page_title: Apollo Abort Guidance System
hierarchical_section_title: Apollo Abort Guidance System
caption_attribution_description: Apollo 11 Hasselblad image from film magazine 36/N - Trans-Lunar. Right window of LM-5. Translation hand controller and Abort Guidance System keypad are visible.
context_page_description: The Apollo Abort Guidance System was a backup computer system providing an abort capability in the event of failure of the Lunar Module's primary guidance system during descent, ascent or rendezvous. As an abort system, it did not support guidance for a lunar landing.
  The AGS was designed by TRW independently of the development of the Apollo Guidance Computer and PGNCS.
  It was the first navigation system to use a strapdown Inertial Measurement Unit rather than a gimbaled gyrostabilized IMU. Although not as accurate as the gimbaled IMU, it provided satisfactory accuracy with the help of the optical telescope and rendezvous radar. It was also lighter and smaller in size.
context_section_description: The Apollo Abort Guidance System (AGS, also known as Abort Guidance Section) was a backup computer system providing an abort capability in the event of failure of the Lunar Module's primary guidance system (Apollo PGNCS) during descent, ascent or rendezvous. As an abort system, it did not support guidance for a lunar landing.
  The AGS was designed by TRW independently of the development of the Apollo Guidance Computer and PGNCS.
  It was the first navigation system to use a strapdown Inertial Measurement Unit rather than a gimbaled gyrostabilized IMU (as used by PGNCS). Although not as accurate as the gimbaled IMU, it provided satisfactory accuracy with the help of the optical telescope and rendezvous radar. It was also lighter and smaller in size.
caption: Abort Guidance System keypad (DEDA) in Apollo 11 Lunar Module (LM-5) on the way to the moon.
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