Photos: Atlas 5 rocket aims for International Space Station

Astronauts Butch Wilmore and Suni Williams arrived at the Cape in T-38 jets, the first such arrival since the space shuttle era. The mission is aiming to launch on Monday, May 6, at 10:34 p.m. EDT (0234 UTC).

Cape Canaveral was the departure point for more space launches in 2015 than in any year since 2003, with 17 takeoffs by Atlas, Falcon and Delta rockets hoisting U.S. military satellites, commercial payloads and cargo for the International Space Station.

Two astronauts floated outside the International Space Station early Friday for the first of four planned spacewalks to wrap up a complex multi-year job to replace 48 aging batteries in the lab’s solar power system with 24 more powerful lithium-ion units.