Rocket experiments temperature measurement

This paper will concentrate on the unique requirements of aeronomic spectroscopy and on the application of image devices to these measurements. Spectrometer 1, Table I, was developed for rocket experiments intended to measure the NIR absorption spectra of 1 0 and 02 molecules in the middle atmosphere. A photodiode array was used as the spectrometric sensor. With this spectrometer we were able to measure the NIR solar radiation spectrum with an altitude resolution better than 2 km. Spectrometer 2, Table I, was basically of the same design as spectrometer 1, except that an image intensifier was optically coupled to the diode array to permit low light-level measurements. The resolution of this spectrometer was adequate for measurements of rotational profiles of the A-band absorption spectra of 02 molecules. We were able to measure the rotational temperature of oxygen molecules, in the stratosphere and the lower mesosphere with an accuracy of + 1.5°, and a spatial resolution better than 2 km. These experiments provided the basis for study of the dynamic processes of atmospheric molecules. Spectrometer 3,... 

Thermal initiation of an explosion as well as the temperature of decomposition of propellants are measured by standard test No. 6 developed by the Joint Army-Navy-Air Force Panel on Liquid Propellants (2). The primary purpose of this test is to determine at what temperature an unstable material will undergo rapid exothermic decomposition. If the rate at which the heat is generated is greater than the rate at which it can be dissipated, an explosion will be likely. This test attempts to predict the result of conditions that can exist in the regenerative heating section of a rocket engine as well as at the propellant injector. Both of these sections experience relatively rapid local temperature rises owing to combustion. 

This article reports on new instrumentation for measuring spectra in rocket, balloon, and spacecraft observations. In the past, most optical measurements, performed in aeronomic optical experiments, were obtained with bandpass filter photometers. However, there are many advantages to measurements of whole spectra, i.e., more informative data can be obtained. For example least-squares curve fitting techniques can be used to obtain more accurate interpretations, rotational and vibrational temperatures can be calculated and dynamic molecular processes can be studied. 

This raises the question whether one can use the relative strengths of the green and red airglows as a measure of the electron temperature. Before this question can be answered, however, the discrepancy between green airglow data from rocket measurement as a function of altitude, and the quantum yield derived for OJCv O) from the CRYRING experiment and from MQDT calculations must be resolved. A possible source of this discrepancy could be the presence of vibrationally excited Of in the ionosphere. Theoretical work to explore the effects of vibrational excitations and isotopic substitutions has been started. 

In thermally non-homogeneous supercritical fluids, very intense convective motion can occur [Ij. Moreovei thermal transport measurements report a very fast heat transport although the heat diffusivity is extremely small. In 1985, experiments were performed in a sounding rocket in which the bulk temperature followed the wall temperature with a very short time delay [11]. This implies that instead of a critical slowing down of heat transport, an adiabatic critical speeding up was observed, although this was not interpreted as such at that time. In 1990 the thermo-compressive nature of this phenomenon was explained in a pure thermodynamic approach in which the phenomenon has been called adiabatic effect [12]. Based on a semi-hydrodynamic method [13] and numerically solved Navier-Stokes equations for a Van der Waals fluid [14], the speeding effect is called the piston effecf. The piston effect can be observed in the very close vicinity of the critical point and has some remarkable properties [1, 15] ... 

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