A spacecraft that is not traveling at an orbital velocity will:
a. get attracted into a different kind of gravity or pole b. will become off-set and be lost within space
This is the main reason why spacecrafts are well computed mathematically and engineering wise in order for it to travel and perform its roles in space.
Orbital velocity can be described as the velocity at which the spacecraft would orbit the Earth at a fixed distance.
Where,
G is the Gravitational constant
M is the mass of the Earth
R is the distance from the Earth's center
If the spacecraft is not launched at orbital velocity then it would not orbit the Earth. The spacecraft could fall back to the Earth or could go into space.
