When astronauts leave the earth's atmosphere and enter space, how do they determine what is north or south?

Answer 1

Nice question: At first glance one would think that N S E W directions become irrelevant in space since these compass points are really a circle of 360° of directions in 2 dimensions on the surface of the globe. When we travel from place A to place B on Earth, on skateboards, cars, trains and even in airplanes, we define the direction of our movement using the axis of our planet's rotation as the cardinal reference point.

In space, that flat circle of directional options becomes a sphere. We still need some common reference to define directions and it needs to be at least a plane with two directions.. but then we need an "up/down" orientation too in order to define our place on an "x,y,z" reference grid. The plane of the solar system, along with its direction of rotation would be okay for our local neighbourhood, but it too might become irrelevant once we found ourselves several light years away from the Sun. Likewise, the plane of our Milky Way galaxy would seem a most convenient reference, but then what would we use once we left our galaxy?

Anyway, modern astronauts really remain firmly within the "grip" of Earth's immediate backyard: They're locked in orbit at several thousands of km/hour only a few hundred km up from the surface so you can say they're really still following the Earth's 2d N S E W grid. So how do they determine North or South? Well, they could do it by looking down at easily recognizable land forms amongst the clouds, or they could do it the same way the rest of us do on cloudless nights: by looking up at the starry background; Polaris and the Southern Cross are probably the easiest references. This would have worked for the Apollo astronauts too.

Compasses, of course, are less reliable, although I should think they would still tend to align along the lines of force of the magnetosphere at orbital altitudes.

Answer 2

North and South are directions which are relative to the magnetic poles of the Earth. Once you leave the Earth and move off into space for a significant distance, North and South no longer have any meaning. It is presumed that you are traveling toward a target somewhere other than Earth.

Let's say your destination was Mars. If that was the case, you would orient yourself facing Mars with the Earth behind you and therefore all references to North and South on the Earth would be meaningless. Your only concern at that point would be maintaining a flight path which was calculated to be the shortest distance to Mars.

It is also important to note that, in this imaginary flight, you will not fly at Mars, but at a calculated point in space where Mars will be when you get there. This is because Mars, just like the Earth is traveling at a high rate of speed in an orbit around the Sun. So, your aim would have to lead the target just like when shooting flying ducks while hunting. So all references would be reduced to the angle in degrees from Earth, or from the Sun, of your flight path and the elevation in degrees (plus or minus) from that flight path. Since the Earth is also moving in an orbit around the Sun it would not make much sense to measure your flight path angle from it over a very long period of time. In this case, the flight might take 3 or 4 months at a minimum because you would have to cover roughly 48 Million Miles.

Answer 3

North is toward Polaris, the north star.

If you want to get real technical, north is toward a point *close* to polaris -- about 0.66 degrees away. But if you want to get that accurate, you will study celestial navigation and learn how to tell directions from seeing just 3 or 4 bright stars.

And about one of the answers above: north is _not_ defined as the direction of the magnetic north pole. That's just a handy generality, because for _most_ places on earth (not all), magnetic compasses point _approximately_ north.

It is interesting to study what is the precise definition of "north", and especially why some people need an accuracy of 1 millionth of a degree. But that's a question for another day.

Answer 4

the directions- N S E and W, are s'posed to b relative to the earth.

when u go to the outer space u need to take something else as reference to specify the directions.
astronauts take some stars as their reference

Answer 5

North and South have no significance in space. There is only 'pitch' and 'yaw'.

Answer 6

By the consellations,
Like ursa major and minor....
You know,
They can be good observed from space.