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The miniaturized Deep Space Atomic Clock was designed for precise and real-time radio navigation in deep space

The Deep Space Atomic Clock (DSAC) is a miniaturized, ultra-precise mercury-ion "atomic clock for precise "radio navigation in deep space. It is orders of magnitude more stable than existing navigation clocks, and has been refined to limit drift of no more than 1 nanosecond in 10 days.[1] It is expected that a DSAC would incur no more than 1 microsecond of error in 10 years of operations.[2] It is expected to improve the precision of deep space navigation, and enable more efficient use of tracking networks. The project is managed by NASA's "Jet Propulsion Laboratory and it will be deployed as part of the U.S. Air Force's "Space Test Program 2 (STP-2) mission aboard a "SpaceX "Falcon Heavy rocket in June 2018.[3][4]



Current ground-based atomic clocks are fundamental to deep space navigation, however, they are too large to be flown in space. This results in tracking data being collected and processed here on Earth (a two-way link) for most deep space navigation applications.[2] The Deep Space Atomic Clock (DSAC) is a miniaturized and stable "mercury ion atomic clock that is as stable as a ground clock. [2] The technology could enable autonomous radio navigation for spacecraft's time-critical events such as orbit insertion or landing, promising new savings on mission operations costs.[1] It is expected to improve the precision of deep space navigation, enable more efficient use of tracking networks, and yield a significant reduction in ground support operations.[1][5]

Its applications in deep space include:[2]

Principle and development[edit]

Over 20 years, engineers at NASA's "Jet Propulsion Laboratory have been steadily improving and miniaturizing the mercury-ion trap atomic clock.[6] The DSAC technology uses the property of "mercury "ions' "hyperfine transition frequency at 40.50 "GHz to effectively "steer" the frequency output of a "quartz oscillator to a near-constant value. DSAC does this by confining the mercury ions with electric fields in a trap and protecting them by applying magnetic fields and shielding.[2][7]

Its development will include a test flight in "low-Earth orbit,[8][9] while using "GPS signals to demonstrate precision orbit determination and confirm its performance in "radio navigation. It will be deployed as part of the U.S. Air Force's "Space Test Program 2 (STP-2) mission aboard a "SpaceX "Falcon Heavy rocket[10] probably in late 2018 during the second test flight of the Falcon Heavy.[11][12]


  1. ^ a b c Boen, Brooke (January 16, 2015). "Deep Space Atomic Clock (DSAC)". NASA. Retrieved 2015-10-27. 
  2. ^ a b c d e "Deep Space Atomic Clock" (PDF). NASA. 2014. Retrieved 2015-10-27. 
  3. ^ SpaceX’s very first Falcon Heavy launch set for this November. Darrell Etherington. Jul 27, 2017
  4. ^ LightSail 2 updates: Prox-1 mission changes, new launch date. Jason Davis. The Planetary Society. July 21, 2017
  5. ^ "NASA to test atomic clock to keep space missions on time". NASA. Gizmag. 30 April 2015. Retrieved 2015-10-28. 
  6. ^ "Technology Demonstration Missions: Deep Space Atomic Clock (DSAC)". Jet Propulsion Laboratory. NASA. 16 January 2015. Retrieved 2015-10-28. 
  7. ^ a b "DSAC (Deep Space Atomic Clock)". NASA. Earth Observation Resources. 2014. Retrieved 2015-10-28. 
  8. ^ Stephen Clark [@StephenClark1] (2016-03-01). "Payload officials with satellites aboard STP-2 mission (second Falcon Heavy) say launch has slipped from Oct. 2016 to March 2017" (Tweet) – via "Twitter. 
  9. ^ David, Leonard (April 13, 2016). "Spacecraft Powered by 'Green' Propellant to Launch in 2017". Space. Retrieved 2016-04-15. 
  10. ^ "Deep Space Atomic Clock". NASA's Jet Propulsion Laboratory. NASA. 27 April 2015. Retrieved 2015-10-28. 
  11. ^ de Selding, Peter B. (June 26, 2017). "SpaceX's Shotwell: 1 Falcon Heavy demo this year; satellite broadband remains 'on the side'". Space Intel Report. Retrieved June 27, 2017. 
  12. ^ SpaceX’s very first Falcon Heavy launch set for this November

External links[edit]

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