How do direction work in space because north,east,west and south are bonded to earth? How does a spacecraft guide itself in the unending space?

Question

How do direction work in space because north,east,west and south are bonded to earth? How does a spacecraft guide itself in the unending space?

In: Physics

Answer 1

Spacecraft are able to determine their position and orientation through a combination of on board sensors (like star sensors) and off board trackers (like radar). Beyond that, it is typical to describe their position and velocity as an orbit. These orbits can be described using a few variables that indicate the size, orientation, and direction of the orbit. These are called “Keplerian Elements.”

So, for example if you wanted to convey information about a satellite above the Earth, you wouldn’t say “It’s 500Km above the ground, moving 7km/s in the Northwest direction” but you could say, “The satellite’s orbit has a semimajor axis of 6800km, with an eccentricity of .01, inclination of 23 degrees…”

Of course, there are other ways of keeping track of and describing these, but that’s one of the most basic ways.