How does a spacecraft get to where its going?

Do small errors in space navigation matter?

Yes. Spacecraft go very long distances. Spacecraft have inertia, which means that they will keep going in the path they are in unless something changes that. If that path is off by even a tiny bit, they will keep going in that path, getting more and more off course, until they are far from their intended course.

If a spacecraft is allowed to go far from its intended course, often the mistake cannot be corrected. Spacecraft often do not have enough fuel to make large course corrections, and by the time the error is realized the object in space they were supposed to fly to may have moved a long distance from where it was supposed to be when the ship met it.

Why does DS1 get off course?
What is a course correction?
How do we know a spacecraft's location?
How do scientists know what the path of an object in space will be?

How does DS1 do a course correction?
When does DS1 do a course correction?
What would happen if DS1 collided with an object in space?

How do we know what's in space?