1 9 6 5 – 1 9 6 6 ), ▁working ▁in ▁a eros pace ▁medicine ▁and ▁phys i ology , ▁and ▁as ▁a ▁National ▁Heart ▁Institute ▁post do ctor al ▁fellow ▁( 1 9 6 6 – 1 9 6 7 ), ▁teaching ▁and ▁research ing ▁card i ov asc ular ▁and ▁exercise ▁phys i ology . ▁From ▁ 1 9 6 7 ▁to ▁ 1 9 8 9 , ▁he ▁pract iced ▁clin ical ▁medicine ▁on ▁a ▁part - time ▁basis ▁at ▁Den ver ▁General ▁Hospital ▁( present ly ▁known ▁as ▁Den ver ▁Health ▁Medical ▁Center ) ▁and ▁served ▁as ▁an ▁adj unct ▁instruct or ▁of ▁phys i ology ▁and ▁bi oph ys ics ▁at ▁the ▁University ▁of ▁Kentucky ▁Medical ▁Center . ▁ ▁He ▁has ▁written ▁or ▁been ▁listed ▁as ▁a ▁co - author ▁of ▁twenty ▁five ▁scientific ▁papers ▁in ▁the ▁areas ▁of ▁a eros pace ▁medicine ▁and ▁phys i ology , ▁temperature ▁reg ulation , ▁exercise ▁phys i ology , ▁and ▁clin ical ▁surg ery . ▁ ▁NASA ▁career ▁Mus gra ve ▁was ▁selected ▁as ▁a ▁scient ist - astr onaut ▁by ▁NASA ▁in ▁August ▁ 1 9 6 7 ▁as ▁a ▁member ▁of ▁NASA ▁A str onaut ▁Group ▁ 6 . ▁After ▁comple ting ▁flight ▁and ▁academic ▁training , ▁he ▁worked ▁on ▁the ▁design ▁and ▁development ▁of ▁the ▁Sk yl ab ▁Program . ▁In ▁ 1 9 7 3 , ▁he ▁was ▁the ▁backup ▁Science ▁Pil ot ▁for ▁Sk yl ab ▁ 2 , ▁becoming ▁the ▁first ▁Group ▁