![A SpaceX Falcon 9 rocket with the company\'s Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA\'s Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA\'s Commercial Crew Program. (Photo/Agencies)](http://www.ecns.cn/hd/2019/03/01/f1cf4b3b245c44a2b66fb6097c7e2adf.jpg)
A SpaceX Falcon 9 rocket with the company's Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA's Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA's Commercial Crew Program. (Photo/Agencies)
![A SpaceX Falcon 9 rocket with the company\'s Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA\'s Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA\'s Commercial Crew Program. (Photo/Agencies)](http://www.ecns.cn/hd/2019/03/01/6e57dedef36f497ea8182dd8e18539df.jpg)
A SpaceX Falcon 9 rocket with the company's Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA's Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA's Commercial Crew Program. (Photo/Agencies)
![A SpaceX Falcon 9 rocket with the company\'s Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA\'s Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA\'s Commercial Crew Program. (Photo/Agencies)](http://www.ecns.cn/hd/2019/03/01/c182e22705a84bf4884dac3601012c3d.jpg)
A SpaceX Falcon 9 rocket with the company's Crew Dragon spacecraft onboard is seen as it is rolled to the launch pad at Launch Complex 39A as preparations continue for the Demo-1 mission, Feb. 28, 2019 at NASA's Kennedy Space Center in Florida. The Demo-1 mission will be the first launch of a commercially built and operated American spacecraft and space system designed for humans as part of NASA's Commercial Crew Program. (Photo/Agencies)