The phrase
"first spacewalk" refers to the very first time a person left their spacecraft and floated outside in space.
Full definition
In 1966, he performed
the first spacewalk.
On Oct. 28, the following day, Kelly would embark on
the first spacewalk of his career.
The inaugural flight of Challenger in 1983 saw the programme's
first spacewalk.
and «in a simulator practicing for
the first spacewalk on my mission.»
The Soviet / Russian cosmonaut Alexei Leonov took an important business trip in 1965 —
the first spacewalk.
Only three years have passed since Shenzhou 7 was sent into space and marked the nation's
first spacewalk.