I AC ▁encourag ed ▁propos ers ▁to ▁think ▁dec ades ▁into ▁the ▁future ▁in ▁purs uit ▁of ▁concepts ▁that ▁would ▁" le ap f rog " ▁the ▁evolution ▁of ▁contemporary ▁a eros pace ▁systems . ▁While ▁N I AC ▁sought ▁advanced ▁concept ▁propos als ▁that ▁stretch ▁the ▁imagination , ▁these ▁concepts ▁were ▁expected ▁to ▁be ▁based ▁on ▁sound ▁scientific ▁principles ▁and ▁att ain able ▁within ▁a ▁ 1 0 ▁to ▁ 4 0 - year ▁time ▁frame . ▁From ▁February ▁ 1 9 9 8 ▁to ▁ 2 0 0 7 , ▁N I AC ▁received ▁a ▁total ▁of ▁ 1 , 3 0 9 ▁propos als ▁and ▁awarded ▁ 1 2 6 ▁Ph ase ▁I ▁gr ants ▁and ▁ 4 2 ▁Ph ase ▁II ▁contract s ▁for ▁a ▁total ▁value ▁of ▁$ 2 7 . 3 ▁million . ▁ ▁NASA ▁announced ▁on ▁March ▁ 1 , ▁ 2 0 1 1 ▁that ▁the ▁N I AC ▁concept ▁would ▁be ▁re - est ab lished ▁at ▁NASA ▁with ▁similar ▁goals , ▁maintain ing ▁the ▁ac ron ym ▁N I AC . ▁ ▁N I AC ▁ 1 9 9 8 – 2 0 0 7 ▁ ▁Studies ▁fund ed ▁by ▁the ▁original ▁N I AC ▁ 1 9 9 8 – 2 0 0 7 ▁include ▁▁ ▁Bio - N ano - M ach ines ▁for ▁Space ▁App lications ▁- ▁Constant inos ▁M av roid is ▁ ▁System ▁Fe as ibility ▁Dem on str ations ▁of ▁C aves ▁and ▁Sub sur face ▁Con