英语作文：jourery to space

Our physiological journey into space actually begins several days before launch. To avoid last minute exposure to colds and flu, you and your crew mates have been in partial isolation at Kennedy Space Center. During isolation, you have gradually adjusted your circadian rhythm to match the sleep-rest cycle required for the mission.

Now, a rookie astronaut, you have already boarded the Space Shuttle Orbiter and, dressed in an orange launch and entry suit, lie in a reclined position strapped into one of the middeck seats. The change in your orientation with respect to gravity produces a headward fluid shift. During launch, you experience as much as 3 Gs of acceleration, but the reclined position preserves blood flow to your brain and you remain conscious and alert throughout the nine minutes it takes to reach orbit.

On entry into weightlessness, the lack of a hydrostatic gradient causes a continuation of this headward fluid shift, leading to puffiness of your fa