Where can I obtain the latest Keplerian elements (keps) for Mir, and how often should I update them?
One of the best sources of Keplerian elements is the Celestial BBS web site at http://www.grove.net/~tkelso/NORAD/elements/mir.txt Note that this site actually includes separate elements for each of Mir’s modules – even though they’re all physically connected! The easiest system is just use the keps for the Mir core module. AMSAT members who are subscribed to the Keplerian elements mailing list receive the keps for Mir and other satellites of interest to the amateur radio community automatically on a weekly basis. During shuttle missions the shuttle’s elements are sent out fairly often. As a rule I tend to update my Mir keps about once a week. Mir is a fairly stable spacecraft and only maneuvers occasionally. However it is useful to update your keps as soon as practical after any major maneuvers (e.g. orbital altitude adjustments). While older keps will still be fairly accurate after the maneuver, they’ll gradually get more and more inaccurate over time. On flights when the shuttle doc
