1. NAME AND TITLE

SOFIP: Evaluator of Space Radiation Environment Encountered by Geocentric Satellites.

Except for plotting capability, SOFIP affords all the options, choices, and variations of UNIFLUX, but with substantially reduced core requirements and running times.

2. CONTRIBUTOR

NASA Goddard Space Flight Center, Greenbelt, Maryland.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

SOFIP evaluates the space radiation environment encountered by geocentric satellites. It is a compact routine of modular composition, designed primarily with structured programming techniques to provide not only maximum efficiency but also core and time economy and ease of use.

5. METHOD OF SOLUTION

The program in its simplest form (stripped of all modules) produces for a given input trajectory a composite integral orbit spectrum of either protons or electrons. Additional features such as running printout, exposure index, peaks per orbit, percent time in electron trapping zones, differential spectrum, solar proton fluences, and punched output are available separately or in any combination with the inclusion of the corresponding (optional) modules.

6. RESTRICTIONS OR LIMITATIONS

Because SOFIP performs calculations for only one particle species in a given run, the model(s) for only one species is(are) needed. In other words, any one run will use either one proton model (AP8MAX or AP8MIN) or one inner zone electron model (AE6MAX or AE5MIN) and one outer zone electron model (AEI7HI or AEI7LO). The program cannot check for invalid combinations of models nor for BLOCK DATA subroutines and uncommented COMMONs statements incorrectly matched. These user errors will produce compilation, linkage, or execution errors.

There is no provision for changing models during execution. Therefore, in a multiple-orbit run, all trajectories are processed for the same species and model(s).

7. TYPICAL RUNNING TIME

The sample problem ran in 6 seconds on the IBM 360/91.

8. COMPUTER HARDWARE REQUIREMENTS

SOFIP is operable on the IBM 360/370 computers. It requires 468 K to compile, 150 K for GO STEP. It uses standard I/O, punch, and one storage media for ORBIT DATA.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran H compiler is required.

10. REFERENCES

E. G. Stassinopoulos, J. J. Hebert, E. L. Butler, and J. L. Barth, SOFIP: A Short Orbital Flux Integration Program, NSSDC/WDC-A-R&S 79-01 (January 1979).

D. M. Sawyer and J. I. Vette, AP-8 Trapped Proton Environment for Solar Maximum and Solar Minimum, NSSDC/WDC-A-R&S 76-06 (December 1976).

M. J. Teague, K. W. Chan, J. I. Vette, AE 6: A Model Environment of Trapped Electrons for Solar Maximum, NSSDC/WDC-A-R&S 76-04 (May 1976).

E. G. Stassinopoulos and G. D. Mead, ALLMAG, GDALMG, LINTRA: Computer Programs for Geomagnetic Field and Field-Line Calculations, NSSDC 72-12 (February 1972).

E. G. Stassinopoulos, SOLPRO: A Computer Code to Calculate Probabilistic Energetic Solar Proton Fluences, NSSDC 75-11 (April 1975).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source codes and sample problem input and output.

12. DATE OF ABSTRACT

January 1982.