Infrared measurements of zodiacal light.

The instrumentation, experimental design, and results of two sounding rocket flights launched to measure zodiacal light at 15 IR wavelengths from 2-30 microns are described. Aries rockets carried radiometers to 400 km altitude for 400 sec of viewing on separate flights in 1980 and 1981. The payloads and data packets reentered and were recovered after parachute descent. A numerical model was devised to account for any emissions or absorptions by the interplanetary dust cloud, which was found amenable to single-size particle distribution description. The mean particle emissivity was determined to be 0.7 (similar to comet tails), and the average albedo was 0.3. The plane of symmetry deviated from the ecliptic, and a new symmetry coefficient was calculated which also matched IRAS data.