[time-nuts] True Time Nut Mission: NASA's Deep Space Atomic Clock (DSAC)

Bill Byrom time at radio.sent.com
Wed Mar 22 01:36:23 EDT 2017

NASA's Deep Space Atomic Clock test mission is moving toward a late-2017
launch (don't all projects slip?). The DSAC was just integrated with the
spacecraft. The clock uses a ~40.5 GHz hyperfine transition of mercury
ions. This steers an ovenized crystal USO (Ultra Stable Oscillator) from
FEI with 1-100 sec stability <2e-13 and drift <1e-10/day. A GPS receiver
is also on board:

NASA information about the DSAC applications at:

Expected DSAC performance (2014 paper). This paper claims an estimated
Allan Deviation of <1e-14 (perhaps 3e-15) at a one day interval when in

Here are the latest two papers I can find (from Feb 2016):

** Deep Space Atomic Clock Technology Demonstration Mission Onboard
Navigation Analog Experiment:

** Preliminary Investigation of Onboard Orbit Determination using Deep
Space Atomic Clock Based Radio Tracking:

Bill Byrom N5BB

----- Original message -----
From: Gregory Beat <w9gb at icloud.com>
To: time-nuts at febo.com
Subject: [time-nuts] True Time Nut Mission: NASA's Deep Space Atomic
Clock (DSAC)
Date: Tue, 12 Jan 2016 17:31:26 -0600

Upcoming Event: Deep Space Atomic Clock
Jan. 14, 2016, at 7 p.m. PT (10 p.m. ET, 0300 UTC)
You can watch this event via USTREAM:  http://www.ustream.tv/NASAJPL2

Todd Ely, DSAC Principal Investigator, JPL
Allen H. Farrington, DSAC Project Manager, JPL
Atomic clocks are an integral, yet almost invisible component of modern
For space exploration, they have been the foundational frequency
standard for NASA's Deep Space Network. NASA's Deep Space Atomic Clock
(DSAC) Technology Demonstration Mission, led by the Jet Propulsion
Laboratory, has been maturing the latest Atomic Clock technologies into
a smaller package, suitable for installation on a variety of deep space
probes to enhance navigation precision and gravity science across the
solar system.
DSAC is scheduled for launch in mid-2016.  
Satellite being built by Surrey Satellite Technologies USA, Englewood,

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