ThedreamofsendinghumanstoMarsiscloserthaneverbefore.Infact,manyscientiststhinkthatthefirstpersontosetfootontheRedPlanetisalivetoday.Butwhereshouldthefirstexplorersvisitwhentheygetthere?　　Horizonhasgatheredtheworld'sleadingexpertsonMarsandaskedthem:wherewouldtheygo,iftheygotthechance-andwhatwouldtheyneedtosurviv..ccc