Let's make this birthday one to remember.

68 years old (Born on June 02, 1956)

Happy Birthday, Mark! You've orbited Earth and commanded missions to the International Space Station—talk about setting birthday expectations sky-high. Your leadership during assembly missions not only helped piece together humanity's greatest orbital puzzle but also proved that astronauts really do have stellar DIY skills.

Here's hoping your special day is filled with laughter brighter than rocket boosters and cake tastier than astronaut ice cream (though that's a low bar). May this year bring you as much success and excitement as docking flawlessly at the ISS—and may gravity always be kind when blowing out those candles. Happy orbit around the sun!