An environmental model for Van Allen belt protons

y of t h e manned and unmanned missions i n space f o r a t l e a s t t h e n e x t t e n years w i l l be composed mainly of e a r t h o r b i t i n g s a t e l l i t e s and space s t a t i o n s .Although t h e r e a r e many environmental a s p e c t s of space which m u s t be explored and e l a b o r a t e d upon b e f o r e t h e s u c c e s s f u l launching of such missions, few a r e s o c r i t i c a l as t h e r a d i a t i o n environment which w i l l be encountered.The r a d i a t i o n environment f o r e a r t h o r b i t i n g v e h i c l e s w i l l c o n s i s t p r i m a r i l y of (1) Van Allen p a r t i c l e s , ( 2 ) s o l a r f l a r e p a r t i c l e s , and ( 3 ) g a l a c t i c cosmic p a r t i c l e s .Of t h e s e t h r e e , the Van Allen b e l t p a r t i c l e s p r e s e n t t h e g r e a t e s t hazard.This r e p o r t summarizes t h e knowledge of t h e energy spectrum and d i s t r i b u t i o n of t h e Van Allen proton b e l t as i t i s known today.A computer program has been developed f o r c a l c u l a t i n g Van Allen p a r t i c l e s i n c i d e n t upon v e h i c l e s i n e a r t h o r b i t s .Based upon t h e 1963 FLUX program of McIlwain, encounter as many as 1.1 x l o 8 protons/cm2/orbit w i t h 40 Mev --< F < 110 MeV.Mev may be as high as 2.2 x lo7 protons/cm'/sec.we f i n d t h a t a v e h i c l e i n a h i g h l y e l l i p t i c o r b i t may I n t h e magnetic e q u a t o r i a l plane, t h e f l u x of protons w i t h E -> .5