this person is called a pedestrian
this person is called a soldier
Modern.
A ship on its first voyage is a ship that is on its maiden voyage.
A holidaymaker or tourist
Such a person could be refered to as precocious.
The person is known as a blackleg.
It is a sailor
A person who goes on a trip for a religious purpose is commonly referred to as a pilgrim.
misionary
An astronaut or a cosmonaut.
In the UK - we call them an 'out-patient'.