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Topic: Hypervelocity

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	Encyclopedia: Hypervelocity
		Hypervelocity is usually refered to a very high velocity, such as over 10,000 feet per second.
		Hypervelocity tends to refer to velocities in the range of a few kilometres per second to some tens of kilometres per second.
		It is especially relevant to the field of space exploration, where hypervelocity impacts can result in anything from minor component degradation to the complete destruction of a spacecraft.
	www.nationmaster.com /encyclopedia/Hypervelocity (295 words)

	The Hypervelocity Impact Society \| Constitution and Bylaws
		The Hypervelocity Impact Society is devoted to the advancement of the science and technology of hypervelocity impact and related technical areas, such as experimental techniques, theoretical and analytical studies, numerical advancements, and material response, required to facilitate an understanding of hypervelocity impact phenomena.
		Hypervelocity impact is defined as the impact regime in which shock effects are important.
		The objectives of the Hypervelocity Impact Society are to foster the development and exchange of technical information in the discipline of hypervelocity impact phenomena by promoting technical excellence, encouraging peer review publications, and holding technical meetings on a periodic basis.
	www.hvis.org /const.html (2890 words)

	Hypervelocity Impacts and the Stability of Organic Material. 15-9044
		Particularly problematic is the question of the stability of organic material under hypervelocity impact conditions.
		Understanding the mechanisms involved in delivering organics to a planetary surface remains difficult to assess due to the lack of experimental results of hypervelocity impacts, particularly in the velocity range of tens of kilometers per second.
		Determining the stability of such organics during the hypervelocity impacts regime of the late heavy bombardment is an obvious problem to investigate; was the environment on Mars conducive to the formation or preservation of organic material delivered from space?
	www.bioengineering.swri.org /3pubs/IRD1999/15904499.htm (526 words)

	Hypervelocity impact shield - Patent 5067388
		A hypervelocity impact shield 10 and method for protecting a wall structure, such as a spacecraft wall 12, from impact with particles of debris having densities of about 2.7 g/cm.sup.3 and impact velocities up to 16 km/s.
		A hypervelocity impact shield as set forth in claim 5 wherein said sheets are formed of a ceramic fabric of continuous polycrystalline metal oxide fibers.
		For a conventional hypervelocity shield concept or design which consists of a single or multi "thin" sheet shield, the orbital debris upon impact typically fragments into a large number of fine solid debris projectiles that are hot but not molten.
	www.freepatentsonline.com /5067388.html (5426 words)

	Hypervelocity Impact Penetration Phenomena in Aluminum Space Structures (Site not responding. Last check: 2007-10-13)
		This paper describes the results of an experimental investigation of the penetration phenomena associated with oblique hypervelocity projectile impact of aluminum dual-wall structures.
		A review of the test data shows that oblique hypervelocity impact penetration phenomena are strongly dependent on impact obliquity and therefore can differ significantly from those associated with normal high-speed impacts.
		It is concluded that the possibility of non-normal impacts and their effects on structural integrity must be considered in the design of any structure that is to be exposed to the hazardous meteoroid and space debris environment.
	www.pubs.asce.org /WWWdisplay.cgi?9002822 (236 words)

	A comparative analysis of the performance of long-range hypervelocity vehicles (Site not responding. Last check: 2007-10-13)
		Long-range hypervelocity vehicles are studied in terms of their motion in powered flight.
		Aerodynamic heating is treated in a manner similar to that employed previously by the senior authors in studying ballistic missiles (NACA rep. 1381), with the exception that radiant as well as convective heat transfer is considered in connection with glide and skip vehicles.
		As a final performance consideration, it is shown that on the basis of equal ratios of mass at take-off to mass at the end of powered flight, the hypervelocity vehicle compares favorably with the supersonic airplane for ranges in the neighborhood of and greater than one half the circumference of the earth.
	naca.larc.nasa.gov /reports/1958/naca-report-1382 (225 words)

	G A L C I T [Caltech] - People - Hans Hornung (Site not responding. Last check: 2007-10-13)
		In hypervelocity blunt-body flows, the vorticity generated by the bow shock is particularly high because of the large density increase across a shock followed by dissociation.
		The project aim is to study the region of maximum vorticity and its wake, first by numerical studies and, after design of a suitable experiment on the basis of the numerical work, in experiments in the hypervelocity shock tunnel.
		An exploratory study of the transition on a slender cone in high enthalpy flows of air, nitrogen and carbon dioxide has shown that under the conditions examined in the hypervelocity shock tunnel, the effect of increasing the enthalpy of the flow is to cause transition to be delayed.
	www.galcit.caltech.edu /People/Faculty/hornung.html (449 words)

	Hypervelocity Impact Craters
		Hypervelocity is a velocity in excess of about 4 kilometres per second.
		The important fact about a hypervelocity impactor is that its kinetic energy is in excess of the energy that the body would release in an explosion if its mass were entirely composed of high explosive!
		The apparent diameter of a hypervelocity impact crater on Earth is very roughly given by multiplying the impactor diameter by a factor of 10 to 20.
	www.ips.gov.au /IPSHosted/neo/info/notes/cratdiam.htm (230 words)

	Centre for Hypersonics - Annual Report 1999 (Site not responding. Last check: 2007-10-13)
		In the new era of hypervelocity space travel, experimental data is increasingly expensive, difficult and dangerous to obtain, but remains a critical component for the development of advanced flight vehicles.
		Large hypervelocity impulse facilities in Australia and overseas are being used to develop the next generation of space launch vehicles.
		Hypervelocity simulations pose a number of challenges to CFD codes: the fluid density can vary over several orders of magnitude, shocks are extremely strong, and the high temperatures existing behind the shocks lead to a strong coupling of aerothermodynamic and chemical effects.
	www.mech.uq.edu.au /hyper/annual_report/cfh_annual_report.html (6813 words)

	Active Skim View of: 5 TOOLS FOR DAMAGE ASSESSMENT AND PREDICTION
		Hypervelocity impact tests are also used to test and design debris shields.
		This method may be useful in investigating aspects of hypervelocity impact phenomena encountered during high-speed impact on aluminum, but determining the extent to which the results of dissimilar materials testing are applicable to damage prediction at velocities of about 10 km/s requires further detailed investigation and evaluation.
		Sharing Hypervelocity Impact Information One of the main reasons for the lack of good models of hypervelocity impact damage is that hypervelocity test data are not formally shared, and the capabilities of many facilities involved in hypervelocity testing are not commonly known.
	www.nap.edu /nap-cgi/skimit.cgi?isbn=0309051258&chap=101-118 (673 words)

	Augmented hypervelocity railgun with single energy source and rail segmentation - Patent 5375504
		These diverse applications translate to a broad range of railgun performance requirement, in which additional factors such as boresize, muzzle energy level, launch velocity, fire rate, barrel life, and systems size to mass ratio are a few of the additional salient characteristics to be considered.
		These improvements are especially needed in the areas of compact power supplies, improved rail life expectancy, hypervelocity projectile capabilities (velocities in the order of ten kilometers per second), and improved electrical energy to kinetic energy transformation efficiencies--efficiencies greater than 40%.
		While the apparatus and method herein described constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus or method and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.
	www.freepatentsonline.com /5375504.html (8547 words)

	NASA WSTF Orbital Debris and Micrometeoroids
		More satellites are being launched and with non-functioning satellite explosions and fragmentation, the threat of debris impact damage on satellites and spacecraft is a major concern.
		The greatest challenge is medium size particles (objects with a diameter between 1 mm to 10 cm) because they are not easily tracked and are large enough to cause catastrophic damage to spacecraft and satellites.
		Conducting hypervelocity impacts on spacecraft and satellite components assesses the risk of orbital debris impacting operating spacecraft and satellites.
	www.wstf.nasa.gov /Hazard/Hyper/debris.htm (434 words)

	Baylor University \|\| Department of Physics \|\| Hypervelocity Impacts and Dusty Plasma Lab and the Space Science ...
		The laser bay and microparticle accelerators are currently operational with the 2J Y¦s ruby laser lab, the 130 mJ ps Nd:Yag laser lab, the accelerator (light gas and electrostatic) lab and the diagnostics/sensor development lab on-line.
		The HIDPL is able to either accelerate or simulate hypervelocity impacts for different mass regimes over a wide range of velocities.
		A computer program which simulates a hypervelocity impact event(s) is called a hydrocode.
	www.baylor.edu /physics/index.php?id=10354 (399 words)

	CISAS Hypervelocity Impact Facility - Facility description (Site not responding. Last check: 2007-10-13)
		CISAS hypervelocity impact facility is based upon a two-stage light-gas gun (LGG), that can achieve a very high shot repetition rate (up to 10 shots per day) together with low operational costs.
		The gun has been designed to be a very flexible system to be applied on a very different problems from low speed up to hypervelocity.
		It can be used in a single stage mode, allowing the acceleration of masses up to 500 grams up to 500 m/s and in a two stage mode allowing the acceleration of masses up to 100 mg up to 5.5 km/s.
	cisas.unipd.it /lgg/facility.html (797 words)

	Microstructural evolution associated with hypervelocity impact crater formation in metallic targets
		This investigation is a fundamental study of the microstructural evolution associated with hypervelocity impact crater formation in metallic targets and ballistic rod penetration of thick metallic plates.
		Similar microbands have been observed by previous researchers in explosively deformed metals but this is the first time in which such microstructures are observed in connection with hypervelocity impact cratering and ballistic rod penetration in copper.
		In this regard, it may be important to use microstructural zone changes as a function of impact velocity as a means to extrapolate the potential effects on the microstructures of materials exposed to a wider range of impact velocities than those achieved by laboratory guns.
	digitalcommons.utep.edu /dissertations/AAI9718116 (525 words)

	NASA - Range Complex
		Together, they offer a unique set of testing possibilities for a wide variety of hypervelocity topics, including the aerodynamics and flow field characteristics of entry vehicles (either for Earth entry or other planetary atmospheres) and other hypersonic vehicles, meteor or asteroid impacts on a planet or moon surface, and micrometeoroid impacts on a spacecraft.
		The facility can also be configured for hypervelocity impact testing and has an aerothermodynamic capability as well.
		NASA Ames has a long tradition of leadership in the use of ballistic ranges and shock tubes for the study of the physics and phenomena associated with hypervelocity flight.
	www.nasa.gov /centers/ames/research/technology-onepagers/range-complex.html (996 words)

	ASEE - Resources\Opportunities - Fellowships - NASA Johnson Space Center - Space Sciences
		JSC maintains three hypervelocity guns, and has played a critical role in designing shields for the International Space Station and developing effective modifications to reduce Shuttle meteoroid/debris risks.
		Results from hypervelocity impact tests and from numerical simulations of hypervelocity impact are used to update software that is maintained by JSC to assess spacecraft damage and failure risk from meteoroid/debris impact.
		We pursue hypervelocity meteorite impact as a geological process to learn about the accretion, differentiation, and the evolution of current, heavily cratered surfaces of planets and their moons, including the collisional evolution of small solar system objects.
	www.asee.org /nffp/johnson03.cfm (3922 words)

	[No title] (Site not responding. Last check: 2007-10-13)
		Attention is given to an earth-to-orbit railgun launcher, polyphase and multiphase railguns, hypervelocity projectile design, determining the Lorentz forces in plasma armatures, pulse power generators, advanced compulsator technology, airborne-platform electric launcher applications, magnetic design for structural stiffness, current multipliers, pulse-forming network design, and cannon-caliber electromagnetic launchers.
		Launcher concepts are briefly examined, and specific examples are given to demonstrate significant recent progress in hypervelocity atmospheric transit and hardening of launch vehicle components to withstand higher launch accelerators by several orders of magnitude.
		Applications include the acceleration of gram- size particles for hypervelocity research and the initiation of fusion by impact, a replacement for chemically propelled artillery, the transportation of cargo and personnel over inaccessible terrain, and the launching of space vehicles to supply massive space operations, and for the disposal of nuclear waste.
	users.adelphia.net /~gsj/abstract.txt (8017 words)

	[No title]
		Second, the relaxation processes associated with vibrational excitation and dissociation (which occur in hypervelocity flows because of aerodynamic heating) provide mechanisms for damping acoustic waves, and may therefore be expected to affect the second mode.
		The first experiments to be performed in the newly completed T5 hypervelocity free-piston shock tunnel in 1991-1993 were designed for a 5 deg half-angle cone also, in order to be able to compare the new high enthalpy results with those from the cold hypersonic wind tunnels.
		In hypervelocity flow simulation it is important to reproduce the actual speed of the flow, so that the vibrational excitation and dissociation are reproduced correctly.
	www.galcit.caltech.edu /~hans/isfahan.doc (4632 words)

	Passive Hypervelocity Boundary Layer Control Using an Acoustically Absorptive Surface (Site not responding. Last check: 2007-10-13)
		A series of exploratory boundary layer transition experiments were performed on a 5.06 degree half-angle cone at zero angle-of-attack in the T5 Hypervelocity Shock Tunnel in order to test a novel hypersonic boundary layer control scheme.
		Recently performed linear stability analyses suggested that transition could be delayed in hypersonic boundary layers by using an ultrasonically absorptive surface that would damp the second mode (Mack mode).
		These experiments indicated that the porous surface was highly effective in delaying transition provided that the pore size was significantly smaller than the viscous length scale.
	www.galcit.caltech.edu /Seminars/Fluids/PastFluids/2000-2001/Rasheed_abs.html (222 words)

	UDRI Capabilities - Hypervelocity Impact Testing and Analysis
		The hypervelocity impact facility at UDRI has 2 two-stage, light-gas gun ranges for hypervelocity testing at velocities up to 24,600 ft/sec (7.5 km/sec).
		A number of different projectile shapes have been launched for hypervelocity impact studies including spheres, discs, rods, cubes, and others.
		Flash radiography of a debris cloud produced by a spherical aluminum projectile impacting a thin aluminum shield at hypervelocity.
	www.udri.udayton.edu /NR/exeres/9E82E5F2-AC29-4467-8F15-0E5A7FEA48F3.htm (136 words)

	Sandia Science News: First hologram made of hypervelocity impact at 4.2 km/sec - Sandia National Laboratories ...
		Researchers at Sandia National Laboratories have obtained a hologram - a three-dimensional image in which the objects appear to float in space - of the shattered debris from a hypervelocity impact at 4.2 kilometers per second.
		Such holograms will be a valuable diagnostic tool for studying the damage caused by impacts at hypervelocities and the fragmentation and particulation from such impacts.
		"While these hypervelocity impact event holograms are fascinating to view, their real utility will be for validating computer codes widely used for 3-D simulations of hydrodynamic events.
	www.findarticles.com /p/articles/mi_m3820/is_n2_v27/ai_12041029 (856 words)

	HST Residue Analysis Data (Site not responding. Last check: 2007-10-13)
		The objective was the chemical characterization of hypervelocity impact residues in the in all impacts.
		Because B is a compound of the CMX coverglass this effect proves the presence of a thin film on the surface of the coverglass.
		A plausible explanation of this film is the recent discovered leakage in the coolant system of a nuclear-powered satellite which is cooled by liquid Na and K. For future chemical characterization of hypervelocity impact residues single element detector like the Ge-targets on LDEF should be used.
	www.estec.esa.nl /madweb/hst/radata/reports/dstrep/dstrep.html (3496 words)

	CISAS Hypervelocity Impact Facility - Home Page (Site not responding. Last check: 2007-10-13)
		These objects travel at very high speeds relative to S/C (in LEO the average relative impact speed is 9-10 km/s).
		At this velocity, even the impact (which is an "hypervelocity impact"- HVI) of small particles result in significant hazard for spacecrafts.
		According to the size and speed of such particles, potential damages can vary from erosion of sensitive surfaces of payloads to perforation of the spacecraft hull or catastrophic blasting of the satellite itself.
	cisas.unipd.it /lgg/lgg.html (189 words)

	The Influence of Hypervelocity Particle Impacts on Shuttle Orbiter Window Residual Strength (Site not responding. Last check: 2007-10-13)
		The residual biaxial flexural strength of samples cored from shuttle orbiter windows impacted by hypervelocity micrometeorites was measured, and related to the depth of the impact crater.
		Results show that the current NASA prediction for hypervelocity impact (HVI) model is significantly conservative.
		This apparently is due to the fact that the assumed geometry of the critical defect geometry used in the model differs significantly from that of the actual defect ensemble associated with an HVI site.
	www.pubs.asce.org /WWWdisplay.cgi?0306242 (111 words)

	The T5 Free-Piston Hypervelocity Shock Tunnel
		All experiments were carried out in the T5 hypervelocity shock tunnel (Figure 2) at GALCIT.
		The facility operates in the standard reflected shock tunnel mode with the exception that the high pressure and temperature on the driver side are produced by free-piston adiabatic compression.
		Further details on the performance and operation of the T5 shock tunnel are given in Hornung[9].
	www.galcit.caltech.edu /~padam/research/node3.html (335 words)

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