Aspacecraft that is not designed to land is called a

A spacecraft that is not designed to land is called a flyby spacecraft.

A flyby spacecraft is designed to come to close proximity with planets or other bodies with the aim of collecting information. It doesn't get captured by gravity, since it isn't caught in the orbit of the planet. Flyby spacecraft are used for space exploration.  

The spacecraft collects information and any data useful as it goes on the exploration and sent the data down to earth or stores it on board if it can't send it down. It requires meticulous planning and simulation before launching into space since once it passes its target and it cannot traverse the target again.