Meteor Entry and Breakup Based on Evolution of NASAs Entry Capsule Design Tools
No abstract available
Prabhu, Dinesh↗
Engineering topics
Tauber, Michael
Publications and source records attributed to Tauber, Michael.
Alvin (Al) Sieff: Thoughts About and Lessons from a Great Engineer
Alvin (Al) Seiff was known as a world-class atmospheric scientist during the last three decades of his life. Equally deserving, however, were his prior achievements as an innovative engineer, an exceptional technical manager, and a mentor of young engineers at NASA Ames Research Center. This paper outlines Al's role in developing Ames ballistic range facilities, probably the most advanced in the world at that time, and his seminal 1963 report that contained the concepts used to reconstruct the atmospheres of Mars, Venus, Jupiter and Titan. Also discussed is my affiliation with Al after he hired me in 1962, including our joint work on Mars missions and investigating the feasibility that a Jupiter probe could survive entry, work that eventually led to the development of the Galileo probe. Finally, suggestions are offered for speeding the analysis and design of thermal protection systems based on lessons learned from successful probes and landers.
Tauber, Michael↗
Ames Research Center Shear Tests of SLA-561V Heat Shield Material for Mars-Pathfinder
This report describes the results of arc-jet testing at Ames Research Center on behalf of Jet Propulsion Laboratory (JPL) for the development of the Mars-Pathfinder heat shield. The current test series evaluated the performance of the ablating SLA-561V heat shield material under shear conditions. In addition, the effectiveness of several methods of repairing damage to the heat shield were evaluated. A total of 26 tests were performed in March 1994 in the 2 in. X 9 in. arc-heated turbulent Duct Facility, including runs to calibrate the facility to obtain the desired shear stress conditions. A total of eleven models were tested. Three different conditions of shear and heating were used. The non-ablating surface shear stresses and the corresponding, approximate, non-ablating surface heating rates were as follows: Condition 1, 170 N/m(exp 2) and 22 W/cm(exp 2); Condition 2, 240 N/m(exp 2) and 40 W/cm(exp 2); Condition 3, 390 N/m(exp 2) and 51 W/cm(exp 2). The peak shear stress encountered in flight is represented approximately by Condition 1; however, the heating rate was much less than the peak flight value. The peak heating rate that was available in the facility (at Condition 3) was about 30 percent less than the maximum value encountered during flight. Seven standard ablation models were tested, of which three models were instrumented with thermocouples to obtain in-depth temperature profiles and temperature contours. An additional four models contained a variety of repair plugs, gaps, and seams. These models were used to evaluated different repair materials and techniques, and the effect of gaps and construction seams. Mass loss and surface recession measurements were made on all models. The models were visually inspected and photographed before and after each test. The SLA-561 V performed well; even at test Condition 3, the char remained intact. Most of the resins used for repairs and gap fillers performed poorly. However, repair plugs made of SLA-561V performed well. Approximately 70 percent of the thermocouples yielded good data.
Tauber, Michael↗
Computational study of a lunar return aerobrake concept
The flow field around a proposed lunar return aerobrake is examined computationally assuming viscous, laminar flow and utilizing an effective gamma approach to incorporate real-gas effects. The flow fields for three cases are calculated with both an axisymmetric and a three-dimensional formulation. The three vehicle configurations have braking panels extended 50 deg, 55 deg, and 60 deg to the inflow (zero lift configurations). The resulting axisymmetric and 3D flow fields are examined, and it is shown that despite complexities in the 3D flow field, the total drag coefficients calculated from modified axisymmetric results are very close to those obtained from the 3D solutions. The aerobrake is shown to achieve total drag coefficients as high as 8.4 for a vehicle with panels deflected to 60 deg.
Polsky, Susan↗
Study Of Spacecraft Capsule Reentering The Atmosphere
Report describes computational study of heating and deceleration of crew capsule of spacecraft entering atmosphere of Earth upon return from Mars. Issues pertaining to heating and deceleration considered in context of related issues pertaining to navigation, maneuverability of spacecraft, and safety.
Tauber, Michael↗
Heat shield erosion in a dusty Martian atmosphere
The study calculates the effects of dust particle impacts on the erosion of the forebody heat shield for a 26-m diameter aerobraking vehicle entering the Martian atmosphere at 8.6 km/s. An explicit thin-layer Navier-Stokes code is used to compute the dustless flowfield about the vehicle for the actual Martian atmospheric composition. The deceleration and melting of the dust particles within the forebody shock layer was computed for dust spherules having initial diameters from 1 to 19 microns. All the particles began vaporizing shortly after entering the shock layer, but most survived to hit the heat shield surface. The two different heat shield materials considered were Shuttle ceramic tiles with glassy surfaces and a moderate-density ablator. For a vehicle with a ballistic coefficient of 200 kg/sq m, a glassy heat shield surface experienced an average of 7 mm of surface erosion, or 20 times the thickness of the glassy layer on ceramic tiles.
Papadopoulos, Periklis↗
Aerobraking in a dusty Martian atmosphere
The effects of dust particle impacts on the erosion of the heat shield were estimated for a 26 m diameter aerobraking vehicle entering the Mars atmosphere at 8.6 km/sec. An explicit Navier-Stokes code was used to compute the flow field about the vehicle for the actual Martian atmospheric composition at a speed of 7.5 km/sec. The deceleration and melting of the dust particles within the forebody shock-layer was computed for dust spherules having initial diameters from 3 to 10 microns. Two heat shield materials were considered: Shuttle tiles with glassy surfaces and a low-density ablator known as Avcoat.
Chang, I-Dee↗