During the Zephyr's launch, Mack and May mention MECO and the Karman line. MECO stands for Main Engine Cut-Off, when a ship has inertia enough to take it out of Earth's gravity. The Karman line is the accepted altitude at which Earth's atmosphere meets outer space.
This reunites actor Peter Mensah, co-creators Jed Whedon and Maurissa Tancharoen, and writer Brent Fletcher after their previous works on Spartacus: Gods of the Arena (2011).