Book Description

A method has been developed for measuring the transfer of energy from a molecular beam to a surface. The method makes use of temperature sensitive Y-cut quartz crystals. A crystal was placed in the beam and the energy transferred to its plating was determined by changes in its oscillating frequency. Crystals having a fundamental frequency of 10 Mc/sec were used and an energy transfer rate of 50 microwatts could be detected. Probe for Measuring Energy Transfer Between a Satellite and the Upper Atmosphere, by D. McKeown, M.G. Fox, and J. Kay: A probe has been developed to measure energy transfer between a satellite surface and the upper atmosphere. Energy transfer is detected by the frequency change of a temperature-sensitive quartz crystal located in the nose of the probe. Transfer rates down to 15 micro W/ sq cm can be measured. Data provided by the probe can be used to determine the accommodation coefficients of surfaces, and periodic variations in the atmospheric density. Results of a satellite flight show that the probe will operate at altitudes up to 500 km where the atmospheric density is still great enough to produce measurable heating.