OM wrote:

....Agreed. Which begs the question as to what ESA is using to compute
the same orbital data.

Sound German engineering?: http://en.wikipedia.org/wiki/Curta_calculator
(Cut to image of ESA headquarters...a dull grinding noise fills the air
as hundreds of French mathematicians crank their Curtas like so many
pepper mills, after training at the Cordon Bleu to develop the arm
strength needed for hours of steady computation.) ;-)
I think we can safely assume the Chinese use something stolen from one
of NASA's "secure" websites.

Pat