The reason for the crew change on Boeing’s starliner mission has become clearer, as one of the reasons commander Chris Ferguson withdrew from the mission has been understood. Just a few days ago, astronaut Chris Ferguson announced that he would step down as commander of Boeing starliner’s first manned flight test mission in 2021. < / P > < p > at the time, Ferguson did not specify the reasons in his statement. He pointed out that he had a commitment before, but it could not be ignored. According to the company’s statement, at least one of Ferguson’s promises is that he must attend his daughter’s wedding. The new crown pandemic has seriously disrupted many, many plans, both in the United States and around the world. In fact, NASA and Boeing have noted that starliner has also been affected by the epidemic, which is not surprising given the delays and setbacks in its history. The launch of the starliner has been delayed several times, rather than a major setback in the failure of the manned test mission, which has greatly delayed Boeing’s schedule. Now that the launch time (for now) overlaps Ferguson’s family activities, he has made the decision to put family first. Spontaneous combustion at a Guangzhou Motor vehicle intersection and other traffic lights in Shenzhen