:A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical curve fitting.<ref>[http://www.ralentz.com/old/space/feynman-report.html Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident]</ref> | :A mathematical model was made to calculate erosion. This was a model based not on physical understanding but on empirical curve fitting.<ref>[http://www.ralentz.com/old/space/feynman-report.html Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident]</ref> |