First Flight Test of Space System Designed for Crew. Nasa.gov. NASA. [March 2, 2019]. (原始内容存档于2021-02-24). Harwood, William. NASA, SpaceX clear Crew Dragon
Starliner Flight Test. Space Coast Daily. 21 July 2021 [22 July 2021]. (原始内容存档于2021-07-22). Clark, Stephen. Boeing plans second Starliner test flight in December
Center)签署两份国家安全太空发射(英语:National Security Space Launch)合同:深空气象观测卫星(英语:Deep Space Climate Observatory)和太空测试项目2(英语:SpaceTestProgram)。2015年,搭载深空气象观测卫星的猎鹰9号运载火箭成功发