Katy Perry and Gayle King are among the famous passengers taking a rocket-powered joyride Monday. But determining the point at which the star-studded crew reaches space isn’t as straightforward as it may seem.

Katy Perry, Gayle King, Jeff Bezos’ fiancée Lauren Sánchez and the rest of Blue Origin’s all-female crew posed in their space suits in a photoshoot over the weekend ahead of their journey Monday. Perry, 40, posted the pictures on Instagram and wrote, “Happy International Day of Human Space Flight Forever in awe of the Universe and it’s alignment .”