NASA打算在其“航天发射系统”(SLS)重型火箭首次发射时就载人,这可能让该火箭研制工作进一步推迟,并带来其它复杂问题。按现行规划,EM-1任务要在2018年底发射,但不载人。首次载人飞行将是定于2021年发射的EM-2。不过,2015年在“猎户座”飞船开展“关键决策点”C研制节点评审时进行的一项评估表明,EM-2任务不晚于2023年4月发 NASA intends to be manned when its “space launch system” (SLS) heavy rocket is first launched, which may further delay the development of the rocket and pose other complications. According to the current plan, the EM-1 mission should be launched by the end of 2018 but not manned. The first manned flight will be EM-2 scheduled for launch in 2021. However, an assessment carried out in 2015 on the Orion spacecraft launch of the Critical Decision Point C node evaluation showed that the EM-2 mission no later than April 2023