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- Program STSORBIT PLUS Satellite Orbit Simulation Page 1
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- Program STSORBIT PLUS
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- Space Shuttle and Satellite Orbit Simulation
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- Version 9218
- April 26, 1991
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- by David H. Ransom, Jr.
- Rancho Palos Verdes, CA
-
- BBS: (310) 541-7299
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-
- BRIEF PROGRAM INSTRUCTIONS
- --------------------------
-
- This file is intended to help the experienced user get started with
- program STSORBIT PLUS (referred to as STSPLUS hereafter). It is NOT
- intended to be a substitute for the full program documentation!
- STSPLUS is a program to track the NASA Space Shuttle and other
- satellites. Orbital data may be entered manually for space shuttle missions
- and NASA/NORAD 2-line elements may be used for all satellites as well as
- for the space shuttle when available.
- The following steps should get the program "up and running" with as
- little fuss and bother as practical.
-
- 1. For hard disk users: Copy all files to a subdirectory called STSPLUS.
-
- For floppy disk users: Copy all files to a separate floppy disk.
-
- See the full documentation for discussion regarding the use of RAM
- disk to improve program performance for 286+ computers.
-
- 2. For hard disk users: Log into the STSPLUS subdirectory using the
- following commands (which assume drive C:):
-
- C:
- CD \STSPLUS
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- For floppy disk users: Log into the floppy disk (drive A: assumed):
-
- A:
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- 3. If you have used a previous version of STSPLUS, note that STSPLUS will
- not read data from file STSPLUS.INI if it was written by a different
- program version. This will eliminate any problems if the format of the
- Program STSORBIT PLUS Satellite Orbit Simulation Page 2
-
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- .INI file has changed and will reset all features to their default
- conditions.
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- 4. Enter the following command to start the program:
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- STSPLUS (for all CGA/EGA/VGA color systems)
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- STSPLUS /M (for all EGA/VGA monochrome systems)
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- 5. The program should start and load its map data. The STSPLUS.EXE file
- is compressed and is decompressed at load time; this may cause a brief
- delay depending upon the computer type used. Once the program is
- properly loaded, a screen will appear which requests that you set the
- UTC Offset for your time zone. Follow the on-screen instructions and
- enter the UTC Offset and the Daylight Flag.
-
- 6. The STSPLUS Main Menu will now appear. Press F1 for a demonstration
- of the program. Press ENTER to stop the demonstration and return to
- the Main Menu.
-
- 7. The distribution package includes a set of NASA 2-line elements with a
- name like NASA974.TXT. This contains orbital information on over 100
- different satellites. Press F2 to load orbital information. The screen
- will display a list of files having the extension .TXT. The
- NASAnnn.TXT file should be one of them. Enter the file name at the
- prompt and press ENTER.
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- 8. The program will ask what satellite you wish to view with a default
- response of "HST" (meaning the Hubble Space Telescope). Press ENTER to
- accept the default or enter another satellite name (such as "MIR" or
- "TDRS"). If the name of the data file begins with the letters "STS",
- the default satellite name will be "STS".
-
- 9. The program will search the data file for the requested satellite and
- display its orbital data if found. If this is the satellite you wish,
- press ENTER when asked. Press SPACE to continue searching.
-
- 10. After the satellite has been selected, STSPLUS will now display a map
- of the world and the ground track of the satellite. The satellite
- itself will be a white symbol along the ground track. EGA and VGA
- systems will display in color; CGA and HGC systems will display in
- monochrome. Press Function Key F1 for on-line help while the ground
- track is displayed.
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- 11. Press ENTER at any time to return to the Main Menu.
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- 12. To display a space shuttle mission, press F4 to enter orbital
- information in STSPLUS's simple orbital model. Enter the launch time
- and date in local time (or use UTC by adding "U" at the end of the
- time entry). If you know the orbital altitude and inclination, enter
- that information; otherwise, press ENTER to accept the default data.
- More accurate NASA 2-line elements are usually available within 24
- hours of a space shuttle launch.
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- 13. STSPLUS has many features which are fully described in the program
- Program STSORBIT PLUS Satellite Orbit Simulation Page 3
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- documentation. Please read that documentation!
-
- 14. The latest version of STSPLUS and current NASA 2-line elements are
- always available on my bulletin board system: RPV ASTRONOMY BBS at
- (213) 541-7299, 2400/1200 baud, 8-N-1. The system has a power
- controller; if it hasn't answered after the FOURTH RING, hang up and
- call back in two minutes. This is a free access BBS with 100MB of
- files and is often busy, so please be patient.
-
-
- USING MISSION ELAPSED TIME WITH 2-LINE ELEMENTS
- -----------------------------------------------
-
- The standard NASA/NORAD 2-line orbital element format does not include
- the launch time or launch date. However, this information is obviously
- required if Mission Elapsed Time (MET) is to be displayed. That information
- must therefore be obtained independently and manually entered into the
- program. The following steps are required:
-
- 1. Start program STSPLUS (see above).
-
- 2. Now load the desired 2-line elements using Function Key F2 on the Main
- Menu. Press ENTER to return from the ground track display to the Main
- Menu.
-
- 3. Press Function Key F5 to adjust the orbital information. Since you are
- using 2-line elements, the only questions asked will be Launch Time
- and Launch Date. Enter the appropriate information. Note that if you
- enter UTC or GMT Launch Time (by adding the letter "U" or "G" at the
- end of the time, upper or lower case), STSPLUS assumes that the date
- you enter will also be the UTC Launch Date.
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- 4. The information will be displayed for approval. Press ENTER to accept
- the data, or press SPACE BAR to repeat the process.
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- 5. Once the data have been accepted, press Function Key F6 to display
- Mission Elapsed Time. Press F6 again to return to Time Elapsed Since
- Epoch. While the ground track is displayed, Function Key F5 may be
- pressed to switch between the two elapsed time calculations. (Press
- Function Key F1 for help during the ground track display.) If a launch
- time and date have not been entered, these commands will have no
- effect and time since epoch will always be displayed.
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- The launch time and launch date will be saved in file STSPLUS.INI and
- need only be entered once. Note, however, that this information must be
- changed or cleared if you change satellites (since it is saved
- independently of the 2-line elements file!). If you display MET for more
- than one satellite, it is a good practice to copy file STSPLUS.INI into a
- backup file (say, HST.INI for the Hubble Space Telescope) once you have set
- the launch time and date. You may then use Function Key F3 from the Main
- Menu to reload that file.
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- The simulated time, taking into account any fast time that may have
- been in effect up to that point, is shown at the lower left of the screen.
- For reference, the launch or epoch time and the actual local time (as
- Program STSORBIT PLUS Satellite Orbit Simulation Page 4
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- determined by the computer's internal DOS clock) are also displayed. The
- MET (Mission Elapsed Time) or T+Epoch display at the lower right of the
- screen shows the current elapsed time in the mission and will include an
- additional message, "(x10)" or "(x60)", when fast time is in effect.
-
- The combination of the FAST and PAUSE modes will let you "look
- ahead" and then freeze the display at a time of interest -- such as when
- the satellite enters your circle of visibility. You can then use the "+"
- and "-" keys to move the satellite position back and forward in time (using
- Function Key F6 to select the time step interval, 1, 10 or 60 seconds) to
- determine the times and positions throughout a pass.
-
- One other suggestion: When you use the PAUSE mode (with or without the
- "+" and "-" keys), a good practice is to press ENTER twice after you exit
- the PAUSE mode to return to the Main Menu and then restart the ground track
- display. This resets the position and times to the current time.
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- USERS WITHOUT A MATH COPROCESSOR CHIP
- -------------------------------------
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- STSPLUS makes very complex calculations to determine the position of
- the Earth, Satellite, and Sun. In addition, graphics operations required to
- display the maps and the satellite track and position also require many
- computer calculations. Slow computers or computers not equipped with a math
- coprocessor chip (8087, 80287, 80387, etc.) may not be able to perform all
- of the required calculations and still keep the display synchronized to
- real time.
- In order to allow these computers to run STSPLUS and provide most of
- the available features, a special SLOW MODE is available which bypasses or
- simplifies some of the more complex or time consuming calculations and cuts
- the display update frequency from once per second to once per ten seconds.
- From the Main Menu, press Function Key F10 followed by F7. This will
- disable the spacecraft circle of visibility feature as well as slowing the
- display update cycle to every five seconds instead of every second. Note
- that the Sun terminator feature is NOT disabled; however, slower computers
- without a math coprocessor chip will be unable to keep up with real time if
- this feature is enabled.
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- PROGRAM REGISTRATION
- --------------------
-
- See the file REGISTER for information on registering STSPLUS. While I
- do not require registration of STSPLUS, I've put a great deal of time and
- effort into the program for more than two years. Registering your copy and
- sending along the very modest contribution will encourage me to continue
- maintaining and improving the program.
-
- David H. Ransom, Jr.
- 7130 Avenida Altisima
- Rancho Palos Verdes, CA 90274