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Introduction
As a service to the satellite user community, CelesTrak provides the
Space Track TLE Retriever—a tool which allows users with an
active Space Track
account to easily download Space Track data sets and use them to generate
standard CelesTrak data sets. The Space Track TLE Retriever is a
standalone Windows-based application which can be run manually, as needed, or
set up to automatically download and generate CelesTrak data sets. All
downloaded data is automatically archived for the user.
Latest Version
The latest version of the Space Track TLE Retriever is Version 1.5.8 (2007 Oct 15). Information on
bug fixes, known bugs, workarounds, and future enhancements can be found in
the Update History.
Usage
The Space Track TLE Retriever consists of two major parts:
- A Space Track section which allows the user to specify which data files to
download (and which formats), specify their Space Track username and password,
and set up for manual or automatic download.
- A CelesTrak section which allows the user to specify which, if any,
CelesTrak data sets to generate.
All settings can be saved from the File menu for future use.
In its simplest form, once the user has selected which Space Track data
sets to download, they need only click Download Data to check for and
download all new user-specified files. To generate CelesTrak data sets, the
user then simply clicks Process Data. All CelesTrak data sets are
quality-checked and formatted to the community-standard TLE format, as has
been the practice with all data published on CelesTrak for decades—using
the latest Space Track data. These files should be immediately ready for use
in existing applications which currently rely on CelesTrak data sets.
Specific detailed information on how to use the Space Track TLE
Retriever is provided below.
Installation
To install the Space Track TLE Retriever, simply extract
TLERetriever.exe into any directory. Then double-click on
TLERetriever.exe to run.
Pull-Down Menus
- File
- Save Settings: Saves all current settings, including Space
Track username and password, in the TLERetriever.ini file located in the
application directory.
- Open My TLEs: All TLEs downloaded from Space Track are
archived in the My TLEs directory under My Documents. The
program automatically determines where My Documents is located and
creates a My TLEs directory on startup, if one does not already
exist. All Space Track data are archived under this directory by year and
then by file type. This menu selection makes it easy to open the My
TLEs directory for direct file access.
- Exit: Exits the program. Will prompt to save changes,
if any have been made since last save.
- Web Sites
- CelesTrak: Opens the user's browser and goes to the
CelesTrak main page.
- Space Track: Opens the user's browser and goes to the
user's Space Track home page. This menu item is only active if the Space
Track username and password are filled in. The program uses this information
to automatically log the user into their Space Track account. It is the
user's responsibility to ensure this information is correct (the program has
no way of verifying it).
- Configuration
- Proxy Server: Allows the user to configure TLE Retriever to use
a proxy server with or without authentication (encrypted authentication is
not supported).
- Help
- Online Help: Opens the user's browser and goes to this
page.
- About: Provides basic information about the Space Track
TLE Retriever. Also includes an e-mail link to the author to provide
user feedback.
Space Track Section
- Space Track Data Sets
- Data Format: Allows the user to specify whether they want
to download two-line or three-line bulk data files from Space Track.
- Current Catalog Files: Allows the user to specify which,
if any, of the Space Track bulk catalog files to download.
NOTE: The Full Catalog data file must be downloaded
(two-line or three line format) to generate CelesTrak data sets.
- Complete Daily Data Files: Space Track provides complete
daily data files (in two-line format only) for each of the past seven days
(which a slight lag). Select Yes to check for and download these
files.
- Space Situation Report (SSR): Select Yes to
download the Space Situation Report. This file is currently updated
once each week and contains information, such as satellite common name,
international designator, source, launch/decay dates, and basic orbital
information. NOTE: This file must be downloaded to generate
CelesTrak data sets if the Full Catalog is downloaded in two-line
format.
- Space Track User Information
- Username: Space Track–provided
username.
- Password: Space Track–provided password.
- Retain username and password: Check this box to save your
Space Track account information in the TLERetriever.ini file for
future use.
- Processing
- Auto Download: If this box is not checked, the user must
manually download and/or process the data. If this box is checked, the
program will be configured to automatically download and/or process the
selected data sets. It will also create a shortcut in the user's
Startup directory to automatically load the application on bootup.
When the application is closed, it remains active in the System Tray
(it may be closed by right-clicking on the System Tray icon and
selecting Close.
- Initial Delay: If Auto Download is checked, this is
the delay in minutes before the program begins automatically downloading and
processing data. The time is measured from when the Auto Download button is
checked or from when the program auto-loads on startup. This value can only
be changed if Auto Download is checked and when it is changed, the
countdown timer will be reset to the current value.
- Auto Download Frequency (per day): If Auto Download
is checked, the program will automatically check for new data and/or process
it one, two, or four times a day. Remember, the Space Track data files are
only updated twice each day. When the program runs, it will pop up on the
screen from the System Tray (all buttons will be inactive) and the
application will close to the System Tray when completed.
- Download Data: Clicking this button will automatically log
the user in to their Space Track account and begin downloading the selected
data files. If the Space Track username and password fields are blank, this
button will be disabled. All files are archived in the My TLEs
directory under My Documents, organized by year and file type. The
user can access the My TLEs directory from the File menu.
- Process Data: Clicking this button will use the latest
Full Catalog and SSR (if the Full Catalog is in
two-line format) to build standard CelesTrak data sets. If these files have
not yet been downloaded, the Process Data button will be disabled.
For each data set, the program checks for the appropriate data set
definition file on CelesTrak to ensure the most up-to-date definition. These
files consist only of the Catalog Number and CelesTrak Common Name (which is
often different than that used by Space Track, to meet a specific user
group's preferences). A sample for the International Space Station data set
might look like:
25544ISS (ZARYA)
28444SOYUZ-TMA 5
28503PROGRESS-M 51
The CelesTrak Common Name may be left blank to allow for using the Space
Track Common Name. All CelesTrak data sets are stored in the
CelesTrak directory under My TLEs.
CelesTrak Section
- CelesTrak Data Sets: All of the standard CelesTrak data sets
available in the Current Data section of CelesTrak before the transition can
be selected in this section. When the Process Data button is clicked,
the data sets are generated from the latest Space Track data and stored in the
CelesTrak directory under My TLEs. The data set definition files
will be maintained current via CelesTrak. In addition to the standard choices,
there is now a choice to generate a CelesTrak standard data set for the entire
on-orbit catalog (Complete Catalog).
- CelesTrak File Extension: Users can now choose to generate
CelesTrak data sets with either .txt or .tle file extensions.
- Generate Palm format: Users can also choose to generate
CelesTrak or user-defined data sets in Palm .pdb format. Each file that is
created is automatically loaded into the Palm Install Tool for
installation during the next hot sync. These files should be compatible with
both the PocketSat and pSatellite tracking programs.
- Enable debug logging: To support finding the cause of program
difficulties, the user may check this box to enable debug logging. The program
must be restarted before logging can begin. Each time the program is restarted,
the log will be reinitialized. If you experience difficulties, please follow
this procedure and send me the resulting TLERetriever.log file for
problem resolution.
- Stop on errors: Uncheck this box to turn off the warning
message produced when TLE Retriever attempts to access the Internet and
cannot find an active connection. This choice will prevent the program from
stopping if the Internet connection is temporarily unavailable when an
automatic process is running unattended (the program will simply reset and
attempt to run again at the next scheduled time). Please note that if this box
is unchecked, it is the user's responsibility to ensure the program has
Internet connectivity since no error message will be produced. Otherwise, it
is possible for the program to run indefinitely without ever doing
anything.
Status Bar
Status for the program will be shown in the status bar at the bottom of the
application. Status includes showing when the program is accessing Space Track
or downloading or processing files. It also includes warning messages which
indicate when data files necessary for processing are not available. These
status messages should also indicate the status of the program should an
unexpected error occur and should be reported via user feedback (at the lower
right of the application or under the Help|About menu item).
User-Defined Data Sets
Users may create as many data sets as desired by creating files of the form
[fname].query and placing them in the My TLEs\User folder. Each .query
file should contain a line for each object which consists of the NORAD Catalog
Number followed immediately by the common name (please be sure that each line
ends with a carriage return and that there are no blank lines at the end of
the file). If only the NORAD Catalog Number is provided, the program will use
the common name found in the Space Track SSR file (if available). Any objects
which are not found in the current catalog will be omitted. Each [fname].query
file will produce an [fname].txt or .tle file in the User folder.
Command-Line Option
Users may run TLE Retriever on an as-needed basis by running the
program with the -update command-line option. That is:
TLERetriever -update
Doing so, the program will begin executing five seconds after loading,
attempting to download the Full Catalog along with any other
user-specified Space Track data files, and then generating the user-specified
CelesTrak data sets, if any. The user should ensure that the Space Track
username and password information have been entered previously, that Retain
username and password is checked, and that the settings have been saved
prior to executing via this method. The program will terminate after all
processes have been completed. This should allow users to schedule TLE
Retriever to run as required in support of other software applications.
Users may schedule TLE Retriever using the command-line option via
Windows' Scheduled Tasks which can be found in the Control
Panel.
VBScript Post Processing
Several users have expressed a need to be able to perform additional
processing in support of existing software applications which may expect data
in specific locations or require some other form of post processing. TLE
Retriever now checks for the existence of the file post.vbs in the
same directory as the program, once it has completed Process Data. The
program also writes a file named newdata.log which contains the full
path name of any Space Track data just downloaded. Users may now create their
own post.vbs file to handle their additional post-processing needs (a
sample is now included with the program for illustration purposes). CelesTrak
will provide links to scripts developed by software developers to help them
tailor their applications for their users.
Combined with the command-line option described above, these features will
allow users to easily configure TLE Retriever to run on a scheduled
basis (e.g., using Windows' Scheduled Tasks under the Control
Panel) or via Auto Download to automatically download Space Track
data sets, generate CelesTrak data sets, and then prepare those files for use
with their existing satellite tracking applications.
Program Shutdown
The program automatically saves the position of the form and information on
the latest Full Catalog and SSR on shutdown. It will also query
the user to save other settings if the form has been changed since the last
time these settings were saved.
Frequently Asked Questions (FAQs)
- Can I specify a data directory other than My TLEs?
- The choice of the My TLEs folder was made for three reasons:
- It was hoped that by defining a standard data location, directory
structure, and file formats that this would make it easier for software
developers to know where to check for and find TLE data on any user's
system. This choice is particularly important due to the restrictions placed
on redistribution of Space Track data which will prevent future applications
from providing their own data.
- With the data in a location under My Documents, it would be easy
for the user—and many other existing Windows applications—to
locate it quickly.
- Because of the restrictions on redistribution of Space Track data, I
felt the data needed to be saved in a location that was user-specific. In a
secure configuration, data in the My TLEs folder would not be visible
to other users of the same machine. As a result, there could be no
suggestion that TLE Retriever was designed to circumvent current US
public law in any way. Allowing the user to specify the location would
permit the selection of locations which could easily be shared with other
users. I chose this limitation to ensure the availability of TLE
Retriever to CelesTrak users would not be jeopardized.
- Why do I get the error message Unable to create directory C:\My
Documents\My TLEs\ 200\\?
- This problem results from the Space Track requirement that you change your
password on the first login to their site. When you first receive your Space
Track username and password, you must first log in to Space Track and change your password.
You may then use your Space Track username and new password to run TLE
Retriever.
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