NTSC Method:

In Landing Site, get on the gunship and take a look at the ledge right of it, against the wall and in between two doors. This ledge is your destination from the gunship and is pictured below.

You have to dash jump from the bottom right of the ship to this ledge, but since there are no enemies in Landing Site, you'll have to dash jump from a scan point. Switch to scan visor and look for a glowing spidervine just above the door past the waterfall, the one that leads to Artifact Temple. This scan point is convienently out of your range from the gunship, yet close enough that you can still lock on to it.

When ready, move as far back on the gunship as you can go without falling off, then go to the right edge of it and dash jump from the spidervine. There are two different styles people use here; some wait a bit after locking on to the spidervine, while others dash jump the instant they lock on. Both work, just make sure you release L as soon as you hit B to dash, or you'll probably have trouble getting on the ledge.

PAL Method:

The difference in PAL is the fact that you can't dash jump from a scan point, so instead of using the glowing spidervine like in NTSC, your only option is to use an enemy.

Go through the door below the spidervine and enter Temple Hall, a room on the path to Artifact Temple. Three seedlings reside here. Lock on to the closest one and head back to the gunship in Landing Site; even when the door closes as you move away, you'll still be locked on to the seedling.

When you reach the gunship, jump on it and do the rest like the NTSC version, the only real difference being you're using a seedling for your dash jump instead of the glowing spidervine outside Temple Hall.

Be careful not to move farther than you need to when going back to the gunship. If you go even a bit behind it, the lock on will break. You're still barely maintaining it when on the gunship at all, so keep that in mind when positioning Samus for the dash jump.