Abstract. Porous-ceramic, thermal protection systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on 8 lb/ft 3 alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrousinsulation/reaction-cured-glass layer (TUFI/RCG). A semi-empirical, first principals impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials. Model extensions to look at the implications of greater than 10 GPa equation of state is also discussed. Predicted penetration probabilities for a vehicle visiting the International Space Station is 60% lower for orbital debris and 95% lower for meteoroids with this model compared to an energy scaled approach.

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Orbital debris impacts on the International Space Station occur frequently.To date, none of the impacting particles has been sufficiently large to penetrate manned pressurized volumes. We used the Manned Spacecraft Crew Survivability code to evaluate the risk to crew of penetrations of pressurized modules at two assembly stages: after Flight I J, when the pressurized elements of Kibo, the Japanese Experiment Module, are present, and after Flight IE, when the European Columbus Module is present.Our code is a Monte Carlo simulation of impacts on the Station that considers several potential event types that could lead to crew loss. Among the statistics tabulated by the program is the probability of death of one or more crew members, expressed as the risk factor, R. This risk factor is dependent on details of crew operations during both ordinary circumstances and decompression emergencies, as well as on details of internal module configurations. We conducted trade studies considering these procedure and configuration details to determine the bounds on R at the IJ and 1E stages in the assembly sequence. Here we compare the R-factor bounds, and procedures and configurations that reduce R at these stages. MSCSurv PROGRAMOrbital debris in Low Earth Orbit (LEO) poses a collision risk to active satellites, including the International Space Station (ISS). NASA has developed methods for modeling orbital debris hypervelocity impacts on the ISS, such as the BUMPER code. In addition to modeling impacts and penetrations, it is necessary to analyze the effects on crewmen and their operations after a penetration.To aid NASA in this goal, the University of Denver Research Institute (DRI) developed a computer program to specifically model impacts and quantify the damage risks to crew and spacecraft.The Processing FlowMSCSurv is a Monte-Carlo based simulation code, written in FORTRAN, and specifically developed to predict the ratio of penetrations leading to the loss of at least one crewmember to the total number of penetrationsthe risk factor, R, for the manned modules of the ISS. In preparing for an MSCSurv run, the analyst must make assumptions regarding crew operations, crew vulnerability to hazardous conditions, hypervelocity impact phenomena, and other factors. Each of these assumptions carries an uncertainty, and MSCSurv calculates uncertainty bounds associated with the R-factors, based on the parameter uncertainties and distributions supplied by the analyst.Following a specified number of penetrations (typically l06) using one set of parameter values, and comprising one simulation, MSCSurv varies input parameters and continues performing simulations. Experience has shown that a few hundred simulations (i.e., a few hundred million penetrations) may be required to develop https://ntrs.nasa.gov/search.jsp?R=20020092103 2018-05-11T02:22:30+00:00Z

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