In order to evaluate entry into the atmosphere of an oblate (equatorial bulge) earth a standard atmosphere was used in conjunction with the standard rotating oblate spheroid. The density variation encountered in any one polar orbit around the earth will vary by about a factor of ten, due to oblateness. Therefore, the important effects on the re-entry trajectory are atmospheric density and oblateness of the earth. The SNAP configuration burn up characteristics will differ considerably between the steep (6/sup 0/) entry of the NASA Scout test and the orbital decay trajectory. However, the test can verify heat transfer rates on the actual configuration, and by proper calculation of material response, the actual decay breakup prediction can be improved.