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The communication of this method is being used by NASA in the ongoing collaborations with groups interested in the X-56A flight test program. Model generation for body freedom flutter Addressing issues in: State Consistency, Low frequency dynamics, Unsteady aerodynamics. Applied approach to X-56A MUTT: Comparing to flight test data.
An Hg(0.84)Zn(0.16)Te alloy crystal was back-melted and partially re-solidified during the first United States Microgravity Laboratory mission in the Marshall Space Flight Center's Crystal Growth Furnace. The experiment was inadvertently terminated at about 30% of planned completion. Nonetheless, it was successfully demonstrated that a HgZnTe alloy ingot partially grown and quenched on the ground can be back-melted and re-grown in space under nearly steady-state growth conditions. An identical "ground-truth" experiment was performed following the mission and a comparison between the properties of the crystals is described. The results indicate the importance of residual microgravity acceleration (less than or approx. equal to 0.4 micro-grams) even in the sub-microgravity range for the slow solidification velocities and large density gradients.
This research grant supported an active sounding rocket program at Penn State University over a period of over 10 years. During this period, the grant supported at least 8 graduate students in Astronomy & Astrophysics for at least a portion of their research. During the same period, our group was involved in seven sounding rocket flights, launched from White Sands, New Mexico, and from Woomera, Australia. Most of these rocket flights, and most of the work supported by this grant, involved the use of X-ray CCD cameras. The first X-ray CCD camera ever flown in space was our sounding rocket observation of SN1987A (flight 36.030 in 1987). Subsequent flights utilized improved CCD detectors, culminating in the'state-of-the-art EEV detector developed for our CUBIC mission, which was flown on 36.093 last May. Data from the last three flights, which observed the diffuse X-ray background with CCDS, include detection of the OVII He(alpha) line in the high latitude diffuse background and detection of the Mg XI He(alpha) line in the North Polar Spur. These results have been reported at meetings of the American Astronomical Society and the SPIE. The analysis of flights 36.092 and 36.106 is part of Jeff Mendenhall's PhD thesis and will be published in the Astrophysical Journal next year. The 36.093 data are currently being analyzed by PhD student Laura Cawley. From 1990 to 1996 this grant supported our development and launch of the CUBIC instrument on the SAC-B satellite, which was designed to measure the spectrum of the soft X-ray diffuse background with moderate energy resolution and high S/N ratio. Unfortunately, this mission terminated shortly after launch due to a failure of the Pegasus XL launch vehicle. This work resulted in publication of 4 papers in the SPIE Proceedings and four others in refereed journals, in addition to several other conference proceedings and contributed papers. In addition to the CCD flights described above, this grant has supported preliminary development of a new sounding rocket payload utilizing a replicated Ni mirror that is being developed at PSU in collaboration with MSFC. Initial testing of the coating technology has produced promising results.
This paper presents a hardware architecture for a health monitoring system (HMS) for the SSME. The architecture study was conducted in conjunction with a NASA sponsored program to develop a framework for SSME HMS for (1) ground test and, potentially (2) flight applications. The requirements for both systems are both stated and analyzed. A multiprocessor distributed VME system is envisioned for the ground-test hardware. By repackaging the boards, the same concept is shown to be usable for the flight system. The paper concludes with an analysis of weight, power, and reliability with respect to variations in functionality.
Zinc-alloyed cadmium telluride (Zn:CdTe) crystals were grown in unit gravity and in microgravity for comparative analysis. Two crystals were grown on USML-1/STS-50 in 1992, and two additional crystals were grown on USML-2/STS-73 in 1995. The Crystal Growth Furnace (CGF) in the seeded Bridgman-Stockbarger crystal growth geometry was utilized on both missions. Crystals grown on USML-1/STS-50 were found to have solidified with partial wall contact due to the near-absence of the hydrostatic pressure in microgravity, a residual g-vector that was not axial, and the nonwetting sample/ampoule wetting conditions. Crystals grown on USML-2/STS-73 included: a sample/ampoule identical to the USML-1/STS-73 sample/ampoule, with the addition of a restraining spring to simulate hydrostatic pressure internally, and a tapered ampoule which accomplished 2.2 cm of crystal growth without wall contact. Infrared transmission of all ground and flight samples was found to be 63-66 percent, very close to the theoretical 66 percent, suggesting good stoichiometric control. Infrared microscopy confirmed that the primary precipitates were Te and their size (1-10 microns) and density suggested that the flight- and ground-base samples experienced similar thermal histories. Longitudinal macrosegregation, calculated using scaling analysis, was predicted to be low. Nearly diffusion controlled growth was achieved even in unit gravity and macrosegregation data could be fit with a diffusion controlled model. Radial segregation was monitored and was found to vary with fraction solidified, particularly through the shoulder region, where the sample cross section was varying significantly. It was also disturbed in the flight samples in regions where asymmetric wall contact was noted. In regions where a steady state was established, the radial segregation was invariant within our experimental measurement error. Flight samples were found to be much higher in structural perfection than samples processed in unit gravity under identical growth conditions. In regions where solidification had occurred without wall contact, the free surfaces evidenced virtually no twinning, although twins appeared in the flight samples in regions of wall contact and were pervasive in the ground samples. These results were confirmed using optical microscopy and synchrotron x-ray white beam topography. Full-width half-maximum rocking curve widths (FWHM), recorded in arc-seconds, were significantly reduced from 20 a-s (1 g) to 9 a-s (micro-g) for the best regions of the crystals. The 9 a-s (FWHM) rocking curve value in the unconfined flight samples equals the best value reported terrestrially for this material. The ground samples exhibited a fully developed (111)[110] dislocation mosaic structure, whereas dislocations within the flight samples were discrete and no mosaic structure was evident. The defect density was quantitatively reduced from 75,000 (1 g) to 800 (micro-g) +/-50 percent. Dislocation etch pit density results were confirmed using transmission synchrotron white beam and monochromated beam topography. The low defect density is thought to have resulted from the near absence of hydrostatic pressure, which allowed the molten boule to solidify with little or no wall contact. This minimized the transfer of hoop stresses during solidification and post-solidification processing.
The DSTB Facility provides a new capability for the National Aeronautics and Space Administration s (NASA s) Space Radiation Shielding Project (SRSP). The objective of the DSTB is to provide a platform to conduct radiation shielding investigations in an environment more similar to deep space than most Low Earth orbits or is achievable at a particle accelerator. The DSTB provides a means to experimentally test radiation shielding effectiveness of various materials and to test the accuracy of radiation transport code predictions in the deep space cosmic ray environment more frequently and at a lower cost compared to space flight missions. New spectrometers, dosimeters and other techniques may be exercised and verified using the DSTB before space flight. The DSTB will be implemented through NASA s National Scientific Balloon Facility (NSBF) which provides polar balloon flights that lift science payloads to high altitude (120,000 A. (36.58km)) to escape much of the shielding effects of the Earth s atmosphere and magnetosphere. Polar flights are conducted through NSBF in coordination with the United States Polar Program. The DSTB will be launched on a Long Duration Balloon (LDB) from McMurdo, Antarctica (77.86 degrees south latitude) for circumpolar flights, nominally 20 days, traveling to the west and typically bounded between 73 to 82 degrees south latitude. Float altitudes for these balloons with payload are 115,000 to 130,000 feet (35.05 to 39.62km). The DSTB will be able to accommodate up to 20 investigations per flight. Annual flight opportunities are planned starting in December 2005. Balloon campaigns in Antarctica occur in December and January during the Austral summer. Since a key goal of the DSTB facility is to efficiently serve the varied needs of the radiation shielding community; it must be designed with a flexible architecture. By implementing the DSTB facility with NASA s balloon program, which operates under reduced formalities compared to space flight, the DSTB facility can adjust for different investigation priorities on successive flights. This flexibility in the DSTB will be applied at several levels; in the distribution of the shared resources for each flight; addressing the payload configuration on a system level for each flight; and utilizing a selection process for investigations that considers yearly flight opportunities as well as the possibility for repeated flights. This approach for operating the DSTB facility will allow it to handle a wide range of investigations.
Systems and methods are provided for an integrated graphical user interface which facilitates the display and editing of aircraft flight-plan data. A user (e.g., a pilot) located within the aircraft provides input to a processor through a cursor control device and receives visual feedback via a display produced by a monitor. The display includes various graphical elements associated with the lateral position, vertical position, flight-plan and/or other indicia of the aircraft's operational state as determined from avionics data and/or various data sources. Through use of the cursor control device, the user may modify the flight-plan and/or other such indicia graphically in accordance with feedback provided by the display. In one embodiment, the display includes a lateral view, a vertical profile view, and a hot-map view configured to simplify the display and editing of the aircraft's flight-plan data.
We present results from a pitcher-catcher experiment utilizing a proton beam generated with nanostructured targets at a petawatt-class, short-pulse laser facility to induce proton-boron fusion reactions in a secondary target. A 45-fs laser pulse with either 400 nm wavelength and 7 J energy, or 800 nm and 14 J, and an intensity of up to 5 × 10 21 W/cm 2 was used to irradiate either thin foil targets or near-solid density, nanostructured targets made of boron nitride (BN) nanotubes. In particular, for 800 nm wavelength irradiation, a BN nanotube target created a proton beam with about five times higher maximum energy and about ten times more protons than a foil target. This proton beam was used to irradiate a thick plate made of boron nitride placed in close proximity to trigger 11 B (p, α) 2α fusion reactions. A suite of diagnostics consisting of Thomson parabola ion spectrometers, postshot nuclear activation measurements, neutron time-of-flight detectors, and differentially filtered solid-state nuclear track detectors were used to measure both the primary proton spectrum and the fusion products. From the primary proton spectrum, we calculated (p, n) and (α,n) reactions in the catcher and compare with our measurements. The nuclear activation results agree quantitatively and neutron signals agree qualitatively with the calculations, giving confidence that primary particle distributions can be obtained from such measurements. These results provide new insights for measuring the ion distributions inside of proton-boron fusion targets.
In order to provide insight for the selection of attitude- and stationkeeping propulsion systems for future communications satellites, current auxiliary-propulsion systems are surveyed. Thruster systems specifically considered are stored gas, vaporizing ammonia/electrothermal, catalytic monopropellant hydrazine, electrothermal monopropellant hydrazine, plenum monopropellant hydrazine, ion, colloid, and pulsed plasma. Each of the thruster types is discussed in three sections: (1) description of thruster system and how it functions, (2) space flight experience, and (3) survey of state-of-the-art thrusters. In addition, a qualitative tabulation of thruster characteristics is included.
Practical tools which can extend the state of the art of moving base flight simulation for research and training are developed. Main approaches to this research effort include: (1) application of the vestibular model for perception of orientation based on motion cues: optimum simulator motion controls; and (2) visual cues in landing.
A parametric study was made to quantitatively define the effects of errors in the state vector predictor used by the Operational Flight Trainer (OFT) rendezvous targeting algorithms. The effect of the predictor accuracy on the OFT rendezvous profile is shown by the sensitivity of various critical rendezvous parameters with respect to downrange and radial predictor error rates. The effect of both inertial (same errors on both vehicles) and relative (differential errors on one vehicle with respect to the other) errors were considered. Relative radial error rates had the largest impact on the rendezvous followed by relative downrange errors, radial inertial errors and downrange inertial errors.
A dispersion analysis considering 3-sigma uncertainties (or perturbations) in platform, vehicle, and environmental parameters was performed for the first orbital flight test (OFT-1) mission. The dispersion analysis is based on the nominal trajectory for the OFT-1 reference flight profile and was performed to determine state vector and performance dispersions (or variations) which result from the indicated 3 sigma uncertainties. The dispersions are determined at major mission events and fixed times from liftoff (time slices). Principal error contributors to the covariance matrix are listed. The dispersion data indicates that the largest position error occurs in the down range component. At main engine cutoff and circularization, the vehicle performance uncertainties are the major contributors to down range error.
Practical tools were developed which extend the state of the art of moving base flight simulation for research and training purposes. The use of visual and vestibular cues to minimize the actual motion of the simulator itself was a primary consideration. The investigation consisted of optimum programming of motion cues based on a physiological model of the vestibular system to yield 'ideal washout logic' for any given simulator constraints.
The conclusion evolved from the three phased study on the configuration development of the X-24C Hypersonic Research Airplane makes it evident that it is practical to design and build the high performance National Hypersonic Flight Research Facility airplane with today's state of the art within the cost and operational constraints established by NASA. The vehicle launched at 31.75 Mg from the B-52 can cruise for 40 seconds at Mach 6.78 on scramjets. Without scramjets it can approach Mach 8 with a 453.6 Kg payload or do 70 seconds of cruise at Mach 6 with a 2.27 Mg payload. Reduction in cost is possible with a vehicle scaled to a lesser mass and capability.
The final Best Estimate Trajectory (BET) products, i.e., the reconstructed trajectory, the Extended BET, AEROBET and MMLE input files, generated for the eighth NASA Space Shuttle flight are documented. The reconstructed trajectory (inertial BET) for this Challenger flight, the first night landing is discussed. State (position, velocity, and attitude) plus three accelerometer scale factors were determined from fitting the Guam S-band data, seven C-band passes, and pseudo Doppler and altimeter during rollout on Runway 22. The anchor epoch utilized for the batch weighted-least-squares determination was Sept. 5, 1983 7h1m50s.0 (25310 GMT seconds). The spacecraft altitude at epoch is approx. 617 kft. IMU2 data were selected for the reconstruction.
The NASA manned space station program's systems technology effort involves the development of novel techniques that will reduce the scope of tasks neeeded for design, development, testing and evaluation of the hardware. Operations technology efforts encompass analyses that will define those techniques best able to improve the efficiency and reduce the costs of space station functions. The technology objective for data management calls for a fault-tolerant, distributed, expandable and adaptable, as well as repairable and user-friendly, flight data management system that employs state-of-the-art hardware and software. The space station's power system includes the largest element, a 'solar blanket', and the heaviest component, the batteries, of all the subsystems. A thermal management system for the power system is of paramount importance. Attention is also given to the exacting demands of attitude control and stabilization and a regenerative life support system of the requisite capacity and reliability.
Decreases of red blood cell mass and plasma volume have been observed consistently following manned space flights. Losses of red cell mass by United States astronauts have averaged 10 to 15% (range: 2 to 21%). Based on postflight estimates of total hemoglobin, Soviet cosmonauts engaged in space missions lasting from 1 to 7 months have exhibited somewhat greater losses. Restoration of red cell mass requires from 4 to 6 weeks following return to Earth, regardless of the duration of space flight.
In order to meet stringent performance goals for power and reuseability, the Space Shuttle Main Engine was designed with many complex, difficult welded joints that provide maximum strength and minimum weight. To this end, the SSME requires 370 meters of welded joints. Automation of some welds has improved welding productivity significantly over manual welding. Application has previously been limited by accessibility constraints, requirements for complex process control, low production volumes, high part variability, and stringent quality requirements. Development of robots for welding in this application requires that a unique set of constraints be addressed. This paper shows how robotic welding can enhance production of aerospace components by addressing their specific requirements. A development program at the Marshall Space Flight Center combining industrial robots with state-of-the-art sensor systems and computer simulation is providing technology for the automation of welds in Space Shuttle Main Engine production.