High Energy Astronomy Observatory

High Energy Astrophysics Observatory can refer to:
 * 1st High Energy Astronomy Observatory (HEAO 1)
 * Einstein Observatory (HEAO 2)
 * 3rd High Energy Astronomy Observatory (HEAO 3)
 * HEAO Program

Note that the correct (original) names for these three satellites are "High Energy Astronomy Observatories", not "Astrophysics".