Updated Integrated Mission Program

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.