Space walk

A space walk refers to being in space outside the hull of a starship or space station, and is usually in zero gravity. 

Space walks require an environmental suit, also known as an EV suit, though occasionally certain crewmen or members of certain species are able to go without. For instance, Lieutenant Commander Data, an android, and The Doctor, a hologram, are able to perform in many environments where most Starfleet crewmen could not. 

In 2373/2063, when the crew of the USS Enterprise (NCC-1701-E) found out that that the Borg that had infested the ship were outside on the hull building an interplexing beacon on the ship's deflector dish, Captain Jean-Luc Picard asked Lieutenant Commander Worf if he had remembered his zero-gravity combat training. Worf revealed it made him sick to his stomach. Despite this, Picard, Worf and Lieutenant Hawk went onto the hull to stop the Borg. 

Space walks were taught at Starfleet Academy in a six week long course during the third year. It was aimed at preparing cadets for walking in space in their space suits. In 2374, Lieutenants B'Elanna Torres and Tom Paris were forced to evacuate their shuttlecraft, shortly before it was destroyed, by putting on their EV suits and beaming into space. Torres, who had never finished the Academy, felt queasy floating around in space, saying it was nothing like the simulations done before the course.