OAO meaning in Space Science ?

Answer: What is Orbiting Astronomical Observatory mean?

The Orbiting Astronomical Observatory (OAO) satellites were a series of four American space observatories launched by NASA between 1966 and 1972, managed by NASA Chief of Astronomy Nancy Grace Roman. These observatories, including the first successful space telescope, provided the first high-quality observations of many objects in ultraviolet light. Although two OAO missions were failures, the success of the other two increased awareness within the astronomical community of the benefits of space-based observations, and led to the instigation of the Hubble Space Telescope.

reference

Full Form	Category
Office of Academic Opportunities	Academic & Science
Oregon Academy of Ophthalmology	Academic & Science
Office for Astronomy Outreach	Academic & Science
Opticians Association of Ohio	Business
on account of	Business
Ontario Association of Optometrists	Community
Ontario Association of Orthodontists	Community
Office of Advocacy and Outreach	General
Online Admissions Offering	General
Oceanographic Autonomous Observations	General
Omer Arbel Office	General
One And Only	General
One Against One	General
Opus Aima Obscurae	General
Orange Avenue Overlay	General
Office of Administrative Operations	General
Outside Air Optimizer	General
Outside Air Optimization	General
Outsourced Ad Ops	General
Operations All Out	General
Original Art Only	Governmental
Over and Over	Messaging
Orbiting Astronomical Observatory	Space Science