Integrated Mission Program (IMP) is a computer program for simulating spacecraft missions around the Earth, Moon, Mars, and/or other large bodies. IMP solves the differential equations of motion by use of a Runge-Kutta numerical-integration algorithm. Users control missions through selection from a large menu of events and maneuvers. Mission profiles, time lines, propellant requirements, feasibility analyses, and perturbation analyses can be computed quickly and accurately. A prior version of IMP, written in FORTRAN 77, was reported in “Program Simulates Spacecraft Missions” (MFS-28606), NASA Tech Briefs, Vol. 17, No. 4 (April 1993), page 60. The present version, written in double-precision Lahey™ FORTRAN 90, incorporates a number of improvements over the prior version. Some of the improvements modernize the code to take advantage of today’s greater central-processing- unit speeds. Other improvements render the code more modular; provide additional input, output, and debugging capabilities; and add to the variety of maneuvers, events, and means of propulsion that can be simulated. The IMP user manuals (of which there are now ten, each addressing a different aspect of the code and its use) have been updated accordingly.

This program was written by Vincent A. Dauro, Sr., of Alpha Technology, Inc., for Marshall Space Flight Center. For further information, access the Technical Support Package (TSP) free on-line at under the Software category. MFS-31695.