The emissometer is an extension of the multiproperty apparatus which is a powerful and unique tool for simultaneously measuring ten thermophysical properties on the same sample of an electrically-conducting solid and of studying its behavior under various environmental conditions. The apparatus features rapid time-to-temperature and data acquisition under minicomputer control yielding state-of-the-art accuracy. Performance evaluation tests of the emissometer are presented. These tests deal with veiling glare, blackbody cavity quality, and temperature distribution in the heating tube and sample. In addition spectral emissivity measurements to at least 10 micrometers have been made on tantalum (reference material), SiC, Si3N4, graphite and carbon-carbon composites from 1500 to 2400 K or their respective degradation temperatures. The new data on the ceramics provides some understanding on their high temperature behavior including the effect of fabrication process and impurities.

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Spectral emissivities are give for Y2O3, Sm2O3, Gd2O3, Er2O3 and Lu2O3 in the visible portion of the spectrum for temperatures up to 1600 deg C. The data were obtained using a carbon arc image furnace as an energy source, a photovoltaic cell as a radiation detector, a thermocouple as a temperature detector, and a magnesium oxide smoked plate as a standard of reflectance. Emissivity is calculated from a curve of combined reflectance and emitted radiation versus temperature by using Kirchoff's law and a method of successive approximations to solve Wien's equation.

Progress in Astronautics and Aeronautics, Volume 18: Thermophysics and Temperature Control of Spacecraft and Entry Vehicles is a selection of technical papers based on two American Institute of Aeronautics and Astronautics meetings, namely, The Thermophysics Specialist Conference, held in Monterey, California on September 13-15, 1965 and the Third Aerospace Sciences Conference, held in New York on January 1966. This book covers the most important problems of thermophysical research and technology. This volume is composed of six parts encompassing 42 chapters. Part I contains papers on the thermal radiation properties of solids, including measuring techniques for solar reflectance and infrared emittance determination, and a paper on radiative transfer. Part II deals with the lunar and planetary thermal environment and includes research papers on emissivities, reflectivities, and polarization by planetary atmospheres and planetary surfaces. Part III discusses the effects of the space environment on the optical properties of thermal control surfaces. This part also presents results of flight experiments with sensors of environmental effects and flight experience with thermal coatings of satellites. Part IV covers the thermophysical measurements of ablative materials and with the char layers formed during the actual vehicle entry period or during laboratory simulation tests. Part V looks into the two comparatively areas of thermophysics, namely, the thermal similitude (thermal modeling) and interface resistance of joints under space conditions. Part VI summarizes the practical experience in thermal design gained on spacecraft flights. Thermophysicists, space engineers and designers, and research workers who are interested in thermophysical technology will find this book invaluable.