ORBIT V0.99, Copyright (c)© 1991 Lorenzo Zago INTRODUCTION NOTES 12 September 1991 This program was - negatively - inspired by the innumerable "space" adventures games available on personal computers. The near totality of these games would tend to give the impression that "driving" a space ship is not too different from a very performing racing car or, in the best cases, from a jet aircraft. Nothing could be farther from the truth. When I realised that nobody had ever thought to program a real space flight simulator, I started to program some routines describing orbital mechanics, some graphic interface, etc. The scope of the program became larger and larger, as I got more aware of the complexity of a simulation which would keep some pretense of realism. This is now a first result: a complex space flight simulator allowing to "travel" in the entire solar system. All types of orbits are realistically simulated. Perturbations by other mass bodies are taken into account, allowing a realistic simulation of interplanetary orbits and deep space trajectories Many different commands are available for orbit manoeuvres. The spacecraft which can be simulated include conventional propulsion units as well as future or science-fiction drives such as nuclear pulse and the fusion drive. The present major limitation of the program is the fact that the simulation considers space to be two-dimensional. This is obviously very distant from reality, but, considering that most objects in the solar system have orbit planes close to the ecliptic (Earth-Sun) plane, it still allows to simulate with soem measure of realism many interplanetary journeys. As I mentioned above, a spacecraft is not driven like a car or an aircraft. One of many differences is that the pilot imperatively needs a board computer (or more likely, several) to figure out what to do. There the multitasking capability of the Amiga proved itself invaluable as it allowed to design a system in which one program would be the actual space flight simulator while several other independent programs constitute the "board computer" functions required for directing the spacecraft to its destination. The main program is written in AmigaBasic and compiled with AC-Basic 1.3. The "board computer" functions are in fact independent programs written in C. DISTRIBUTION CONDITIONS This software package is NOT in the public domain. Copyright and all rights are reserved by the author. The present version (ORBIT V0.99) is a beta version which may be distributed free of charge by an individual to another individual ONLY for evaluation and debugging purpose and as long as it is accompanied by this file and the entire and unmodified content of the 'orbit1' and 'orbit2' directories. This version of ORBIT may not be distributed for a fee nor as part of a public domain series, nor it may be advertized in any way without the written permission of the author. Inquiries are welcome: permission is generally given but I would like to be informed. For the time being, permission is given to put this software on free-access non-profit FTP or network servers only. PUBLISHER SOUGHT I do not think that this software by itself could generate sufficient commercial interest (if I am wrong please tell me). However I can well imagine a book describing in an accessible-to-anyone way the main elements of orbit mechanics, space trajectories and present and future spacecraft systems, which INCLUDES this software, allowing the reader to (almost) literally "drive" hands-on through many examples: orbit manoeuvres, rendez-vous, Earth/Moon flights, interplanetary trajectories, planet fly-by, new propulsion systems (Orion, fusion drives, solar sails, etc.). I believe that if such a book was published with the proper introduction it could draw great interest. I have already written many texts which could be chapters of this book. If any publisher is interested, please e-mail or write me. SHAREWARE CONDITIONS The main program and the content of the 'orbit1:' and 'orbit2:' directories of the two distribution disks are FREEWARE, within the limitations specified in the previous paragraphs. However, registration of interested users is encouraged. Registered persons will be notified of new versions, and, if interested, may participate to the further development of the ORBIT software. Donations are not solicited but will be accepted and will be thanked with the following additional items: For a donation of 20 US$, or equivalent in other currency: - One complete update and notification of further ones. - More situation and spacecraft input files. - Supplementary documentation including: More tutorials: Journey to Ganymede (a Jupiter satellite) with a fusion drive spaceship. Description of file format for command sequences (scripts), useful for didactic demostrations. Description of all input file formats. For a donation of 50 US$, or equivalent in other currency: All items mentioned above plus: - All major updates for one year. - More tutorials: Apollo-type Moon/Earth trajectories; Voyager II fly-by of Jupiter. - C sources of all tool programs (the board computer functions), so that you can easily make new ones. - Description of all elements interfacing ORBIT (the simulator) with the tool programs. For a donation of 100 US$, or equivalent in other currency: All items mentioned above plus: - Source of the main ORBIT program (about 5000 AmigaBasic statements). The author's rights remain reserved. Cash is preferred but cheques from any bank are accepted. PROGRAM DOCUMENTATION Read the Orbit.Installation file, in particular for installing ORBIT on the hard disk. File Orbit.install.floppy will help you to run ORBIT from floppy disks. ORBIT needs all the subdirectories and files found in the orbit1/ and orbit2/ directories. ORBIT also needs the arp, mathieeedoubbas, iff and my own orbit.library, some ARP commands and the ConMan console handler. Check the orbit.AmigaDos.files file for a list of all files required in the standard AmigaDos directories. If the program does not run, it is likely that something (a library, for instance) is missing somewhere. A basic set of documentation files is found in the orbit1/doc directory. You should print them for easier consultation. The same files can be read from the ORBIT HELP menu when running the program. Additional documentation will be sent to registered users. Once ORBIT is properly installed, just run the program and, at the file requester "Load Situation" load one of the files DEMO.orb, MoonJourney.orb or VoyagerIIstart.orb. These files will start an automatic command sequence which will let you observe respectively an orbital rendez-vous, an Apollo-type journey to the Moon and back, and the Jupiter fly-by of Voyager II. DISCLAIMER This program is distributed WITHOUT ANY WARRANTY. The author accepts no responsibility for the usefulness or accuracy of this program. ACKNOWLEDGEMENTS ORBIT includes a lot of tools, software modules and ideas taken from other PD programs. The following developers are gratefully acknowledged: - The ARP developers. - Helene (Lee) Taran for the pop-up menus used in the Command_Window module. - Nic Wilson for the SAM IFF sound file player. - The unknown author of the 'soundon' and 'soundoff' routines, found in the PD disk RW5 (with a criticism: 'soundoff' does not release the chip memory used). - William S. Hawes for Conman 1.3. - Commodore for the 'More' program. - Mike Meyer, for some code borrowed from his miniclock program. - Jonathan Potter for the Palette tool. I hope that I have not forgotten anyone or violated any of the authors' rights. Please send registrations, comments, suggestions, bug reports, new input files (spaceships, objects, situations) to: Lorenzo Zago Buergerplatz 18 Email D-8046 Garching UUCP: lzago@eso.uucp or eso!lzago Germany Internet: lzago@eso.org or lzago@eso.uucp@EU.net bitnet: lza@dgaeso51.bitnet span: eso::lza