The Livescience article NASA's Tiny New Atomic Clock Could Let Spacecraft Drive Themselves in Deep Space says:

But the radiation still changes the way the electronics operate. And those changes impact the sensitive equipment atomic clocks use to measure time slipping by, threatening to introduce inaccuracies. Multiple times a day, Seubert pointed out, the Air Force uploads corrections to the GPS satellites' clocks to keep them from drifting out of sync with clocks on the ground.

The goal of the DSAC, she said, is to establish a system that's not only portable and simple enough to be installed on any spacecraft but also hardy enough to operate in space over the long term without requiring constant adjustments from Earth-based teams.

Question: At what altitude was the first Deep Space Atomic Clock placed in Earth orbit? Does it experience a sufficiently high radiation environment there to demonstrate it's ability to withstand radiation in deep space?


The DSAC is in LEO at an altitude of 720 km, with an inclination of 24°. The radiation environment, in that kind of orbit, can vary quite dramatically with altitude (more than with inclination), as the Beppo-SAX experiment has shown. Astronauts on board of (somewhat) shielded vehicles typically receive 0.3 - 1 mSv/day in radiation dose. NASA states it to be radiation tolerant at levels similar to GPS Rb clocks, so it does demonstrate an ability to withstand radiation in deep space over time spans significant for space travel (order of magnitude of years).

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    $\begingroup$ Stack Exchange answers should be more than a series of links. If one or more of these states that the radiation level at the altitude indicated is representative of deep space, then can you add a block quote of the section that says that? If the links rot, or if people have difficulty accessing the IEEE papers (they might be paywalled, I can't tell right now) then the answer has much less value if you don't quote the relevant sections here. If "NASA states" something that answers my question, then please quote the statement here in your answer. Thanks! $\endgroup$ – uhoh Aug 31 '19 at 8:16
  • $\begingroup$ btw you link to the same IEEE paper twice, was that intentional or is there a missing link? $\endgroup$ – uhoh Aug 31 '19 at 8:17

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