John Grunsfeld, the former astronaut who now heads NASA’s Science Mission Directorate, thinks that traveling light could get people to Mars by the 2040s
信息
- 节目
- 发布时间2014年12月10日 UTC 18:17
- 长度2 分钟
- 分级儿童适宜
John Grunsfeld, the former astronaut who now heads NASA’s Science Mission Directorate, thinks that traveling light could get people to Mars by the 2040s