Re: Should a "C" class be listed as OK in Element Manager?

Allen Thomson (
Wed, 2 Jun 1999 17:09:01 -0500

An excellent question -- my short-form answer is "yes, any character should
be allowed as character 8 of line 1."

Long form: As I understand it, this is a classification designator used by
NORAD. U being "unclassified", C  "confidential", S (which I've occasionally
seen slip through, though not on any very interesting objects)  "secret", T
"top secret," and, who knows, perhaps other letters for things even toper

In the present (GPS) case, Jim Varney has chosen to use C (presumably for
"computed") to distingish the GPS elements he computes from information
available at a JPL site (
 presumably to distinguish them from official NORAD disseminations). Jim may
want to comment on this.   I, because I don't like to mess with data more
than necessary, simply transfer the elements to the elyymmdd files with the
C left in.

You could also argue that elements derived from visual observations of
presumably classified objects not carried by NORAD should have a different
letter than U -- but again, I like to pass things on as received. I'd even
argue that U can stand for "unofficial" as well as "unclassified."  :-)

It will get even more confusing in the future if, in addition to NORAD,
computations, and unofficial visual observations, yet other sources of
orbital elements become available . If the Russians, Germans, Japanese,
Chinese, French, etc. put their elsets on the net, it's going to be very
hard to assign any  meaning to the eighth character, short of some ISO

So, going back to the top, I'd say, "Don't do validity checks on that