On 30 May 2020,two National Aeronautics and Space Adminis-tration(NASA)astronauts,Robert Behnken and Douglas Hurley,made history as the first two people to travel to the International Space Station(ISS)aboard a private spacecraft(Fig.1).Nine weeks later,on 2 August 2020,the SpaceX(Hawthorne,CA,USA)built and operated Crew Dragon returned Behnken and Hurley back to Earth,safely completing the mission.