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Program to Optimize Simulated Trajectories (POST)

Version certified by NASA; Version 5.1 March 1997.


POST is a generalized point mass, discrete parameter targeting and optimization program. POST provides the capability to target and optimize point mass trajectories for a powered or unpowered vehicle near an arbitrary rotating, oblate planet. POST has been used successfully to solve a wide variety of atmospheric ascent and reentry problems, as well as exoatmospheric orbital transfer problems.


Year - $1000
Month - $250
Week - $75
Day - $25
Initiation Fee - $200
Export controlled

POST3D Plot The generality of the program is evidenced by its multiple phase simulation capability that features generalized  planet and vehicle models. This flexible simulation capability is augmented by an efficient discrete parameter optimization capability that includes equality and inequality constraints.

The original 3 degree-of-freedom (3D) version of the Program to Optimize Simulated Trajectories (POST) was developed in 1970 as a Space Shuttle Trajectory Optimization Program. Since that time, the program has been significantly improved with additional capabilities added in the area of vehicle modeling, trajectory simulation, and targeting and optimization. The program is capable of simulating and optimizing trajectories for a wide variety of aerospace vehicles operating in the vicinity of a single planetary body.
The program is constructed according to the following guidelines designed to provide complete generality of simulation modeling:
  1. Modular program construction;
  2. Generalized routines to allow simulation of various types of vehicles;
  3. Generality of input, output, targeting and event criteria variables.
Additional guidelines adhered to are:
  1. FORTRAN 77 and C programming language;
  2. Use of structured programming constructs, e.g., IF-THEN-ELSE, etc.;
  3. Use of character type variables consistent with byte-oriented computers.