page_title: Project Beacon
section_title: Background
hierarchical_section_title: Project Beacon / Background
caption_attribution_description: English: Photo of Langley aeronautical engineer William James O'Sullivan, Jr., developer of NACA/NASA balloon satellites.
context_page_description: Beacon was one of America's first satellite programs. A balloon satellite, its objective was to study atmospheric density at its orbital altitude and to be the first United States satellite visible to the naked eye. Booster problems caused both orbital attempts to end in failure.
context_section_description: Beacon was an International Geophysical Year (IGY) satellite program developed by the NACA's Space Vehicle Group at Langley under aeronautical engineer William James O'Sullivan, Jr.  O'Sullivan held the belief that measuring the air density at orbital altitudes would be of critical importance to a space agency and that a simple balloon satellite, several meters in diameter, would be well suited to the task as their relatively large size and low mass make them especially sensitive to air drag effects.  After the launch of Sputnik, a high priority was placed on orbiting an American satellite that would be visible from the ground.  O'Sullivan's balloon satellite would accomplish that purpose, as, once in orbit, it would be as bright as a third or fourth magnitude star, enabling easy optical and photographic tracking.  This brightness led to the satellite being called "Beacon."
caption: Langley aeronautical engineer William James O'Sullivan, Jr.
exif: {}