struct s ▁for ▁Mars ▁Hab itation ▁and ▁Scient ific ▁Ex pl oration ▁( C aves ▁of ▁Mars ▁Project ) ▁- ▁Pen el ope ▁J . ▁Boston ▁ ▁L un ar ▁space ▁elev ator ▁- ▁Jer ome ▁Pear son ▁ ▁- ▁final ▁report . pdf ▁ ▁Mag net ic ▁sail ▁- ▁Robert ▁Z ub rin ▁ ▁Mars ▁Ent om opter ▁- ▁Anthony ▁Col oz za ▁/ ▁Robert ▁Michel son ▁ ▁- ▁Ph ase ▁II ▁final ▁report . pdf ▁ ▁M ini - mag net os pher ic ▁pl asma ▁prop ulsion ▁- ▁ ▁Robert ▁M . ▁Wing lee ▁ ▁M oment um ▁exchange ▁t ether ▁- ▁Thomas ▁J . ▁Bog ar ▁ ▁- ▁final ▁report . pdf ▁ ▁New ▁World s ▁Mission ▁- ▁Web ster ▁C ash ▁ ▁Space ▁elev ator ▁- ▁Brad ley ▁C . ▁Edwards ▁ ▁Cl osing ▁of ▁the ▁Original ▁N I AC ▁On ▁July ▁ 2 , ▁ 2 0 0 7 , ▁N I AC ▁announced ▁that ▁" N AS A , ▁faced ▁with ▁the ▁constraints ▁of ▁ach ieving ▁the ▁V ision ▁for ▁Space ▁Ex pl oration , ▁has ▁made ▁the ▁difficult ▁decision ▁to ▁terminate ▁N I AC , ▁which ▁has ▁been ▁fund ed ▁by ▁NASA ▁since ▁in ception . ▁Effect ive ▁August ▁ 3 1 , ▁ 2 0 0 7 , ▁the ▁original ▁N I AC ▁organization ▁ceased ▁operations . ▁ ▁Re vised ▁N I AC ▁Following ▁the ▁term ination ▁of ▁the ▁original ▁N I AC ▁program , ▁Congress ▁requested ▁a ▁review ▁of ▁the ▁N I AC