English Dictionary

on rails

prep_phrase

(video games) Rail-based. / (video games, of a character or object) Constrained to travel along a preset fixed path. / Used other than figuratively or idiomatically: see on, rails.

The roller coaster ride was on rails.

意味（1）

(video games) Rail-based.

意味（2）

(video games, of a character or object) Constrained to travel along a preset fixed path.

So, first of all, let's clear it out of the way: it is not possible to deorbit any of the moons in the game. They are all on rails, and nothing you can do will adjust their orbit in any way whatsoever.

意味（3）

Used other than figuratively or idiomatically: see on, rails.