OK. First.<br /><br />"It will cost over 500 billion dollars to fund a mission to Mars."<br /><br />False. Complete fabrication.<br />In 1989. president Bush Sr. promoted his Space Exploration Initiative. On presidents request, NASA conducted infamous 90 day study.<br /><br />They had imagined a program that would:<br /><br />Have a significant unmanned study of Moon and Mars, for both scientific purposes, and in preparation of manned missions.<br />Construction of additional Space Shuttle orbiters, development and deployment of Shuttle C.<br />Development of a conventional heavy lift launch vehicle with LEO capacity ~150tons.<br />Construction of Space Station Freedom, that was supposed to be capable of assembly and maintenance of Moon/Mars craft.<br />Development of Orbital Transfer Vehicle for in space reusable transportation within cislunar space.<br /><br />Manned flight to Moon, construction of a lunar base, its maintenance and expansion over years. Before 2010 astronauts would return to Moon, around 2010 lunar base construction would begin, and that program would continue onwards with no planned cancellation or termination. That is, support of lunar operations at least until 2030. By end of that period, multiple scientific and industrial bases on Moon.<br /><br />Flight to Mars, earliest at 2019, later flights starting construction of Mars manned outpost. I think it also mentioned exploration of Phobos and Deimos and a construction of a outpost on one.<br /><br />I cant really remember whether SEI ever included a manned GEO station.<br /><br />Price for all that, over almost 40 years of operations, was somewhere above 400 billion, not 500 billion, that was rounded up by news reporters. And to mention that that plan included (i think) a 50% reserve in funds included.<br /><br />