I made an actual Starcom: Unknown Space map of the tomb labyrinth. So you can navigate how you wish. When you arrive at the planet you are at the box on the top right that says “ENTER”. Therefore, by pressing SOUTH once, you enter the box immediately below it.
The Map
I hope it’s easily visible. The other words I’ve written aside from “ENTER” are “TRAP” (below ENTER), “SKELE” on the right, I don’t remember what this is but it has some significance. Then “BEAST” that also gives you +20 RP , and finally “SCEPTER” where you find the target item. Anyway, have fun!