DOOP

Still figuring out what I want to do with this

Some simple python code to do astrodynamics work in python.

• hohman transfers
• convert between classical orbital parameters and position/velocity in ECI
• convert between some useful reference frames:
  • Earth Central Inertial (ECI) [x,y,z]
  • Earth Centered, Earth Fixed (ECEF) [x,y,z]
  • North East Down (NED) [x,y,z]
  • Geocentric [lat,lon,alt]

Documents

Two Line Elements (TLEs)

TBD

Classical Orbital Elements

• Semimajor-axis (a)[km]: orbit size
• Eccentricity (e)[unitless]: orbit shape (0=circule, 1=straight line)
• Inclination (i)[deg]: orbital plane inclination measure from ascending node
• Argument of Perigee (w)[deg]: orbit orientation
• Ascending Node (Omega)[deg]: location of ascending node
• True Anomaly (v)[deg]: location of satellite in orbit relative to perigee
• Mean Anomaly (M)[deg]: fictitious angle that varies linearly with time

Other Useful Packages

• spaceman3D reading tles, plotting, appears dead, don't think it works correctly ... everything has same RAAN
• orbital reading tles, plotting, appears dead
• spg4 propagation, seems ok
• tle-tools not sure value, seems dead
• ESA: pykep more for inter-planetary stuff
• astrodynamics looks good, but it is Matlab code
• OrPytal does orbits without specific parameters

References

• Wiki: Earth parameters
• Wiki: Orbital elements
• Wiki: TLE Format
• celestrak.com TLEs

MIT License

Copyright (c) 2020 Kevin J. Walchko

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.