Important notice for AlienSun users regarding satellite TLEs
If you frequently use TLE files or will be requiring them for continued use of AlienSun, please read this notice.
Updated 2005 September 30
CelesTrak, the website which AlienSun is set up by default to access this information from, announced last year that it would stop offering TLEs. However, they have been granted permission to distribute them temporarily, and are currently doing so at this time. We recommend you visit them at www.celestrak.com frequently to keep track of the latest developments.
On 2005 January 11, we posted on this site the fact that CelesTrak had announced that they were going to cease to offer public access to TLE data after March 31, 2005. Please see their notice for more information.
On 2004 November 5, we linked to the following briefing issued by the Air Force Space Command, in PDF format, to announce that TLE availability will be limited to a paid service for reasons of national security. We do not yet know and cannot anticipate in what form the AFSPC will provide TLE files, therefore should you be required to use their data, you may need to update the stored files manually.
Description of AlienSun's TLE cache
AlienSun caches old TLE files so that they may be of use in predicting future satellite positions more accurately, and so that past positions can be retrieved within the timeframe that the user has been regularly updating them. Old TLEs are stored in subdirectories under the Backup folder in the application's install path (typically C:\Program Files\AlienSun unless a different path was specified during installation). These subdirectories take the form of an 8 digit number, representing the year, month, and day the old TLEs were superceded. For example, 20060511 is May 11, 2006 and all the TLEs in that folder will be valid for no later than that date.
To manually update the TLE files, you will need to first back up the old files by creating a folder for today's date and moving all existing TLEs from the application path to the new folder. Then either download the new TLEs or save them from your browser's File->Save menu, placing them in AlienSun's install path and making sure to rename them so that they have a .tle extension rather than .txt or whatever other extension is provided. Note that if the layout is different from CelesTrak's site, you may need to copy-paste the blocks of characters using a text editor such as Notepad.
Updated TLEs will take effect immediately when AlienSun's Add Orbit dialog box is invoked.
If you have any questions or require further support, please e-mail me.
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