The attempt to send and land astronauts on Mars risks billions of dollars and the lives of those brave enough to attempt it. Is the possible benefit really worth the risk? And is it really achievable? Guiding us through this ethical and scientific minefield is Dr Kevin Fong. Kevin's diverse background in astrophysics, aeronautics and medicine makes him uniquely placed to understand the technical and human challenges of this perilous journey. With the help of the BBC's rich archive and a cast of supporting experts, Kevin leads us through the journey to Mars stage by stage. For Kevin, not only is this the toughest journey we will ever attempt, it is one that he feels we ultimately must make if we are to survive as a species. 2019年是尼尔·阿姆斯特朗登陆月球50周年。这是太空竞赛的巅峰，也是整个20世纪最伟大的科技成就，但是我们是否应该派宇航员前往火星呢？美国国家航空航天局在1969年成功登陆月球之后，最大的目标就是派遣宇航员登陆火星表面，但事实证明这比想象中难度更大。太空处于真空状态，人类显得出奇脆弱。宇航员至少需要六个月时间才能抵达火星。在此期间，它们必须要保护自己免受太空高强度辐射的威胁，要承受远离家园的心理后果，还要准备大量的氧气。这些还只是登陆火星计划中的部分问题。