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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The coding performance of the Probe-Orbiter-Earth communication link is analyzed and compared for several cases. It is assumed that the coding system consists of a convolutional code at the Probe, a quantizer and another convolutional code at the Orbiter, and two cascaded Viterbi decoders or a combined decoder on the ground.
Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) is a technology demonstration of an inflatable aeroshell to slow down and protect heavy and valuable payloads when entering atmospheres such as those of the Earth and Mars. The ultimate project goal is to enable future payload deliveries to Mars. The LOFTID is based on more than a decade of development of the hypersonic inflatable aerodynamic decelerator (HIAD) technology, which consists of a stack of the inflatable concentric rings that make up the inflatable structure that is covered with a Flexible Thermal Protection System (FTPS) and, when combined, form the inflatable aeroshell. The goal of the LOFTID demonstration was to verify that a flexible heat shield, packed into a small-volume payload, can be inflated exoatmospherically to sizes much larger than that of the launch vehicle fairing and survive re-entry into the Earth atmosphere while withstanding a temperature excess of 1,600 °C. The LOFTID is part of Technology Demonstration Missions (TDM) under the National Aeronautics and Space Administration (NASA) Space Technology Mission Directorate (STMD). The NASA Armstrong Flight Research Center (AFRC) (Edwards, California) is part of the LOFTID program, where a space-launch version of the fiber optic sensing system (FOSS) is integrated into the avionics bay of the re-entry vehicle to provide high-spatial-density temperature measurements in three strategic locations of the vehicle. The program is part of a partnership agreement between the NASA Launch Service Program (LSP) at Kennedy Space Center (KSC) (Merritt Island, Florida) and the main Center of the LOFTID program at NASA Langley Research Center (LaRC) (Hampton, Virginia). This paper will first give a brief introduction of the FOSS, then discuss how the FOSS was integrated into LOFTID, in terms of fiber sensor integration into various sections of the vehicle, as well as integration of the FOSS interrogator into the avionics bay. Finally, data analysis during the LOFTID re-entry will be discussed.
Astronomical observations which reflect the optical and dynamical properties of interstellar and interplanetary grains are the primary means of identifying the shape, size, and the chemistry of extraterrestrial grain materials. Except for recent samplings of extraterrestrial particles in near-Earth orbit and in the stratosphere observations were the only method of deducing the properties of extraterrestrial particles. In order to elucidate the detailed characteristics of observed dust, the observations must be compared with theoretical studies, some of which are discussed in this volume, or compared with terrestrial laboratory experiments. The formation and optical characterization of simulated interstellar and interplanetary dust with particular emphasis on studying the properties on irregularly shaped particles were discussed. Efforts to develop the techniques to allow dust experiments to be carried out in low-Earth orbit were discussed, thus extending the conditions under which dust experiments may be performed.
The environment of low Earth orbit presents unique material interactions due to the presence of atomic oxygen and solar spectrum UV. A variety of degradation mechanisms can occur depending, inlarge part, on the specific material system involved. This talk will review the characterization of two ablative materials, PICA-D and HEEET, as well as relevant adhesive joints and coatings. PICA-D is a variant of the phenolic impregnated carbon ablator (PICA) and is the baseline thermal protection system (TPS) on Dragonfly and the lander for Mars Sample Return (MSR). HEEET is a 3D woven system from which MSR’s Earth entry TPS is derived. The samples for these materials were flown in orbit during the Materials International Space Station Experiment-13 (MISSE-13) which launched on March 6, 2020 and returned to Earth on January 13, 2021. Changes to surface microstructure and reflectivity will be presented along with tomographic analysis. The effect of differential erosion rates on the composites and the impacts of the orbit environment on coating performances will be discussed in the context of TPS performance and mission design aspects.
The environment of low Earth orbit presents unique material interactions due to the presence of atomic oxygen and solar spectrum UV. A variety of degradation mechanisms can occur depending, in large part, on the specific material system involved. This talk will review the characterization of two ablative materials, PICA-D and HEEET, as well as relevant adhesive joints and coatings. PICA-D is a variant of the phenolic impregnated carbon ablator (PICA) and is the baseline thermal protection system (TPS) on Dragonfly and the lander for Mars Sample Return (MSR). HEEET is a 3D woven system from which MSR’s Earth entry TPS is derived. The samples for these materials were flown in orbit during the Materials International Space Station Experiment-13 (MISSE-13) which launched on March 6, 2020 and returned to Earth on January 13, 2021. Changes to surface microstructure and reflectivity will be presented along with tomographic analysis. The effect of differential erosion rates on the composites and the impacts of the orbit environment on coating performances will be discussed in the context of TPS performance and mission design aspects.
External, internal reaction, and angular velocity variation compensation torque requirements for orientation control of solar Brayton power system in ecliptic earth orbit
As developing national and international space ventures, which seek to employ NASA's Deep Space Network (DSN) for tracking and data acquisition, evolve, it is essential for navigation and tracking system analysts to evaluate the operational capability of Deep Space Station antennas. To commission the DSN for use in tracking a highly eccentric Earth orbiter could quite possibly yield the greatest challenges in terms of slewing capability; certainly more so than with a deep-space probe. The focus here is on the determination of the maximum slew rates needed to track a specific high Earth orbiter, namely the Japanese MUSES-B spacecraft of the Very Long Baseline Interferometry Space Observatory Program. The results suggest that DSN 34-m antennas are capable of meeting the slew rate requirements for the nominal MUSES-B orbital geometries currently being considered.
Flat plate solar thermoelectric generator panels for near-Earth orbit, discussing design and fabrication
Flat plate solar thermoelectric generator panels for near-Earth orbits, comparing design, fabrication and testing to photovoltaic cells
Solar conversion/energy storage power systems for satellites in near earth orbits to provide continuous power supply
Design requirements for reactor power system of manned earth orbital space station
Flight performance evaluation of Atlas Centaur restart capability in earth orbit
Weather effect on landing site selection for earth orbital recovery operations
Central travel angle and time for reentry from near earth orbits - graphs
Earth Orbiter test site programs in relation to US mineral needs
Guidance and navigation system design for automatic stationkeeping one earth orbiting vehicle with respect to other
It is shown that for satellites in circular Earth orbits with altitudes of 500 kilometers to 1500 kilometers, and for satellites in elliptical orbits with an approximate 4000 kilometer height of perigee, a high degree least squares polynomial (e.g., a 9th or 10th degree in some cases) is required to smooth both range and range rate data for purposes of input to orbit determination programs. In order to circumvent this problem, functions of range and range rate are smoothed with lower degree least squares polynomials (e.g., 3rd and 4th degree) and it is shown that under the above geometric constraints the standard deviation of fit can be reduced to levels commensurate with typical S-band tracking system resolution which is 1 to 2 meters in range and 0.005 meters/second in range rate for a 1 per second data rate. Also shown are the effects of Gaussian random noise, biases, and periodic noise. This analysis includes numerous examples applied to the 44 point data smoothing interval currently used in much of the operational preprocessing at the Goddard Space Flight Center.
Attitude estimation of earth orbiting satellites (including Large Space Telescope) subjected to environmental disturbances and noises was investigated. Modern control and estimation theory is used as a tool to design an efficient estimator for attitude estimation. Decomposed linear recursive filters for both continuous-time systems and discrete-time systems are derived. By using this accurate estimation of the attitude of spacecrafts, state variable feedback controller may be designed to achieve (or satisfy) high requirements of system performance.