There’s no north or anything, are there coordinates or you just point at a planet and go for it?
In: Physics
I’ll just address how it’s currently done, not future tech like using pulsars.
The orbit of the Earth around the sun defines “north and south”. This is called the plane of the ecliptic. If you’re above that plane (aka positive direction using the right hand rule), that’s north. To fully locate yourself with three coordinates in 3D space, we also define an arbitrary star (Aries) to be the “starting point” along the rotation of the Earth’s orbit.
There are two aspects to navigating space:
1) Where is my spacecraft pointing?
2) Where is my spacecraft located?
The most popular method to determine pointing is a “star tracker”. Constellations of stars are (relatively) static in the sky. If your star tracker takes a picture of the Big Dipper, you know where you’re pointing with respect to the (relatively) fixed background stars.
To determine where you’re located in deep space, we have what are effectively radar antennas on the Earth. These point at a distance spacecraft, broadcast a signal, and wait for an echo. The timing of the echo tells you how far away the spacecraft is, and the frequency shift tells you how fast it’s moving. After multiple echos over time, you can fully locate the spacecraft in 3 dimensions, and then tell it how to maneuver to reach a targeted planet or other location (since it knows where it’s pointing, it can fire thrusters correctly).
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