NASA spacewalk: Watch astronauts Kate Rubins, Victor Glover outside the space station

Both NASA crew members are veteran spacewalkers at this point. Glover has already conducted two spacewalks since arriving at the space station in November. This will be his third.

Rubins previously conducted spacewalks during her first rotation on the space station in 2016, so this will be her third as well.

If this Sunday's spacewalk seems earlier than previous spacewalks - especially given that it's occurring on the weekend - well, it is. But "it's not really a Monday through Friday kind of program," reminded Kenny Todd, deputy manager for the International Space Station program, during a press conference Wednesday.