This article is about the AI. For radar, see Doppler radar.

Doppler, serial number 8575, was a UNSC Artificial intelligence.

In 2552, Doppler was the Space Dock Quartermaster for Reach Station Gamma in orbit of Reach. Just prior to the Battle of Reach, Doppler alerted FLEETCOM that the UNSC Circumference had failed to delete its NAV database as per the Cole Protocol.[1] When the SPARTAN-II team led by John-117 arrived at Reach Station Gamma, they tried to contact Doppler but were unsuccessful, indicating that he had self-destructed in accordance with the Cole Protocol.


  • Doppler is most likely named after the famous Austrian physicist Christian Doppler, famed with discovering the Doppler effect.



  1. Halo: The Fall of Reach, page 302

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