Aparentemente eles têm gravidade artificial no verso Friday '.
Do capítulo 27:
I dislike the Beanstalk [the space elevator] and I don’t care much for the twenty-four hour Station. Aside from its spectacular and always changing view of Earth it has nothing to offer but high prices and cramped quarters. Its artificial gravity surges uncomfortably and always seems to go out just in time to put soup in your face.
e capítulo 30:
Did the (artificial) gravity feel steady now? I couldn’t be sure. I was quite dizzy but that might be an aftereffect of vomiting—for I had certainly thrown up as thoroughly as if I had been riding that goddam Beanstalk.
Existem algumas outras menções de gravidade artificial, mas não há necessidade de ser redundante.