I suggest that the article is full of holes.

For example the writer writes:
==============================
"The atomic clock was first operated for about 20 days
to measure its clock rate before turning on the synthesizer.
The frequency measured during that interval was
+442.5 parts in 10^12 faster than clocks on the ground;
if left uncorrected this would have resulted
in timing errors of about 38,000 nanoseconds per day."
============================================================

Note that 442.5 parts in 10^12 in twenty days
is 22 parts in 10^12 per day.
( 22 pico seconds, or .02 nanoseconds per day. )

And note that as there are 86,400 x 10^9 nanoseconds per day,
( 24 * 60 * 60 * 1x10^9)
that 38,000 nanoseconds per 86,400 x 10^9 nanoseconds,
is 22 parts in 10^8
NOT 22 parts in 10^12.

In other words, the writer incorrectly states
that a drift of 22 parts in 10^12 per day,
would result in an error of 22 parts in 10^8 per day.

I am thinking about posting copy
from that (And other oft quoted articles)
article in sci.physics under my own name,
to see how the sci.physics Taliban
react to me posting stuff like that.