This challenge is named mars, and is located within module world.
When users start this challenge, their environment will have:
/flag/challenge/orbit/challenge/planets.txt
In this challenge, orbit reads in the flag and seeds random off of it.
While this is a challenge-specific detail, it is a broadly useful idea.
It allows for the challenge's behavior to be dynamically dependent on the flag.
This offers a similar paradigm to instanced challenge files.
However, it is dynamically instanced, rather than statically instanced.
Statically instanced values may be accessed by a student, while dynamically instanced values may not be (since they are dependent on the flag).
Which style is appropriate depends on the specifics of the challenge.