Solar thermal propulsion IHPRPT Demonstration Program

Lester, Dean M.; Wassom, Steven R.; Pearson, Jennifer; Holmes, Michael

doi:10.2514/6.2000-5109

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…[14][15][16]) is shown in Figure 3. This reflector has a different geometry than the 0.3 meter reflector described above, in terms of the angle subtended by the plane that slices the parabolic surface.…”

Section: Description Of the Inflatable Antennasmentioning

confidence: 99%

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

Sreekantamurthy¹,

Gaspar

Mann³

et al. 2007

48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Ultra-light weight and ultra-thin membrane inflatable antenna concepts are fast evolving to become the state-of-the-art antenna concepts for deep-space applications. NASA Langley Research Center has been involved in the structural dynamics research on antenna structures. One of the goals of the research is to develop structural analysis methodology for prediction of the static and dynamic response characteristics of the inflatable antenna concepts. This research is focused on the computational studies to use nonlinear large deformation finite element analysis to characterize the ultra-thin membrane responses of the antennas. Recently, structural analyses have been performed on a few parabolic reflector antennas of varying size and shape, which are referred in the paper as 0.3 meters subscale, 2 meters half-scale, and 4 meters full-scale antenna. The various aspects studied included nonlinear analysis methodology and solution techniques, ways to speed convergence in iterative methods, the sensitivities of responses with respect to structural loads, such as inflation pressure, gravity, and pretension loads in the ground and in-space conditions, and the ultra-thin membrane wrinkling characteristics. Several such intrinsic aspects studied have provided valuable insight into evaluation of structural characteristics of such antennas. While analyzing these structural characteristics, a quick study was also made to assess the applicability of dynamics scaling of the half-scale antenna. This paper presents the details of the nonlinear structural analysis results, and discusses the insight gained from the studies on the various intrinsic aspects of the analysis methodology. The predicted reflector surface characteristics of the three inflatable ultra-thin membrane parabolic reflector antenna concepts are presented as easily observable displacement fringe patterns with associated maximum values, and normal mode shapes and associated frequencies. Wrinkling patterns are presented to show how surface wrinkle progress with increasing tension loads. Antenna reflector surface accuracies were found to be very much dependent on the type and size of the antenna, the reflector surface curvature, reflector membrane supports in terms of spacing of catenaries, as well as the amount of applied load.

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Section: Description Of the Inflatable Antennasmentioning

confidence: 99%

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

Sreekantamurthy¹,

Gaspar

Mann³

et al. 2007

48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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“…The thrust is computed using Eq. (6) and theṁ corresponding to the equilibrium temperature T eq F =ṁgIsp…”

Section: Theorymentioning

confidence: 99%

Focused Solar Ablation: A Nanosat-Based Method for Active Removal of Space Debris

Alexeenko¹,

Venkattraman²

2011

47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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A novel concept for the active removal of space debris using solar power is proposed. Focused solar ablation is an in-space propulsion concept based on using concentrator mirrors on nanosats and using the solar power to evaporate material from the debris to produce deceleration thrust thereby providing the ∆V necessary to deorbit. An energy balance is used along with free-molecular effusion theory to estimate the thrust produced by the concept and the corresponding deorbit times for an aluminum debris masses of 10 kg and 0.27 kg for various concentrator mirror areas and the diameter of the spot on which the solar power is concentrated. The analysis shows that the deorbit times of a few hours for both masses showing that the method is attractive for active space debris removal. Experiments performed using electron beams to evaporate aluminum in a vacuum chamber show that the method is also practically feasible to deorbit space debris using solar power available in low earth orbit (LEO).

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“…This promising feature has led the United States Air Force (USAF) and National Aeronautics and Space Administration (NASA) to develop STP for orbit transfer vehicles (OTVs), doubling the geostationary orbit (GEO) mission payload capability. [1][2][3][4][5][6][7][8][9] A vital component in STP is the thruster, which is made of refractory metals such as tungsten, rhenium, tantalum, and molybdenum or advanced high-temperature ceramics because of the high propellant temperature involved -up to 3,000 K. 6,7) The USAF is developing an integrated solar upper stage (ISUS) and integrated high payoff rocket propulsion technology (IHPRPT) for a solar orbit transfer vehicle (SOTV) of the Air Force Research Laboratory (AFRL). 8,9) Tungsten, used for the thruster in conventional SOTVs concepts and experiments, however, becomes brittle due to recrystallization at high temperatures, as has also been reported for a DC arcjet nozzle of pure tungsten after operation.…”

Section: Introductionmentioning

confidence: 99%

Single-Crystal Molybdenum Solar Thermal Propulsion Thruster

Sahara¹,

Watanabe²,

Shimizu³

et al. 2003

Trans. Japan Soc. Aero. S Sci.

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We detail the design, fabrication, and experimental and calculation results for three cavity solar thermal propulsion (STP) thrusters -medium, small, and very small -made of single-crystal molybdenum (SC-Mo), developed in the National Aerospace Laboratory of Japan (NAL). We obtained very high temperatures -2,300 K for the propellant gas and 2,200 K on the outer surface of the thruster -at an appropriate propellant flow with the small thruster by solar-heating with a suitable concentrator of 1.05 m in diameter, which corresponds to an 800-second-class specific impulse thruster. Temperatures obtained in experiments were much lower than expected, however. To find points for improvement and evaluate thruster performance in space, we conducted a model calculation that confirmed the thruster could achieve an 800 to 900-second-class specific impulse with a 0.1-2 N class thrust magnitude in space. STP is thus a candidate for near-future propulsion in applications such as upper stages of orbit transfer vehicles.

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Solar thermal propulsion IHPRPT Demonstration Program

Cited by 5 publications

References 2 publications

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

Focused Solar Ablation: A Nanosat-Based Method for Active Removal of Space Debris

Single-Crystal Molybdenum Solar Thermal Propulsion Thruster

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