Dictionary
High' En'ergy Astrophys'ical Observ'atory
one of a series of three U.S. satellites launched (1977–79) into orbit around the earth and equipped with instruments for studying high-energy phenomena, as x-rays, gamma rays, and cosmic rays.
Abbr.: HEAO
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.