Zilio, L.; Faccenda, M.; Capitanio, F. A.

    2014-12-01

    Since the early theory of Wegener, the break-up and drift of continents have been controversial and hotly debated topics. To assist the interpretation of the break-up and drift mechanisms and its relation with mantle circulation patterns, we carried out a 2D numerical modelling of the dynamics of these processes. Different regimes of upper plate deformation are studied as consequence of stress coupling with convection patterns. Subduction of the oceanic plate and induced mantle flow propagate basal tractions to the upper plate. This mantle drag forces (FMD) can be subdivided in two types: (1) active mantle drag occurring when the flow drives plate motion (FAD), and (2) passive mantle drag (FPD), when the asthenosphere resists plate motion. The active traction generated by the convective cell is counterbalanced by passive mantle viscous drag away from it and therefore tension is generated within the continental plate. The shear stress profiles indicate that break-up conditions are met where the gradient of the basal shear stress is maximised, however the break-up location varies largely depending on the convection style primarily controlled by slab stagnation on the transition zone, avalanching through or subduction in the lower mantle. We found good correspondence between our models and the evolution of convergent margins on Earth, giving precious insights into the break-up and drifting mechanisms of some continental plates, such as the North and South American plates, Calabria and the Japan Arc.

  11. Breakup locations: Intertwining effects of nuclear structure and reaction dynamics

    NASA Astrophysics Data System (ADS)

    Dasgupta, M.; Simpson, E. C.; Luong, D. H.; Kalkal, Sunil; Cook, K. J.; Carter, I. P.; Hinde, D. J.; Williams, E.

    2016-05-01

    Studies at the Australian National University aim to distinguish breakup of the projectile like-nucleus that occurs when approaching the target from that when receding from the target. Helped by breakup simulations, observables have been found that are sensitive to the breakup location, and thus to the mean-lives of unbound states; sensitivity to even sub-zeptosecond lifetime is found. These results provide insights to understand the reaction dynamics of weakly bound nuclei at near barrier energies.

  12. Satellite reentry predictions for the Italian civil protection authorities

    NASA Astrophysics Data System (ADS)

    Anselmo, Luciano; Pardini, Carmen

    2013-06-01

    In just 5 months, from September 2011 to January 2012, three campaigns of reentry predictions were carried out in support of the Italian civil protection authorities. The satellites involved were UARS, ROSAT and Fobos-Grunt, which received widespread attention for the marginal risk on the ground associated with their uncontrolled reentry. From the technical point of view, the three reentry campaigns offered the occasion to compare some semi-empirical thermospheric density models under varying solar and geomagnetic activity conditions, dealing with spacecraft characterized by quite different configurations, shapes, masses and attitude control. However, what made the experience substantially different from usual reentry test campaigns was the strict interaction with the civil protection community and the public. In fact, in order to provide understandable and unambiguous information useful for civil protection planning and applications, the nominal reentry time predictions were of no use, while a particular care was devoted to the definition of appropriate reentry uncertainty windows. The attention of the civil protection authorities was focused, of course, on the Italian territory, so the relevant question for any planning was the following: given a certain uncertainty window, where and when a fragment might have crossed the national airspace and hit the ground? In order to meet this demand, during the last 3-4 days of satellite residual lifetime, reentries where simulated over Italy to obtain quite accurate ground tracks, debris swaths and air space crossing time windows associated with the critical passes over the national territory still included in the current uncertainty window. This information was updated, if needed, but remained relatively stable and accurate until the reentry, not much affected by the actual trajectory evolution due to the varying air drag. In other words, it was easy to understand for people not familiar with orbital dynamics, unambiguous

  13. Water Landing Characteristics of a Reentry Capsule

    NASA Technical Reports Server (NTRS)

    1958-01-01

    Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

  14. NASA Team Captures Hayabusa Spacecraft Reentry

    NASA Video Gallery

    A group of astronomers from NASA, the Japan Aerospace Exploration Agency (JAXA) and other organizations had a front row seat to observe the Hayabusa spacecraft's fiery plunge into Earth's atmospher...

  15. Recent Breakups in the Asteroid Belt

    NASA Astrophysics Data System (ADS)

    Nesvorny, D.

    2005-08-01

    Much of what we see in the asteroid belt today is a consequence of past collisions, which shaped the size-frequency distribution of asteroids and led to their heavily-cratered surfaces. Perhaps the most remarkable features of the belt are the asteroid families [1]. An asteroid family is a group of asteroid fragments with similar orbits and spectra produced by a collisional breakup of a large parent body. More than fifty families have been identified to date in the main belt [2]. These structures, when properly analyzed, hold important clues to the interior structure of asteroids, the physics of large scale collisions, and the overall evolution of the main belt since its formation [3]. Most of the known families are very old and thus have experienced significant dynamical and collisional erosion since their formation. This makes it difficult to clearly distinguish between features produced by the original breakup and those produced by on-going processes. Recent dynamical studies, however, have identified several asteroid families that are extremely young: the Iannini, Karin and Veritas families apparently formed at <5, 5.8 and 8.3 Ma, respectively [4,5]. These families represent nearly pristine examples of ejected fragments produced by disruptive asteroid collisions, because the observed remnants of recent breakups have apparently suffered limited dynamical and collisional erosion. Here we will discuss how studies of young asteroid families help us glean insights into the physics of large scale collisions, dynamical processes that affect small bodies in the Solar System, and the surface and interior properties of asteroids. [1] Hirayama, 1918, AJ 31, 185--188. [2] Zappala et al., 2002, In Asteroids III, pp. 619-629. [3] Bottke et al., 2005, Icarus, 175, 111-140. [4] Nesvorny et al., 2002, Nature 417, 720--722. [5] Nesvorny et al., 2003, ApJ 591, 486--497.

  16. Multipass Beam Breakup in Energy Recovery Linacs

    SciTech Connect

    Eduard Pozdeyev; Christopher Tennant; Joseph Bisognano; M Sawamura; R. Hajima; T.I. Smith

    2005-03-19

    This paper is a compilation of several presentations on multipass beam breakup (BBU) in energy recovery linacs (ERL) given at the 32nd Advanced ICFA Beam Workshop on ERLs. The goal of this paper is to summarize the progress achieved in analytical, numerical, and experimental studies of the instability and outline available and proposed BBU mitigation techniques. In this paper, a simplified theory of multipass BBU in recirculating linacs is presented. Several BBU suppression techniques and their working principles are discussed. The paper presents an overview of available BBU codes. Results of experimental studies of multipass BBU at the Jefferson Laboratory (JLab) FEL Upgrade are described.

  17. Elastic Coulomb breakup of 34Na

    NASA Astrophysics Data System (ADS)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  18. Pangea formation and break-up

    NASA Astrophysics Data System (ADS)

    Torsvik, Trond

    2013-04-01

    The Palaeozoic was dominated by the great continent Gondwana. Other continents included Laurentia and Baltica that fused (together with Avalonia), forming Laurussia after the closure of the Iapetus Ocean, making the second largest continental entity in the Silurian. By the Carboniferous at around 320 Ma, Gondwana and Laurussia amalgamated, forming Pangea that was surrounded by the Panthalassa and Paleotethys Oceans. Pangea did not include all continental crust. For example, the South and North China Blocks were not part of Pangea at any given time and also during the Early Permian phase of Pangea assembly, the Neotethys opened, and Cimmerian terranes drifted away from the NE Gondwana margin while the Paleotethys was being subducted beneath Eurasia. An additional, unresolved question is whether Siberia was fully joined to Pangea before the eruption of the Siberian Traps (251 Ma). Practically all Permian Pangea reconstructions using palaeomagnetic data result in considerable overlap between Laurussia and Gondwana, as both are straddling the equator, and thus Gondwana must be moved sideways to avoid this overlap, and at a younger time displaced dextrally to achieve the well established starting point for Pangea break-up in the Jurassic. Octupole contributions can eliminate this overlap, but just by changing the internal fits within Laurussia and correcting all detrital sedimentary poles for inclination shallowing using a use a benchmark flattening (f) value of 0.6 (unless previously corrected using either the inclination-elongation method or anisotropy of magnetic susceptibility information) lead to an almost perfect Pangea-A type fit. Pangea break-up profoundly changed our planet, and the most important phase of break-up started when the Central Atlantic Ocean opened (ca. 195 Ma). Perhaps not coincidentally, the region where the Atlantic spreading started was preceded by the emplacement of the Central Atlantic Magmatic Province, one of the largest large igneous

  19. Breakup of Liquid Sheets and Jets

    NASA Astrophysics Data System (ADS)

    Lin, S. P.

    2003-09-01

    This book is an exposition of what we know about the physics underlying the onset of instability in liquid sheets and jets. Wave motion and breakup phenomena subsequent to the onset of instability are also carefully explained. Physical concepts are established through mathematics, accurate numerical analysis and comparison of theory with experiments. Exercises are provided for students new to the subject. Researchers interested in topics ranging from transition to turbulence, hydrodynamic stability or combustion will find this book a useful resource, whether their background lies in engineering, physics, chemistry, biology, medicine or applied mathematics.

  20. An integrated approach for risk object re-entry predictions in terms of KS elements and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Sharma, R. K.; Anil Kumar, A. K.; Xavier James Raj, M.

    The accurate estimation of the orbital lifetime of decaying near-Earth objects is of considerable importance for prediction of risk object re-entry time and proper planning of mitigation strategies and hazard assessment. It has become necessary to use extremely complex force models to match with the present operational requirements and observational techniques. The problem becomes all the more complicated in the near-Earth environment due to the fact that the object is influenced by the non-spherical effects of the Earth's gravitational field as well as the dissipative effects of the Earth's atmosphere. The database available for the re-entry time or orbital lifetime prediction of the debris objects is based on the set of Two Line Elements (TLEs) provided by the agencies like NORAD. These TLEs provide information regarding the orbital parameters together with rate of mean motion decay and an equivalent ballistic coefficient B*. The objects physical parameters like mass, area of cross section, shape and dimensions are not available accurately and the modelling of the atmosphere in which objects decay takes place is also uncertain. Besides, the tumbling effect of the body and gas molecular interaction, further makes the prediction of re-entry time a very complicated exercise. The method of the K-S total-energy element equations (Stiefel & Scheifele 1971) is a powerful method for numerical solution with respect to any type of perturbing forces, as the equations are less sensitive to round-off and truncation errors in the numerical algorithm. The equations are everywhere regular in contrast with the classical Newtonian equations, which are singular at the collision of the two bodies. The equations are smoothed for eccentric orbits because eccentric anomaly is the independent variable. Genetic Algorithms (Deb 1995) has received a great deal of attention regarding their potential as an optimisation technique for complex functions. This paper highlights the implementation

  1. Infrasound and Seismic Observation of Hayabusa Reentry as An Artificial Meteorite Fall

    NASA Astrophysics Data System (ADS)

    Ishihara, Y.; Hiramatsu, Y.; Yamamoto, M.; Furumoto, M.; Fujita, K.

    2011-12-01

    The Hayabusa, the world first sample-return minor body explorer, came back to the Earth, and reentered into the Earth's atmosphere on June 13, 2010. Following the reentries of the Genesis in 2004 and the Stardust in 2006, the return of the Hayabusa Sample Return Capsule (H-SRC) was the third direct reentry event from the interplanetary transfer orbit to the Earth at a velocity of over 11.2 km/s. In addition, it was the world first case of the direct reentry of the spacecraft (H-S/C) itself from the interplanetary transfer orbit. The H-SRC and the H-S/C reentries are very good analogue for studying bolide size meteors and meteorite falls. We, therefore, conducted a ground observation campaign for aspects of meteor sciences. We carried out multi-site ground observations of the Hayabusa reentry in the Woomera Prohibited Area (WPA), Australia. The observations were configured with optical imaging with still and video recordings, spectroscopies, and shockwave detection with infrasound and seismic sensors. In this study, we report details of the infrasound/seismic observations and those results. To detect shockwaves from the H-SRC and the H-S/C, we installed three small aperture infrasound/seismic arrays as the main stations. In addition, we also installed three single component seismic sub stations and an audible sound recorder. The infrasound and seismic sensors clearly recorded sonic boom type shockwaves from the H-SRC and disrupted fragments of the H-S/C itself. The audible recording also detected those shockwave sounds in the human audible band. Positive overpressure values of shockwaves (corresponding to the H-SRC) recorded at three main stations are 1.3 Pa, 1.0 Pa, and 0.7 Pa with the slant distance of 36.9 km, 54.9 km, and 67.8 km (i.e., the source altitude of 36.5 km, 38.9km, and 40.6 km), respectively. These amplitudes of shockwave overpressures are systematically smaller than those of theoretical predictions. We tried to identify the sources of shockwaves

  2. Relating Breakup and Incomplete Fusion of Weakly Bound Nuclei through a Classical Trajectory Model with Stochastic Breakup

    SciTech Connect

    Diaz-Torres, A.; Hinde, D. J.; Dasgupta, M.; Gasques, L. R.; Tostevin, J. A.

    2007-04-13

    A classical dynamical model that treats breakup stochastically is presented for low energy reactions of weakly bound nuclei. The three-dimensional model allows a consistent calculation of breakup, incomplete, and complete fusion cross sections. The model is assessed by comparing the breakup observables with continuum discretized coupled-channel quantum mechanical predictions, which are found to be in reasonable agreement. Through the model, it is demonstrated that the breakup probability of the projectile as a function of its distance from the target is of primary importance for understanding complete and incomplete fusion at energies near the Coulomb barrier.

  3. Pesticides re-entry dermal exposure of workers in greenhouses.

    PubMed

    Caffarelli, V; Conte, E; Correnti, A; Gatti, R; Musmeci, F; Morali, G; Spagnoli, G; Tranfo, G; Triolo, L; Vita, M; Zappa, G

    2004-01-01

    This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out. PMID:15756864

  4. Predictions of cardiovascular responses during STS reentry using mathematical models

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.; Srinivasan, R.

    1985-01-01

    The physiological adaptation to weightless exposure includes cardiovascular deconditioning arising in part from a loss of total circulating blood volume and resulting in a reduction of orthostatic tolerance. The crew of the Shuttle orbiter are less tolerant to acceleration forces in the head-to-foot direction during the reentry phase of the flight at a time they must function at a high level of performance. The factors that contribute to orthostatic intolerance during and following reentry and to predict the likelihood of impaired crew performance are evaluated. A computer simulation approach employing a mathematical model of the cardiovascular system is employed. It is shown that depending on the severity of blood volume loss, the reentry acceleration stress may be detrimental to physiologic function and may place the physiologic status of the crew near the borderline of some type of impairment. They are in agreement with conclusions from early ground-based experiments and from observations of early Shuttle flights.

  5. Maternal distress and women's reentry into family and community life.

    PubMed

    Arditti, Joyce; Few, April

    2008-09-01

    This paper advances conceptualization of maternal distress following incarceration. We utilized a multiple case study methodology based on interviews with 10 mothers who demonstrated various permutations of "the triple threat" (depression, domestic violence, and substance abuse; Arditti & Few, 2006). Findings suggest that depressive symptomology persisted and worsened for mothers in our study and that maternal distress was indicative not only of women's psychological state, but also a relational and situational construct that embodied women's core experience. Maternal distress was largely characterized by health challenges, dysfunctional intimate relationships, loss related trauma, guilt and worry over children, and economic inadequacy. Further, maternal distress seemed to be intensified by the punitive traumatic context of prison and lessened by rehabilitation opportunities as well as support by kin and probation officers after reentry. Recommendations for clinicians and professionals who work with reentry mothers center around the need to alleviate maternal distress and better address women's emotional and physical health needs during incarceration and reentry. PMID:18831309

  6. Casualty Risk Assessment Controlled Re-Entry of EPS - Ariane 5ES - ATV Mission

    NASA Astrophysics Data System (ADS)

    Arnal, M.-H.; Laine, N.; Aussilhou, C.

    2012-01-01

    To fulfil its mission of compliance check to the French Space Operations Act, CNES has developed ELECTRA© tool in order to estimate casualty risk induced by a space activity (like rocket launch, controlled or un-controlled re-entry on Earth of a space object). This article describes the application of such a tool for the EPS controlled re-entry during the second Ariane 5E/S flight (Johannes Kepler mission has been launched in February 2011). EPS is the Ariane 5E/S upper composite which is de-orbited from a 260 km circular orbit after its main mission (release of the Automated Transfer Vehicle - ATV). After a brief description of the launcher, the ATV-mission and a description of all the failure cases taken into account in the mission design (which leads to "back-up scenarios" into the flight software program), the article will describe the steps which lead to the casualty risk assessment (in case of failure) with ELECTRA©. In particular, the presence on board of two propulsive means of de-orbiting (main engine of EPS, and 4 ACS longitudinal nozzles in case of main engine failure or exhaustion) leads to a low remaining casualty risk.

  7. Near-Optimal Re-Entry Trajectories for Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Chou, H.-C.; Ardema, M. D.; Bowles, J. V.

    1997-01-01

    A near-optimal guidance law for the descent trajectory for earth orbit re-entry of a fully reusable single-stage-to-orbit pure rocket launch vehicle is derived. A methodology is developed to investigate using both bank angle and altitude as control variables and selecting parameters that maximize various performance functions. The method is based on the energy-state model of the aircraft equations of motion. The major task of this paper is to obtain optimal re-entry trajectories under a variety of performance goals: minimum time, minimum surface temperature, minimum heating, and maximum heading change; four classes of trajectories were investigated: no banking, optimal left turn banking, optimal right turn banking, and optimal bank chattering. The cost function is in general a weighted sum of all performance goals. In particular, the trade-off between minimizing heat load into the vehicle and maximizing cross range distance is investigated. The results show that the optimization methodology can be used to derive a wide variety of near-optimal trajectories.

  8. School reentry for children with acquired central nervous systems injuries.

    PubMed

    Carney, Joan; Porter, Patricia

    2009-01-01

    Onset of acquired central nervous system (CNS) injury during the normal developmental process of childhood can have impact on cognitive, behavioral, and motor function. This alteration of function often necessitates special education programming, modifications, and accommodations in the education setting for successful school reentry. Special education is not necessarily a special classroom, but an individualized set of educational needs, determined by a multidisciplinary school team, to promote educational success. The purpose of this article is to inform those pediatricians and pediatric allied health professionals treating children with CNS injury of the systems in place to support successful school reentry and their role in contributing to developing an appropriate educational plan. PMID:19489086

  9. Radiation and Ablation Cooling for Manned Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Roberts, L.

    1960-01-01

    The necessity of reducing heat transfer to reentry vehicles has led I to the consideration of both radiative and ablation shields. The paper reviews briefly the heating problems for manned vehicles and the means whereby ablation and radiation afford thermal protection. The principal energy disposal and weight parameters are then presented and their relation to the vehicle and trajectory parameters is discussed. A comparative analysis of three types of ablation shield is made and broad conclusions are drawn as to the type of shield most appropriate to manned reentry vehicles.

  10. Reentry: a key mechanism for integration of brain function

    PubMed Central

    Edelman, Gerald M.; Gally, Joseph A.

    2013-01-01

    Reentry in nervous systems is the ongoing bidirectional exchange of signals along reciprocal axonal fibers linking two or more brain areas. The hypothesis that reentrant signaling serves as a general mechanism to couple the functioning of multiple areas of the cerebral cortex and thalamus was first proposed in 1977 and 1978 (Edelman, 1978). A review of the amount and diversity of supporting experimental evidence accumulated since then suggests that reentry is among the most important integrative mechanisms in vertebrate brains (Edelman, 1993). Moreover, these data prompt testable hypotheses regarding mechanisms that favor the development and evolution of reentrant neural architectures. PMID:23986665

  11. Missile Aerodynamics for Ascent and Re-entry

    NASA Technical Reports Server (NTRS)

    Watts, Gaines L.; McCarter, James W.

    2012-01-01

    Aerodynamic force and moment equations are developed for 6-DOF missile simulations of both the ascent phase of flight and a tumbling re-entry. The missile coordinate frame (M frame) and a frame parallel to the M frame were used for formulating the aerodynamic equations. The missile configuration chosen as an example is a cylinder with fixed fins and a nose cone. The equations include both the static aerodynamic coefficients and the aerodynamic damping derivatives. The inclusion of aerodynamic damping is essential for simulating a tumbling re-entry. Appended information provides insight into aerodynamic damping.

  12. From the Classroom to the Community: Exploring the Role of Education during Incarceration and Reentry

    ERIC Educational Resources Information Center

    Brazzell, Diana; Crayton, Anna; Mukamal, Debbie A.; Solomon, Amy L.; Lindahl, Nicole

    2009-01-01

    Recognizing the pressing need to explore the issues surrounding education, incarceration, and reentry, the Prisoner Reentry Institute at John Jay College of Criminal Justice and the Urban Institute hosted the Reentry Roundtable on Education on March 31 and April 1, 2008, at John Jay College of Criminal Justice in New York City. The two-day…

  13. 14 CFR 433.3 - Issuance of a license to operate a reentry site.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... site. 433.3 Section 433.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A REENTRY SITE § 433.3 Issuance of a license to operate a reentry site. (a) The FAA issues a license to operate a reentry site when...

  14. 14 CFR 433.3 - Issuance of a license to operate a reentry site.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Issuance of a license to operate a reentry site. 433.3 Section 433.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A REENTRY SITE § 433.3 Issuance of a license to operate a reentry site....

  15. 14 CFR 433.3 - Issuance of a license to operate a reentry site.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... site. 433.3 Section 433.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A REENTRY SITE § 433.3 Issuance of a license to operate a reentry site. (a) The FAA issues a license to operate a reentry site when...

  16. 14 CFR 433.3 - Issuance of a license to operate a reentry site.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... site. 433.3 Section 433.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A REENTRY SITE § 433.3 Issuance of a license to operate a reentry site. (a) The FAA issues a license to operate a reentry site when...

  17. 14 CFR 433.3 - Issuance of a license to operate a reentry site.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... site. 433.3 Section 433.3 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A REENTRY SITE § 433.3 Issuance of a license to operate a reentry site. (a) The FAA issues a license to operate a reentry site when...

  18. Exploring Inmate Reentry in a Local Jail Setting: Implications for Outreach, Service Use, and Recidivism

    ERIC Educational Resources Information Center

    White, Michael D.; Saunders, Jessica; Fisher, Christopher; Mellow, Jeff

    2012-01-01

    Although prisoner reentry has taken center stage in correctional research and policy discussions, there has been little emphasis on reentry among jail populations. This paper examines a jail-based reentry program in New York City that begins while individuals are incarcerated and includes 90 days of postrelease services. This article explores…

  19. Controlling Violent Offenders Released to the Community: An Evaluation of the Boston Reentry Initiative

    ERIC Educational Resources Information Center

    Braga, Anthony A.; Piehl, Anne M.; Hureau, David

    2009-01-01

    Despite the high level of funding and policy interest in prisoner reentry, there is still little rigorous scientific evidence to guide jurisdictions in developing reentry programs to enhance public safety, particularly for managing those who pose the greatest safety risks. The Boston Reentry Initiative (BRI) is an interagency initiative to help…

  20. 14 CFR 435.43 - Payload reentry review requirements and procedures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Payload reentry review requirements and procedures. 435.43 Section 435.43 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  1. 14 CFR 435.15 - Rights not conferred by reentry license.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Rights not conferred by reentry license. 435.15 Section 435.15 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING REENTRY OF A REENTRY VEHICLE OTHER THAN A REUSABLE LAUNCH VEHICLE (RLV) General § 435.15 Rights...

  2. 14 CFR 431.57 - Information requirements for payload reentry review.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Information requirements for payload reentry review. 431.57 Section 431.57 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload Reentry Review...

  3. Who Goes Back to Prison; Who Does Not: A Multiyear View of Reentry Program Participants

    ERIC Educational Resources Information Center

    Severson, Margaret E.; Veeh, Christopher; Bruns, Kimberly; Lee, Jaehoon

    2012-01-01

    Existing studies of reentry programs in the United States focus on the successes and failures of reentering offenders when compared to matched reentering offenders who did not receive structured reentry services. Little attention has been focused solely on the reentry participants themselves, and on how the level of program exposure may be related…

  4. Modeling of Turbulence Effects on Liquid Jet Atomization and Breakup

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Chen, C. P.

    2005-01-01

    Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. This study aims to model the turbulence effect in the atomization process of a cylindrical liquid jet. Two widely used models, the Kelvin-Helmholtz (KH) instability of Reitz (blob model) and the Taylor-Analogy-Breakup (TAB) secondary droplet breakup by O Rourke et al, are further extended to include turbulence effects. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and the initial flow conditions. For the secondary breakup, an additional turbulence force acted on parent drops is modeled and integrated into the TAB governing equation. The drop size formed from this breakup regime is estimated based on the energy balance before and after the breakup occurrence. This paper describes theoretical development of the current models, called "T-blob" and "T-TAB", for primary and secondary breakup respectivety. Several assessment studies are also presented in this paper.

  5. Breakup Effects on University Students' Perceived Academic Performance

    ERIC Educational Resources Information Center

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2012-01-01

    The Problem: Problems that might be expected to affect perceived academic performance were studied in a sample of 283 university students. Results: Breakup Distress Scale scores, less time since the breakup and no new relationship contributed to 16% of the variance on perceived academic performance. Variables that were related to academic…

  6. Orbit, reentry, and landing attachment for globes

    NASA Technical Reports Server (NTRS)

    Pritchard, E. B.

    1970-01-01

    Navigational device, invented to aid recovery of spacecraft from any orbit, also illustrates motions of satellites relative to earth and their entry-ranging requirements. Device rapidly and accurately defines lateral range requirements for spacecraft returning to any desired site without manual or computerized calculation of orbital equations of motion.

  7. Orbiter Gap Filler Bending Model for Re-entry

    NASA Technical Reports Server (NTRS)

    Campbell, Charles H.

    2007-01-01

    Pressure loads on a protruding gap filler during an Orbiter reentry are investigated to evaluate the likelihood of extraction due to pressure loads, and to ascertain how much bending will be induced by re-entry pressure loads. Oblique shock wave theory is utilized to develop a representation of the pressure loads induced on a gap filler for the ISSHVFW trajectory, representative of a heavy weight ISS return. A free body diagram is utilized to react the forces induced by the pressure forces. Preliminary results developed using these methods demonstrate that pressure loads, alone, are not likely causes of gap filler extraction during reentry. Assessment of the amount a gap filler will bend over is presented. Implications of gap filler bending during re-entry include possible mitigation of early boundary layer transition concerns, uncertainty in ground based measurement of protruding gap fillers from historical Orbiter flight history, and uncertainty in the use of Orbiter gap fillers for boundary layer prediction calibration. Authors will be added to the author list as appropriate.

  8. 38 CFR 21.8022 - Entry and reentry.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) VOCATIONAL REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children of... reentry. (a) Date of program entry. VA may not enter a child into a vocational training program or provide... receives an application for a vocational training program filed in accordance with § 21.8014....

  9. School Reentry for Children with Acquired Central Nervous Systems Injuries

    ERIC Educational Resources Information Center

    Carney, Joan; Porter, Patricia

    2009-01-01

    Onset of acquired central nervous system (CNS) injury during the normal developmental process of childhood can have impact on cognitive, behavioral, and motor function. This alteration of function often necessitates special education programming, modifications, and accommodations in the education setting for successful school reentry. Special…

  10. Astronauts McNair and Stewart prepare for reentry

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronauts Ronald E. McNair and Robert L. Stewart prepare for the re-entry phase of the shuttle Challenger near the end of the 41-B mission. The are stationed behind the crew commander and pilot. Stewart is already wearing his helmet. McNair is stowing some of his gear.

  11. Estimates of nitric oxide production for lifting spacecraft reentry

    NASA Technical Reports Server (NTRS)

    Park, C.

    1971-01-01

    The amount of nitric oxide which may be produced by heating of air during an atmospheric reentry of a lifting spacecraft is estimated by three different methods. Two assume nitrogen fixation by the process of sudden freezing, and the third is a computer calculation using chemical rate equations.

  12. Reentry Issues upon Returning from Study Abroad Programs

    ERIC Educational Resources Information Center

    Wielkiewicz, Richard M.; Turkowski, Laura W.

    2010-01-01

    The impact of returning from studying abroad was surveyed in 669 college students. Students who studied abroad scored significantly higher on a Reentry Shock scale, reflecting skepticism toward U.S. culture, than those who did not. They were also more likely to consume alcohol. Study abroad had no detectable influence on students' romantic…

  13. 38 CFR 21.8022 - Entry and reentry.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Entry and reentry. 21.8022 Section 21.8022 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) VOCATIONAL REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children of Vietnam Veterans and Veterans with...

  14. Planned Flight of the Terrestrial HIAD Orbital Reentry (THOR)

    NASA Technical Reports Server (NTRS)

    Dillman, Robert; Hughes, Stephen; DiNonno, John; Bodkin, Richard; White, Joseph; DelCorso, Joseph; Cheatwood, F. M.

    2014-01-01

    The Terrestrial HIAD Orbital Reentry (THOR) is planned for flight in 2016 as a secondary payload on an Orbital Sciences commercial resupply mission to the International Space Station. THOR will launch with its Hypersonic Inflatable Aerodynamic Decelerator (HIAD) stowed as a small cylinder between the second stage motor and the launch vehicle fairing. Once the Cygnus cargo vehicle has separated from the second stage, THOR will likewise separate, autonomously re-orient itself, perform a deorbit burn, then inflate the HIAD to a 3.5m diameter cone before atmospheric interface. THOR is a follow-on mission to the IRVE-3 flight test of 2012. The high energy of orbital reentry will allow THOR to demonstrate the performance of its improved, second-generation inflatable structure and flexible TPS materials, in a more energetic entry environment than previous suborbital test flights.This paper discusses the sequence of events planned to occur as part of the THOR mission. Specific topics will include the THOR mission concept, reentry vehicle design for the expected flight environment, the on-board sensors that will allow quantification of vehicle performance, and how we intend to retrieve the flight data from a reentry vehicle splashing down in international waters.

  15. Study Abroad Reentry: Behavior, Affect, and Cultural Distance

    ERIC Educational Resources Information Center

    Gray, Kelsey M.; Savicki, Victor

    2015-01-01

    Reentry has become a more focused aspect of study abroad in recent years as the field has moved away from a laissez-faire approach and toward an emphasis on intervention and support of study abroad students in their efforts to make sense of their experiences (Vande Berg, Paige & Lou, 2012). Although not a new concept (Brathurst & La Brack,…

  16. STS-107 Debris Characterization Using Re-entry Imaging

    NASA Technical Reports Server (NTRS)

    Raiche, George A.

    2009-01-01

    Analysis of amateur video of the early reentry phases of the Columbia accident is discussed. With poor video quality and little theoretical guidance, the analysis team estimated mass and acceleration ranges for the debris shedding events observed in the video. Camera calibration and optical performance issues are also described.

  17. Sensors measure surface ablation rate of reentry vehicle heat shield

    NASA Technical Reports Server (NTRS)

    Russel, J. M., III

    1966-01-01

    Sensors measure surface erosion rate of ablating material in reentry vehicle heat shield. Each sensor, which is placed at precise depths in the heat shield is activated when the ablator surface erodes to the location of a sensing point. Sensor depth and activation time determine ablator surface erosion rate.

  18. Calibration of Radar Based Re-Entry Predictions

    NASA Astrophysics Data System (ADS)

    Lemmens, S.; Bastida Virgili, B.; Flohrer, T.; Gini, F.; Krag, H.; Steiger, C.

    2015-03-01

    The availability of GPS observations via the telemetry during GOCE’s (Gravity Field and Steady-State Ocean Circulation Explorer) entire re-entry campaign enabled the generation of high quality orbit products which can be used as input to re-entry predictions. These high precision orbits can be used as reference to assess the quality of orbits generated from other sources. Here we verify the accuracy of orbits based on radar tracking data, obtained by dedicated observations with the Tracking & Imaging Radar system from the Fraunhofer High Frequency Physics and Radar Techniques institute, with respect to the a post-processed GPS based reference orbit. This leads to time-depended quantification of the orbit determination uncertainties on the re-entry predictions. Furthermore, the ballistic coefficient determined by the orbit determination and its time dependent evolution can be used to a priori estimate the attitude behaviour of GOCE, which can be compared to the telemetry. The attitude behaviour can be analysed by the use of inverse synthetic aperture radar (ISAR) images, also obtained by dedicated observation by TIRA. The effect of adding this knowledge on the attitude evolution to the re-entry predictions is evaluated.

  19. Young Men's Reentry after Incarceration: A Developmental Paradox

    ERIC Educational Resources Information Center

    Arditti, Joyce A.; Parkman, Tiffaney

    2011-01-01

    We apply a life course perspective to study young men's transition to adulthood within the context of their return to family after a period of incarceration. Our phenomenological analysis was based on 9 in-depth, semi-structured interviews with formerly incarcerated men between the age of 18 and 24. Our findings revealed that reentry was a…

  20. An Assessment of a Community College Reentry Program for Women.

    ERIC Educational Resources Information Center

    Forrest, Joy Davis

    In 1980, a study was conducted to determine the characteristics, attitudes, and subsequent experiences of women who had completed the Women's Education Development Incentive (WENDI) re-entry program at Brevard Community College, Florida, in 1977. From the original mailing of 79 questionnaires, 33 usable responses were returned. Two-thirds of the…

  1. Retinal progenitor cells, differentiation, and barriers to cell cycle reentry.

    PubMed

    Davis, Denise M; Dyer, Michael A

    2010-01-01

    Neurogenesis in the retina occurs via the coordination of proliferation, cell cycle exit and differentiation of retinal progenitor cells. Until recently, it was widely assumed that once a retinal progenitor cell produced a postmitotic neuron, there was no possibility for cell-cycle re-entry. However, recent studies have shown that mature differentiated horizontal neurons with reduced Rb pathway function can re-enter the cell cycle and proliferate while maintaining their differentiated features. This chapter will explore the molecular and cellular mechanisms that help to keep differentiated retinal neurons and glia postmitotic. We propose that there are cell-type specific barriers to cell-cycle re-entry by differentiated neurons and these may include apoptosis, chromatin/epigenetics mechanisms, cellular morphology and/or metabolic demands that are distinct across cell populations. Our data suggest that differentiated neurons span a continuum of cellular properties related to their ability to re-enter the cell cycle and undergo cytokinesis while maintaining their differentiated features. A deeper understanding of these processes may allow us to begin to explain the cell type specificity of neuronal cell death and tumor susceptibility. For example, neurons that have more barriers to cell-cycle re-entry may be less likely to form tumors but more likely to undergo degeneration. Conversely, neurons that have fewer barriers to cell-cycle re-entry may be more likely to form tumors but less likely to undergo degeneration. PMID:20959166

  2. Reusable Reentry Satellite (RRS): Thermal control trade study

    NASA Technical Reports Server (NTRS)

    Wallace, Clark

    1990-01-01

    The design and assessment work performed in defining the on-orbit Thermal Control Subsystem (TCS) requirements for the Reusable Reentry Satellite (RRS) is discussed. Specifically, it describes the hardware and design measures necessary for maintaining the Payload Module (PM) Environmental Control Life Support System (ECLSS) heat exchanger, the hydrazine propellant, and PM water supply within their required temperature limits.

  3. The characteristics and consequences of the break-up of the Fengyun-1C spacecraft

    NASA Astrophysics Data System (ADS)

    Johnson, Nicholas L.; Stansbery, E.; Liou, J.-C.; Horstman, M.; Stokely, C.; Whitlock, D.

    2008-07-01

    The intentional break-up of the Fengyun-1C spacecraft on 11 January 2007 via a hypervelocity collision with a ballistic object created the most severe artificial debris cloud in Earth orbit since the beginning of space exploration. More than 2000 debris of the order of 10 cm or greater in size have been identified by the US Space Surveillance Network. The majority of these debris reside in long-lived orbits. The NASA Orbital Debris Program Office has conducted a thorough examination of the nature of the Fengyun-1C debris cloud, using Space Surveillance Network (SSN) data for larger debris and special Haystack radar observations for smaller debris. These data have been compared with the NASA standard satellite break-up model for collisions, and the results are presented in this paper. The orbital longevity of the debris have also been evaluated for both small and large debris. The consequent long-term spatial density effects on the low Earth orbit regime and the potential effect of the debris cloud on the growth of the near-Earth satellite population have been addressed.

  4. The Characteristics and Consequences of the Break-up of the Fengyun-1C Spacecraft

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.; Stansbery, Eugene; Liou, Jer-chyi; Horstman, Matt; Stokeley, Christopher; Whitlock, David

    2007-01-01

    The intentional break-up of the Fengyun-1C spacecraft on 11 January 2007 via hypervelocity collision with a ballistic object created the most severe artificial debris cloud in Earth orbit since the beginning of space exploration. More than 900 debris on the order of 10 cm or greater in size have been identified by the U.S. Space Surveillance Network (SSN). The majority of these debris reside in long-lived orbits. The NASA Orbital Debris Program Office has conducted a thorough examination of the nature of the Fengyun-1C debris cloud, using SSN data for larger debris and special Haystack radar observations for smaller debris. These data have been compared with the NASA standard satellite break-up model for collisions, and the results are presented in this paper. The orbital longevity of the debris have also been evaluated for both small and large debris. The consequent long-term spatial density effects on the low Earth orbit (LEO) regime are then described. Finally, collision probabilities between the Fengyun-1C debris cloud and the resident space object population of 1 January 2007 have been calculated. The potential effect on the growth of the near-Earth satellite population is presented.

  5. A real-time digital computer program for the simulation of automatic spacecraft reentries

    NASA Technical Reports Server (NTRS)

    Kaylor, J. T.; Powell, L. F.; Powell, R. W.

    1977-01-01

    The automatic reentry flight dynamics simulator, a nonlinear, six-degree-of-freedom simulation, digital computer program, has been developed. The program includes a rotating, oblate earth model for accurate navigation calculations and contains adjustable gains on the aerodynamic stability and control parameters. This program uses a real-time simulation system and is designed to examine entries of vehicles which have constant mass properties whose attitudes are controlled by both aerodynamic surfaces and reaction control thrusters, and which have automatic guidance and control systems. The program has been used to study the space shuttle orbiter entry. This report includes descriptions of the equations of motion used, the control and guidance schemes that were implemented, the program flow and operation, and the hardware involved.

  6. Gravity wave and tidal structures between 60 and 140 km inferred from space shuttle reentry data

    NASA Technical Reports Server (NTRS)

    Fritts, David C.; Wang, Ding-Yi; Blanchard, Robert C.

    1993-01-01

    This study presents an analysis of density measurements made using high-resolution accelerometers aboard several space shuttles at altitudes from 60 to 140 km during reentry into the earth's atmosphere. The observed density fluctuations are interpreted in terms of gravity waves and tides and provide evidence of the importance of such motions well into the thermosphere. Height profiles of fractional density variance reveal that wave amplitudes increase at a rate consistent with observations at lower levels up to about 90 km. The rate of amplitude growth decreases at greater heights, however, and appears to cease above about 110 km. Wave amplitudes are nevertheless large at these heights and suggest that gravity waves may play an important role in forcing of the lower thermosphere.

  7. Electrohydrodynamic (EHD) stimulation of jet breakup

    NASA Technical Reports Server (NTRS)

    Crowley, J. M.

    1982-01-01

    Electrohydrodynamic (EHD) excitation of liquid jets offers an alternative to piezoelectric excitation without the complex frequency response caused by piezoelectric and mechanical resonances. In an EHD exciter, an electrode near the nozzle applies an alternating Coulomb force to the jet surface, generating a disturbance which grows until a drop breaks off downstream. This interaction is modelled quite well by a linear, long wave model of the jet together with a cylindrical electric field. The breakup length, measured on a 33 micrometer jet, agrees quite well with that predicted by the theory, and increases with the square of the applied voltage, as expected. In addition, the frequency response is very smooth, with pronounced nulls occurring only at frequencies related to the time which the jet spends inside the exciter.

  8. Comment on breakup densities of hot nuclei

    NASA Astrophysics Data System (ADS)

    Viola, V. E.; Kwiatkowski, K.; Yennello, S. J.; Natowitz, J. B.

    2006-06-01

    In [V.E. Viola et al., Phys. Rev. Lett. 93 (2004) 132701, D.S. Bracken et al., Phys. Rev. C 69 (2004) 034612] the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing excitation energy. Subsequently, Raduta et al. [Ad. Raduta et al., Phys. Lett. B 623 (2005) 43] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this Letter we point out that this apparent inconsistency is due to a selective comparison of theory and data that overlooks the evolution of the fragment multiplicities as a function of excitation energy.

  9. Team formation and breakup in multiagent systems

    NASA Astrophysics Data System (ADS)

    Rao, Venkatesh Guru

    The goal of this dissertation is to pose and solve problems involving team formation and breakup in two specific multiagent domains: formation travel and space-based interferometric observatories. The methodology employed comprises elements drawn from control theory, scheduling theory and artificial intelligence (AI). The original contribution of the work comprises three elements. The first contribution, the partitioned state-space approach is a technique for formulating and solving co-ordinated motion problem using calculus of variations techniques. The approach is applied to obtain optimal two-agent formation travel trajectories on graphs. The second contribution is the class of MixTeam algorithms, a class of team dispatchers that extends classical dispatching by accommodating team formation and breakup and exploration/exploitation learning. The algorithms are applied to observation scheduling and constellation geometry design for interferometric space telescopes. The use of feedback control for team scheduling is also demonstrated with these algorithms. The third contribution is the analysis of the optimality properties of greedy, or myopic, decision-making for a simple class of team dispatching problems. This analysis represents a first step towards the complete analysis of complex team schedulers such as the MixTeam algorithms. The contributions represent an extension to the literature on team dynamics in control theory. The broad conclusions that emerge from this research are that greedy or myopic decision-making strategies for teams perform well when specific parameters in the domain are weakly affected by an agent's actions, and that intelligent systems require a closer integration of domain knowledge in decision-making functions.

  10. Calculating Beam Breakup in Superconducting Linear Accelerators

    SciTech Connect

    Geoffrey Krafft; Joseph Bisognano; Sharon Laubach

    1990-02-09

    As the intensity of a particle beam passing through a linear accelerator is raised, interactions between particles play an increasingly prominent role in determining the overall dynamics of the beam. These many body effects, known collectively as beam breakup, tend to degrade the quality of the transported beam, and hence they must be calculated to accurately predict the evolution of the beam as it traverses the accelerator. Several codes which compute various collective effects have been developed and used to simulate the dynamics of beams passing through superconducting accelerator structures. All the codes use the same basic algorithm: the beam is tracked through elements giving the focusing forces on the particles, and at the appropriate locations in the linac, localized forces are impressed on the particles which model the electromagnetic interactions. Here, a difficulty is that the usual ''Coulomb'' interaction between particles is changed by the electromagnetic environment of the accelerator. By such calculations it has been shown that recirculating linear accelerators such as the one being built at the Continuous Electron Beam Accelerator Facility (CEBAF) should remain stable against multipass beam breakup instability as long as the average current does not exceed about 20 mA, that the beam quality at CEBAF will be degraded when the single bunch charge approaches 10{sup 9} electrons, and that the beam quality of superconducting linacs that are optimized for high current transport begins to decrease at around 10{sup 10} electrons per bunch. The latter result is of interest to individuals who would use superconducting linacs as beam sources for free electron lasers or for superconducting colliders for high energy physics research.

  11. The Mesozoic breakup of the Weddell Sea

    NASA Astrophysics Data System (ADS)

    KöNig, Matthias; Jokat, Wilfried

    2006-12-01

    A new set of rotations is presented that describes a refined model for the early opening of the Weddell Sea between South America and Antarctica and the Mesozoic breakup of Gondwana. Published high-resolution aeromagnetic data from the eastern Weddell Sea and additional track data farther west in the Weddell Sea were used to constrain the new model for the opening of the Weddell Sea. Rotation parameters derived for the South America-Antarctica spreading regime were combined with constraints on the South America-Africa and Africa-Antarctica spreading systems to calculate a refined model for the Mesozoic breakup of Gondwana. Thereafter, at the time when the north-south oriented separation between Africa and Antarctica is initiated by rifting in the Somali and Mozambique basins (˜167 Ma), stretching and extension takes place in a basin comprising continental crust of the Filchner-Ronne Shelf, the Falkland Island block and the Maurice Ewing Bank. The first true ocean floor in the Weddell Sea is formed at about 147 Ma, after rifting between the Antarctic Peninsula and southernmost South America occurred. This is about 15-20 Myr later than previously estimated. Separation between South America and Antarctica takes place at slow spreading rates (14-12 mm/yr half rate) from 147 to 122 Ma and after 122 Ma (M2) at ultraslow spreading rates (˜8 mm/yr half rate) with little change in the NNW spreading direction throughout this time. A revised age range is proposed for the formation of the Explora Wedge (150-138 Ma), which is more than 30 Myr later than previously published (˜183 Ma).

  12. Early breakup of Gondwana: constraints from global plate motion models

    NASA Astrophysics Data System (ADS)

    Seton, Maria; Zahirovic, Sabin; Williams, Simon; Whittaker, Joanne; Gibbons, Ana; Muller, Dietmar; Brune, Sascha; Heine, Christian

    2015-04-01

    Supercontinent break-up and amalgamation is a fundamental Earth cycle, contributing to long-term sea-level fluctuations, species diversity and extinction events, long-term greenhouse-icehouse cycles and changes in the long-wavelength density structure of the mantle. The most recent and best-constrained example involves the fragmentation of Gondwana, starting with rifting between Africa/Madagascar and Antarctica in the Early Jurassic and ending with the separation of the Lord Howe microcontinental blocks east of Australia in the Late Cretaceous. Although the first order configuration of Gondwana within modern reconstructions appears similar to that first proposed by Wegener a century ago, recent studies utilising a wealth of new geophysical and geological data provide a much more detailed picture of relative plate motions both during rifting and subsequent seafloor spreading. We present our latest global plate motion model that includes extensive, new regional analyses. These include: South Atlantic rifting, which started at 150 Ma and propagated into cratonic Africa by 145 Ma (Heine et al., 2013); rifting and early seafloor spreading between Australia, India and Antarctica, which reconciles the fit between Broken Ridge-Kergulean Plateau and the eastern Tasman region (Whittaker et al., 2013); rifting of continental material from northeastern Gondwana and its accretion onto Eurasia and SE Asia including a new model of microcontinent formation and early seafloor spreading in the eastern Indian Ocean (Gibbons et al., 2012; 2013; in review; Williams et al., 2013; Zahirovic et al., 2014); and a new model for the isolation of Zealandia east of Australia, with rifting initiating at 100 Ma until the start of seafloor spreading in the Tasman Sea at ~85 Ma (Williams et al., in prep). Using these reconstructions within the open-source GPlates software, accompanied by a set of evolving plates and plate boundaries, we can explore the factors that govern the behavior of plate

  13. The Role of Prevention in Promoting Continuity of Health Care in Prisoner Reentry Initiatives

    PubMed Central

    Lanza, A. Stephen; Dyson, William; Gordon, Derrick M.

    2013-01-01

    Most incarcerated individuals will return to the community, and their successful reentry requires consideration of their health and how their health will affect their families and communities. We propose the use of a prevention science framework that integrates universal, selective, and indicated strategies to facilitate the successful reentry of men released from prison. Understanding how health risks and disparities affect the transition from prison to the community will enhance reentry intervention efforts. To explore the application of the prevention rubric, we evaluated a community-based prisoner reentry initiative. The findings challenge all involved in reentry initiatives to reconceptualize prisoner reentry from a program model to a prevention model that considers multilevel risks to and facilitators of successful reentry. PMID:23488516

  14. Trends of ice breakup date in south-central Ontario

    NASA Astrophysics Data System (ADS)

    Fu, Congsheng; Yao, Huaxia

    2015-09-01

    Large-scale ice phenology studies have revealed overall patterns of later freeze, earlier breakup, and shorter duration of ice in the Northern Hemisphere. However, there have been few studies regarding the trends, including their spatial patterns, in ice phenology for individual waterbodies on a local or small regional scale, although the coherence of ice phenology has been shown to decline rapidly in the first few hundred kilometers. In this study, we extracted trends, analyzed affecting factors, and investigated relevant spatial patterns for ice breakup date time series at 10 locations with record length ≥90 years in south-central Ontario, Canada. Wavelet methods, including the multiresolution analysis (MRA) method for nonlinear trend extraction and the wavelet coherence (WTC) method for identifying the teleconnections between large-scale climate modes and ice breakup date, are proved to be effective in ice phenology analysis. Using MRA method, the overall trend of ice breakup date time series (1905-1991) varied from earlier ice breakup to later ice breakup, then to earlier breakup again from south to north in south-central Ontario. Ice breakup date is closely correlated with air temperature during certain winter/spring months, as well as the last day with snow on the ground and number of snow-on-ground days. The influences of solar activity and Pacific North American on ice breakup were comparatively uniform across south-central Ontario, while those of El Niño-Southern Oscillation, North Atlantic Oscillation, and Arctic Oscillation on ice phenology changed with distance of 50-100 km in the north-south direction.

  15. The TAB method for numerical calculation of spray droplet breakup

    NASA Astrophysics Data System (ADS)

    Orourke, P. J.; Amsden, A. A.

    A short history is given of the major milestones in the development of the stochastic particle method for calculating liquid fuel sprays. The most recent advance has been the discovery of the importance of drop breakup in engine sprays. A new method, called TAB, for calculating drop breakup is presented. Some theoretical properties of the method are derived; its numerical implementation in the computer program KIVA is described; and comparisons are presented between TAB-method calculations and experiments and calculations using another breakup model.

  16. Ground Observation of the Hayabusa Reentry: The Third Opportunity of Man-made Fireball from Interplanetary Orbit

    NASA Astrophysics Data System (ADS)

    Ishihara, Y.; Yamamoto, M.; Hiramatsu, Y.; Furumoto, M.; Fujita, K.

    2010-12-01

    After 7 years and 6,000,000,000 km of challenging cruise in the solar system, the Hayabusa did come back to the Earth on June 13, 2010. The Hayabusa, the first sample-return explorer to NEA, landed on 25243 Itokawa in 2005, capturing surface particles on the S-type asteroid into its sample return capsule (SRC). Following to the reentries of the Genesis in 2004 and the Stardust in 2006, the return of the Hayabusa SRC was the third direct reentry event from the interplanetary transfer orbit to the Earth at a velocity of over 11.2 km/s. In addition, it was world first case of direct reentry of spacecraft from interplanetary transfer orbit. After the successful resumption of the SRC, it was carefully sent to ISAS/JAXA, and at present, small particles expected to be the first sample-return materials from the minor planet are carefully investigated. In order to obtain precise trajectory information to ensure the quick procedure for the Hayabusa SRC resumption team, we observed the Hayabusa SRC reentry by optically in Australian night sky. High-resolution imaging and spectroscopy were carried out with several high-sensitivity instruments to investigate thermal-protection process of thermal protection ablator (TPA) as well as interaction process between SRC surface materials and upper atmospheric neutral and plasma components. Moreover, shockwaves were observed by infrasound/seismic sensor arrays on ground to investigate reentry related shockwaves as well as air-to-ground coupling process at the extremely rare opportunity. With respect to nominal trajectory of the Hayabusa SRC reentry, four optical stations were set inside and near the Woomera Prohibited Area, Australia, targeting on peak-heat and/or front-heat profiles of ablating TPA for engineering aspect. Infrasound and seismic sensors were also deployed as three arrayed stations and three single stations to realize direction findings of sonic boom type shockwaves from the SRC and spacecraft and point source type

  17. Cardiovascular effects of anti-G suit and cooling garment during space shuttle re-entry and landing

    NASA Technical Reports Server (NTRS)

    Perez, Sondra A.; Charles, John B.; Fortner, G. William; Hurst, Victor 4th; Meck, Janice V.

    2003-01-01

    BACKGROUND: Many cardiovascular changes associated with spaceflight reduce the ability of the cardiovascular system to oppose gravity on return to Earth, leaving astronauts susceptible to orthostatic hypotension during re-entry and landing. Consequently, an anti-G suit was developed to protect arterial pressure during re-entry. A liquid cooling garment (LCG) was then needed to alleviate the thermal stress resulting from use of the launch and entry suit. METHODS: We studied 34 astronauts on 22 flights (4-16 d). Subjects were studied 10 d before launch and on landing day. Preflight, crewmembers were suited with their anti-G suits set to the intended inflation for re-entry. Three consecutive measurements of heart rate and arterial pressure were obtained while seated and then again while standing. Three subjects who inflated the anti-G suits also donned the LCG for landing. Arterial pressure and heart rate were measured every 5 min during the de-orbit maneuver, through maximum G-loading (max-G) and touch down (TD). After TD, crew-members again initiated three seated measurements followed by three standing measurements. RESULTS: Astronauts with inflated anti-G suits had higher arterial pressure than those who did not have inflated anti-G suits during re-entry and landing (133.1 +/- 2.5/76.1 +/- 2.1 vs. 128.3 +/- 4.2/79.3 +/- 2.9, de-orbit; 157.3 +/- 4.5/102.1 +/- 3.6 vs. 145.2 +/- 10.5/95.7 + 5.5, max-G; 159.6 +/- 3.9/103.7 +/- 3.3 vs. 134.1 +/- 5.1/85.7 +/- 3.1, TD). In the group with inflated anti-G suits, those who also wore the LCG exhibited significantly lower heart rates than those who did not (75.7 +/- 11.5 vs. 86.5 +/- 6.2, de-orbit; 79.5 +/- 24.8 vs. 112.1 +/- 8.7, max-G; 84.7 +/- 8.0 vs. 110.5 +/- 7.9, TD). CONCLUSIONS: The anti-G suit is effective in supporting arterial pressure. The addition of the LCG lowers heart rate during re-entry.

  18. Longterm analytical orbit decay and reentry prediction

    NASA Astrophysics Data System (ADS)

    Klinkrad, H. H.

    An analytical approach to the prediction of close-Earth satellite orbits of moderate eccentricities is outlined. Based on the method of general averaging and on the principle of separation of perturbations, known results for the averaged time rates of change of the mean orbital elements due to J2, J3, and J4 are superimposed with results of the averaged air drag perturbation equations to obtain the total rates, which are then used to propagate the mean Kepler state in step-sizes of 1 to 15 orbits. The improved air drag model incorporates, in an analytically integrable representation, a rotating atmosphere, a variable aerodynamically effective satellite cross section, and a state-of-the-art MSIS'77 derived air density model as function of all major atmospheric parameters.

  19. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, Jyri; Harri, Ari-Matti; Aleksashkin, Sergey; Koryanov, Vsevolod; Arruego, Ignacio; Schmidt, Walter; Haukka, Harri; Finchenko, Valery; Martynov, Maxim; Ostresko, Boris; Ponomarenko, Andrey; Kazakovtsev, Viktor; Martin, Susanna; Siili, Tero

    2014-05-01

    A new generation of inflatable Entry, Descent and Landing System (EDLS) for Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth's atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry. 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth's atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. 'Mini-1' category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: qmax (kW/m2): maximal specific heat flux, Q (MJ/m2): specific integral heat flux to DV front shield, m (kg): descent vehicle (DV) mass, V (m/s): re-entry velocity and Θ (deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet ('Mini-1' category) -type lander, with mass of 22kg, being

  20. Investigation of the intermediate-energy deuteron breakup reaction

    SciTech Connect

    Divadeenam, M.; Ward, T.E.; Mustafa, M.G.; Udagawa, T.; Tamura, T.

    1989-01-01

    The Udagawa-Tamura formalism is employed to calculate the proton singles both in the bound and unbound regions. Both the Elastic-Breakup (EB) and the Breakup-Fusion (BF) processes are considered to calculate the doubly-differential cross section for light and intermediate mass nuclei. The calculated spectra for 25 and 56 MeV deuterons reproduce the experimental spectra very well except for the spectra at large angle and at low energies, of the outgoing particle. Contributions due to precompound and evaporation processes are estimated to supplement the spectral results based on the Elastic-Breakup and Breakup-Fusion mechanisms. An extension of the model calculations to higher deuteron energies is being made to test the (EB + BF) model limitations. 5 refs., 1 fig.

  1. Breakup of 87 MeV [sup 11]B

    SciTech Connect

    Wolfs, F.L.H.; White, C.A.; Bryan, D.C.; Freeman, C.G.; Herrick, D.M.; Kurz, K.L.; Mathews, D.H.; Perera, P.A.A.; Zanni, M.T. )

    1994-05-01

    A segmented focal plane detector has been used to study the breakup of 87 MeV [sup 11]B ions incident on a [sup 12]C target into [sup 4]He and [sup 7]Li fragments at relative energies between 0 and 4 MeV. The relative energy spectra are dominated by sequential breakup of the 9.28 MeV, 10.26+10.33 MeV, and 10.60 MeV excited states in [sup 11]B. The measured breakup yields decrease with increasing center-of-mass scattering angle, consistent with predictions made using single-step inelastic distorted wave Born approximation calculations. Applications of this technique to study the breakup of [sup 16]O at low relative energies will be discussed.

  2. Description of the four-nucleon collisions by including breakup

    NASA Astrophysics Data System (ADS)

    Lazauskas, Rimantas

    2016-03-01

    Four-nucleon reactions above the breakup threshold are described by solving Faddeev-Yakubovsky equations for the realistic nuclear Hamiltonians. Complex-scaling method is applied in order to simplify the boundary conditions.

  3. Analysis of Damped Oscillations during Reentry: A New Approach to Evaluate Cardiac Restitution☆

    PubMed Central

    Munteanu, Adelina; Kondratyev, Aleksandar A.; Kucera, Jan P.

    2008-01-01

    Abstract Reentry is a mechanism underlying numerous cardiac arrhythmias. During reentry, head-tail interactions of the action potential can cause cycle length (CL) oscillations and affect the stability of reentry. We developed a method based on a difference-delay equation to determine the slopes of the action potential duration and conduction velocity restitution functions, known to be major determinants of reentrant arrhythmogenesis, from the spatial period P and the decay length D of damped CL oscillations. Using this approach, we analyzed CL oscillations after the induction of reentry and the resetting of reentry with electrical stimuli in rings of cultured neonatal rat ventricular myocytes grown on microelectrode arrays and in corresponding simulations with the Luo-Rudy model. In the experiments, P was larger and D was smaller after resetting impulses compared to the induction of reentry, indicating that reentry became more stable. Both restitution slopes were smaller. Consistent with the experimental findings, resetting of simulated reentry caused oscillations with gradually increasing P, decreasing D, and decreasing restitution slopes. However, these parameters remained constant when ion concentrations were clamped, revealing that intracellular ion accumulation stabilizes reentry. Thus, the analysis of CL oscillations during reentry opens new perspectives to gain quantitative insight into action potential restitution. PMID:17921218

  4. Linking collisional and accretionary orogens during Rodinia assembly and breakup: Implications for models of supercontinent cycles

    NASA Astrophysics Data System (ADS)

    Cawood, Peter A.; Strachan, Robin A.; Pisarevsky, Sergei A.; Gladkochub, Dmitry P.; Murphy, J. Brendan

    2016-09-01

    Periodic assembly and dispersal of continental fragments has been a characteristic of the solid Earth for much of its history. Geodynamic drivers of this cyclic activity are inferred to be either top-down processes related to near surface lithospheric stresses at plate boundaries or bottom-up processes related to mantle convection and, in particular, mantle plumes, or some combination of the two. Analysis of the geological history of Rodinian crustal blocks suggests that internal rifting and breakup of the supercontinent were linked to the initiation of subduction and development of accretionary orogens around its periphery. Thus, breakup was a top-down instigated process. The locus of convergence was initially around north-eastern and northern Laurentia in the early Neoproterozoic before extending to outboard of Amazonia and Africa, including Avalonia-Cadomia, and arcs outboard of Siberia and eastern to northern Baltica in the mid-Neoproterozoic (∼760 Ma). The duration of subduction around the periphery of Rodinia coincides with the interval of lithospheric extension within the supercontinent, including the opening of the proto-Pacific at ca. 760 Ma and the commencement of rifting in east Laurentia. Final development of passive margin successions around Laurentia, Baltica and Siberia was not completed until the late Neoproterozoic to early Paleozoic (ca. 570-530 Ma), which corresponds with the termination of convergent plate interactions that gave rise to Gondwana and the consequent relocation of subduction zones to the periphery of this supercontinent. The temporal link between external subduction and internal extension suggests that breakup was initiated by a top-down process driven by accretionary tectonics along the periphery of the supercontinent. Plume-related magmatism may be present at specific times and in specific places during breakup but is not the prime driving force. Comparison of the Rodinia record of continental assembly and dispersal with that

  5. Inheritance of pre-existing weakness in continental breakup: 3D numerical modeling

    NASA Astrophysics Data System (ADS)

    Liao, Jie; Gerya, Taras

    2013-04-01

    The whole process of continental rifting to seafloor spreading is one of the most important plate tectonics on the earth. There are many questions remained related to this process, most of which are poorly understood, such as how continental rifting transformed into seafloor spreading? How the curved oceanic ridge developed from a single straight continental rift? How the pre-existing weakness in either crust or lithospheric mantle individually influences the continental rifting and oceanic spreading? By employing the state-of-the-art three-dimensional thermomechanical-coupled numerical code (using Eulerian-Lagrangian finite-difference method and marker-in-cell technic) (Gerya and Yuen, 2007), which can model long-term plate extension and large strains, we studied the whole process of continental rifting to seafloor spreading based on the following question: How the pre-existing lithospheric weak zone influences the continental breakup? Continental rifts do not occur randomly, but like to follow the pre-existing weakness (such as fault zones, suture zones, failed rifts, and other tectonic boundaries) in the lithosphere, for instance, the western branch of East African Rift formed in the relatively weak mobile belts along the curved western border of Tanzanian craton (Corti et al., 2007; Nyblade and Brazier, 2002), the Main Ethiopian Rift developed within the Proterozoic mobile belt which is believed to represent a continental collision zone (Keranen and Klemperer, 2008),the Baikal rift formed along the suture between Siberian craton and Sayan-Baikal folded belt (Chemenda et al., 2002). The early stage formed rift can be a template for the future rift development and continental breakup (Keranen and Klemperer, 2008). Lithospheric weakness can either reduce the crustal strength or mantle strength, and leads to the crustal or mantle necking (Dunbar and Sawyer, 1988), which plays an important role on controlling the continental breakup patterns, such as controlling the

  6. Inflatable Re-entry Vehicle Experiment (IRVE-4) Overview

    NASA Technical Reports Server (NTRS)

    Litton, Daniel K.; Bose, David M.; Cheatwood, F. McNeil; Hughes, Stephen; Wright, Henry S.; Lindell, Michael C.; Derry, Stephen D.; Olds, Aaron

    2011-01-01

    The suite of Inflatable Re-Entry Vehicle Experiments (IRVE) is designed to further our knowledge and understanding of Hypersonic Inflatable Aerodynamic Decelerators (HIADs). Before infusion into a future mission, three challenges need to be addressed: surviving the heat pulse during re-entry, demonstrating system performance at relevant scales, and demonstrating controllability in the atmosphere. IRVE-4 will contribute to a better understanding of controllability by characterizing how a HIAD responds to a set of controlled inputs. The ability to control a HIAD is vital for missions that are g-limited, require precision targeting and guidance for aerocapture or entry, descent, and landing. The IRVE-4 flight test will focus on taking a first look into controlling a HIAD. This paper will give an overview of the IRVE-4 mission including the control response portion of the flight test sequence, and will provide a review of the mission s development.

  7. Design of a recovery system for a reentry vehicle

    NASA Technical Reports Server (NTRS)

    Von Eckroth, Wulf; Garrard, William L.; Miller, Norman

    1993-01-01

    Engineers are often required to design decelerator systems which are deployed in cross-wind orientations. If the system is not designed to minimize 'line sail', damage to the parachutes could result. A Reentry Vehicle Analysis Code (RVAC) and an accompanying graphics animation software program (DISPLAY) are presented in this paper. These computer codes allow the user to quickly apply the Purvis line sail modeling technique to any vehicle and then observe the relative motion of the vehicle, nose cap, suspension lines, pilot and drogue bags and canopies on a computer screen. Data files are created which allow plots of velocities, spacial positions, and dynamic pressures versus time to be generated. The code is an important tool for the design engineer because it integrates two degrees of freedom (DOF) line sail equations with a three DOF model of the reentry body and jettisoned nose cap to provide an animated output.

  8. The breakup of (16)O and its astrophysical implications

    NASA Astrophysics Data System (ADS)

    Bryan, Diane Carol

    1998-07-01

    The feasibility of using the breakup of 16O to obtain information about the 12C(/alpha,/gamma)16O radiative capture reaction has been studied in a series of experiments performed at the Nuclear Structure Research Laboratory at the University of Rochester. The 16O breakup fragments-12C and 4He-were identified using a new focal-plane detector capable of identifying these fragments down to a relative energy of 50 keV. The relative energy spectra obtained from 16O breakup on a 58Ni target are dominated by sequential breakup from 9.85 MeV, and 10.36 MeV excited states in 16O. There is also some evidence of breakup at relative energies below 1 MeV. Interpretation of this low energy yield in terms of E2 Coulomb excitation leads to a value of SE2=346 keV b at Erel=0.828 MeV after making a correction for the contribution due to nuclear breakup. This suggests that the rate of the 12C(/alpha,/gamma)16O reaction at astrophysical energies is much higher than is presently accepted, which would have an enormous impact on stellar nucleosynthesis.

  9. A new model for auroral breakup during substorms

    SciTech Connect

    Rothwell, P.L.; Block, L.P.; Falthammar, C.G.; Silevitch, M.B.

    1989-04-01

    A model for substorm breakup is developed, based on the relaxation of stretched (closed) dipolar field lines, and the formation of an incipient current wedge within a single arc structure. It is argued that the establishment of a coupled current structure within a single arc leads to a quasi-stable system; i.e., the pre-breakup regime. Perturbation of the pre-breakup structure leads to an instability criterion. It is found, consistent with observations, that narrower auroral arcs at lower L shells undergo the most explosive poleward expansion. According to this model, the precise location at which breakup occurs depends on the O/sup +/ density in the plasma sheet, the level of magnetic activity (K/sub p/), and the intensity of the substorm westward electrojet in the ionosphere. An enhancement of any of these features will cause breakup to occur at lower L shells. Comparison of our model with the Heppner-Maynard polar-cap potential model indicates that breakup is restricted to the west of the Harang discontinuity consistent with recent observations from the Viking satellite.

  10. EXPERT: An atmospheric re-entry test-bed

    NASA Astrophysics Data System (ADS)

    Massobrio, F.; Viotto, R.; Serpico, M.; Sansone, A.; Caporicci, M.; Muylaert, J.-M.

    2007-06-01

    In recognition of the importance of an independent European access to the International Space Station (ISS) and in preparation for the future needs of exploration missions, ESA is conducting parallel activities to generate flight data using atmospheric re-entry test-beds and to identify vehicle design solutions for human and cargo transportation vehicles serving the ISS and beyond. The EXPERT (European eXPErimental Re-entry Test-bed) vehicle represents the major on-going development in the first class of activities. Its results may also benefit in due time scientific missions to planets with an atmosphere and future reusable launcher programmes. The objective of EXPERT is to provide a test-bed for the validation of aerothermodynamics models, codes and ground test facilities in a representative flight environment, to improve the understanding of issues related to analysis, testing and extrapolation to flight. The vehicle will be launched on a sub-orbital trajectory using a Volna missile. The EXPERT concept is based on a symmetrical re-entry capsule whose shape is composed of simple geometrical elements. The suborbital trajectory will reach 120 km altitude and a re-entry velocity of 5 6km/s. The dimensions of the capsule are 1.6 m high and 1.3 m diameter; the overall mass is in the range of 250 350kg, depending upon the mission parameters and the payload/instrumentation complement. A consistent number of scientific experiments are foreseen on-board, from innovative air data system to shock wave/boundary layer interaction, from sharp hot structures characterisation to natural and induced regime transition. Currently the project is approaching completion of the phase B, with Alenia Spazio leading the industrial team and CIRA coordinating the scientific payload development under ESA contract.

  11. Ares I-X Separation and Reentry Trajectory Analyses

    NASA Technical Reports Server (NTRS)

    Tartabini, Paul V.; Starr, Brett R.

    2011-01-01

    The Ares I-X Flight Test Vehicle was launched on October 28, 2009 and was the first and only test flight of NASA s two-stage Ares I launch vehicle design. The launch was successful and the flight test met all of its primary and secondary objectives. This paper discusses the stage separation and reentry trajectory analysis that was performed in support of the Ares I-X test flight. Pre-flight analyses were conducted to assess the risk of stage recontact during separation, to evaluate the first stage flight dynamics during reentry, and to define the range safety impact ellipses of both stages. The results of these pre-flight analyses were compared with available flight data. On-board video taken during flight showed that the flight test vehicle successfully separated without any recontact. Reconstructed trajectory data also showed that first stage flight dynamics were well characterized by pre-flight Monte Carlo results. In addition, comparisons with flight data indicated that the complex interference aerodynamic models employed in the reentry simulation were effective in capturing the flight dynamics during separation. Finally, the splash-down locations of both stages were well within predicted impact ellipses.

  12. Displacements of Metallic Thermal Protection System Panels During Reentry

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Blosser, Max L.; Wurster, Kathryn E.

    2006-01-01

    Bowing of metallic thermal protection systems for reentry of a previously proposed single-stage-to-orbit reusable launch vehicle was studied. The outer layer of current metallic thermal protection system concepts typically consists of a honeycomb panel made of a high temperature nickel alloy. During portions of reentry when the thermal protection system is exposed to rapidly varying heating rates, a significant temperature gradient develops across the honeycomb panel thickness, resulting in bowing of the honeycomb panel. The deformations of the honeycomb panel increase the roughness of the outer mold line of the vehicle, which could possibly result in premature boundary layer transition, resulting in significantly higher downstream heating rates. The aerothermal loads and parameters for three locations on the centerline of the windward side of this vehicle were calculated using an engineering code. The transient temperature distributions through a metallic thermal protection system were obtained using 1-D finite volume thermal analysis, and the resulting displacements of the thermal protection system were calculated. The maximum deflection of the thermal protection system throughout the reentry trajectory was 6.4 mm. The maximum ratio of deflection to boundary layer thickness was 0.032. Based on previously developed distributed roughness correlations, it was concluded that these defections will not result in tripping the hypersonic boundary layer.

  13. High performance modeling of atmospheric re-entry vehicles

    NASA Astrophysics Data System (ADS)

    Martin, Alexandre; Scalabrin, Leonardo C.; Boyd, Iain D.

    2012-02-01

    Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, an appropriate gas flow chemistry model needs to be included in the CFD calculations. Using a recently developed chemistry model for ablating carbon-phenolic-in-air species, a CFD calculation of the Stardust re-entry at 71 km is presented. The code used for that purpose has been designed to take advantage of the nature of the problem and therefore remains very efficient when a high number of chemical species are involved. The CFD result demonstrates the need for such chemistry model when modeling the flow field around an ablative material. Modeling of the nonequilibrium radiation spectra is also presented, and compared to the experimental data obtained during Stardust re-entry by the Echelle instrument. The predicted emission from the CN lines compares quite well with the experimental results, demonstrating the validity of the current approach.

  14. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, Jyri; Aleksashkin, Sergey; Martynov, Maxim; Schmidt, Walter; Harri, Ari-Matti; Vsevolod Koryanov, D.; Kazakovtcev, Victor; Haukka, Harri; Arruego, Ignacio; Finchenko, Valery; Ostresko, Boris; Ponomarenko, Andrei; Martin, Susanna; Siili, Tero

    Abstract A new generation of inflatable Entry, Descent and Landing System (EDLS) or Mars has been developed. It is used in both the initial atmospheric entry and atmospheric descent before the semi-hard impact of the penetrator into Martian surface. The EDLS applicability to Earth’s atmosphere is studied by the EU/RITD [1] project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry 1. EDLS for Earth The dynamical stability of the craft is analysed, concentrating on the most critical part of the atmospheric re-entry, the transonic phase. In Martian atmosphere the MetNet vehicle stability during the transonic phase is understood. However, in the more dense Earth’s atmosphere, the transonic phase is shorter and turbulence more violent. Therefore, the EDLS has to be sufficiently dynamically stable to overcome the forces tending to deflect the craft from its nominal trajectory and attitude. The preliminary design of the inflatable EDLS for Earth will be commenced once the scaling of the re-entry system and the dynamical stability analysis have been performed. The RITD-project concentrates on mission and applications achievable with the current MetNet-type (i.e. “Mini-1” category) of lander, and on requirements posed by other type Earth re-entry concepts. 2. Entry Angle Determination for Mini-1 - lander For successful Earth landing, the suitable re-entry angle and velocity with specific descent vehicle (DV) mass and heat flux parameters need to be determined. These key parameters in determining the Earth re-entry for DV are: - qmax (kW/m2): maximal specific heat flux, - Q (MJ/m2): specific integral heat flux to DV front shield, - m (kg): descent vehicle (DV) mass, - V (m/s): re-entry velocity and - theta(deg.): flight-path angle at Earth re-entry For Earth re-entry, the calculation results in the optimal value of entry velocity for MetNet (“Mini-1” category) -type

  15. Spectroscopy of Project Fire 1, April 14, 1964. [comparison of reentry vehicle and meteor spectra

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1973-01-01

    The Fire 1 test was designed to study the heating of an Apollo-type reentry vehicle. The total reentry complex weighed approximately 230 kg and entered the upper atmosphere at a velocity of 11.5 km/s. The spectrum of the reentry complex has been studied in the wavelength range 3700 to 8800 A, where 102 multiplets of 21 atoms and the band systems of 5 diatomic molecules have been identified. Comparisons with meteor spectra are made.

  16. Re-Entry of Women to the Labour Market After an Interruption in Employment.

    ERIC Educational Resources Information Center

    Seear, B. N.

    The problems involved in the re-entry of women into employment were studied, and the extent to which there exists a demand for employment for re-entry women was examined. A growing number of women are seeking re-entry in a wide range of income levels. The demand for part-time work appears to exceed supply. Official machinery for assisting re-entry…

  17. Sonic boom measurement test plan for Space Shuttle STS-3 reentry

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.

    1982-01-01

    The lateral area from the reentry ground track affected by sonic boom overpressure levels is determined. Four data acquisition stations are deployed laterally to the STS-3 reentry flight track. These stations provide six intermediate band FM channels of sonic boom data, universal time synchronization, and voice annotation. All measurements are correlated with the vehicle reentry flight track information along with atmospheric and vehicle operation conditions.

  18. Physics-Based Modeling of Meteor Entry and Breakup

    NASA Technical Reports Server (NTRS)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kanq; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup. Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood. On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heat shields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kWcm2. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses.With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  19. Physics-Based Modeling of Meteor Entry and Breakup

    NASA Technical Reports Server (NTRS)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  20. Physics-Based Modeling of Meteor Entry and Breakup

    NASA Technical Reports Server (NTRS)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A.; Brandis, Aaron M.; Chen, Yih-Kanq; Jaffe, Richard L.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup. Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood. On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is less than 13 km/s (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/cm2. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to greater than 20 km/s; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current

  1. Breakup of Droplets in an Accelerating Gas Flow

    NASA Technical Reports Server (NTRS)

    Dickerson, R. A.; Coultas, T. A.

    1966-01-01

    A study of droplet breakup phenomena by an accelerating gas flow is described. The phenomena are similar to what propellant droplets experience when exposed to accelerating combustion gas flow in a rocket engine combustion zone. Groups of several dozen droplets in the 100-10 750-micron-diameter range were injected into a flowing inert gas in a transparent rectangular nozzle. Motion photography of the behavior of the droplets at various locations in the accelerating gas flow has supplied quantitative and qualitative data on the breakup phenomena which occur under conditions similar to those found in large rocket engine combustors. A blowgun injection device, used to inject very small amounts of liquid at velocities of several hundred feet per second into a moving gas stream, is described. The injection device was used to inject small amounts of liquid RP-1 and water into the gas stream at a velocity essentially equal to the gas velocity where the group of droplets was allowed to stabilize its formation in a constant area section before entering the convergent section of the transparent nozzle. Favorable comparison with the work of previous investigators who have used nonaccelerating gas flow is found with the data obtained from this study with accelerating gas flow. The criterion for the conditions of minimum severity required to produce shear-type droplet breakup in an accelerating gas flow is found to agree well with the criterion previously established at Rocketdyne for breakup in nonaccelerating flow. An extension of the theory of capillary surface wave effects during droplet breakup is also presented. Capillary surface waves propagating in the surface of the droplet, according to classical hydrodynamical laws, are considered. The waves propagate tangentially over the surface of the droplet from the forward stagnation point to the major diameter. Consideration of the effects of relative gas velocity on the amplitude growth of these waves allows conclusions to be

  2. Hard breakup of two nucleons from the He3 nucleus

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak M.; Granados, Carlos

    2009-07-01

    We investigate a large angle photodisintegration of two nucleons from the He3 nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard nucleon-nucleon scattering, the HRM allows the expression of the amplitude of a two-nucleon breakup reaction through the convolution of photon-quark scattering, NN hard scattering amplitude, and nuclear spectral function, which can be calculated using a nonrelativistic He3 wave function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for NN scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as s-11. Second, the s11 weighted cross section will have the shape of energy dependence similar to that of s10 weighted NN elastic scattering cross section. Also one predicts an enhancement of the pp breakup relative to the pn breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn breakup cross sections. This is due to the fact that the same-helicity pp-component is strongly suppressed in the ground state wave function of He3. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer NN breakup reactions for circularly polarized photons. For the pp breakup this asymmetry is predicted to be zero while for the pn it is close to (2)/(3).

  3. Infrasound/seismic observation of the Hayabusa reentry: Observations and preliminary results

    NASA Astrophysics Data System (ADS)

    Ishihara, Yoshiaki; Hiramatsu, Yoshihiro; Yamamoto, Masa-yuki; Furumoto, Muneyoshi; Fujita, Kazuhisa

    2012-07-01

    The Hayabusa, the world's first sample-return minor body explorer, returned to the Earth, and reentered the Earth's atmosphere on June 13, 2010. Multi-site ground observations of the Hayabusa reentry were carried out in the Woomera Prohibited Area (WPA), Australia. The ground observations were configured with optical imaging with still and video recordings, spectroscopies, and shockwave detection with infrasound and seismic sensors. At three main stations, we installed small aperture infrasound/seismic arrays, as well as three single component seismic sub stations. The infrasound and seismic sensors clearly recorded sonic-boom-type shockwaves from the Hayabusa Sample Return Capsule (H-SRC) and the disrupted fragments of the Hayabusa Spacecraft (H-S/C) itself. Positive overpressure values of shockwaves (corresponding to the H-SRC) recorded at the three main stations were 1.3 Pa, 1.0 Pa, and 0.7 Pa with slant distances of 36.9 km, 54.9 km, and 67.8 km, respectively. Incident vectors of the shockwave from the H-SRC at all three arrays are estimated by an F-K spectrum and agree well with those predicted. Particle motions of ground motions excited by the shockwave show characteristics of a typical Rayleigh wave.

  4. Middle-high latitude N2O distributions related to the arctic vortex breakup

    NASA Astrophysics Data System (ADS)

    Zhou, L. B.; Zou, H.; Gao, Y. Q.

    2006-03-01

    The relationship of N2O distributions with the Arctic vortex breakup is first analyzed with a probability distribution function (PDF) analysis. The N2O concentration shows different distributions between the early and late vortex breakup years. In the early breakup years, the N2O concentration shows low values and large dispersions after the vortex breakup, which is related to the inhomogeneity in the vertical advection in the middle and high latitude lower stratosphere. The horizontal diffusion coefficient (K,,) shows a larger value accordingly. In the late breakup years, the N2O concentration shows high values and more uniform distributions than in the early years after the vortex breakup, with a smaller vertical advection and K,, after the vortex breakup. It is found that the N2O distributions are largely affected by the Arctic vortex breakup time but the dynamically defined vortex breakup time is not the only factor.

  5. Morphological classification of low viscosity drop bag breakup in a continuous air jet stream

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Liu, Hai-Feng; Li, Wei-Feng; Xu, Jian-Liang

    2010-11-01

    To investigate the effect of Rayleigh-Taylor wave number in the region of maximum cross stream dimension (NRT) on drop breakup morphology, the breakup properties of accelerating low viscosity liquid drops (water and ethanol drops, diameter=1.2-6.6 mm, Weber number=10-80) were investigated using high-speed digital photography. The results of morphological analysis show a good correlation of the observed breakup type with NRT; bag breakup occurred when NRT was 1/√3 -1, bag-stamen breakup at 1-2, and dual-bag breakup at 2-3. The number of nodes in bag breakup, bag-stamen breakup, and dual-bag breakup all increased with Weber number. The experimental results are consistent with the model estimates and in good agreement with those reported in the literature.

  6. Drop breakup and deformation in sudden onset strong flows

    NASA Astrophysics Data System (ADS)

    Marks, Charles Raphael

    This work characterizes the deformation and breakup of a single drop subjected to a sudden onset shear flow. The drop is immersed in a second fluid (the matrix) with which it is immiscible. A cylindrical couette device is used to create a flow field which, in the absence of the drop, would constitute a close approximation of simple shear flow. The magnitude of the imposed shear rate was greater than that which would be necessary to just break the drop. The experiments conducted were limited to matrix fluid viscosities above 7Pa˙ s and shear rates below 15/s, ensuring that the flows considered were inertialess. The matrix fluid was a corn syrup solution. The drop fluids were polybutadiene, paraffin oil and silicone oil, leading to a range of interfacial tensions. At the shear rates used in these experiments the fluids used Newtonian. Viscosity ratios (drop/matrix) ranging from 0.01 to 1 were considered. Two breakup mechanisms were observed to contribute to the dispersion of the original drop. In all cases elongative end pinching, defined by this study, caused the ends of a stretching drop to break off and form daughter drops. Breakup due to elongative end pinching was always the first breakup observed. The daughter drops formed by elongative end pinching were always the largest daughter drops formed. In cases when the experimental conditions were sufficiently stronger than the critical conditions (needed to just barely break up the drop), a second type of breakup, capillary wave breakup, was also observed. Measurement of the characteristic time scales and length scales were made of each type of breakup. The lengths (a) were found to scale as capillary numbers: Ca=a mg/s. The times (t) were found to scale as strains: s=t g. A qualitative explanation for the capillary number scaling is presented and quantitatively compared to predictions based on small deformation analysis. Additionally the daughter drop size distributions resulting from drop breakup is characterized

  7. Selective breakup of lipid vesicles under acoustic microstreaming flow

    NASA Astrophysics Data System (ADS)

    Pommella, Angelo; Garbin, Valeria

    2014-11-01

    The dynamics of lipid vesicles under small deformation in simple shear flow is well characterized: complex behaviors such as tumbling, breathing, and tank-treading are observed depending on the viscosity contrast between inner and outer fluid, vesicle excess area, membrane viscosity, and bending modulus. In contrast, phenomena upon large deformation are still poorly understood, in particular vesicle breakup. Simple shear flow geometries do not allow to reach the large stresses necessary to cause vesicle breakup. We use the acoustic microstreaming flow generated by an oscillating microbubble to study the large deformation and breakup of giant unilamellar vesicles. The deformation is governed by a capillary number based on the membrane elasticity K : Ca = ηγ˙a / K where η is the viscosity of the outer fluid, a the vesicle radius, and γ˙ the shear rate. We explore the effect of the mechanical properties of the membrane, and demonstrated selective breakup of vesicles based on the difference in membrane elasticity. The results reveal the influence of membrane mechanical properties in shear-induced vesicle breakup and the possibility to control in a quantitative way the selectivity of the process, with potential applications in biomedical technologies. The authors acknowledge funding from EU/FP7 Grant Number 618333.

  8. Breakup of {sup 11}B at low relative energies

    SciTech Connect

    Bryan, D.C.; White, C.A.; Wolfs, F.L.H.

    1993-04-01

    The authors have used the segmented focal plane detector of the Rochester Enge split-pole spectrograph to study the breakup of 87 MeV {sup 11}B ions incident on a {sup 12}C target into {sup 4}He and {sup 7}Li fragments at relative energies between 0 MeV and 4 MeV and at laboratory angles between 7.5{degrees} and 25{degrees}. The total kinetic energy spectra of the breakup fragments is dominated by elastic breakup (all reaction products are left in their ground state). The reconstructed relative energy spectra for elastic breakup are dominated by sequential breakup of {sup 11}B via the 9.27 MeV, 10.26 MeV, and 10.60 MeV excited states in {sup 11}B. The measured yields are compared with the calculated cross sections of exciting these states, using DWBA calculations and B(EL) values obtained from radiative capture measurements of {sup 4}He and {sup 7}Li.

  9. Dynamics of bubble breakup at a T junction.

    PubMed

    Lu, Yutao; Fu, Taotao; Zhu, Chunying; Ma, Youguang; Li, Huai Z

    2016-02-01

    The gas-liquid interfacial dynamics of bubble breakup in a T junction was investigated. Four regimes were observed for a bubble passing through the T junction. It was identified by the stop flow that a critical width of the bubble neck existed: if the minimum width of the bubble neck was less than the critical value, the breakup was irreversible and fast; while if the minimum width of the bubble neck was larger than the critical value, the breakup was reversible and slow. The fast breakup was driven by the surface tension and liquid inertia and is independent of the operating conditions. The minimum width of the bubble neck could be scaled with the remaining time as a power law with an exponent of 0.22 in the beginning and of 0.5 approaching the final fast pinch-off. The slow breakup was driven by the continuous phase and the gas-liquid interface was in the equilibrium stage. Before the appearance of the tunnel, the width of the depression region could be scaled with the time as a power law with an exponent of 0.75; while after that, the width of the depression was a logarithmic function with the time. PMID:26986389

  10. Dynamics of bubble breakup at a T junction

    NASA Astrophysics Data System (ADS)

    Lu, Yutao; Fu, Taotao; Zhu, Chunying; Ma, Youguang; Li, Huai Z.

    2016-02-01

    The gas-liquid interfacial dynamics of bubble breakup in a T junction was investigated. Four regimes were observed for a bubble passing through the T junction. It was identified by the stop flow that a critical width of the bubble neck existed: if the minimum width of the bubble neck was less than the critical value, the breakup was irreversible and fast; while if the minimum width of the bubble neck was larger than the critical value, the breakup was reversible and slow. The fast breakup was driven by the surface tension and liquid inertia and is independent of the operating conditions. The minimum width of the bubble neck could be scaled with the remaining time as a power law with an exponent of 0.22 in the beginning and of 0.5 approaching the final fast pinch-off. The slow breakup was driven by the continuous phase and the gas-liquid interface was in the equilibrium stage. Before the appearance of the tunnel, the width of the depression region could be scaled with the time as a power law with an exponent of 0.75; while after that, the width of the depression was a logarithmic function with the time.

  11. Breakup Reactions of Neutron Drip Line Nuclei Near N=20

    NASA Astrophysics Data System (ADS)

    Nakamura, Takashi

    2011-09-01

    Coulomb breakup at intermediate energies is a useful experimental tool for investigating the microscopic structure of neutron drip-line nuclei. Here, results from the inclusive Coulomb breakup experiment of 31Ne on a lead target at RIBF(RI Beam Factory) at RIKEN are presented. The experiment was performed as one of day-one campaign experiments at RIBF, using a 48Ca primary beam at 345 MeV/nucleon. A unique feature of a halo nucleus is the enhanced electric dipole strength of the order of 1 W.u.(Weisskopf unit) at very low excitation energies around 1 MeV (soft E1 excitation). Owing to high sensitivity of the Coulomb breakup to the soft E1 excitation, a measurement of inclusive Coulomb breakup cross section can be used to identify the halo structure of a certain drip-line nucleus. We have indeed observed a strong enhancement of the Coulomb breakup cross section of 540(70) mb for 31Ne on Pb at 230 MeV/nucleon, nearly as high as that for the known halo nucleus 19C, thereby giving evidence of the halo structure in 31Ne. The finding of a new halo structure for such a heavy system, compared to the known halo nuclei, is the first step for the understanding of halo phenomena along the neutron drip line towards heavier nuclei. We discuss also the change of shell structure in 31Ne, as a nucleus in the island of inversion.

  12. Rescue Shuttle Flight Re-Entry: Controlling Astronaut Thermal Exposure

    NASA Technical Reports Server (NTRS)

    Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Polk, J. D.; Son, Chang; Bue, Grant

    2008-01-01

    A rescue mission for the STS-125 Hubble Telescope Repair Mission requires reentry from space with 11 crew members aboard, exceeding past cabin thermal load experience and risking crew thermal stress potentially causing cognitive performance and physiological decrements. The space shuttle crew cabin air revitalization system (ARS) was designed to support a nominal crew complement of 4 to 7 crew and 10 persons in emergencies, all in a shirt-sleeve environment. Subsequent to the addition of full pressure suits with individual cooling units, the ARS cannot maintain a stable temperature in the crew cabin during reentry thermal loads. Bulk cabin thermal models, used for rescue mission planning and analysis of crew cabin air, were unable to accurately represent crew workstation values of air flow, carbon dioxide, and heat content for the middeck. Crew temperature models suggested significantly elevated core temperatures. Planning for an STS-400 potential rescue of seven stranded crew utilized computational fluid dynamics (CFD) models to demonstrate inhomogeneous cabin thermal properties and improve analysis compared to bulk models. In the absence of monitoring of crew temperature, heart rate, metabolic rate and incomplete engineering data on the performance of the integrated cooling garment/cooling unit (ICG/CU) at cabin temperatures above 75 degrees F, related systems & models were reevaluated and tests conducted with humans in the loop. Changes to the cabin ventilation, ICU placement, crew reentry suit-donning procedures, Orbiter Program wave-off policy and post-landing power down and crew extraction were adopted. A second CFD and core temperature model incorporated the proposed changes and confirmed satisfactory cabin temperature, improved air distribution, and estimated core temperatures within safe limits. CONCLUSIONS: These changes in equipment, in-flight and post-landing procedures, and policy were implemented for the STS-400 rescue shuttle & will be implemented in

  13. Ukrainian prisoners and community reentry challenges: implications for transitional care

    PubMed Central

    Morozova, Olga; Azbel, Lyuba; Grishaev, Yevgeny; Dvoryak, Sergii; Wickersham, Jeffrey A.; Altice, Frederick L.

    2013-01-01

    Purpose The study aims to assess reentry challenges faced by Ukrainian prisoners and to determine the factors associated with having a greater number of challenges in order to suggest pre- and post-release interventions with the aim of facilitating community reintegration. Design/methodology/approach A representative national cross-sectional study with a sample size of 402 prisoners was conducted among imprisoned adults within six months of release. The study consisted of interviews and biological testing for infectious diseases. Anticipated reentry challenges were assessed using a structured questionnaire. Findings The most difficult and relatively important challenges identified were finding a job or a stable source of income and staying out of prison following release. Risk-specific challenges pertinent to drug users and HIV-infected individuals were assessed as difficult, but generally less important. Similarly, challenges associated with reducing drug relapse were ranked as less important, with only 0.6 percent identifying opioid substitution therapy as a helpful measure. In the multivariate analysis, having a greater number of challenges is associated with previous incarcerations, drug use immediately before incarceration and lower levels of social support. Practical implications To facilitate community re-integration, it is vital to design interventions aimed at reducing recidivism and improvement of social support through comprehensive case management as well as to improve understanding about and address drug dependence issues among inmates by implementing evidence-based treatment both within prisons and after release. Originality/value This is the first comprehensive assessment of community reentry challenges by prisoners in the former Soviet Union. PMID:25152767

  14. Modeling Tear Film Evaporation and Breakup with Duplex Films

    NASA Astrophysics Data System (ADS)

    Stapf, Michael; Braun, Richard; Begley, Carolyn; Driscoll, Tobin; King-Smith, Peter Ewen

    2015-11-01

    Tear film thinning, hyperosmolarity, and breakup can irritate and damage the ocular surface. Recent research hypothesizes deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. We consider a model for team film evolution incorporating two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of salt concentration, osmosis, evaporation as modified by the lipid layer, and the polar portion of the lipid layer. Numerically solving the resulting model, we explore the conditions for tear film breakup and analyze the response of the system to changes in our parameters. Our studies indicate sufficiently fast peak values or sufficiently wide areas of evaporation promote TBU, as does diffusion of solutes. In addition, the Marangoni effect representing polar lipids dominates viscous dissipation from the non-polar lipid layer in the model. This work was supported in part by NSF grant 1412085 and NIH grant 1R01EY021794.

  15. Flap effectiveness appraisal for winged re-entry vehicles

    NASA Astrophysics Data System (ADS)

    de Rosa, Donato; Pezzella, Giuseppe; Donelli, Raffaele S.; Viviani, Antonio

    2016-05-01

    The interactions between shock waves and boundary layer are commonplace in hypersonic aerodynamics. They represent a very challenging design issue for hypersonic vehicle. A typical example of shock wave boundary layer interaction is the flowfield past aerodynamic surfaces during control. As a consequence, such flow interaction phenomena influence both vehicle aerodynamics and aerothermodynamics. In this framework, the present research effort describes the numerical activity performed to simulate the flowfield past a deflected flap in hypersonic flowfield conditions for a winged re-entry vehicle.

  16. Successful Reentry: The Perspective of Private Correctional Health Care Providers

    PubMed Central

    Greifinger, Robert B.

    2006-01-01

    Due to public health and safety concerns, discharge planning is increasingly prioritized by correctional systems when preparing prisoners for their reintegration into the community. Annually, private correctional health care vendors provide $3 billion of health care services to inmates in correctional facilities throughout the U.S., but rarely are contracted to provide transitional health care. A discussion with 12 people representing five private nationwide correctional health care providers highlighted the barriers they face when implementing transitional health care and what templates of services health care companies could provide to state and counties to enhance the reentry process. PMID:17131191

  17. A conceptual design study of the reusable reentry satellite

    NASA Technical Reports Server (NTRS)

    Swenson, Byron L.; Mascy, Alfred C.; Carter, Bruce; Cartledge, Alan; Corridan, Robert E.; Edsinger, Larry E.; Jackson, Robert W.; Keller, Robert; Murbach, Marcus S.; Wercinski, Paul F.

    1988-01-01

    Experimentation leading to an understanding of life processes under reduced and extremely low gravitational forces will profoundly contribute to the success of future space missions involving humans. In addition to research on gravitational biology, research on the effects of cosmic radiation and the interruption and change of circadian rhythms on life systems is also of prime importance. Research in space, however, is currently viewed by biological scientists as an arena that is essential, yet largely inaccessible to them for their experimentation. To fulfill this need, a project and spacecraft system described as the Reusuable Reentry Satellite or Lifesat has been proposed by NASA.

  18. Hypersonic Pitching-Moment Shift for Stardust Reentry Capsule Forebody

    NASA Technical Reports Server (NTRS)

    Wood, William A.

    1997-01-01

    Aerodynamic coefficients are presented for perfect-gas and equilibrium-air solutions of the Navier-Stokes equations about the Stardust reentry-capsule forebody at Mach numbers of 4.6, 7, 8.5, and 10. A comparison with Newtonian-flow assumptions indicates a divergence of the aerodynamic coefficients from Newtonian-flow for Mach numbers less than 10. The static stability of the forebody is reduced by a factor of 2.5 with decreasing freestream Mach number between Mach 10 and 7.

  19. Some Landing Studies Pertinent to Glider-Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Houbolt, John C.; Batterson, Sidney A.

    1960-01-01

    Results are presented of some landing studies that may serve as guidelines in the consideration of landing problems of glider-reentry configurations. The effect of the initial conditions of sinking velocity, angle of attack, and pitch rate on impact severity and the effect of locating the rear gear in various positions are discussed. Some information is included regarding the influence of landing-gear location on effective masses. Preliminary experimental results on the slideout phase of landing include sliding and rolling friction coefficients that have been determined from tests of various skids and all-metal wheels.

  20. Continuing Medical Education, Maintenance of Certification, and Physician Reentry

    PubMed Central

    Luchtefeld, Martin; Kerwel, Therese G.

    2012-01-01

    Continuing medical education serves a central role in the licensure and certification for practicing physicians. This chapter explores the different modalities that constitute CME along with their effectiveness, including simulation and best education practices. The evolution to maintenance of certification and the requirements for both the American Board of Surgery and the American Board of Colon and Rectal Surgery are delineated. Further progress in the education of practicing surgeons is evidenced through the introduction of laparoscopic colectomy and the improvements made from the introduction of laparoscopic cholecystectomy. Finally, reentry of physicians into practice following a voluntary leave of absence, a new and challenging issue for surgeons, is also discussed. PMID:23997673

  1. RITD - Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Haukka, H.; Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Arruego, I.; Schmidt, W.; Finchenko, V.; Martynov, M.; Ponomarenko, A.; Kazakovtsev, V.; Martin, S.

    2015-10-01

    We have developed an atmospheric re-entry and descent system concept based on inflatable hypersonic decelerator techniques that were originally developed for Mars. The ultimate goal of this EU-funded RITD-project (Re-entry: Inflatable Technology Development) was to assess the benefits of this technology when deploying small payloads from low Earth orbits to the surface of the Earth with modest costs. The principal goal was to assess and develop a preliminary EDLS design for the entire relevant range of aerodynamic regimes expected to be encountered in Earth's atmosphere during entry, descent and landing. Low Earth Orbit (LEO) and even Lunar applications envisaged include the use of the EDLS approach in returning payloads of 4-8 kg down to the surface.

  2. Effect of boiling regime on melt stream breakup in water

    SciTech Connect

    Spencer, B.W.; Gabor, J.D.; Cassulo, J.C.

    1986-01-01

    A study has been performed examining the breakup and mixing behavior of an initially coherent stream of high-density melt as it flows downward through water. This work has application to the quenching of molten core materials as they drain downward during a postulated severe reactor accident. The study has included examination of various models of breakup distances based upon interfacial instabilities dominated either by liquid-liquid contact or by liquid-vapor contact. A series of experiments was performed to provide a data base for assessment of the various modeling approaches. The experiments involved Wood's metal (T/sub m/ = 73/sup 0/C, rho = 9.2 g/cm/sup 3/, d/sub j/ = 20 mm) poured into a deep pool of water. The temperature of the water and wood's metal were varied to span the range from single-phase, liquid-liquid contact to the film boiling regime. Experiment results showed that breakup occurred largely as a result of the spreading and entrainment from the leading edge of the jet. However, for streams of sufficient lengths a breakup length could be discerned at which there was no longer a coherent central core of the jet to feed the leading edge region. The erosion of the vertical trailing column is by Kelvin-Helmoltz instabilities and related disengagement of droplets from the jet into the surrounding fluid. For conditions of liquid-liquid contact, the breakup length has been found to be about 20 jet diameters; when substantial vapor is produced at the interface due to heat transfer from the jet to the water, the breakup distance was found to range to as high as 50 jet diameters. The former values are close to the analytical prediction of Taylor, whereas the latter values are better predicted by the model of Epstein and Fauske.

  3. Project EGRESS: Earthbound Guaranteed Reentry from Space Station. the Design of an Assured Crew Recovery Vehicle for the Space Station

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Unlike previously designed space-based working environments, the shuttle orbiter servicing the space station will not remain docked the entire time the station is occupied. While an Apollo capsule was permanently available on Skylab, plans for Space Station Freedom call for a shuttle orbiter to be docked at the space station for no more than two weeks four times each year. Consideration of crew safety inspired the design of an Assured Crew Recovery Vehicle (ACRV). A conceptual design of an ACRV was developed. The system allows the escape of one or more crew members from Space Station Freedom in case of emergency. The design of the vehicle addresses propulsion, orbital operations, reentry, landing and recovery, power and communication, and life support. In light of recent modifications in space station design, Project EGRESS (Earthbound Guaranteed ReEntry from Space Station) pays particular attention to its impact on space station operations, interfaces and docking facilities, and maintenance needs. A water-landing medium-lift vehicle was found to best satisfy project goals of simplicity and cost efficiency without sacrificing safety and reliability requirements. One or more seriously injured crew members could be returned to an earth-based health facility with minimal pilot involvement. Since the craft is capable of returning up to five crew members, two such permanently docked vehicles would allow a full evacuation of the space station. The craft could be constructed entirely with available 1990 technology, and launched aboard a shuttle orbiter.

  4. Universality for the breakup of invariant tori in Hamiltonian flows

    NASA Astrophysics Data System (ADS)

    Chandre, C.; Govin, M.; Jauslin, H. R.; Koch, H.

    1998-06-01

    In this article, we describe a new renormalization-group scheme for analyzing the breakup of invariant tori for Hamiltonian systems with two degrees of freedom. The transformation, which acts on Hamiltonians that are quadratic in the action variables, combines a rescaling of phase space and a partial elimination of irrelevant (nonresonant) frequencies. It is implemented numerically for the case applying to golden invariant tori. We find a nontrivial fixed point and compute the corresponding scaling and critical indices. If one compares flows to maps in the canonical way, our results are consistent with existing data on the breakup of golden invariant circles for area-preserving maps.

  5. On the breakup of tectonic plates by polar wandering

    NASA Technical Reports Server (NTRS)

    Liu, H.-S.

    1974-01-01

    The equations for the stresses in a homogeneous shell of uniform thickness caused by a shift of the axis of rotation are derived. The magnitude of these stresses reaches a maximum value of the order of 10 to the 9th power dyn/sq cm, which is sufficient for explaining a tectonic breakup. In order to deduce the fracture pattern according to which the breakup of tectonic plates can be expected the theory of plastic deformation of shells is applied. The analysis of this pattern gives an explanation of the existing boundary systems of the major tectonic plates as described by Morgan (1968), LePichon (1968) and Isacks et al. (1968).

  6. On Slater's criterion for the breakup of invariant curves

    NASA Astrophysics Data System (ADS)

    Abud, C. V.; Caldas, I. L.

    2015-07-01

    We numerically explore Slater's theorem in the context of dynamical systems to study the breakup of invariant curves. Slater's theorem states that an irrational translation over a circle returns to an arbitrary interval in at most three different recurrence times expressible by the continued fraction expansion of the related irrational number. The hypothesis considered in this paper is that Slater's theorem can be also verified in the dynamics of invariant curves. Hence, we use Slater's theorem to develop a qualitative and quantitative numerical approach to determine the breakup of invariant curves in the phase space of area-preserving maps.

  7. Social Support, Motivation, and the Process of Juvenile Reentry: An Exploratory Analysis of Desistance

    ERIC Educational Resources Information Center

    Panuccio, Elizabeth A.; Christian, Johnna; Martinez, Damian J.; Sullivan, Mercer L.

    2012-01-01

    Many scholarly works and studies have explored the experience of reentry and desistance for adult offenders, but fewer studies have focused on these processes among juvenile offenders. Using qualitative case studies of juveniles released from secure confinement, this study explores the desistance process during juvenile reentry by examining how…

  8. Balancing Act: The Adaptation of Traditional Judicial Roles in Reentry Court

    ERIC Educational Resources Information Center

    Taylor, Caitlin J.

    2012-01-01

    While research has confirmed their role adaptation and importance in reducing recidivism in drug courts, little research has documented the role of the judge in reentry courts. Based on interviews with participants and the workgroup, court observations, and a document analysis, this study revealed that judges in a federal reentry court program…

  9. Reflections on Reentry after Teaching in China. Occasional Papers in Intercultural Learning, Number 14.

    ERIC Educational Resources Information Center

    Miller, Marcia D.

    The shock of reentry for any sojourner upon returning to their native land may be as great, if not greater, than the initial adjustment period that occurs upon arrival in the foreign country. Intercultural travelers should prepare for the reentry process and the resultant cultural lag upon their return home with the same care that they practiced…

  10. Community-Based Juvenile Reentry Services: The Effects of Service Dosage on Juvenile and Adult Recidivism

    ERIC Educational Resources Information Center

    Abrams, Laura S.; Terry, Diane; Franke, Todd M.

    2011-01-01

    In this study the authors examined the influence of length of participation in a community-based reentry program on the odds of reconviction in the juvenile and adult criminal justice systems. A structured telephone survey of reentry program alumni was conducted with 75 transition-age (18-25 year-old) young men. Binary logistic regression analysis…

  11. Exploring Career Decision-Making Experiences of Mexican American Re-Entry Community College Women

    ERIC Educational Resources Information Center

    Dominguez, Cecilia Sophia

    2010-01-01

    The purpose of this phenomenological investigation was to increase understanding of the career perspectives of 12 Mexican American, re-entry women who were attending a community college. The questions guiding this investigation were: (a) How do Mexican American re-entry college women describe their career decision-making experiences, (b) What do…

  12. Recidivism among Participants of a Reentry Program for Prisoners Released without Supervision

    ERIC Educational Resources Information Center

    Wikoff, Nora; Linhorst, Donald M.; Morani, Nicole

    2012-01-01

    As higher numbers of individuals are released from prison and rejoin society, reentry programs can help former offenders reintegrate into society without continuing to engage in crime. This quasi-experimental study examined whether participation in reentry programming was associated with reduced recidivism among offenders who were no longer under…

  13. Gender Differences in the Perceived Needs and Barriers of Youth Offenders Preparing for Community Reentry

    ERIC Educational Resources Information Center

    Fields, Diane; Abrams, Laura S.

    2010-01-01

    This study explored how gender differences may influence the community reentry experiences of incarcerated youth. Structured surveys assessing risk factors for re-offending, perceived reentry needs, and anticipated barriers to meeting these needs were administered to a convenience sample of males (n = 36) and females (n = 35) who were within 60…

  14. 14 CFR 431.61 - Incorporation of payload reentry determination in license application.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Incorporation of payload reentry determination in license application. 431.61 Section 431.61 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH AND REENTRY OF A REUSABLE LAUNCH VEHICLE (RLV) Payload...

  15. A Randomized Trial of a Multimodal Community-Based Prisoner Reentry Program Emphasizing Substance Abuse Treatment

    ERIC Educational Resources Information Center

    Grommon, Eric; Davidson, William S., II; Bynum, Timothy S.

    2013-01-01

    Prisoner reentry programs continue to be developed and implemented to ease the process of transition into the community and to curtail fiscal pressures. This study describes and provides relapse and recidivism outcome findings related to a randomized trial evaluating a multimodal, community-based reentry program that prioritized substance abuse…

  16. A Cooperative Endeavor for Integrating Re-Entry Adults in a 4-Year University.

    ERIC Educational Resources Information Center

    Rawlins, Melanie E.; Lenihan, Genie O.

    1982-01-01

    Describes a cooperative venture between a counselor educator and a university counseling center in providing a program for reentry adults. Counseling graduate students participated in organizing and conducting workshops for reentry students and providing a noontime information series organized around psychological life adjustment themes.…

  17. Spacecraft For Transport Between The Earth And The Moon

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Sherwood, Brent; Woodcock, Gordon R.

    1995-01-01

    Report proposes development of family of spacecraft for transport between Earth and Moon. Development program oriented toward evolutionary improvements of equipment with minimal redesign of hardware. Intention to develop lineage of spacecraft, designs evolved to adapt to changing requirements and fabricated on long-lived production lines. Conceptual future enhancements include different propulsion systems, transfer habitats, crew cabs, and aerobrakes for reentry to atmoshphere of Earth.

  18. Gender Differences in the Perceived Needs and Barriers of Youth Offenders Preparing for Community Reentry

    PubMed Central

    Abrams, Laura S.

    2010-01-01

    This study explored how gender differences may influence the community reentry experiences of incarcerated youth. Structured surveys assessing risk factors for re-offending, perceived reentry needs, and anticipated barriers to meeting these needs were administered to a convenience sample of males (n = 36) and females (n = 35) who were within 60 days of release from two probation camps in Southern California. Bivariate analyses found significant gender differences in prior risk factors, educational aspirations, expressed mental health needs, anticipated use of services, and reentry concerns. Minimal gender differences were detected in perceived employment needs and barriers and self-efficacy to avoid recidivism. The findings support the need for gender-specific reentry programming in some key areas and also draw attention to the importance of removing barriers to successful reentry for all incarcerated youth. PMID:20730108

  19. Investigations of Control Surface Seals for Re-entry Vehicles

    NASA Technical Reports Server (NTRS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.; DeMange, Jeffrey J.; Rivers, H. Kevin; Hsu, Su-Yuen

    2002-01-01

    Re-entry vehicles generally require control surfaces (e.g., rudders, body flaps) to steer them during flight. Control surface seals are installed along hinge lines and where control surface edges move close to the vehicle body. These seals must operate at high temperatures and limit heat transfer to underlying structures to prevent them from overheating and causing possible loss of vehicle structural integrity. This paper presents results for thermal analyses and mechanical testing conducted on the baseline rudder/fin seal design for the X-38 re-entry vehicle. Exposure of the seals in a compressed state at the predicted peak seal temperature of 1900 F resulted in loss of seal resiliency. The vertical Inconel rudder/fin rub surface was re-designed to account for this loss of resiliency. Room temperature compression tests revealed that seal unit loads and contact pressures were below limits set to protect Shuttle thermal tiles on the horizontal sealing surface. The seals survived an ambient temperature 1000 cycle scrub test over sanded Shuttle tiles and were able to disengage and re-engage the tile edges during testing. Arc jet tests confirmed the need for seals in the rudder/fin gap location because a single seal caused a large temperature drop (delta T = 1710 F) in the gap.

  20. Effect of Counterflow Jet on a Supersonic Reentry Capsule

    NASA Technical Reports Server (NTRS)

    Chang, Chau-Lyan; Venkatachari, Balaji Shankar; Cheng, Gary C.

    2006-01-01

    Recent NASA initiatives for space exploration have reinvigorated research on Apollo-like capsule vehicles. Aerothermodynamic characteristics of these capsule configurations during reentry play a crucial role in the performance and safety of the planetary entry probes and the crew exploration vehicles. At issue are the forebody thermal shield protection and afterbody aeroheating predictions. Due to the lack of flight or wind tunnel measurements at hypersonic speed, design decisions on such vehicles would rely heavily on computational results. Validation of current computational tools against experimental measurement thus becomes one of the most important tasks for general hypersonic research. This paper is focused on time-accurate numerical computations of hypersonic flows over a set of capsule configurations, which employ a counterflow jet to offset the detached bow shock. The accompanying increased shock stand-off distance and modified heat transfer characteristics associated with the counterflow jet may provide guidance for future design of hypersonic reentry capsules. The newly emerged space-time conservation element solution element (CESE) method is used to perform time-accurate, unstructured mesh Navier-Stokes computations for all cases investigated. The results show good agreement between experimental and numerical Schlieren pictures. Surface heat flux and aerodynamic force predictions of the capsule configurations are discussed in detail.

  1. Robust adaptive backstepping control for reentry reusable launch vehicles

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Wu, Zhong; Du, Yijiang

    2016-09-01

    During the reentry process of reusable launch vehicles (RLVs), the large range of flight envelope will not only result in high nonlinearities, strong coupling and fast time-varying characteristics of the attitude dynamics, but also result in great uncertainties in the atmospheric density, aerodynamic coefficients and environmental disturbances, etc. In order to attenuate the effects of these problems on the control performance of the reentry process, a robust adaptive backstepping control (RABC) strategy is proposed for RLV in this paper. This strategy consists of two-loop controllers designed via backstepping method. Both the outer and the inner loop adopt a robust adaptive controller, which can deal with the disturbances and uncertainties by the variable-structure term with the estimation of their bounds. The outer loop can track the desired attitude by the design of virtual control-the desired angular velocity, while the inner one can track the desired angular velocity by the design of control torque. Theoretical analysis indicates that the closed-loop system under the proposed control strategy is globally asymptotically stable. Even if the boundaries of the disturbances and uncertainties are unknown, the attitude can track the desired value accurately. Simulation results of a certain RLV demonstrate the effectiveness of the control strategy.

  2. Investigations of Control Surface Seals for Re-Entry Vehicles

    NASA Astrophysics Data System (ADS)

    Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.; DeMange, Jeffrey J.; Rivers, H. Kevin; Hsu, Su-Yuen

    2002-07-01

    Re-entry vehicles generally require control surfaces (e.g., rudders, body flaps) to steer them during flight. Control surface seals are installed along hinge lines and where control surface edges move close to the vehicle body. These seals must operate at high temperatures and limit heat transfer to underlying structures to prevent them from overheating and causing possible loss of vehicle structural integrity. This paper presents results for thermal analyses and mechanical testing conducted on the baseline rudder/fin seal design for the X-38 re-entry vehicle. Exposure of the seals in a compressed state at the predicted peak seal temperature of 1900 F resulted in loss of seal resiliency. The vertical Inconel rudder/fin rub surface was re-designed to account for this loss of resiliency. Room temperature compression tests revealed that seal unit loads and contact pressures were below limits set to protect Shuttle thermal tiles on the horizontal sealing surface. The seals survived an ambient temperature 1000 cycle scrub test over sanded Shuttle tiles and were able to disengage and re-engage the tile edges during testing. Arc jet tests confirmed the need for seals in the rudder/fin gap location because a single seal caused a large temperature drop (delta T = 1710 F) in the gap.

  3. Atmospheric reentry flight test of winged space vehicle

    NASA Astrophysics Data System (ADS)

    Inatani, Yoshifumi; Akiba, Ryojiro; Hinada, Motoki; Nagatomo, Makoto

    A summary of the atmospheric reentry flight experiment of winged space vehicle is presented. The test was conducted and carried out by the Institute of Space and Astronautical Science (ISAS) in Feb. 1992 in Kagoshima Space Center. It is the first Japanese atmospheric reentry flight of the controlled lifting vehicle. A prime objective of the flight is to demonstrate a high speed atmospheric entry flight capability and high-angle-of-attack flight capability in terms of aerodynamics, flight dynamics and flight control of these kind of vehicles. The launch of the winged vehicle was made by balloon and solid propellant rocket booster which was also the first trial in Japan. The vehicle accomplishes the lfight from space-equivalent condition to the atmospheric flight condition where reaction control system (RCS) attitude stabilization and aerodynamic control was used, respectively. In the flight, the vehicle's attitude was measured by both an inertial measurement unit (IMU) and an air data sensor (ADS) which were employed into an auto-pilot flight control loop. After completion of the entry transient flight, the vehicle experienced unexpected instability during the atmospheric decelerating flight; however, it recovered the attitude orientation and completed the transonic flight after that. The latest analysis shows that it is due to the ADS measurement error and the flight control gain scheduling; what happened was all understood. Some details of the test and the brief summary of the current status of the post flight analysis are presented.

  4. 8 CFR 211.3 - Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Expiration of immigrant visas, reentry... Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551. An immigrant visa... holder embarked or enplaned before the expiration of his or her immigrant visa, reentry permit,...

  5. 8 CFR 211.3 - Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Expiration of immigrant visas, reentry... Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551. An immigrant visa... holder embarked or enplaned before the expiration of his or her immigrant visa, reentry permit,...

  6. Asymptotic and near-target direct breakup of 6Li and 7Li

    NASA Astrophysics Data System (ADS)

    Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

    2016-04-01

    Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

  7. Armor breakup and reformation in a degradational laboratory experiment

    NASA Astrophysics Data System (ADS)

    Orrú, Clara; Blom, Astrid; Uijttewaal, Wim S. J.

    2016-06-01

    Armor breakup and reformation was studied in a laboratory experiment using a trimodal mixture composed of a 1 mm sand fraction and two gravel fractions (6 and 10 mm). The initial bed was characterized by a stepwise downstream fining pattern (trimodal reach) and a downstream sand reach, and the experiment was conducted under conditions without sediment supply. In the initial stage of the experiment an armor formed over the trimodal reach. The formation of the armor under partial transport conditions led to an abrupt spatial transition in the bed slope and in the mean grain size of the bed surface, as such showing similar results to a previous laboratory experiment conducted with a bimodal mixture. The focus of the current analysis is to study the mechanisms of armor breakup. After an increase in flow rate the armor broke up and a new coarser armor quickly formed. The breakup initially induced a bed surface fining due to the exposure of the finer substrate, which was accompanied by a sudden increase in the sediment transport rate, followed by the formation of an armor that was coarser than the initial one. The reformation of the armor was enabled by the supply of coarse material from the upstream degrading reach and the presence of gravel in the original substrate sediment. Here armor breakup and reformation enabled slope adjustment such that the new steady state was closer to normal flow conditions.

  8. 24 CFR 982.315 - Family break-up.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... an occurrence of domestic violence, dating violence, or stalking as provided in 24 CFR part 5... provided in 24 CFR part 5, subpart L, and whether the abuser is still in the household. (5) Other factors... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Family break-up. 982.315...

  9. 24 CFR 982.315 - Family break-up.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... an occurrence of domestic violence, dating violence, or stalking as provided in 24 CFR part 5... provided in 24 CFR part 5, subpart L, and whether the abuser is still in the household. (5) Other factors... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Family break-up. 982.315...

  10. 24 CFR 982.315 - Family break-up.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... an occurrence of domestic violence, dating violence, or stalking as provided in 24 CFR part 5... provided in 24 CFR part 5, subpart L, and whether the abuser is still in the household. (5) Other factors... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Family break-up. 982.315...

  11. 24 CFR 982.315 - Family break-up.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... an occurrence of domestic violence, dating violence, or stalking as provided in 24 CFR part 5... provided in 24 CFR part 5, subpart L, and whether the abuser is still in the household. (5) Other factors... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Family break-up. 982.315...

  12. A Cure for Multipass Beam Breakup in Recirculating Linacs

    SciTech Connect

    Byung C. Yunn

    2004-07-02

    We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.

  13. A METHOD TO CONTROL MULTIPASS BEAM BREAKUP IN RECIRCULATING LINACS

    SciTech Connect

    Byung Yunn

    2003-05-01

    We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.

  14. 24 CFR 982.315 - Family break-up.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Family break-up. 982.315 Section 982.315 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC AND INDIAN HOUSING, DEPARTMENT OF HOUSING AND URBAN...

  15. Drop deformation and breakup in flows with and without shear

    NASA Astrophysics Data System (ADS)

    Kékesi, Tímea; Amberg, Gustav; Prahl Wittberg, Lisa

    2015-11-01

    The deformation and breakup of liquid drops in gaseous flows are studied numerically using the Volume of Fluid method. Fragmentation of fuel drops has a key role in combustion, determining the rate of mixing and the efficiency of the process. It is common to refer to Weber number 12 as the onset of breakup, and to define breakup mode regimes as a function of Weber number. These definitions are established for simple flows and do not take density and viscosity ratios into account. The main objective of this work is the dynamics of the drop leading to breakup. Fully developed uniform flows and flows with various shear rates are considered. A Weber number of 20, Reynolds numbers 20-200, density ratios 20-80, and viscosity ratios 0.5-50 were used. Results for uniform flows are presented in Kékesi T. et al. (2014). The final aim of the project is to extend existing atomization models for fuel sprays by accounting for density and viscosity ratios in addition to the Reynolds and Weber numbers already present in current models. Estimations for the lifetime of the drop are provided; furthermore, the history of the drag coefficient is compared for several cases. Examples of the observed phenomena and ideas for possible model modifications will be presented. This work is supported by the Swedish Research Council and the Linné FLOW Centre.

  16. Breakup of New Orleans Households after Hurricane Katrina

    ERIC Educational Resources Information Center

    Rendall, Michael S.

    2011-01-01

    Theory and evidence on disaster-induced population displacement have focused on individual and population-subgroup characteristics. Less is known about impacts on households. I estimate excess incidence of household breakup resulting from Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads…

  17. Breakup of three particles within the adiabatic expansion method

    NASA Astrophysics Data System (ADS)

    Garrido, E.; Kievsky, A.; Viviani, M.

    2014-07-01

    General expressions for the breakup cross sections in the laboratory frame for 1+2 reactions are given in terms of the hyperspherical adiabatic basis. The three-body wave function is expanded in this basis and the corresponding hyperradial functions are obtained by solving a set of second order differential equations. The S matrix is computed by using two recently derived integral relations. Even though the method is shown to be well suited to describe 1+2 processes, there are particular configurations in the breakup channel (for example, those in which two particles move away close to each other in a relative zero-energy state) that need a huge number of basis states. This pathology manifests itself in the extremely slow convergence of the breakup amplitude in terms of the hyperspherical harmonic basis used to construct the adiabatic channels. To overcome this difficulty the breakup amplitude is extracted from an integral relation as well. For the sake of illustration, we consider neutron-deuteron scattering. The results are compared to the available benchmark calculations.

  18. Application of the Constrained Admissible Region Multiple Hypothesis Filter to Initial Orbit Determination of a Break-up

    NASA Astrophysics Data System (ADS)

    Kelecy, Tom; Shoemaker, Michael; Jah, Moriba

    2013-08-01

    A break-up in Low Earth Orbit (LEO) is simulated for 10 objects having area-to-mass ratios (AMR's) ranging from 0.1-10.0 m2/kg. The Constrained Admissible Region Multiple Hypothesis Filter (CAR-MHF) is applied to determining and characterizing the orbit and atmospheric drag parameters (CdA/m) simultaneously for each of the 10 objects with no a priori orbit or drag information. The results indicate that CAR-MHF shows promise for accurate, unambiguous and autonomous determination of the orbit and drag states.

  19. The role of deep subduction in supercontinent breakup

    NASA Astrophysics Data System (ADS)

    Capitanio, Fabio; Dal Zilio, Luca; Faccenda, Manuele

    2016-04-01

    The breakup of continents is a crucial stage of the episodic aggregation and dispersal of tectonic plates. In particular, the transition from a stable supercontinent to its rifting, breakup and subsequent drifting is one of the least understood aspects of plate tectonics. Over the last decades, several works have highlighted the potential role of pre-existing weaknesses or that of raising mantle plumes in assisting the localization of strain. However, to sustain large-scale divergent regime over geological time, extensional stresses are strictly required. Here we present results from 2-D thermo-mechanical numerical experiments and we show that rifting and drifting of continents result from lithospheric subduction at convergent margins, when this extends to lower mantle depths. We quantify the drag exerted by subduction-induced mantle flow along the basal surface of continental plates, comparing models where lithospheric slabs stagnate above the upper-lower mantle boundary with those where slabs penetrate into the lower mantle. When subduction is upper mantle-confined, divergent basal tractions localize at distances comparable to the effective upper mantle thickness (~500 km), causing the breakup of a microcontinent and opening of a marginal basin. Instead, when the descending lithosphere subducts deeper, extensional stresses localize at greater distances from the trench (≥ 2900 km), are higher and are sustained over a longer time. Although relatively low, basal shear stresses integrated over large plates generate tension forces that may exceed the strength of the continental lithosphere, eventually leading to breakup and opening of an intervening distal basin. The models illustrate that the mechanism leading to the formation of back-arc basins above upper mantle-confined subduction provides a viable explanation for the opening of larger basins above deeper subduction. Examples include the Atlantic Ocean formation and the South and North American plates drifting

  20. GOCE Re-Entry Predictions for the Italian Civil Protection Authorities

    NASA Astrophysics Data System (ADS)

    Pardini, Carmen; Anselmo, Luciano

    2015-03-01

    The uncommon nature of the GOCE reentry campaign, sharing an uncontrolled orbital decay with a finely controlled attitude along the atmospheric drag direction, made the reentry predictions for this satellite an interesting case study, especially because nobody was able to say a priori if and when the attitude control would have failed, leading to an unrestrained tumbling and a sudden variation of the orbital decay rate. As in previous cases, ISTI/CNR was in charge of reentry predictions for the Italian civil protection authorities, monitoring also the satellite decay in the frame of an international reentry campaign promoted by the Inter-Agency Space Debris Coordination Committee (IADC). Due to the peculiar nature of the GOCE reentry, the definition of reliable uncertainty windows was not easy, especially considering the critical use of this information for civil protection evaluations. However, after an initial period of test and analysis, reasonable and conservative criteria were elaborated and applied, with good and consistent results through the end of the reentry campaign. In the last three days of flight, reentries were simulated over Italy to obtain quite accurate ground tracks, debris swaths and air space crossing time windows associated with the critical passes over the national territory still included in the global uncertainty windows.

  1. Reentry Preparedness among Soon-to-be-Released Inmates and the Role of Time Served

    PubMed Central

    Wolff, Nancy; Shi, Jing; Schumann, Brooke E.

    2014-01-01

    Purpose While reentry funding is flowing into states, its target efficiency and effectiveness depends on whether it goes to the right people in the right ways. The purpose of this study was to examine whether and how the amount of time incarcerated affects reentry readiness. Materials and Methods A population-based survey was conducted. Approximately 4000 soon-to-be-released male inmates were drawn from a state correctional system. Readiness is described in terms of feeling ready and material, social, and treatment resources available for reentry by time served on current conviction (episode effect) and since age 18 (cumulative effect). Generalized hierarchical linear models were used to estimate the effects of demographic, criminological, and time served variables on reentry readiness outcomes. Results Reentry vulnerability increased with time served since turning 18 (cumulative effect) but not with time served on the current conviction (episode effect). Inmates serving more than 10 years since turning 18 were at greatest reentry risk. Conclusions The findings indicate that inmates who have served more prison time over their lifetime have more pronounced needs and risks suggesting that reentry funding be targeted towards those who have served more time over the course of their lifetime. PMID:24431474

  2. Similarity between the primary and secondary air-assisted liquid jet breakup mechanisms.

    PubMed

    Wang, Yujie; Im, Kyoung-Su; Fezzaa, Kamel

    2008-04-18

    We report an ultrafast synchrotron x-ray phase-contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. There exist great similarities between the primary (jet) and the secondary (drop) breakup, and in the primary breakup on different length scales. A transition from a ligament- to a membrane-mediated breakup is identified around an effective Weber number We' approximately 13. This observation reveals the critical role an effective Weber number plays in determining the atomization process and strongly supports the cascade breakup model. PMID:18518113

  3. Collision, Coalescence and Breakup of Raindrops. Part I: Experimentally Established Coalescence Efficiencies and Fragment Size Distributions in Breakup.

    NASA Astrophysics Data System (ADS)

    Low, T. B.; List, Roland

    1982-07-01

    The collision, coalescence and breakup of single raindrop pairs were studied at terminal velocities and laboratory pressure (100 kPa) in 761 collision experiments (out of 14 000 attempts). Six size combinations were used with drop pair diameters of [0.18;.0.0395 cm], [0.40; 0.0395 cm], [0.44; 0.0395 cm], [0.18; 0.0715 cm], [0.18; 0.10 cm] and [0.30; 0.10 cm]. For averaging purposes the experiments were repeated over one hundred times for each pair.The new coalescence efficiencies and fragment size distributions in breakup turned out to be consistent with those of McTaggart-Cowan and List (1975b) and permitted the combination of the two data sets into a single data bank spanning essentially the entire range of raindrop sizes.The analysis addressed three main geometric shapes formed by the drops after initial contact, namely, filaments, sheets and disks, and the fragment size distributions after breakup. Significant collisional growth, i.e., coalescence, occurred only when drops <0.06 cm in diameter were struck by larger ones. An empirical equation involving collision kinetic (CKE) and surface tension energies was developed to approximate the observed coalescence efficiencies.Breakup fragment size distributions normally show two or three peaks, one close to the size of the large drop of the collision pair, one at times (for filaments) reflecting the small drop, and the third centered at sizes below the small drop diameter. At high energy collisions involving larger drops the mechanism most favorable for coalescence was the disk shape because with its high deformation it is able to dissipate the most energy either through air drag or by internal viscosity through oscillations. The lowest collision energy for breakup is required for filaments; more is needed for sheets and most for disks.

  4. Seeker multispectral atmospheric reentry technology (SMART) window development

    NASA Astrophysics Data System (ADS)

    Gal, G.; Herman, B.; Morrow, H.; Anderson, W.; Hsu, I.; Stubbs, D.

    1992-05-01

    Seeker Multispectral Atmospheric Reentry Technology (SMART) window development is concerned with the application of innovative technologies to develop an internally cooled window with minimum aperture size for a large field-of-regard (FOR) multispectral seeker installed in an endoatmospheric hypersonic kill vehicle. The window should be very small and lightweight and have a built-in scanner to cover the FOR. The design of such a window requires input from several critical areas, including system requirements, optical design, fabrication of micro-optical components, cooling, optomechanical design, mechanical stress analysis, and flow-field analysis. This paper describes our approach to the development of a SMART window and the current state of our design.

  5. Thermal response of Space Shuttle wing during reentry heating

    NASA Technical Reports Server (NTRS)

    Gong, L.; Ko, W. L.; Quinn, R. D.

    1984-01-01

    A structural performance and resizing (SPAR) finite element thermal analysis computer program was used in the heat transfer analysis of the space shuttle orbiter that was subjected to reentry aerodynamic heatings. One wing segment of the right wing (WS 240) and the whole left wing were selected for the thermal analysis. Results showed that the predicted thermal protection system (TPS) temperatures were in good agreement with the space transportation system, trajectory 5 (STS-5) flight-measured temperatures. In addition, calculated aluminum structural temperatures were in fairly good agreement with the flight data up to the point of touchdown. Results also showed that the internal free convection had a considerable effect on the change of structural temperatures after touchdown.

  6. Thermal response of Space Shuttle wing during reentry heating

    NASA Technical Reports Server (NTRS)

    Gong, L.; Ko, W. L.; Quinn, R. D.

    1984-01-01

    A structural performance and resizing (SPAR) finite element thermal analysis computer program was used in the heat transfer analysis of the Space Shuttle Orbiter that was subjected to reentry aerodynamic heatings. One wing segment of the right wing (WS 240) and the whole left wing were selected for the thermal analysis. Results showed that the predicted thermal protection system (TPS) temperatures were in good agreement with the space transportation system, trajectory 5 (STS-5) flight-measured temperatures. In addition, calculated aluminum structural temperatures were in fairly good agreement with flight data up to the point of touchdown. Results also showed that the internal free convection has a considerable effect on the change of structural temperatures after touchdown.

  7. High-Energy Atmospheric Reentry Test Aerothermodynamic Analysis

    NASA Technical Reports Server (NTRS)

    Mazaheri, Alireza

    2013-01-01

    This paper presents an assessment of the aerothermodynamic environment around an 8.3 meter High Energy Atmospheric Reentry Test (HEART) vehicle. This study generated twelve nose shape configurations and compared their responses at the peak heating trajectory point against the baseline nose shape. The heat flux sensitivity to the angle of attack variations are also discussed. The possibility of a two-piece Thermal Protection System (TPS) design at the nose is also considered, as are the surface catalytic affects of the aeroheating environment of such configuration. Based on these analyses, an optimum nose shape is proposed to minimize the surface heating. A recommendation is also made for a two-piece TPS design, for which the surface catalytic uncertainty associated with the jump in heating at the nose-IAD juncture is reduced by a minimum of 93%. In this paper, the aeroshell is assumed to be rigid and the inflatable fluid interaction effect is left for future investigations

  8. MHD of Aircraft Re-entry: Limits and Perspectives

    SciTech Connect

    Seller, G.; Capitelli, M.; Longo, S.; Armenise, I.; Bruno, D.

    2005-05-16

    In the present work, starting from classical MHD scheme, based on Maxwell equations, Euler fluid dynamic equations and generalised Ohm law, a critical study of fluid dynamics, electromagnetism, chemical and physical behaviour of plasma is carried out, and then a aircraft re-entry MHD numerical scheme is implemented. This scheme is used for MHD calculations in different conditions, in the range of low magnetic force and intermediate electrical conductivity. Initial imposed magnetic fields are uniform, but also some cases with coil generated magnetic fields are considered. Calculations of magnetic field and induced currents are extended also inside the blunt body. Results show interesting physical and electromagnetic effects. Comparison with other methods shows possible development in keeping into account other physical and chemical effects.

  9. A Flight Control Approach for Small Reentry Vehicles

    NASA Technical Reports Server (NTRS)

    Bevacqoa, Tim; Adams, Tony; Zhu. J. Jim; Rao, P. Prabhakara

    2004-01-01

    Flight control of small crew return vehicles during atmospheric reentry will be an important technology in any human space flight mission undertaken in the future. The control system presented in this paper is applicable to small crew return vehicles in which reaction control system (RCS) thrusters are the only actuators available for attitude control. The control system consists of two modules: (i) the attitude controller using the trajectory linearization control (TLC) technique, and (ii) the reaction control system (RCS) control allocation module using a dynamic table-lookup technique. This paper describes the design and implementation of the TLC attitude control and the dynamic table-lookup RCS control allocation for nonimal flight along with design verification test results.

  10. Re-Entry Guidance Using an Energy-State Equation

    NASA Astrophysics Data System (ADS)

    Abe, Akio; Shimada, Yuzo; Uchiyama, Kenji

    This paper presents a new guidance and control system for a re-entry vehicle. In the conventional drag acceleration control system employed for the present space shuttles, the velocity is an unobservable state variable and the associated pole tends to be unstable. Therefore, in this study, a condition which allows all the states to be observable is introduced using a state-space linearization method. It is also shown that energy and its rate are appropriate for the state variables. A guidance law is analytically derived on the basis of the obtained state equation with respect to the energy by solving a two-point boundary-value problem. Furthermore, a tracking control system is designed to make the position, velocity, and flight path angle of the vehicle track the reference states generated in the guidance system. Finally, numerical simulation is performed to verify the validity of the obtained plant expression, and the effectiveness of the proposed guidance and control system.

  11. Space shuttle rendezous, radiation and reentry analysis code

    NASA Technical Reports Server (NTRS)

    Mcglathery, D. M.

    1973-01-01

    A preliminary space shuttle mission design and analysis tool is reported emphasizing versatility, flexibility, and user interaction through the use of a relatively small computer (IBM-7044). The Space Shuttle Rendezvous, Radiation and Reentry Analysis Code is used to perform mission and space radiation environmental analyses for four typical space shuttle missions. Included also is a version of the proposed Apollo/Soyuz rendezvous and docking test mission. Tangential steering circle to circle low-thrust tug orbit raising and the effects of the trapped radiation environment on trajectory shaping due to solar electric power losses are also features of this mission analysis code. The computational results include a parametric study on single impulse versus double impulse deorbiting for relatively low space shuttle orbits as well as some definitive data on the magnetically trapped protons and electrons encountered on a particular mission.

  12. Reentry-F Flowfield Solutions at 80,000 ft.

    NASA Technical Reports Server (NTRS)

    Wood, William A.; Riley, Christopher J.; Cheatwood, F. McNeil

    1997-01-01

    Three equilibrium-air numerical solutions are presented for the Reentry-F flight-test vehicle at Mach 20, 80,000 Ft. conditions, including turbulent flow predictions. The three solutions are from a thin-layer Navier-Stokes code, coupled thin-layer and parabolized Navier-Stokes codes, and an approximate viscous shock-layer code. Boundary-layer and shock-layer profiles are presented and compared between the three solutions, revealing close agreement between the three solution methods. Notable exceptions to the close agreement, with 7-10 percent discrepancies, occur in the density profiles at the boundary-layer edge, in the boundary-layer velocity profiles, and in the shock-layer profiles in regions influenced by the nose bluntness.

  13. Non-intrusive flow measurements on a reentry vehicle

    NASA Technical Reports Server (NTRS)

    Miles, R. B.; Satavicca, D. A.; Zimmermann, G. M.

    1983-01-01

    This study evaluates the utility of various non-intrusive techniques for the measurement of the flow field on the windward side of the Space Shuttle or a similar re-entry vehicle. Included are linear (Rayleigh, Raman, Mie, Laser Doppler Velocimetry, Resonant Doppler Velocimetry) and nonlinear (Coherent Anti-Stokes Raman, Laser Induced Fluorescence) light scattering, electron beam fluorescence, thermal emission and mass spectroscopy. Flow field properties are taken from a nonequilibrium flow model by Shinn, Moss and Simmonds at NASA Langley. Conclusions are, when possible, based on quantitative scaling of known laboratory results to the conditions projected. Detailed discussion with researchers in the field contributed further to these conclusions and provided valuable insights regarding the experimental feasibility of each of the techniques.

  14. Thermal Analysis of Small Re-Entry Probe

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Prabhu, Dinesh K.; Chen, Y. K.

    2012-01-01

    The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test.

  15. Breakup characteristics of a liquid jet in subsonic crossflow

    NASA Astrophysics Data System (ADS)

    Gopala, Yogish

    This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop a better understanding of the spray breakup processes and to provide better experimental inputs to improve the fidelity of numerical models. A review of the literature in this field identified the fundamental physical processes involved in the breakup of the spray and the dependence of spray properties on operating conditions. The time taken for the liquid column to break up into ligaments and droplets, the primary breakup time and the effect of injector geometry on the spray formation processes and spray properties as the key research areas in which research done so far has been inadequate. Determination of the location where the liquid column broke up was made difficult by the presence of a large number of droplets surrounding it. This study utilizes the liquid jet light guiding technique that enables accurate measurements of this location for a wide range of operating conditions. Prior to this study, the primary breakup time was thought to be a function the density ratio of the liquid and the gas, the diameter of the orifice and the air velocity. This study found that the time to breakup of the liquid column depends on the Reynolds number of the liquid jet. This suggests that the breakup of a turbulent liquid jet is influenced by both the aerodynamic breakup processes and the turbulent breakup processes. Observations of the phenomenon of the liquid jet splitting up into two or more jets were made at some operating conditions with the aid of the new visualization technique. Finally, this thesis investigates the effect of injector geometry on spray characteristics. One injector was a round edged orifice with a length to diameter ratio of 1 and a

  16. An Automated Method to Compute Orbital Re-entry Trajectories with Heating Constraints

    NASA Technical Reports Server (NTRS)

    Zimmerman, Curtis; Dukeman, Greg; Hanson, John; Fogle, Frank R. (Technical Monitor)

    2002-01-01

    Determining how to properly manipulate the controls of a re-entering re-usable launch vehicle (RLV) so that it is able to safely return to Earth and land involves the solution of a two-point boundary value problem (TPBVP). This problem, which can be quite difficult, is traditionally solved on the ground prior to flight. If necessary, a nearly unlimited amount of time is available to find the 'best' solution using a variety of trajectory design and optimization tools. The role of entry guidance during flight is to follow the pre- determined reference solution while correcting for any errors encountered along the way. This guidance method is both highly reliable and very efficient in terms of onboard computer resources. There is a growing interest in a style of entry guidance that places the responsibility of solving the TPBVP in the actual entry guidance flight software. Here there is very limited computer time. The powerful, but finicky, mathematical tools used by trajectory designers on the ground cannot in general be converted to do the job. Non-convergence or slow convergence can result in disaster. The challenges of designing such an algorithm are numerous and difficult. Yet the payoff (in the form of decreased operational costs and increased safety) can be substantiaL This paper presents an algorithm that incorporates features of both types of guidance strategies. It takes an initial RLV orbital re-entry state and finds a trajectory that will safely transport the vehicle to Earth. During actual flight, the computed trajectory is used as the reference to be flown by a more traditional guidance method.

  17. Landing Characteristics of a Lenticular-Shaped Reentry Vehicle

    NASA Technical Reports Server (NTRS)

    Blanchard, Ulysse J.

    1961-01-01

    An experimental investigation was made of the landing characteristics of a 1/9-scale dynamic model of a lenticular-shaped reentry vehicle having extendible tail panels for control after reentry and for landing control (flare-out). The landing tests were made by catapulting a free model onto a hard-surface runway and onto water. A "belly-landing" technique in which the vehicle was caused to skid and rock on its curved undersurface (heat shield), converting sinking speed into angular energy, was investigated on a hard-surface runway. Landings were made in calm water and in waves both with and without auxiliary landing devices. Landing motions and acceleration data were obtained over a range of landing attitudes and initial sinking speeds during hard-surface landings and for several wave conditions during water landings. A few vertical landings (parachute letdown) were made in calm water. The hard-surface landing characteristics were good. Maximum landing accelerations on a hard surface were 5g and 18 radians per sq second over a range of landing conditions. Horizontal landings on water resulted in large violent rebounds and some diving in waves. Extreme attitude changes during rebound at initial impact made the attitude of subsequent impact random. Maximum accelerations for water landings were approximately 21g and 145 radians per sq second in waves 7 feet high. Various auxiliary water-landing devices produced no practical improvement in behavior. Reduction of horizontal speed and positive control of impact attitude did improve performance in calm water. During vertical landings in calm water maximum accelerations of 15g and 110 radians per sq second were measured for a contact attitude of -45 deg and a vertical velocity of 70 feet per second.

  18. Reusable Reentry Satellite (RRS): Propulsion system trade study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The purpose of the Reusable Reentry Satellite (RRS) Propulsion System Trade Study described in this summary report was to investigate various propulsion options available for incorporation on the RRS and to select the option best suited for RRS application. The design requirements for the RRS propulsion system were driven by the total impulse requirements necessary to operate within the performance envelope specified in the RRS System Requirements Documents. These requirements were incorporated within the Design Reference Missions (DRM's) identified for use in this and other subsystem trade studies. This study investigated the following propulsion systems: solid rocket, monopropellant, bipropellant (monomethyl hydrazine and nitrogen tetroxide or MMH/NTO), dual-mode bipropellant (hydrazine and nitrogen tetroxide or N2H4/NTO), liquid oxygen and liquid hydrogen (LO2/LH2), and an advanced design propulsion system using SDI-developed components. A liquid monopropellant blowdown propulsion system was found to be best suited for meeting the RRS requirements and is recommended as the baseline system. This system was chosen because it is the simplest of all investigated, has the fewest components, and is the most cost effective. The monopropellant system meets all RRS performance requirements and has the capability to provide a very accurate deorbit burn which minimizes reentry dispersions. In addition, no new hardware qualification is required for a monopropellant system. Although the bipropellant systems offered some weight savings capability for missions requiring large deorbit velocities, the advantage of a lower mass system only applies if the total vehicle design can be reduced to allow a cheaper launch vehicle to be used. At the time of this trade study, the overall RRS weight budget and launch vehicle selection were not being driven by the propulsion system selection. Thus, the added cost and complexity of more advanced systems did not warrant application.

  19. CARINA - A space vehicle with re-entry capabilities for microgravity experiments

    NASA Astrophysics Data System (ADS)

    Borriello, G.; Sansone, A.; Ricciardi, A.

    1992-08-01

    An Italian autonomous space vehicle with recovery capabilities, named CARINA (Capsula di Rientro Non Abitata), is described with special attention given to the technological developments in areas pertaining to the reentry system, including reentry aerothermodynamics and the design of the thermal protection system. Consideration is also given to the configuration of the CARINA vehicle (comprised of the expendable Service Module and the Apollo-like Reentry Module), the subsystems and their performances, the mission life cycle, the microgravity utilization aspects, and the programmatic aspects.

  20. NASA Upper Atmosphere Research Satellite (UARS) Re-Entry Prediction and Analysis

    NASA Technical Reports Server (NTRS)

    Stansbery, Eugene; Johnson, Nick L.

    2012-01-01

    No NASA or USG human casualty reentry risk limits existed when UARS was designed, built, and launched. Time of reentry estimates were within normal limits NASA, the USG, and some foreign space agencies now seek to limit human casualty risks from reentering space objects to less than 1 in 10,000. UARS was a moderate-sized space object. Uncontrolled reentries of objects more massive than UARS are not frequent, but neither are they unusual. Since the beginning of the space age, there has been no confirmed report of an injury resulting from reentering space objects.

  1. Model for oxygen recombination on silicon-dioxide surfaces. II - Implications toward reentry heating

    NASA Technical Reports Server (NTRS)

    Jumper, E. J.; Seward, W. A.

    1992-01-01

    This paper briefly reviews the model for recombination of oxygen on a silicon-dioxide surface presented in detail in a previous paper. New data supporting the model is also presented. The ramifications of the model toward the production of excited molecular oxygen is examined as it pertains to surface heating. A reentry simulation is given and compared to STS-2 reentry data, and conclusions are drawn as to the implications of the recombination model toward reentry heating. A possible buffering of the heating above a critical temperature associated with the physics of the model is also discussed.

  2. Mechanisms and systematics of breakup in reactions of {sup 9}Be at near-barrier energies

    SciTech Connect

    Rafiei, R.; Rietz, R. du; Luong, D. H.; Hinde, D. J.; Dasgupta, M.; Evers, M.; Diaz-Torres, A.

    2010-02-15

    Below-barrier no-capture breakup measurements of the weakly bound {sup 9}Be nucleus, incident on targets ranging in atomic number from 62 to 83, have been carried out using a large-area high-resolution back-angle detector array. It is shown that the three-body reconstructed reaction Q-value and relative energy of the breakup fragments together reveal the full dynamics of the breakup mechanism, identifying all physical processes that lead to the breakup of the projectile-like nucleus. Contrasting with the simple expectation of direct breakup into the most energetically favored clusters, the data show that breakup following n-transfer dominates the total breakup yield. Breakup from long-lived states in the projectile-like nucleus, which on the reaction time scale may be considered stable, has been isolated from the prompt breakup yield. It has been shown that the prompt breakup probability essentially depends on the surface separation of the interacting nuclei. The measured prompt breakup probability functions for each target have been used together with a classical trajectory model to predict the above-barrier suppression of complete fusion. The suppression factor, expressed as the fraction of incomplete fusion, is nearly independent of target charge.

  3. Recent results of invariant torus breakup in nontwist maps

    NASA Astrophysics Data System (ADS)

    Wurm, Alexander; Fuchss, Kathrin; Morrison, P. J.

    2006-10-01

    As simple models for degenerate Hamiltonian systems, nontwist maps have been used to describe, e.g., magnetic field lines in toroidal plasma devices with reversed magnetic shear profiles. Of particular interest in these maps are the so-called shearless invariant tori which correspond to transport barries in the physical system. We investigate the breakup of shearless tori in several maps and with several different winding numbers, in order to understand the dependence of the details of the breakup on the winding number and on the symmetries of the map model. Here we report on recent results of this investigation.[1][1] K. Fuchss, A. Wurm, A. Apte, and P.J. Morrison, to appear in Chaos (2006); K. Fuchss, A. Wurm, and P.J. Morrison, preprint/submitted to PRL (2006).

  4. Elastic breakup cross sections of well-bound nucleons

    NASA Astrophysics Data System (ADS)

    Wimmer, K.; Bazin, D.; Gade, A.; Tostevin, J. A.; Baugher, T.; Chajecki, Z.; Coupland, D.; Famiano, M. A.; Ghosh, T. K.; Grinyer, G. F.; Howard, M. E.; Kilburn, M.; Lynch, W. G.; Manning, B.; Meierbachtol, K.; Quarterman, P.; Ratkiewicz, A.; Sanetullaev, A.; Showalter, R. H.; Stroberg, S. R.; Tsang, M. B.; Weisshaar, D.; Winkelbauer, J.; Winkler, R.; Youngs, M.

    2014-12-01

    The 9Be(28Mg,27Na ) one-proton removal reaction with a large proton separation energy of Sp(28Mg ) =16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the removal of more weakly bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

  5. Core transitions in the breakup of exotic nuclei

    NASA Astrophysics Data System (ADS)

    Summers, N. C.; Nunes, F. M.; Thompson, I. J.

    2006-03-01

    An interesting physical process has been unveiled: Dynamical core excitation during a breakup reaction of loosely bound core+N systems. These reactions are typically used to extract spectroscopic information and/or astrophysical information. A new method, the eXtended Continuum Discretized Coupled Channel (XCDCC) method, was developed to incorporate, in a consistent way and to all orders, core excitation in the bound and scattering states of the projectile, as well as dynamical excitation of the core as it interacts with the target. The model predicts cross sections to specific states of the core. It is applied to the breakup of Be11 on Be9 at 60 MeV/nucleon, and the calculated cross sections are in improved agreement with the data. The distribution of the cross section amongst the various core states is shown to depend on the reaction model used, and not simply on the ground state spectroscopic factors.

  6. High Energy Break-Up of Few-Nucleon Systems

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak

    2008-03-01

    We discus recent developments in theory of high energy two-body break-up reactions of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model (HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon by the outgoing two nucleons. Within HRM we discuss hard break-up reactions involving 2D and 3He targets. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

  7. Study of transfer and breakup reactions with the plastic box

    SciTech Connect

    Stokstad, R.G.; Albiston, C.R.; Bantel, M.; Chan, Y.; Countryman, P.J.; Gazes, S.; Harvey, B.G.; Homeyer, H.; Murphy, M.J.; Tserruya, I.

    1984-12-01

    The study of transfer reactions with heavy-ion projectiles is complicated by the frequent presence of three or more nuclei in the final state. One prolific source of three-body reactions is the production of a primary ejectile in an excited state above a particle threshold. A subset of transfer reactions, viz., those producing ejectiles in bound states, can be identified experimentally. This has been accomplished with a 4..pi.. detector constructed of one-millimeter-thick scintillator paddles of dimension 20 cm x 20 cm. The paddles are arranged in the form of a cube centered around the target with small entrance and exit apertures for the beam and the projectile-like fragments, (PLF). The detection of a light particle (e.g., a proton or an alpha particle) in coincidence with a PLF indicates a breakup reaction. The absence of any such coincidence indicates a reaction in which all the charge lost by the projectile was transferred to the target. With this technique we have studied the transfer and breakup reactions induced by 220 and 341 MeV /sup 20/Ne ions on a gold target. Ejectiles from Li to Ne have been measured at several scattering angles. The absolute cross sections, angular distributions and energy spectra for the transfer and breakup reactions are presented. Relatively large cross sections are observed for the complete transfer of up to seven units of charge (i.e., a nitrogen nucleus). The relatively large probabilities for ejectiles to be produced in particle-bound states suggest that on the average, most of the excitation energy in a collision resides in the heavy fragment when mass is transferred from the lighter to the heavier fragment. The gross features and trends in the energy spectra for transfer and breakup reactions are similar. 20 references.

  8. Radial electron-beam-breakup transit-time oscillator

    SciTech Connect

    Mostrom, M.A.; Kwan, T.J.T.

    1995-01-01

    A new radially-driven electron-beam-breakup transit-time oscillator has been investigated analytically and through computer simulation as a compact low-impedance high-power microwave generator. In a 1MV, 50kA device 35cm in radius and 15cm long, with no external magnetic field, 5GW of extracted power and a growth rate of 0.26/ns have been observed. Theoretical maximum efficiencies are several times higher.

  9. The Effect of Crustal Strength on Volcanism During Continental Breakup

    NASA Astrophysics Data System (ADS)

    Armitage, J. J.; Petersen, K. D.; Perez-Gussinye, M.; Collier, J.; Pik, R.

    2015-12-01

    Segmentation is a fundamental property of rifted margins which is thought to be inherited from pre-breakup lithospheric structure. The volume of melt emplaced during rifting typically varies across these segments. Notable examples are the Gulf of California, break-up in the South Atlantic, and the Afar depression. For example in Afar there is a clear north south transition from break-up in the Erta Ale segment, where there is localised young (<1 Ma) volcanism, to the Dabbahu segment where there is the 4-1 Ma Stratoid volcanic series and distributed faulting. Along the Namibian and conjugate Argentinian margin there is evidence that surface area of seaward dipping reflectors change across segments. Such lateral changes in volcanism over a relatively short spatial scale are hard to explain by change in mantle temperature. We will demonstrate that crustal strength places a crucial control on the volume and composition of melt generated during break-up. We have compared models of extension with a weaker and strong lower crust based on observed rock rheologies. Melt composition and volume is found to be a function of the lower crustal rheology as it effects the shape of the melt zone during extension. By comparing a suite models we find that Afar volcanism can be matched by models with both a weak or strong lower crust. If however the crust is weaker then the equivalent volume and composition is created with less crustal thinning but over a greater period of time. The difference in time required to generate significant volcanic rock may explain the change in surface area of sub-areal volcanism in both Afar, where there is a transition of strong to weak crust from Erta Ale to Dabbahu, and off-shore Namibia. Lateral variation in volcanism between segments may therefore be fundamentally controlled by the crust.

  10. JET BREAKUP AND SPRAY FORMATION IN A DIESEL ENGINE.

    SciTech Connect

    GLIMM,J.; LI,X.; KIM,M.N.; OH,W.; MARCHESE,A.; SAMULYAK,R.; TZANOS,C.

    2003-06-17

    The breakup of injected fuel into spray is of key interest to the design of a fuel efficient, nonpolluting diesel engine. We report preliminary progress on the numerical simulation of diesel fuel injection spray with the front tracking code FronTier. Our simulation design is set to match experiments at ANL, and our present agreement is semi-quantitative. Future efforts will include mesh refinement studies, which will better model the turbulent flow.

  11. The Soviet Breakup and U.S. Foreign Policy.

    ERIC Educational Resources Information Center

    Lynch, Allen

    1991-01-01

    This issue of a quarterly publication on world affairs explores the historical significance of the disintegration of the Soviet Union and the implication for U.S. foreign policy. With the breakup of the USSR in 1990-91, Russia for the first time this century does not have control over the non-Russian nations of its former empire in Central Asia,…

  12. Breakup modes of fluid drops in confined shear flows

    NASA Astrophysics Data System (ADS)

    Barai, Nilkamal; Mandal, Nibir

    2016-07-01

    Using a conservative level set method we investigate the deformation behavior of isolated spherical fluid drops in a fluid channel subjected to simple shear flows, accounting the following three non-dimensional parameters: (1) degree of confinement (Wc = 2a/h, where a is the drop radius and h is the channel thickness); (2) viscosity ratio between the two fluids (λ = μd/μm, where μd is the drop viscosity and μm is the matrix viscosity); and (3) capillary number (Ca). For a given Wc, a drop steadily deforms to attain a stable geometry (Taylor number and inclination of its long axis to the shear direction) when Ca < 0.3. For Ca > 0.3, the deformation behavior turns to be unsteady, leading to oscillatory variations of both its shape and orientation with progressive shear. This kind of unsteady deformation also occurs in a condition of high viscosity ratios (λ > 2). Here we present a detailed parametric analysis of the drop geometry with increasing shear as a function of Wc, Ca, and λ. Under a threshold condition, deforming drops become unstable, resulting in their breakup into smaller droplets. We recognize three principal modes of breakup: Mode I (mid-point pinching), Mode II (edge breakup), and Mode III (homogeneous breakup). Each of these modes is shown to be most effective in the specific field defined by Ca and λ. Our study also demonstrates the role of channel confinement (Wc) in controlling the transition of Mode I to III. Finally, we discuss implications of the three modes in determining characteristic drop size distributions in multiphase flows.

  13. Dynamics of Cold-Air Pool Breakup: Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Lareau, N.; Horel, J.

    2013-12-01

    Persistent cold-air pools (CAPs) impact urban mountain valleys during the winter leading to prolonged episodes of unhealthy air quality. One associated scientific challenge is accurately forecasting the breakup of these CAPs. For example, there is often uncertainty regarding the interaction of passing weather systems with the stratification within a valley. Will the disturbance be sufficient to destroy the CAP, or will the CAP persist for many more days bringing continued elevated levels of pollution? To address these questions this study examines the dynamical processes that affect the time scale and character of CAP breakup. To do so we use idealized large eddy simulations (LES) to examine the sensitivity of CAP removal to variations in wind, topography, and stratification. The simulations are based on field observations from the Persistent Cold-Air Pool Study (PCAPS). Results indicate that the upstream terrain-flow interaction is important in controlling both the timescale and structure of the CAP breakup. For example, when the flow plunges over the confining topography it leads to enhanced turbulent mixing, CAP displacement, and shorter timescales for complete CAP removal. In contrast, when no mountain wave is present the upstream edge of the CAP remains sheltered from the wind-driven mixing and the break-up is first observed over downstream portions of the basin. Meanwhile, changes in the CAP stratification impact internal circulations that develop in response to the imposed wind forcing. These circulations have significance for the distribution of pollution within CAPs. A concise summary of these results will be presented. Snapshot from a simulation of strong winds disrupting a CAP confined between two ridges. Potential temperature (a), vertical velocity (b), and wind speed (c).

  14. Pedagogy of Individual Choice and Female Inmate Reentry in the U.S. Southwest

    PubMed Central

    Kellett, Nicole Coffey; Willging, Cathleen Elizabeth

    2011-01-01

    Much of the mental health, substance use, and educational programming within a particular women’s prison in the southwestern United States promotes individual choice and agency. Incarcerated women from rural areas are told that their ability to succeed outside prison is primarily dependent upon their personal choices. Comparably little attention is given to preparing women for their upcoming release or to overcoming structural barriers that could undermine successful reentry within rural communities. As a result, these returning citizens, many of whom grapple with mental illness and alcohol or drug dependence, blame themselves for their inability to surmount these barriers. In this qualitative research, we draw upon the perspectives of 99 incarcerated women to clarify how ideologies of individual choice promulgated in reentry pedagogy clash with contextual factors within rural communities to derail the reentry process. We also consider community reentry from Amartya Sen’s capabilities framework and discuss how this model could inform needed interventions. PMID:21864909

  15. Segment Specification for the Payload Segment of the Reusable Reentry Satellite: Rodent Module Version

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

  16. The Reentry Adult College Student: An Exploration of the Black Male Experience

    ERIC Educational Resources Information Center

    Rosser-Mims, Dionne; Palmer, Glenn A.; Harroff, Pamela

    2014-01-01

    This chapter shares findings from a qualitative study on reentry adult Black males' postsecondary education experiences and identifies strategies to help this population matriculate through college and graduate.

  17. Assessment of the on-ground risk during re-entries

    NASA Astrophysics Data System (ADS)

    Klinkrad, H.

    2001-10-01

    The present paper outlines methods which allow to quantify and monitor the on-ground population risk in the course of a hazardous re-entry event. The risk potential will be derived from an object related casualty cross-section, the endangered ground swath, and the underlying population density. Means will be described to perform a long-term risk assessment for a given latitude band, and a short-term risk assessment for a given nodal longitude of the final re-entry orbit. In case of residual manoeuvring capabilities strategies will be outlined to manage and reduce the risk potential by controlling the nodal longitude of the final orbit, and the impact footprint. The usefulness of these concepts will be demonstrated for the historic re-entries of Skylab and Salyut-7, and for the recent re-entry of the Mir space station.

  18. Mechanisms of Familial Influence on Reentry among Formerly Incarcerated Latino Men.

    PubMed

    Lee, Jane Jean-Hee; Guilamo-Ramos, Vincent; Muñoz-Laboy, Miguel; Lotz, Kevin; Bornheimer, Lindsay

    2016-07-01

    In the United States more than 10,000 people are released from state and federal prisons every week and often reenter the communities in which they were arrested. Formerly incarcerated individuals face considerable challenges to securing employment and housing. Subsequently, approximately two-thirds of former prisoners are rearrested within three years of their release. Latino men represent the fastest growing ethnic group of prisoners in the United States with unique cultural and social needs during the reentry process. The present study examined the role of the family in the reentry process through in-depth interviews (N = 16) with formerly incarcerated Latino men (FILM). The authors sought to identify familial processes specific to Latino men with potential to affect engagement and participation in reentry programs. Findings suggest that family mechanisms of social control and social support influence FILM's reentry. Social work practitioners who work with this growing population can engage familial processes to prevent recidivism and promote desistance. PMID:27501637

  19. Segment specification for the payload segment of the reusable reentry satellite: Rodent module version

    NASA Astrophysics Data System (ADS)

    1991-02-01

    The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

  20. Low-Subsonic-Speed Static Longitudinal Stability and Control Characteristics of a Winged Reentry-Vehicle Configuration Having Wingtip Panels that Fold up for High-Drag Reentry

    NASA Technical Reports Server (NTRS)

    Ware, George M.

    1960-01-01

    An investigation of the low-subsonic-speed static longitudinal stability and control characteristics of a model of a manned reentry-vehicle configuration capable of high-drag reentry and glide landing has been a made in the Langley free-flight tunnel. The model had a modified 63 deg delta plan-form wing with a fuselage on the upper surface. This configuration had wingtip panels designed to fold up 90 deg for the high-drag reentry phase of the flight and to extend horizontally for the glide landing. Data for the basic configurations and modifications to determine the effects of plan form, wingtip panel incidence, dihedral, and vertical position of the wingtip panels are presented without analysis.

  1. The Breakup of Water Cylinders Behind Normal Shocks

    NASA Astrophysics Data System (ADS)

    Meng, J. C.; Colonius, T.

    2012-11-01

    We simulate the drift and breakup of a water cylinder in the flow behind a normal shock. The unsteady Euler equations, closed using the stiffened-gas equation of state, are solved with a compressible, multicomponent, shock- and interface-capturing algorithm. The effects of surface tension and viscosity are negligible at early times compared to the larger shear forces. Computed drift velocities are in good agreement with experiments. For the high- speed flow regimes considered, the breakup mode is stripping. Pressure gradients arise on the cylinder's surface causing it to deform laterally. As the cylinder is flattened, sheets of liquid are drawn off the periphery and break up further downstream. Unsteady vortex shedding is observed in the wake of the disintegrating cylinder. As the shock Mach number is increased, higher airflow velocities result in faster breakup and greater cylinder accelerations. These accelerations are subject to fluctuations that grow with shock strength. Qualitative features of the flow are compared to images from experiments on cylinders and drops.

  2. Transverse liquid fuel jet breakup, burning, and ignition

    SciTech Connect

    Li, H.

    1990-12-31

    An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

  3. Transverse liquid fuel jet breakup, burning, and ignition

    SciTech Connect

    Li, H.

    1990-01-01

    An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

  4. The breakup of thin air films caught under impacting drops

    NASA Astrophysics Data System (ADS)

    Thoroddsen, Sigurdur; Thoraval, Marie-Jean; Takehara, Kohsei; Etoh, T. Goji

    2012-11-01

    When a drop impacts a pool at very low velocities V, an air layer cushions the impact and prevents immediate contact. This air layer is stretched into a hemispheric shape and thins to a submicron thickness. We use silicone oils, where these films are more stable than for water [Saylor & Bounds (2012), AIChE J., online: doi 10.1002/aic.13764 ]. We observe three main breakup mechanisms which are imprinted onto the micro-bubble morphology. First, for lowest V the film ruptures at isolated holes which grow rapidly, leaving bubble necklaces where their edges meet. Based on micro-bubble volumes, we show the film breaks by van der Waals, when its thickness ~ 100 nm. Secondly, for slightly larger V a ring of holes appearing a fixed depth, where the film is thinnest, producing bubble chandeliers. Finally, for larger V an air jet within the drop, ruptures it at the bottom tip, in an axisymmetric breakup. We measure the rupture speed and find that for very viscous liquids, the breakup moves faster than the capillary-viscous velocity, through the repeated ruptures. [Thoroddsen, Thoraval, Takehara & Etoh (2012), J. Fluid Mech. online: doi:10.1017/jfm.2012.319].

  5. Droplet Breakup and Other Problems Involving Surface Tension Driven Flows.

    NASA Astrophysics Data System (ADS)

    Brenner, Michael P.

    We explore several problems involving fluid flows driven by surface tension. The first part of the thesis concerns droplet breakup. The major focus is on the formation of singularities occurring when a mass of fluid breaks into two pieces. We explore this phenomena in many different physical situations, including droplet breakup in a Hele Shaw cell, rupturing of thin films on a solid surface, the breaking of Plateau borders in soap froths, and fluid dripping from a cylindrical nozzle. In most of the above examples the singularities are characterized by self similar solutions of nonlinear partial differential equations. For the dripping faucet, the similarity solution is unstable to finite (but small) amplitude perturbations; the consequence of this is that in practice the breakup of a three dimensional droplet is a nonsteady process, with new structures continually generated as the interface breaks. Through asymptotic analysis, we show that the amount of noise necessary to destabilize the similarity solution decreases rapidly as the singularity is approached. For fluids of moderate viscosity fluctuations in the interfacial shape of atomic size are sufficient to destabilize the interface when the thickness is less than one micron. The second part of the thesis addresses problems in wetting. We present an analysis of a droplet spreading on a solid surface, which results in an understanding of the experimentally observed spreading laws. Finally, we present an explanation of the mechanism for the instability that occurs when a contact line is driven by a constant force. The explanation is consistent with recent experimental data.

  6. Coalescence and breakup of large droplets in turbulent channel flow

    NASA Astrophysics Data System (ADS)

    Scarbolo, Luca; Bianco, Federico; Soldati, Alfredo

    2015-07-01

    Coalescence and breakup of large deformable droplets dispersed in a wall-bounded turbulent flow are investigated. Droplets much larger than the Kolmogorov length scale and characterized by a broad range of surface tension values are considered. The turbulent field is a channel flow computed with pseudo-spectral direct numerical simulations, while phase interactions are described with a phase field model. Within this physically consistent framework, the motion of the interfaces, the capillary effects, and the complex topological changes experienced by the droplets are simulated in detail. An oil-water emulsion is mimicked: the fluids are considered of same density and viscosity for a range of plausible values of surface tension, resulting in a simplified system that sets a benchmark for further analysis. In the present conditions, the Weber number (We), that is, the ratio between inertia and surface tension, is a primary factor for determining the droplets coalescence rate and the occurrence of breakups. Depending on the value of We, two different regimes are observed: when We is smaller than a threshold value (We < 1 in our simulations), coalescence dominates until droplet-droplet interactions are prevented by geometric separation; when We is larger than the threshold value (We > 1), a permanent dynamic equilibrium between coalescence and breakup events is established.

  7. Hard breakup of the deuteron into two Δ -isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos; Sargsian, Misak

    2011-04-01

    Photodisintegration of the deuteron into two Δ-isobars at large center of mass angles is studied within the QCD hard rescattering model (HRM). According to the HRM, the reaction proceeds in three main steps: the photon knocks the quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons emerging at large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn --> ΔΔ scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. We predict that the cross section of the deuteron breakup to Δ++Δ- is 4-5 times larger than that of the breakup to the Δ+Δ0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard Δ-isobars are the result of the disintegration of initial ΔΔ components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both Δ++Δ- and Δ+Δ0 channels are expected to be similar. This work was supported by U.S. Department of Energy Grant under contract DE-FG02-01ER41172, and by the FIU DEA program.

  8. Hard breakup of the deuteron into two Δ isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos G.; Sargsian, Misak M.

    2011-05-01

    We study high-energy photodisintegration of the deuteron into two Δ isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn→ΔΔ scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn→ΔΔ scattering. We predict that the cross section of the deuteron breakup to Δ++Δ- is 4-5 times larger than that of the breakup to the Δ+Δ0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard Δ isobars are the result of the disintegration of the preexisting ΔΔ components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both Δ++Δ- and Δ+Δ0 channels to be similar.

  9. Breakup of the Bell monopoly: Lessons for electric utilities

    SciTech Connect

    Piepmeier, J.M. ); Jermain, D.O. ); Egnor, T.L. )

    1993-07-01

    Technological change, not regulatory change, was the prime mover behind the Bell breakup. Now, for the first time, technology threatens to recast the economic structure of the electric utility industry as well. Previous analyses of the restructuring of the telecommunications industry, as represented by the 1984 breakup of the Bell monopoly, focus on regulatory change as the precipitator and principal agent. Technology is recognized as an important factor but not the primary trigger. This view confounds the roles of the independent and dependent variables in the economic system. The mistake is more than misperception of a single, isolated event that is now over and done with; it is fundamental and it must be corrected in order to understand the implications that restructuring holds for electric utility monopolies. Technology, not regulation, was the primary trigger in the Bell System breakup. Technology acted as a virus, infecting the monopoly economics of telecommunications and in turn driving a complete transformation of that industry. Regulatory change was the consequence, not the cause.

  10. Beam breakup calculations for the second axis of DARHT

    SciTech Connect

    Fawley, William M.; Chen, Y.-J.; Houck, T.L.

    1999-08-20

    The accelerator for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility will produce a 4-kA, 20-MeV, 2-{micro}s output electron beam with a design goal of less than 1000 {pi} mm-mrad normalized transverse emittance and less than 0.5-mm beam centroid motion. In order to meet this goal, the beam transport must have excellent optics and the beam breakup instability (BBU) must be limited in growth. Using a number of simulation codes such as AMOS and BREAKUP, we have modeled the transverse impedances of the DARHT-II accelerator cells and the electron beam response to different transverse excitations such as injector RF noise, magnetic dipole fields arising from the 90-degree bend between the cathode stalk and insulator column, and downstream solenoid alignment errors. The very low Q ({approx}2) predicted for the most important TM dipole modes has prompted us to extend the BREAKUP code to be able to use the dipole wakefields calculated by AMOS in addition to the most usual discrete frequency BBU mode model. We present results for the predicted BBU growth and the empirical sensitivity to various machine parameters.

  11. Nonlinear dynamics and breakup of free-surface flows

    SciTech Connect

    Eggers, J.

    1997-07-01

    Surface-tension-driven flows and, in particular, their tendency to decay spontaneously into drops have long fascinated naturalists, the earliest systematic experiments dating back to the beginning of the 19th century. Linear stability theory governs the onset of breakup and was developed by Rayleigh, Plateau, and Maxwell. However, only recently has attention turned to the nonlinear behavior in the vicinity of the singular point where a drop separates. The increased attention is due to a number of recent and increasingly refined experiments, as well as to a host of technological applications, ranging from printing to mixing and fiber spinning. The description of drop separation becomes possible because jet motion turns out to be effectively governed by one-dimensional equations, which still contain most of the richness of the original dynamics. In addition, an attraction for physicists lies in the fact that the separation singularity is governed by universal scaling laws, which constitute an asymptotic solution of the Navier-Stokes equation before and after breakup. The Navier-Stokes equation is thus continued uniquely through the singularity. At high viscosities, a series of noise-driven instabilities has been observed, which are a nested superposition of singularities of the same universal form. At low viscosities, there is rich scaling behavior in addition to aesthetically pleasing breakup patterns driven by capillary waves. The author reviews the theoretical development of this field alongside recent experimental work, and outlines unsolved problems. {copyright} {ital 1997} {ital The American Physical Society}

  12. FEM calculations of drop breakup beyond the first singularity

    NASA Astrophysics Data System (ADS)

    Suryo, Ronald; Basaran, Osman

    2007-11-01

    Computational analysis of drop breakup, which is of common occurrence in nature and technology, is important for advancing understanding of pinch-off singularities and developing new technologies. During drop formation from a tube, as more liquid flows from the tube into the drop, the drop elongates and thins. At the incipience of breakup, a spherical mass -- the precursor of the primary drop -- is connected to the liquid in the tube by a thin thread -- the precursor of one or more satellites. Numerical algorithms for analyzing this phenomenon at finite Reynolds number have been of two types: ones based on finite element methods (FEMs) and others based on various diffuse interface (DI) techniques. Numerical solutions must agree with scaling solutions of interface pinch-off, which are exact solutions of the nonlinear Navier-Stokes equations, and experiments. To date, the DI approach, despite its coarseness, has been more popular because it is simple and can predict the formation of several drops in sequence. Predictions made with FEM algorithms have been shown to be in excellent agreement with scaling theories and measurements but only until the instant of first breakup. Here we describe new FEM computations of unparalleled accuracy to predict the dynamics of continuous drop formation and support them with high-speed visualization experiments.

  13. Breakup length of harmonically stimulated capillary jets - theory and experiments

    NASA Astrophysics Data System (ADS)

    Garcia Garcia, Francisco Javier; Gonzalez Garcia, Heliodoro; Castrejon-Pita, Jose Rafael; Castrejon-Pita, Alfonso Arturo

    2014-11-01

    A stream of liquid breaks up into several drops by the action of surface tension. Capillary breakup forms the basis of some modern digital technologies, especially inkjet printing (including 3D manufacturing). Therefore, the control and prediction of the breakup length of harmonically modulated capillary jets is of great importance, in particular in Continuous InkJet systems (CIJ). However, a theoretical model that rigorously takes into account the physical characteristics of the system, and that properly describes this phenomenon did not exist until now. In this work we present a simple transfer function, derived from first principles, that accurately predicts the experimentally obtained breakup lengths of pressure-modulated capillary jets. No fitting parameters are necessary. A detailed description of the theoretical model and experimental setup will be presented. Spanish government (FIS2011-25161), Junta de Andalucia (P09-FQM-4584 and P11-FQM-7919), EPSRC-UK (EP/H018913/1), Royal Society and John Fell Fund (OUP).

  14. Inverted Break-up Behaviour in Continuous Inkjet (CIJ) Printing

    NASA Astrophysics Data System (ADS)

    McIlroy, Claire; Harlen, Oliver; Morrison, Neil

    2014-11-01

    Although droplet creation during continuous jetting of Newtonian fluids has been widely studied, unsolved problems surrounding the break-up dynamics remain. Jetting through a nozzle creates a stream of liquid that is rendered unstable by surface tension. This instability creates a succession of main drops connected by thin filaments, with drop separation determined by the fastest growing wavelength. In order to control break-up and increase printing speeds, continuous inkjet (CIJ) printing exploits the effects of finite amplitude modulations in the jet velocity profile giving conditions where jet stability deviates from the usual Rayleigh behaviour. To explore these non-linear effects, we have developed a one-dimensional jetting model. In particular, we identify a modulation range for which pinching occurs upstream of the connecting filament, rather than downstream - a phenomenon we call ``inverted'' break-up. Furthermore, this behaviour can be controlled by the addition of harmonics to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry. EPSRC Innovation in Industrial Technology.

  15. Orbital Envelope for Debris Generated by a Satellite Breakup: A stochastic Study

    NASA Astrophysics Data System (ADS)

    Vieira Neto, Ernesto; Winter, Othon

    2012-07-01

    The collision between the Russian satellite Kosmos-2251 and the American satellite Iridium 33 in February 2009 leads to several questions about the debris resulted in that collision. For example, we could ask how much of the debris stay in orbit, or how much of these debris decay to Earth. This are the kind of simple questions that we try to answer in this study. The fragmentation process occurs in a large branch of natural phenomena and thus it is a very important field of interest. We can find in the literature numerous theories about fragmentation, but none is complete and much of these theories could be used only for particular cases. Objects which breakup due a collision can generate fragments of various size. The size distribution generated by the destruction depends on many factors, as the physical properties of the object, the way the object was broken, the geometry of the impact, and the energy of the projectile used to break it. After we solve the problem of find a size distribution of the fragments, the next problem is to know the velocity distribution of these fragments, which is also a difficult problem to be modeled. Our method is to make a stochastic simulations of a satellite breakup using random walk, and thus we study the spread of the debris when we distribute random impulses to the fragments. With this process we obtain the velocity distribution of the particles to use it in the orbital evolution of the debris. Thus, We had split our problem into three steps: in the first step we fragment the satellite do produce a size distribution for the debris; in the second step we give linear momenta to the fragments to obtain the velocity distribution; finally, in the third step we use this velocity distribution to study the orbital envelope generated by the debris. Peculiarities of this model and the results we have achieved will be shown in the presentation.

  16. An uncommon case of spontaneous conversion from AV re-entry tachycardia to AV nodal re-entry tachycardia in a patient with dual tachycardia

    PubMed Central

    Zeljković, Ivan; Benko, Ivica; Manola, Šime; Radeljić, Vjekoslav; Pavlović, Nikola

    2016-01-01

    We report the case of a 46-year old patient in whom an electrophysiology study (EP) was performed due to paroxysmal supraventricular tachycardia documented in 12-lead ECG. During the EP study, supraventricular tachycardia was induced easily and it corresponded to orthodromic AV reentry tachycardia (AVRT) using a concealed left free wall accessory pathway. However, during the study AVRT spontaneously and repeatedly converted to the typical slow-fast AV node reentry tachycardia (AVNRT). Both accessory and AV nodal slow pathways were ablated, due to the finding that both AVRT and AVNRT were independently inducible during the EP study. PMID:27134441

  17. Longitudinal stability analysis of a suborbital re-entry demonstrator for a deployable capsule

    NASA Astrophysics Data System (ADS)

    Iacovazzo, Michele; Carandente, Valerio; Savino, Raffaele; Zuppardi, Gennaro

    2015-01-01

    In the field of atmospheric re-entry technology several research and industrial projects are based on the design of deployable, umbrella-like Thermal Protection Systems (TPSs) and aero-brakes. These systems are made of flexible, high temperature resistant fabrics, folded at launch and deployed in space for de-orbit and re-entry operations. This technology is very promising for low cost research and industrial applications, but requires to be validated by experimental flight tests. The University of Naples "Federico II" is currently working on the development of different down-scaled technological demonstrators for this kind of capsule to be launched by different classes of sounding rockets. In the present work an aerodynamic longitudinal stability analysis for a possible, suborbital re-entry demonstrator, has been performed in continuum and rarefied regimes. The longitudinal stability behavior of the capsule, along the entire re-entry path, has been investigated in the whole range of angle of attack and, in particular, around the nominal and the reverse equilibrium re-entry attitudes (i.e. around 0° and 180°, respectively) to implement a proper re-entry strategy able not to compromise the effectiveness of the flying system.

  18. A search for H-chondritic chromite grains in sediments that formed immediately after the breakup of the L-chondrite parent body 470 Ma ago

    NASA Astrophysics Data System (ADS)

    Heck, Philipp R.; Schmitz, Birger; Rout, Surya S.; Tenner, Travis; Villalon, Krysten; Cronholm, Anders; Terfelt, Fredrik; Kita, Noriko T.

    2016-03-01

    A large abundance of L-chondritic material, mainly in the form of fossil meteorites and chromite grains from micrometeorites, has been found in mid-Ordovician 470 Ma old sediments globally. The material has been determined to be ejecta from the L chondrite parent body breakup event, a major collision in the asteroid belt 470 Ma ago. In this study we search the same sediments for H-chondritic chromite grains in order to improve our understanding of the extraterrestrial flux to Earth after the asteroid breakup event. We have used SIMS in conjunction with quantitative SEM/EDS to determine the three oxygen isotopic and elemental compositions, respectively, of a total of 120 randomly selected, sediment-dispersed extraterrestrial chromite grains mainly representing micrometeorites from 470 Ma old post-breakup limestone from the Thorsberg quarry in Sweden and the Lynna River site in Russia. We show that 99% or more of the grains are L-chondritic, whereas the H-chondritic fraction is 1% or less. The L-/H-chondrite ratio after the breakup thus was >99 compared to 1.1 in today's meteoritic flux. This represents independent evidence, in agreement with previous estimates based on sediment-dispersed extraterrestrial chromite grain abundances and sedimentation rates, of a two orders of magnitude higher post-breakup flux of L-chondritic material in the micrometeorite fraction. Finally, we confirm the usefulness of three oxygen isotopic SIMS analyses of individual extraterrestrial chromite grains for classification of equilibrated ordinary chondrites. The H- and L-chondritic chromites differ both in their three oxygen isotopic and elemental compositions, but there is some overlap between the groups. In chromite, TiO2 is the oxide most resistant to diagenesis, and the combined application of TiO2 and oxygen three-isotope analysis can resolve uncertainties arising from the compositional overlaps.

  19. The Development of a CO2 Test Capability in the NASA JSC ARCJet for Mars Reentry Simulation

    NASA Technical Reports Server (NTRS)

    DelPapa, Steven V.; Suess, Leonard; Shafer, Brian

    2011-01-01

    The Atmospheric Reentry Materials and Structures Evaluation Facility (ARMSEF) located at NASA Johnson Space Center is used for simulating the extreme environment experienced upon reentry for the development and certification of thermal protection systems (TPS). The facility supports a large variety of programs and was heavily leveraged for the certification and operational support of the TPS for the Orbiter and, more recently, the development of the heat shield for CEV. This paper will provide more detail into the heritage of the facility. Unique attributes of the facility include a modular aerodynamically stabilized arc heater and independently controlled O2 and N2 for the test gases. When combining the O2 and N2 in a 23:77 mass ratio respectively the Earth s atmosphere is accurately simulated and via modification of this ratio the investigation of the effects of atomic oxygen on a material s response is possible. In the summer of 2010 a development effort was started to add CO2 as a third independently controlled test gas such that, when combined with N2, opens up the possibility of accurately simulating a Martian reentry environment. This paper will discuss the test facility, especially the arc heater, in more detail. Initial testing involved relatively low concentrations of CO2 combined with N2 for the primary purpose of gathering data to answer two pressing safety concerns. The first being the rate of production of carbon monoxide (CO) within the ejector vacuum system. The main concern was that CO can be flammable and possibly explosive at high enough concentrations and pressures. The hazard control during the development phase involved the use of injecting N2 inside the test chamber diffuser to dilute and reduce the concentration of any and all CO present. A residual gas analyzer (RGA) was used to determine the relative amount of CO in the exhaust gas and provide a conversion rate of CO2 to CO. This paper will discuss in more detail the results of the RGA

  20. GPK-2 re-entry and deepening -- a technical report

    SciTech Connect

    Baumgartner, J.; Gerard, A.; Barla, R.; Socomine, S.A.

    1999-01-01

    Between mid February to end of May 1999 (in 104 days) the well GPK2 at the Soultz HDR site was successfully re-entered and deepened from 3876 m to a final depth of 5084 m and fully completed. Re-entry included the pulling of the existing 321 1 m long internal 9 5/8-inch by 7-inch casing string, fishing of a submersible pump and some 150 m of 2 3/8-inch tubing, sealing of a major loss zone and opening of a 6 1/4-inch well section in granite (3211-3876 m) to 8 1/2-inch hole size. The well was extended to 5048 m in 8 1/2'' hole size and again completed with a floating 9 5/8-inch by 7-inch casing string. The casing shoe is at 4431 m. A bottom hole core was taken in the depth range 5048-5051 m. The core recovery was app. 40%. A pilot hole in 6 1/4-inch was drilled from 5051-5084 m for in situ stress measurements using the hydraulic fracturing technique. The re-entry and deepening of the well GPK2 was accompanied by several technical developments. New casing packer elements based on inflatable metal shells were developed in a close cooperation between SOCOMINE and MeSy GmbH (patent pending). These packer elements were successfully integrated into the completion of the well. The full weight of the casing string is supported by these elements which are filled with and imbedded in cement. High temperature cementing strategies (up to 170-190 C) for the complex saline fluids encountered in Soultz (High Magnesium Resistant Cements) were developed in a cooperation between Schlumberger Dowell (Vechta), SOCOMINE, SII of Houston, Ruhr-University Bochum, BGR Hannover and IFP Paris. The development of several high temperature logging tools (200 C range, 6-arm caliper, PTF probe) was initiated with CSMA (Cornwall) during the preparation of the deepening of GPK2. Initial scientific investigations included borehole logging (NGS, CLIPER, ARI, UBI, TEMPERATURE), geological investigations (cuttings, core) and seismic monitoring while drilling. During the first temperature log performed

  1. Supercontinental inheritance and its influence on supercontinental breakup: The Central Atlantic Magmatic Province and the breakup of Pangea

    NASA Astrophysics Data System (ADS)

    Whalen, Lisa; Gazel, Esteban; Vidito, Christopher; Puffer, John; Bizimis, Michael; Henika, William; Caddick, Mark J.

    2015-10-01

    The Central Atlantic Magmatic Province (CAMP) is the large igneous province (LIP) that coincides with the breakup of the supercontinent Pangea. Major and trace element data, Sr-Nd-Pb radiogenic isotopes, and high-precision olivine chemistry were collected on primitive CAMP dikes from Virginia (VA). These new samples were used in conjunction with a global CAMP data set to elucidate different mechanisms for supercontinent breakup and LIP formation. On the Eastern North American Margin, CAMP flows are found primarily in rift basins that can be divided into northern or southern groups based on differences in tectonic evolution, rifting history, and supercontinental inheritance. Geochemical signatures of CAMP suggest an upper mantle source modified by subduction processes. We propose that the greater number of accretionary events, or metasomatism by sediment melts as opposed to fluids on the northern versus the southern Laurentian margin during the formation of Pangea led to different subduction-related signatures in the mantle source of the northern versus southern CAMP lavas. CAMP samples have elevated Ni and low Ca in olivine phenocrysts indicating a significant pyroxenite component in the source, interpreted here as a result of subduction metasomatism. Different collisional styles during the Alleghanian orogeny in the North and South may have led to the diachroneity of the rifting of Pangea. Furthermore, due to a low angle of subduction, the Rheic Plate may have underplated the lithosphere then delaminated, triggering both the breakup of Pangea and the formation of CAMP.

  2. Re-Entry Simulation and Landing Area for YES2

    NASA Technical Reports Server (NTRS)

    Calzada, Silvia

    2005-01-01

    The REST simulator includes many parameters: a) Inertial <-> Fix to Earth reference system; b) Geodetic <-> Geocentric coordinates; c) Rotational velocity of the Atmosphere; d) Effect of the rotation of the Earth; e) Bulge effect of the Earth; f) Spherical harmonic expansion for the Earth s gravitational potential, J2 (zonal); g) Heat flux, temperature in the wall; h) Drag coefficient for different regimes; i) Flow regime status; j) Density model NRLMSISE-00; k) Wind model HWM-93; l) G2S atmospheric model with the latest meteorological conditions and m) Landing area (Monte Carlo Simulations)

  3. "The stress will kill you": prisoner reentry as experienced by family members and the urgent need for support services.

    PubMed

    Grieb, Suzanne M; Crawford, Amelia; Fields, Julie; Smith, Horace; Harris, Richard; Matson, Pamela

    2014-08-01

    The role of incarceration and community reentry after incarceration has been studied extensively for individual and community health; however, little attention has been given to the experiences of individuals who provide support to those in reentry. Through a community-academic partnership, seven focus groups were conducted with 39 individuals supporting a family member in reentry in the summer of 2012. The primary objectives of the focus groups were to explore community experiences and perspectives regarding providing support during a family member's reentry from a period of incarceration and any desired support for themselves during this time. Five themes emerged under a metatheme of stress, indicating that family members experience acute stress as a result of family reentry that adds to the chronic stress they already endure. Programs that acknowledge the difficult role of family members as supporters during an individual's reentry and provide support to them are desperately needed. PMID:25130233

  4. Initiation of reentry inside the vulnerable window of the heart

    NASA Astrophysics Data System (ADS)

    Baudenbacher, Petra; Baudenbacher, Franz; Aliev, Rubin; Wikswo, John

    2000-03-01

    Cardiac vulnerability refers to the initiation of self-sustained waves after the application of a stimulus in the wake of a propagating pulse, which can lead to arrhythmias and fibrillation. We used optical mapping of the transmembrane potential on the epicardium of Langendorff-perfused, di-4-ANNEPS stained isolated rabbit hearts. After a planar wave was launched by an S1 stimulus with line electrodes perpendicular to the fiber direction, an S2 stimulus was applied with a point electrode at a different location at a time ΔT after S1. The S1 strength was 2-4×threshold S2=2×S1. The spatio-temporal dynamics of S2 responses shows three distinct excitation regions: For ΔT>160ms, a point shaped hypopolarized region (make excitation) leads to propagation symmetrical in both directions perpendicular to the wire. For ΔT<160ms, a dog-bone shaped hyperpolarized region is followed by a hypopolarized region (break excitation), leading to an asymmetrical curved wave due to partial functional block, and in some cases reentry, especially at shorter time intervals. For ΔT<115ms, break excitation occurs without propagation. Stimulating inside the vulnerable window results in multiple responses due to functional block and allows us to extract the propagation velocity as a function of refractoriness.

  5. Aerothermodynamic Analysis of Commercial Experiment Transporter (COMET) Reentry Capsule

    NASA Technical Reports Server (NTRS)

    Wood, William A.; Gnoffo, Peter A.; Rault, Didier F. G.

    1996-01-01

    An aerothermodynamic analysis of the Commercial Experiment Transporter (COMET) reentry capsule has been performed using the laminar thin-layer Navier-Stokes solver Langley Aerothermodynamic Upwind Relaxation Algorithm. Flowfield solutions were obtained at Mach numbers 1.5, 2, 5, 10, 15, 20, 25, and 27.5. Axisymmetric and 5, 10, and 20 degree angles of attack were considered across the Mach-number range, with the Mach 25 conditions taken to 90 degrees angle of attack and the Mach 27.5 cases taken to 60 degrees angle of attack. Detailed surface heat-transfer rates were computed at Mach 20 and 25, revealing that heating rates on the heat-shield shoulder ,can exceed the stagnation-point heating by 230 percent. Finite-rate chemistry solutions were performed above Mach 10, otherwise perfect gas computations were made. Drag, lift, and pitching moment coefficients are computed and details of a wake flow are presented. The effect of including the wake in the solution domain was investigated and base pressure corrections to forebody drag coefficients were numerically determined for the lower Mach numbers. Pitching moment comparisons are made with direct simulation Monte Carlo results in the more rarefied flow at the highest Mach numbers, showing agreement within two-percent. Thin-layer Navier-Stokes computations of the axial force are found to be 15 percent higher across the speed range than the empirical/Newtonian based results used during the initial trajectory analyses.

  6. Joint computational/experimental aerodynamics research on a reentry vehicle

    SciTech Connect

    Oberkampf, W.L.; Aeschliman, D.P.

    1990-01-01

    Although computational aerodynamics simulation has been taking more responsibility during recent years, wind tunnel experimentation has continued to play the major role in flight vehicle analysis and design.This role, however, is changing because of the great strides in the capability and confidence in numerical simulations. For a small, well defined, class of supersonic and hypersonic flow problems, high quality numerical solutions are now believed to represent the physics of the problem more accurately than a wind tunnel experimental can simulate the free flight conditions. An example of this is the supersonic or hypersonic, laminar, perfect gas flow over a spherically blunted cone at low angle of attack. In this paper, aerodynamic force and moment measurements and flow visualization results are presented for a reentry vehicle configuration at Mach 8. All of the results were obtained in the Sandia Mach 8 long duration, blow-down, hypersonic wind tunnel. The basic vehicle configuration is a spherically blunted cone with a slice parallel with the axis of the vehicle. Onto the slice portion of the vehicle can be attached flaps with three different deflection angles, 10, 20 and 30 deg. Flow visualization results include surface oil flow, spark Schlieren, and liquid crystal photographs. 1 ref., 7 figs.

  7. Reentry heat transfer analysis of the space shuttle orbiter

    NASA Technical Reports Server (NTRS)

    Ko, W. L.; Quinn, R. D.; Gong, L.

    1982-01-01

    A structural performance and resizing finite element thermal analysis computer program was used in the reentry heat transfer analysis of the space shuttle. Two typical wing cross sections and a midfuselage cross section were selected for the analysis. The surface heat inputs to the thermal models were obtained from aerodynamic heating analyses, which assumed a purely turbulent boundary layer, a purely laminar boundary layer, separated flow, and transition from laminar to turbulent flow. The effect of internal radiation was found to be quite significant. With the effect of the internal radiation considered, the wing lower skin temperature became about 39 C (70 F) lower. The results were compared with fight data for space transportation system, trajectory 1. The calculated and measured temperatures compared well for the wing if laminar flow was assumed for the lower surface and bay one upper surface and if separated flow was assumed for the upper surfaces of bays other than bay one. For the fuselage, good agreement between the calculated and measured data was obtained if laminar flow was assumed for the bottom surface. The structural temperatures were found to reach their peak values shortly before touchdown. In addition, the finite element solutions were compared with those obtained from the conventional finite difference solutions.

  8. The SRB heat shield: Aeroelastic stability during reentry

    NASA Technical Reports Server (NTRS)

    Ventres, C. S.; Dowell, E. H.

    1977-01-01

    Wind tunnel tests of a 3% scale model of the aft portion of the SRB equipped with partially scaled heat shields were conducted for the purpose of measuring fluctuating pressure levels in the aft skirt region. During these tests, the heat shields were observed to oscillate violently, the oscillations in some instances causing the heat shields to fail. High speed films taken during the tests reveal a regular pattern of waves in the fabric starting near the flow stagnation point and progressing around both sides of the annulus. The amplitude of the waves was too great, and their pattern too regular, for them to be attributed to the fluctuating pressure levels measured during the tests. The cause of the oscillations observed in the model heat shields, and whether or not similar oscillations will occur in the full scale SRB heat shield during reentry were investigated. Suggestions for modifying the heat shield so as to avoid the oscillations are provided, and recommendations are made for a program of vibration and wind tunnel tests of reduced-scale aeroelastic models of the heat shield.

  9. Reentry heat transfer analysis of the space shuttle orbiter

    NASA Astrophysics Data System (ADS)

    Ko, W. L.; Quinn, R. D.; Gong, L.

    A structural performance and resizing finite element thermal analysis computer program was used in the reentry heat transfer analysis of the space shuttle. Two typical wing cross sections and a midfuselage cross section were selected for the analysis. The surface heat inputs to the thermal models were obtained from aerodynamic heating analyses, which assumed a purely turbulent boundary layer, a purely laminar boundary layer, separated flow, and transition from laminar to turbulent flow. The effect of internal radiation was found to be quite significant. With the effect of the internal radiation considered, the wing lower skin temperature became about 39 C (70 F) lower. The results were compared with fight data for space transportation system, trajectory 1. The calculated and measured temperatures compared well for the wing if laminar flow was assumed for the lower surface and bay one upper surface and if separated flow was assumed for the upper surfaces of bays other than bay one. For the fuselage, good agreement between the calculated and measured data was obtained if laminar flow was assumed for the bottom surface. The structural temperatures were found to reach their peak values shortly before touchdown. In addition, the finite element solutions were compared with those obtained from the conventional finite difference solutions.

  10. RITD — Adapting Mars Entry, Descent and Landing System for Earth

    NASA Astrophysics Data System (ADS)

    Heilimo, J.; Harri, A.-M.; Aleksashkin, S.; Koryanov, V.; Arruego, I.; Schmidt, W.; Haukka, H.; Finchenko, V.; Martynov, M.; Ostresko, B.; Ponomarenko, A.; Kazakovtsev, V.; Martin, S.; Siili, T.

    2014-06-01

    The EDLS applicability to Earth’s atmosphere is studied by the EU/RITD project. Project focuses to the analysis and tests of the transonic behaviour of this compact and light weight payload entry system at the Earth re-entry.

  11. An Automated Method to Compute Orbital Re-Entry Trajectories with Heating Constraints

    NASA Technical Reports Server (NTRS)

    Zimmerman, Curtis; Dukeman, Greg; Hanson, John; Fogle, Frank R. (Technical Monitor)

    2002-01-01

    Determining how to properly manipulate the controls of a re-entering re-usable launch vehicle (RLV) so that it is able to safely return to Earth and land involves the solution of a two-point boundary value problem (TPBVP). This problem, which can be quite difficult, is traditionally solved on the ground prior to flight. If necessary, a nearly unlimited amount of time is available to find the "best" solution using a variety of trajectory design and optimization tools. The role of entry guidance during flight is to follow the pre-determined reference solution while correcting for any errors encountered along the way. This guidance method is both highly reliable and very efficient in terms of onboard computer resources. There is a growing interest in a style of entry guidance that places the responsibility of solving the TPBVP in the actual entry guidance flight software. Here there is very limited computer time. The powerful, but finicky, mathematical tools used by trajectory designers on the ground cannot in general be made to do the job. Nonconvergence or slow convergence can result in disaster. The challenges of designing such an algorithm are numerous and difficult. Yet the payoff (in the form of decreased operational costs and increased safety) can be substantial. This paper presents an algorithm that incorporates features of both types of guidance strategies. It takes an initial RLV orbital re-entry state and finds a trajectory that will safely transport the vehicle to a Terminal Area Energy Management (TAEM) region. During actual flight, the computed trajectory is used as the reference to be flown by a more traditional guidance method.

  12. Simulation-Based Analysis of Reentry Dynamics for the Sharp Atmospheric Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Tillier, Clemens Emmanuel

    1998-01-01

    This thesis describes the analysis of the reentry dynamics of a high-performance lifting atmospheric entry vehicle through numerical simulation tools. The vehicle, named SHARP, is currently being developed by the Thermal Protection Materials and Systems branch of NASA Ames Research Center, Moffett Field, California. The goal of this project is to provide insight into trajectory tradeoffs and vehicle dynamics using simulation tools that are powerful, flexible, user-friendly and inexpensive. Implemented Using MATLAB and SIMULINK, these tools are developed with an eye towards further use in the conceptual design of the SHARP vehicle's trajectory and flight control systems. A trajectory simulator is used to quantify the entry capabilities of the vehicle subject to various operational constraints. Using an aerodynamic database computed by NASA and a model of the earth, the simulator generates the vehicle trajectory in three-dimensional space based on aerodynamic angle inputs. Requirements for entry along the SHARP aerothermal performance constraint are evaluated for different control strategies. Effect of vehicle mass on entry parameters is investigated, and the cross range capability of the vehicle is evaluated. Trajectory results are presented and interpreted. A six degree of freedom simulator builds on the trajectory simulator and provides attitude simulation for future entry controls development. A Newtonian aerodynamic model including control surfaces and a mass model are developed. A visualization tool for interpreting simulation results is described. Control surfaces are roughly sized. A simple controller is developed to fly the vehicle along its aerothermal performance constraint using aerodynamic flaps for control. This end-to-end demonstration proves the suitability of the 6-DOF simulator for future flight control system development. Finally, issues surrounding real-time simulation with hardware in the loop are discussed.

  13. Spiral waves and reentry dynamics in an in vitro model of the healed infarct border-zone

    PubMed Central

    Chang, Marvin G.; Zhang, Yibing; Chang, Connie Y.; Xu, Linmiao; Emokpae, Roland; Tung, Leslie; Marbán, Eduardo; Abraham, M. Roselle

    2015-01-01

    Rationale Reentry underlies most ventricular tachycardias (VT) seen post-myocardial infarction (MI). Mapping studies reveal that the majority of VTs late post-MI arise from the infarct border-zone (IBZ). Objective To investigate reentry dynamics and the role of individual ion channels on reentry in in vitro models of the healed IBZ. Methods and Results We designed in vitro models of the healed IBZ by co-culturing skeletal myotubes (SkM) with neonatal rat ventricular myocytes (NRVMs) and performed optical mapping at high temporal and spatial resolution. In culture, NRVMs mature to form striated myocytes and electrically uncoupled SkMs simulate fibrosis seen in the healed IBZ. High resolution mapping revealed that SkMs produced localized slowing of conduction velocity (CV), increased dispersion of CV and directional-dependence of activation delay without affecting myocyte excitability. Reentry was easily induced by rapid pacing in co-cultures; treatment with lidocaine, a Na+ channel blocker, significantly decreased reentry rate and CV, increased reentry pathlength and terminated 30% of reentrant arrhythmias (n=18). In contrast, nitrendipine, an L-type Ca2+ channel (LTCC) blocker terminated 100% of reentry episodes while increasing reentry cycle length and pathlength and decreasing reentry CV (n=16). K+ channel blockers increased reentry APD, but infrequently terminated reentry (n=12). Conclusions Co-cultures reproduce several architectural and EP features of the healed IBZ. Reentry termination by LTCC, but not Na+ channel blockers suggests a greater Ca2+-dependence of propagation. These results may help explain the low efficacy of pure Na+ channel blockers in preventing and terminating clinical VTs late after MI. PMID:19815825

  14. Observations of breakup processes of liquid jets using real-time X-ray radiography

    NASA Technical Reports Server (NTRS)

    Char, J. M.; Kuo, K. K.; Hsieh, K. C.

    1988-01-01

    To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process.

  15. Fine structure of breakup development inferred from satellite and ground-based observations

    NASA Astrophysics Data System (ADS)

    Kornilova, T. A.; Kornilov, I. A.; Kornilov, O. I.

    2008-05-01

    More than 60 breakups, including weak activations of the pseudo-breakup type, moderate breakups, and events of very strong auroral activity, were analyzed using ground-based TV data, together with satellite auroral images. We studied the fine subvisual details of spatial and temporal dynamics of active auroral forms and surrounding diffuse luminosity, both in the longitudinal and latitudinal directions of the TV camera field of view. For all types of breakups a close interconnection of auroral activity was found across and along the auroral oval.

  16. Systematical Behavior of Breakup Effects on Complete Fusion at Energies above the Coulomb Barrier

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Zhao, Wei-Juan; Gomes, P. R. S.; Zhao, En-Guang; Zhou, Shan-Gui

    We investigate the systematical behavior of the breakup effects on the complete fusion (CF) cross sections at energies above the Coulomb barrier. The CF cross sections are suppressed by the prompt breakup of the projectiles. This suppression effect, expressed as the ratio of the reduced fusion function and the universal fusion function (UFF), for reactions induced by the same projectile, is independent of the target and mainly determined by the lowest energy breakup channel of the projectile. There holds a good exponential relation between the suppression factor and the energy corresponding to the lowest breakup threshold.

  17. Bag-breakup control of surface drag in hurricanes

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Zilitinkevich, Sergej; Kandaurov, Alexander; Ermakova, Olga; Kozlov, Dmitry; Sergeev, Daniil

    2016-04-01

    Air-sea interaction at extreme winds is of special interest now in connection with the problem of the sea surface drag reduction at the wind speed exceeding 30-35 m/s. This phenomenon predicted by Emanuel (1995) and confirmed by a number of field (e.g., Powell, et al, 2003) and laboratory (Donelan et al, 2004) experiments still waits its physical explanation. Several papers attributed the drag reduction to spume droplets - spray turning off the crests of breaking waves (e.g., Kudryavtsev, Makin, 2011, Bao, et al, 2011). The fluxes associated with the spray are determined by the rate of droplet production at the surface quantified by the sea spray generation function (SSGF), defined as the number of spray particles of radius r produced from the unit area of water surface in unit time. However, the mechanism of spume droplets' formation is unknown and empirical estimates of SSGF varied over six orders of magnitude; therefore, the production rate of large sea spray droplets is not adequately described and there are significant uncertainties in estimations of exchange processes in hurricanes. Herewith, it is unknown what is air-sea interface and how water is fragmented to spray at hurricane wind. Using high-speed video, we observed mechanisms of production of spume droplets at strong winds by high-speed video filming, investigated statistics and compared their efficiency. Experiments showed, that the generation of the spume droplets near the wave crest is caused by the following events: bursting of submerged bubbles, generation and breakup of "projections" and "bag breakup". Statistical analysis of results of these experiments showed that the main mechanism of spray-generation is attributed to "bag-breakup mechanism", namely, inflating and consequent blowing of short-lived, sail-like pieces of the water-surface film. Using high-speed video, we show that at hurricane winds the main mechanism of spray production is attributed to "bag-breakup", namely, inflating and

  18. Early afterdepolarizations promote transmural reentry in ischemic human ventricles with reduced repolarization reserve

    PubMed Central

    Dutta, Sara; Mincholé, Ana; Zacur, Ernesto; Quinn, T. Alexander; Taggart, Peter; Rodriguez, Blanca

    2016-01-01

    Aims Acute ischemia is a major cause of sudden arrhythmic death, further promoted by potassium current blockers. Macro-reentry around the ischemic region and early afterdepolarizations (EADs) caused by electrotonic current have been suggested as potential mechanisms in animal and isolated cell studies. However, ventricular and human-specific arrhythmia mechanisms and their modulation by repolarization reserve remain unclear. The goal of this paper is to unravel multiscale mechanisms underlying the modulation of arrhythmic risk by potassium current (IKr) block in human ventricles with acute regional ischemia. Methods and results A human ventricular biophysically-detailed model, with acute regional ischemia is constructed by integrating experimental knowledge on the electrophysiological ionic alterations caused by coronary occlusion. Arrhythmic risk is evaluated by determining the vulnerable window (VW) for reentry following ectopy at the ischemic border zone. Macro-reentry around the ischemic region is the main reentrant mechanism in the ischemic human ventricle with increased repolarization reserve due to the ATP-sensitive potassium current (IK(ATP)) activation. Prolongation of refractoriness by 4% caused by 30% IKr reduction counteracts the establishment of macro-reentry and reduces the VW for reentry (by 23.5%). However, a further decrease in repolarization reserve (50% IKr reduction) is less anti-arrhythmic despite further prolongation of refractoriness. This is due to the establishment of transmural reentry enabled by electrotonically-triggered EADs in the ischemic border zone. EADs are produced by L-type calcium current (ICaL) reactivation due to prolonged low amplitude electrotonic current injected during the repolarization phase. Conclusions Electrotonically-triggered EADs are identified as a potential mechanism facilitating intramural reentry in a regionally-ischemic human ventricles model with reduced repolarization reserve. PMID:26850675

  19. The effects of bed rest on crew performance during simulated shuttle reentry. Volume 1: Study overview and physiological results

    NASA Technical Reports Server (NTRS)

    Chambers, A.; Vykukal, H. C.

    1974-01-01

    A centrifuge study was carried out to measure physiological stress and control task performance during simulated space shuttle orbiter reentry. Jet pilots were tested with, and without, anti-g-suit protection. The pilots were exposed to simulated space shuttle reentry acceleration profiles before, and after, ten days of complete bed rest, which produced physiological deconditioning similar to that resulting from prolonged exposure to orbital zero g. Pilot performance in selected control tasks was determined during simulated reentry, and before and after each simulation. Physiological stress during reentry was determined by monitoring heart rate, blood pressure, and respiration rate. Study results indicate: (1) heart rate increased during the simulated reentry when no g protection was given, and remained at or below pre-bed rest values when g-suits were used; (2) pilots preferred the use of g-suits to muscular contraction for control of vision tunneling and grayout during reentry; (3) prolonged bed rest did not alter blood pressure or respiration rate during reentry, but the peak reentry acceleration level did; and (4) pilot performance was not affected by prolonged bed rest or simulated reentry.

  20. Final Rifting and Continental Breakup in the South China Sea

    NASA Astrophysics Data System (ADS)

    Franke, D.; Savva, D.; Pubellier, M. F.; Steuer, S.; Mouly, B.; Auxietre, J. L.; Meresse, F.; Chamot-Rooke, N. R. A.

    2014-12-01

    The magma-poor or intermediate magmatic South China Sea basin shows a triangular shape with a SW pointing apex, which manifests a preceding propagating rift. The earliest phase of rifting started in the Early Paleocene when a Mesozoic convergent margin changed to extension. After about 30 Myrs of rifting, breakup in the major eastern subbasin of the SCS occurred in the Early Oligocene and subsequent breakup of the southwest subbasin took place in the Late Oligocene. Seismic reflection data imaging conjugate crustal sections result in a conceptual model for rift-evolution at conjugate margins in time and space. Distinct are regular undulations in the crust-mantle boundary. Individual rift basins are bounded to crustal blocks by listric normal faults on either side. Moho uplifts are distinct beneath major rift basins, while the Moho is downbended beneath crustal blocks. Most of the basin-bounding faults sole out within the middle crust. At the distal margins, detachment faults are located at a mid-crustal level where a weak zone decouples crust and mantle lithosphere during rifting. The lower crust in contrast is interpreted as being strong. Only in the region within about 50 km from the oceanic domain we suggest that normal faults reach the mantle, enabling potentially a coupling between the crust and the mantle. Here, at the proximal margins detachment fault dip either seaward or landward. Largely symmetric structures result from the initial rifting stage. At the future breakup position either of the rift basin bounding faults subsequently penetrates the entire crust, resulting in asymmetry at this location. However, asymmetric deformation which is controlled by large scale detachment faulting is confined to narrow areas and does not result in a margin-wide simple-shear model. Rather considerable along-margin variations are suggested resulting in alternating "upper and lower plate" margins.