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A thermal control materials using a polyimide film named UPILEX-S™ is investigated concerning incident angle dependence of solar absorptance, temperature dependence of total hemispherical emittance, performances in flight and ground tests, and causes of degradation. The experiment indicated that the absorption coefficient increases at 0.44μm wavelength under protons and electrons radiation. The degradation seems to be caused by the generation of radicals.

One of the main causes of the inadequate transient response of a 4-valve engine was established as being partition wall-wetting. The possibility of resolving this problem by improving fuel atomization was investigated. An air-mix type injector, although producing finer droplets with more uniform distribution, was not found effective in improving transient response. The development of a two-hole injector is described. This new injector produces twin sprays which are directed into the siamese intake ports without wetting the partition wall. As a consequence, the lean A/F ratio excursion is reduced, torque stumble is eliminated and the conversion efficiency of a three-way catalyst is increased.