FILE - A SpaceX Falcon 9 rocket, with four private citizens onboard, lifts off in this time-exposure photo from Kennedy Space Center's Launch Pad 39-A, Wednesday, Sept. 15, 2021, in Cape Canaveral, Fla. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/John Raoux, File)

FILE - A SpaceX Falcon 9 lifts off with four private citizens from pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., Wednesday Sept. 15, 2021. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/John Raoux, File)

FILE - A SpaceX Falcon 9 rocket, with four private citizens onboard, lifts off from Kennedy Space Center's Launch Pad 39-A Wednesday, Sept. 15, 2021, in Cape Canaveral , Fla. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/Chris O'Meara, File)

FILE - Jared Isaacman, left, and Hayley Arceneaux prepare to head to launchpad 39A for a launch on a SpaceX Falcon 9 at the Kennedy Space Center in Cape Canaveral, Fla., Wednesday Sept. 15, 2021. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/John Raoux, File)

FILE - Inspiration4 crew member Jared Isaacman, right, waves to family members before a trip to Kennedy Space Center's Launch Pad 39-A and a planned liftoff on a SpaceX Falcon 9 rocket, Sept. 15, 2021, in Cape Canaveral, Fla. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/John Raoux, File)

FILE - Sian Proctor, right, talks to a friend from a car window before a trip to Kennedy Space Center's Launch Pad 39-A and a planned liftoff on a SpaceX Falcon 9 rocket Wednesday, Sept. 15, 2021, in Cape Canaveral, Fla. New research presents the largest set of information yet regarding how the human body reacts to spaceflight. (AP Photo/John Raoux, File)